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__NOTOC__
 
{{Infobox_Disease |
<br />
   Name          = Brain herniation |
 
== University Education ==
_NOTOC__
{{DiseaseDisorder infobox |
   Name          = Apraxia |
  ICD10          = {{ICD10|R|48|2|r|47}} |
  ICD9          = {{ICD9|438.81}}, {{ICD9|784.69}} |
  ICDO          = |
   Image          = |
   Image          = |
   Caption        = |
   Caption        = |
  DiseasesDB    = |
  ICD10          = {{ICD10|G|93|5|g|90}} |
  ICD9          = {{ICD9|348.4}} |
  ICDO          = |
   OMIM          = |
   OMIM          = |
  OMIM_mult      = |
   MedlinePlus    = 001421 |
   MedlinePlus    = 003203 |
   MeshID        = |
  DiseasesDB    = 31600 |
   MeshID        = D001072 |
}}
}}
{{CMG}} {{AE}} {{Parul}}
{{SI}}
{{SI}}
{{CMG}} {{AE}} {{Parul}} {{Norina Usman}}


'''For patient information click [[{{PAGENAME}} (patient information)|here]]'''


{{SK}} Dyspraxia
'''''Keywords and synonyms:''''' Cerebral herniation, cerebellar herniation, uncal herniation, central herniation, supratentorial herniation, infratentorial herniation, transtentorial herniation, tonsillar herniation, cingulate herniation, transcalvarial herniation


==Overview==
==Overview==
'''Herniation''', a deadly side effect of very high [[intracranial pressure]], occurs when the [[brain]] shifts across structures within the [[skull]].  The brain can shift by such structures as the [[falx cerebri]], the [[tentorium cerebelli]], and even through the hole called the [[foramen magnum]] in the base of the skull (through which the [[spinal cord]] connects with the brain).  Herniation can be caused by a number of factors that increase intracranial pressure such as [[traumatic brain injury]].  Because herniation puts extreme pressure on parts of the brain, it is often fatal. Therefore, extreme measures are taken in hospital settings to prevent the condition by reducing [[intracranial pressure]].


'Praxis', a Greek work, is the ability to perform the learned movements. It usually comprises of three components, namely, ideation, motor planning, and execution that results in purposeful movements. Apraxia, however, is the inability to perform these skilled and learned movements when there is a breakdown in any component of praxis. This disorder makes it difficult to perform daily tasks and negatively impact the quality of life. Apraxia is a complex neurological disease with cognitive-motor dysfunction. It can occur as a result of brain trauma/disease, and higher motor functional neuronal pathways damage in the setting of preserved comprehension, coordination, elementary sensory and motor systems. The most common types of apraxia are Ideational and Ideomotor.
==Historical Perspective==


==Historical Perspective==
In 1783, a medical educator and anatomist from Scotland, Alexander Monro, first proposed the concept of Intracranial pressure in his paper 'Observations on the Structure and Functions of the Nervous System'. In this paper, he stated his observations about brain, cranial cavity, and cranial blood flow. He mentioned that the cranial cavity is rigid and it encloses the incompressible brain. He hypothesized that the blood volume is constant in the cranial cavity at all times. There is a continuous balance between outflowing venous and incoming arterial blood.
 
This hypothesis was supported by George Kellie's (Monore's former student) experiments, and 'Monro–Kellie hypothesis' came into existence. According to this, the sum of brain volume, cerebrospinal fluid, and intrcranial blood flow is constant.<ref name="Mokri2001">{{cite journal|last1=Mokri|first1=B.|title=The Monro-Kellie hypothesis: Applications in CSF volume depletion|journal=Neurology|volume=56|issue=12|year=2001|pages=1746–1748|issn=0028-3878|doi=10.1212/WNL.56.12.1746}}</ref>
 
==Classification==
 
 
There are two major classes of herniation: supratentorial and infratentorial.<ref name="Orlando Regional">Orlando Regional Healthcare, Education and Development. 2004. [http://www.manimalia.org/docs/TBI.pdf "Overview of Adult Traumatic Brain Injuries."] Retrieved on [[February 6]], [[2007]]</ref>. Depending on which structures of the brain have been displaced, herniation is further sub-classified.<ref name="Shepherd">Shepherd S. 2004. [http://www.emedicine.com/med/topic2820.htm "Head trauma."] Emedicine.com.  Retrieved on [[January 28]], [[2007]].</ref>
 
Tentorium Cerebelli is one of the four duramater folds (Extention of outermost meningeal layer, duramater). It serves as a landmark and divides the cranial cavity structures into supra and infra tentorial. This dural extention has a fixed and free margin. The free margin of tentorium cerebelli is called as 'Tentorial notch".<ref name="RaiIwanaga2018">{{cite journal|last1=Rai|first1=Rabjot|last2=Iwanaga|first2=Joe|last3=Shokouhi|first3=Gaffar|last4=Oskouian|first4=Rod J|last5=Tubbs|first5=R. Shane|title=The Tentorium Cerebelli: A Comprehensive Review Including Its Anatomy, Embryology, and Surgical Techniques|journal=Cureus|year=2018|issn=2168-8184|doi=10.7759/cureus.3079}}</ref>
 
{{familytree/start |summary=Brain Herniation}}
{{familytree | | | | | | | | | | | | | | | | A01 |A01='''Brain Herniation'''}}
{{familytree | | | | | | | | | |,|-|-|-|-|-|-|^|-|-|-|-|-|-|.| | | | | | | | | | | }}
{{familytree | | | | | | | | | B01 | | | | | | | | | | | | B02 | | | | | | | | | | | |B01='''[[Supratentorial]] Herniation'''<br> occurs above<br> the tentorial notch|B02='''[[Infratentorial]] Herniation'''<br> occurs below<br> the tentorial notch}}
{{familytree | | | |,|-|-|-|v|-|^|-|v|-|-|-|.| | | | |,|-|-|^|-|-|.|}}
{{familytree | | | D01 | | D02 | | D03 | | D04 | | | | D05 | | D06 |D01=Uncal|D02=Central<br> or transtentorial|D03=Cingulate<br> or subfalcine<br> (most common type)|D04=Transcalvarial<br> or<br> External herniation|D05=Upward<br> transtentorial<br> or<br> Upward<br> Cerebellar|D06=Tonsillar<br> or<br> Downward<br> Cerebellar}}
{{familytree/end}}
 
 
===Central herniation===
In ''central herniation'', (also called "transtentorial herniation") the [[diencephalon]] and parts of the [[temporal lobes]] of both of the [[cerebral hemisphere]]s are squeezed through a notch in the [[tentorium cerebelli]].<ref name="Shepherd"/><ref name="Cornell">Cornell. 1998.  Introduction to neuropathology. Reaction to injury: Brain histology." Cornell University Medical College. </ref>  Downward herniation can stretch branches of the [[basilar artery]] (paramedian artery), causing them to tear and bleed, known as a [[Duret hemorrhage]].  The result is usually fatal.<ref name="Cornell"/>
 
===Uncal herniation===
In uncal herniation, a common subtype of transtentorial herniation, the innermost part of the [[temporal lobe]], the [[uncus]], can be squeezed so much that it goes by the [[tentorium cerebelli|tentorium]] and puts pressure on the [[brainstem]].<ref name="Shepherd"/> The tentorium is a structure within the [[skull]] formed by the [[meninges|meningeal]] layer the dura mater.  Tissue may be stripped from the [[cerebral cortex]] in a process called [[decortication]].<ref name="McCaffrey">McCaffrey P. 2001.  [http://www.csuchico.edu/~pmccaff/syllabi/SPPA336/336unit11.html "The neuroscience on the web series: CMSD 336 neuropathologies of language and cognition."] California State University, Chico. Retrieved on [[August 7]], [[2007]]. </ref>  The uncus can squeeze the [[third cranial nerve]], which controls [[parasympathetic]] input to the [[eye]] on the side of the affected nerve.  This interrupts the parasympathetic neural transmission, causing the [[pupil (eye)|pupil]] of the affected eye to [[dilate]] and fail to constrict in response to light as it should, so a dilated unresponsive pupil is an important sign of increased intracranial pressure.<ref name="Cornell"/> Pupillary dilation often precedes a later finding of cranial nerve III compression, which is deviation of the eye to a "down and out" position due to loss of innervation to all ocular motility muscles except for the lateral rectus (innervated by cranial nerve VI) and the superior oblique (innervated by cranial nerve IV). Cranial arteries may be compressed during the herniation.  Compression of the posterior cerebral artery may result in loss of the contralateral visual field.  A later important finding, the ''false localizing sign'', results from compression of the contralateral cerebral crus, which contains descending corticospinal fibers. This leads to ipsilateral (to herniating uncus) hemiparesis of the body. This type of herniation can also damage the brain stem, causing lethargy, slow heart rate, respiratory abnormalities, and pupil dilation.<ref name="McCaffrey"/>  Uncal herniation may advance to central herniation.<ref name="Orlando Regional"/>
 
===Cerebellar herniation===
Increased pressure in the posterior [[Posterior cranial fossa|fossa]] can cause the [[cerebellum]] to move up through the tentorial opening in ''upward'', or ''cerebellar herniation''.<ref name="Shepherd"/>  The [[midbrain]] is pushed through the tentorial notch. This also pushes the midbrain down.
 
===Tonsillar herniation===
In ''tonsillar herniation'', also called ''downward cerebellar herniation'',<ref name="Orlando Regional"/> the cerebellar tonsils move downward through the [[foramen magnum]] possibly causing compression of the lower brainstem and upper cervical spinal cord as they pass through the foramen magnum.<ref name="Shepherd"/> Increased pressure on the brainstem can result in dysfunction of the centers in the brain responsible for controlling respiratory and cardiac function.
 
Tonsillar herniation of the cerebellum is also known commonly as a [[Chiari Malformation]] (CM)  which previously was called an Arnold Chiari Malformation (ACM).  There are at least three types of Chiari malformation that are widely recognized, and they represent very different disease processes with different symptoms and prognosis.  These conditions can be found in asymptomatic patients, as an incidental finding, or can be so severe as to be life-threatening.  This condition is now being diagnosed more frequently by radiologists as more and more patients undergo MRI scans of their heads.  Cerebellar ectopia is a term used by radiologists to describe cerebellar tonsils that are "low lying" but that do not meet the radiographic criteria for definition as a Chiari malformation.  The currently accepted radiographic definition for a Chiari malformation are cerebellar tonsils that lay at least 5mm below the level of the foramen magnum.  Some  clinicians have reported that some patients appear to experience symptoms consistent with a Chiari malformation without radiographic evidence of tonsillar herniation.  Sometimes these patients are described as having a 'Chiari 0'.<br />
 
There are many suspected causes of tonsillar herniation including (but not exclusively)- Spinal cord tethering or occult tight filum terminale (pulling down on the brainstem and surrounding structures); decreased or malformed posterior fossa (the lower, back part of the skull) not providing enough room for the cerebellum; hydrocephalus or abnormal CSF volume pushing the tonsils out; connective tissue disorders, such as Ehlers Danlos Syndrome, can be associated as well.(These may affect the ability of the brain, as well as the supporting joints, to maintain proper position/strength; in pediatric cases, ACM is often an 'incidental' finding while doing a work up for scoliosis, which is usually associated with certain connective tissue disorders).
 
For further evaluation of tonsillar herniation, CINE flow studies are suggested. This type of MRI will look at the flow of CSF at the cranio-cervical joint.  For persons experiencing symptoms with seemingly minimal herniation, especially if the symptoms are better in the suppine position and worse upon standing/upright, an upright MRI may be useful.
 
===Cingulate herniation===
In ''cingulate'' or ''subfalcine herniation'', the most common type, the innermost part of the [[frontal lobe]] is scraped under part of the [[falx cerebri]], the dura mater at the top of the head between the two [[brain hemisphere|hemispheres of the brain]].<ref name="Shepherd"/><ref name="dawodu">Dawodu ST. 2007. [http://www.emedicine.com/pmr/topic212.htm Traumatic brain injury: Definition, epidemiology, pathophysiology.] Emedicine.com. Retrieved on [[January 28]], [[2007]].</ref> Cingulate herniation can be caused when one hemisphere swells and pushes the [[cingulate gyrus]] by the falx cerebri.<ref name="Orlando Regional"/> This does not put as much pressure on the brainstem as the other types of herniation, but it may interfere with [[blood vessel]]s in the frontal lobes that are close to the site of injury (anterior cerebral artery), or it may progress to central herniation.<ref name="Shepherd"/>  Interference with the blood supply can cause dangerous increases in ICP that can lead to more dangerous forms of herniation.<ref name="hudson">Kristi Hudson.  2006. [http://dynamicnursingeducation.com/class.php?class_id=37 Brain Herniation Syndromes - 2 Nursing CEs.] Dynamic Nursing Education.  Retrieved on [[September 6]], [[2007]].</ref>  Symptoms for cingulate herniation are not well defined.<ref name="hudson"/>  Usually occurring in addition to uncal herniation, cingulate herniation may present with [[abnormal posturing]] and [[coma]].<ref name="Orlando Regional"/>  Cingulate herniation is frequently believed to be a precursor to other types of herniation.<ref name="hudson"/>


*Steinthal introduced the term '[[apraxia]]' in 1971. However, a German physician, Hugo Lipmann first established the conceptual knowledge and published complete description of apraxia after studying the gestures in a 48-year old [[stroke]] patient who had a left hemispheric stroke.
<gallery>
*Lipmann noticed that, despite of resolution of the paresis, the patient was unable to perform tasks such as buttoning the shirt, with no affect on spontaneous movements, and doing simple tasks on command. He observed this phenomenon specifically in patients with left hemispheric lesions. He also concluded that the planning of the motor movements occurs in the motor area of the left side of the brain.Lipmann further proposed that the 'praxis' information flows from the posterior brain areas (parietal and occipital lobes) to the anterior (motor cortex).
Image:
*The major subtypes classified by Lipmann were ideational, ideomotor, and limb-kinetic apraxia.
*One of the behavioral neurologist, Norman Geschwind, presented that the superior longitudinal fasciculus involvement disconnects the Wernike's are from the left premotor cortex, leading to 'apraxia'.


== Classification==
Subfalcine-herniation-002.jpg|Subfalcine-herniation
The most common types of apraxia are-


* '''''Ideomotor apraxia''':'' The most commonly known type of apraxia is Ideomotor apraxia, or decreased performance of skilled motor performances despite integral language, sensory and motor function. It can be seen more frequently in [[neurodegenerative disorders]] and [[stroke]] patients.Ideomotor apraxia is classically demonstrated when a patient questioned verbally to make a motion with a limb. Patients with Ideomotor apraxia display spatial and temporal errors, inconvenient timing, amplitude, sequencing, configuration,  limb position in space. It is an inability to carry out, learned motor acts, command, adequate motor, and sensory abilities. Ideomotor apraxia can be due to cerebral damage in numerous areas, including the left parietal lobe, the intrahemispheric association fibers, the dominant hemisphere motor association cortex, and the anterior corpus callosum. Patients often use their arm as an object relatively than indicating how to use the object . Patients are frequently able to achieve the same acts without struggle in their daily lives. This process has been called the "voluntary-automatic dissociation".These patients have a deficiency in their skill to plan or ample motor actions that depend on semantic memory. They can describe how to achieve a response, but incapable to "imagine" or do the movement. Though the capability to perform an act inevitably when cued remains complete, this is recognized as automatic-voluntary dissociation.In Ideomotor apraxia, there is difficulty or inability to execute familiar or learned movements on command despite of understanding the command and willingness to perform that action. The characteristic of this type of [[apraxia]] is the inability to a transitive movement. For example, the person can describe how a tool such as comb is used, but, when asked to use that tool, he is unable to perform the task (i.e. combing the hair) using the comb.
</gallery>


* '''''Ideational apraxia:''''' like the name depicts, problem in conceptualization of the task. The person may be able to name the objects correctly but fails to coceptualize how that object is used.
===Transcalvarial Herniation===
* '''''Constructional apraxia'':''' It is a condition resulting from neurological damage, which is demonstrated by the inability to construct and copy to command two- and three-dimensional stimuli. Constructional apraxia has been a classic sign of a parietal lobe lesion, and as a valuable tool to escalate the spatial abilities functioned by this lobe. It has become gradually clear that Constructional apraxia is a complex construct that can be observed with very different tasks that are only slightly interrelated, and hit various kinds of visuospatial, attentional, perceptual, planning, and motor mechanisms.The patient with constructional apraxia is unable to construct, draw, or copy simple configurations; for example, intersecting shapes; they have trouble drawing basic shapes or copying a simple diagram.
In ''transcalvarial herniation'', the brain squeezes through a fracture or a surgical site in the skull.<ref name="Orlando Regional"/>
* '''''Buccofacial or orofacial apraxia''':'' This is the most common type of apraxia; patients cannot convey facial movements on requests, such as voluntary movements of the tongue, cheeks, lips, pharynx, or larynx on command, for example, include licking lips, whistling, coughing, or winking).
* '''''Limb-kinetic apraxia''':'' It is the failure to make precise movements with an arm, finger, or leg. For example, a person may have trouble tying their shoes, waving hello, or typing on a computer''.''
* '''''Gait apraxia''':'' Apraxia of gait is a rare locomotion syndrome categorized by the incapability of lifting the feet from the floor regardless of discontinuous stepping action. The accountable site of lesions is in the basal ganglia and frontal lobe.


*Certain task-specific apraxiahave been identified, and these include-
==Natural History, Complications and Prognosis==
**Sitting apraxia
The patient may become paralyzed on the same side as the lesion causing the pressure, or damage to parts of the brain caused by herniation may cause paralysis on the side opposite the lesion.<ref name="Cornell"/> Damage to the [[midbrain]], which contains the [[reticular activating network]] that regulates [[consciousness]] will result in [[coma]].<ref name="Cornell"/> Damage to the cardio-respiratory centers in the [[medulla]] will cause [[respiratory arrest|respiratory]] and [[cardiac arrest]].<ref name="Cornell"/>
**Dressing apraxia
**Eyelid opening apraxia


*Other types of apraxia, include-
**Classic apraxia
**Ideokinetic apraxia
**Motor apraxia
**Oculomotor apraxia


==Pathophysiology==
==Pathophysiology==
The exact pathogenesis of [disease name] is not fully understood.
OR


*'Praxis' comprises three components, which include ideation, motor planning, and execution to carry out the purposeful movement. There are particular regions of the brain that represent specific component functions, and these regions together work as a ‘praxis system’ to process and execute a purposeful movement. Dysfunction in any of these regions, namely, frontal and parietal cortex, basal ganglia, and the white matter which connects theses areas, leads to apraxia.
It is thought that [disease name] is the result of / is mediated by / is produced by / is caused by either [hypothesis 1], [hypothesis 2], or [hypothesis 3].


*The movements which requires tools are transitive movements, and the ones which do not require tools are intransitive. The intransitive movements are gestural which can be meaningful (communicative), or meaningless movements (not representational). In apraxia, transitive movements are affected more frequently as compared to intransitive movements.
OR


*The observations of the patients in the clinical practice is the basis of most of the knowledge about 'apraxia'. Apraxia has been mostly seen in chronic left hemispheric lesions and Alzheimer's disease. The left hemispheric lesions cause more difficulty to perform transitive movements, as compared to intransitive movements and imitating gestures. Left hemisphere has a major role in 'praxis' and this may be due to specific stored representations in left hemisphere and their retrieval. On the other hand, Alzheimer's patients have preserved transitive movements, but shows deficits in gestures. Therefore, the type of apraxia depends on the type of neurological disease and the area of the brain affected by it.
[Pathogen name] is usually transmitted via the [transmission route] route to the human host.


*Different brain regions which have role in cognition and movement are involved in complex 'Praxis' movements. The conceptualization of a purposeful task involves prefrontal, left premotor, middle temporal and parietal areas of the brain..
OR


*Neuroimaging studies have been done to investigate praxis correlations, but studies done so far vary widely on focus areas of praxis. One of the study reported left temporal lobe correltion with praxis because of its role in somatic memory retrieval.. Left premotor cortex, left parietal lobule, and parietal cortex have also been shown to have a role in praxis as they are involved in knowledge of tools and their use, grasping movements, spatiotemporal information integration, respectively.. Stronger left lateralization (especially posterior parietal and premotor cortex) for gesture production in praxis has been suggested by neuroimaging studies.
Following transmission/ingestion, the [pathogen] uses the [entry site] to invade the [cell name] cell.
 
OR
 
 
[Disease or malignancy name] arises from [cell name]s, which are [cell type] cells that are normally involved in [function of cells].
 
OR
 
The progression to [disease name] usually involves the [molecular pathway].
 
OR
 
The pathophysiology of [disease/malignancy] depends on the histological subtype.


==Causes==
==Causes==
Damage to brain can lead to apraxia. When apraxia progresses in a person who was before able to perform the abilities or task, it is termed as acquired apraxia.


The most common causes of apraxia are:
Conditions that lead to elevation of inracranial pressure increase the risk of brain herniation. These include-
 
Localized or generalized swelling of the brain
Space-occupying lesions
Increase intracranial venous blood pressure (venous sinus thrombosis, Heart failure, jugular venous obstruction)
Obstruction of Cerebro-spinal Fluid flow
 
Traumatic (bRAIN HEMORRHAGES, CONTUSION)
Space-occupying lesions (eg, brain tumor, edema, or abscess; contusions; hematomas)
Generalized swelling or edema of the brain (eg, due to acute liver failure or hypertensive encephalopathy)
Increased venous pressure (eg, due to heart failure, obstruction of superior mediastinal or jugular veins, or venous sinus thrombosis)
Obstruction of the CSF flow (eg, due to hydrocephalus or extensive meningeal disease)
There are multispectral factors that can predispose to raised intracranial pressure and brain herniation syndrome such as[1]:
 
Hematoma (traumatic epidural and subdural hematoma, contusions, intracerebral hemorrhage)
Malignant infarction
Tumors
Infections (abscess, empyema, hydatid cyst)
Hydrocephalus
Diffuse subarachnoid hemorrhage
Pneumocephalus (traumatic or postoperative)
CSF over drainage
Metabolic-hepatic encephalopathy
 
 
Disease name] may be caused by [cause1], [cause2], or [cause3].
 
OR
 
Common causes of [disease] include [cause1], [cause2], and [cause3].


*Neurodegenerative illness
OR
*Brain tumor
*Dementia
*Stroke
* Traumatic brain injury


== Differentiating Apraxia from Other Diseases==
The most common cause of [disease name] is [cause 1]. Less common causes of [disease name] include [cause 2], [cause 3], and [cause 4].
==Epidemiology and Demographics==
The information available on the incidence of apraxia in adults is limited. As apraxia is most common in children, the incidence is approximately 1 to 2 children per 1,000 (0.1%–0.2%) worldwide. Prevalence rates of  apraxia range among 0 and 34% for patients with Right hemisphere stroke and 28–57% for patients with Left hemisphere stroke.Real tool-use loss prevalence rates were stated with 25–54% impaired level of patients. Apraxia commonly affects individuals older than 50 years of age. Apraxia affects men and women equally.


==Risk Factors==
OR
Apraxia is a rare disease caused by stroke; it has the same risk factors as a stroke.  <ref><nowiki><ref name="pmid18957186"></nowiki>{{cite journal| author=Gross RG, Grossman M| title=Update on apraxia. | journal=Curr Neurol Neurosci Rep | year= 2008 | volume= 8 | issue= 6 | pages= 490-6 | pmid=18957186 | doi=10.1007/s11910-008-0078-y | pmc=2696397 | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=18957186  }}</ref>.


*High blood pressure
The cause of [disease name] has not been identified. To review risk factors for the development of [disease name], click [[Pericarditis causes#Overview|here]].
*High cholesterol
*Diabetes
*Smoking
*Prior stroke or cardiovascular disease
*Prior transient ischemic attack (TIA)
*Dialysis treatment


==Screening ==
==Diagnosis==
There is insufficient evidence to recommend routine screening for [[apraxia.]]
===Diagnostic Study of Choice===
The diagnosis of [disease name] is made when at least [number] of the following [number] diagnostic criteria are met: [criterion 1], [criterion 2], [criterion 3], and [criterion 4].


== Natural History, Complications, and Prognosis==
OR


===== Natural History:: =====
The diagnosis of [disease name] is based on the [criteria name] criteria, which include [criterion 1], [criterion 2], and [criterion 3].


*The symptoms of apraxia typically develop during early or later years depending on the cause and the location affected.
OR
*Often, patients with apraxia are not aware of their shortfalls. Therefore, the history of a patient's capability to accomplish skilled movements should be obtained from the patient's caregiver or the patient himself.
*Caregivers should be asked about the capability of patients to perform activities of daily living and perform tasks involving household tools such as using a toothbrush, knife, and fork appropriately, using kitchen utensils correctly and safely to prepare a meal; using tools such as scissors or hammer correctly.
*Caregivers should also be asked about the whole activity level of the patient and whether decreases in his or her total actions have happened.
*The patient may sit on the couch and watch television without showing interest in essential activities he or she use to do in the past.
*This indifference can be related to many kinds of brain dysfunction, but it sporadically occurs because the patient is incapable of performing his or her usual activities.


====Complications====
The diagnosis of [disease name] is based on the [definition name] definition, which includes [criterion 1], [criterion 2], and [criterion 3].
Common complications of apraxia include:


*Broca's Aphasia
OR
*Acalculi
*Right-left Confusion
*Alexia with agraphia
*Wernicke's Aphasia.


===== Prognosis =====
There are no established criteria for the diagnosis of [disease name].


*Patients with apraxia are not able to do things independently and may distress carrying out everyday responsibilities. Activities should be avoided that can lead to injury and take the appropriate safety actions. Over-all, patients with apraxia rely on others for their daily activities and need at least some notch of command; skilled nursing care may be obligatory. Patients with the tumor or degenerative diseases usually develop into amplified levels of dependence.
===History and Symptoms===
The majority of patients with [disease name] are asymptomatic.


== Diagnosis==
OR


*Many tests have been developed to evaluate apraxia but most are difficult to apply in clinics as they are not rapid tests. Additionally, most of those lack in sensitivity and validity.
The hallmark of [disease name] is [finding]. A positive history of [finding 1] and [finding 2] is suggestive of [disease name]. The most common symptoms of [disease name] include [symptom 1], [symptom 2], and [symptom 3]. Common symptoms of [disease] include [symptom 1], [symptom 2], and [symptom 3]. Less common symptoms of [disease name] include [symptom 1], [symptom 2], and [symptom 3].
**''De Renzi ideomotor apraxia test''for ideomotor apraxia assessment, can be tested in either side brain damage. It is a 24-item scale test.
**''Test of upper limb apraxia (TULIA)'' is a 48 item test, is preferred test as it has a good validity and reliability. It can be used to test-
***non-symbolic (meaningless)
***intransitive (communicative)
***transitive (tool-related) gestures.20
**''Apraxia Screen of TULIA (AST)'' is a short bedside test with 12 items, with a high sensitivity and specificity. The basis of this test is TULIA test.


=== History and Symptoms===
===Physical Examination===
===Physical Examination===
Patients with [disease name] usually appear [general appearance]. Physical examination of patients with [disease name] is usually remarkable for [finding 1], [finding 2], and [finding 3].
OR
Common physical examination findings of [disease name] include [finding 1], [finding 2], and [finding 3].
OR
The presence of [finding(s)] on physical examination is diagnostic of [disease name].
OR
The presence of [finding(s)] on physical examination is highly suggestive of [disease name].
===Laboratory Findings===
An elevated/reduced concentration of serum/blood/urinary/CSF/other [lab test] is diagnostic of [disease name].
OR
Laboratory findings consistent with the diagnosis of [disease name] include [abnormal test 1], [abnormal test 2], and [abnormal test 3].
OR
[Test] is usually normal among patients with [disease name].
OR
Some patients with [disease name] may have elevated/reduced concentration of [test], which is usually suggestive of [progression/complication].
OR
There are no diagnostic laboratory findings associated with [disease name].
===Electrocardiogram===
There are no ECG findings associated with [disease name].
OR
An ECG may be helpful in the diagnosis of [disease name]. Findings on an ECG suggestive of/diagnostic of [disease name] include [finding 1], [finding 2], and [finding 3].
===X-ray===
There are no x-ray findings associated with [disease name].
OR
An x-ray may be helpful in the diagnosis of [disease name]. Findings on an x-ray suggestive of/diagnostic of [disease name] include [finding 1], [finding 2], and [finding 3].
OR
There are no x-ray findings associated with [disease name]. However, an x-ray may be helpful in the diagnosis of complications of [disease name], which include [complication 1], [complication 2], and [complication 3].
===Echocardiography or Ultrasound===
There are no echocardiography/ultrasound  findings associated with [disease name].
OR
Echocardiography/ultrasound  may be helpful in the diagnosis of [disease name]. Findings on an echocardiography/ultrasound suggestive of/diagnostic of [disease name] include [finding 1], [finding 2], and [finding 3].
OR
There are no echocardiography/ultrasound  findings associated with [disease name]. However, an echocardiography/ultrasound  may be helpful in the diagnosis of complications of [disease name], which include [complication 1], [complication 2], and [complication 3].
===CT scan===
===CT scan===
There are no CT scan findings associated with [disease name].
OR
[Location] CT scan may be helpful in the diagnosis of [disease name]. Findings on CT scan suggestive of/diagnostic of [disease name] include [finding 1], [finding 2], and [finding 3].
OR
There are no CT scan findings associated with [disease name]. However, a CT scan may be helpful in the diagnosis of complications of [disease name], which include [complication 1], [complication 2], and [complication 3].
===MRI===
===MRI===
There are no MRI findings associated with [disease name].
OR
[Location] MRI may be helpful in the diagnosis of [disease name]. Findings on MRI suggestive of/diagnostic of [disease name] include [finding 1], [finding 2], and [finding 3].
OR
There are no MRI findings associated with [disease name]. However, a MRI may be helpful in the diagnosis of complications of [disease name], which include [complication 1], [complication 2], and [complication 3].
===Other Imaging Findings===
===Other Imaging Findings===
There are no other imaging findings associated with [disease name].
OR
[Imaging modality] may be helpful in the diagnosis of [disease name]. Findings on an [imaging modality] suggestive of/diagnostic of [disease name] include [finding 1], [finding 2], and [finding 3].
===Other Diagnostic Studies===
===Other Diagnostic Studies===
There are no other diagnostic studies associated with [disease name].
OR
[Diagnostic study] may be helpful in the diagnosis of [disease name]. Findings suggestive of/diagnostic of [disease name] include [finding 1], [finding 2], and [finding 3].
OR
Other diagnostic studies for [disease name] include [diagnostic study 1], which demonstrates [finding 1], [finding 2], and [finding 3], and [diagnostic study 2], which demonstrates [finding 1], [finding 2], and [finding 3].
Treatment
Medical Therapy
Brain Herniation is a medical emergency and requires prompt management. Cautious adjustment of intracranial pressure should be done in all patients who develop displacement of the brain tissue. Based on Monroe-Kellie hypothesis, balance in brain volume, CSF volume and intracranial blood
OR
The mainstay of treatment for [disease name] is [therapy].
OR  The optimal therapy for [malignancy name] depends on the stage at diagnosis.
OR
[Therapy] is recommended among all patients who develop [disease name].
OR


==Treatment==
Pharmacologic medical therapy is recommended among patients with [disease subclass 1], [disease subclass 2], and [disease subclass 3].


*No standardized treatment is available for apraxia. The frequency of limb apraxia in left hemispheric stroke patients is reported to be nearly 51%and, hence, the therapeutic efforts are so far mostly concentrated towards stroke patients (left hemispheric stroke patients). Based on the studies, following treatment modalities have been considered so far-
OR
**''Rehabilitative treatment''- 30 sessions, each lasting 50 minutes, 3 times weekly have been tried.
**''Behavioral training Program''-These include gesture-production exercises.


*With treatment, an improvement in praxis and daily living activities is seen in apraxia patients, based on some studies. The communicative gestures training has led to significant improvement of the gestures which were practiced during the training sessions, with some unpracticed gestures also showing some improvement. However, the sustainability of these positive results is not clear. Although rehabilitative training has been reported to benefit, but, for sustained benefit, training alone is not sufficient.
Pharmacologic medical therapies for [disease name] include (either) [therapy 1], [therapy 2], and/or [therapy 3].


*''Noninvasive brain stimulation''- This method had been used widely for many neurological disorders, but there is very limited data for its use in cognitive disorders. However, some studies have shown that this technique has been tried for therapeutic and investigational purpose for this complex neurological disorder and may show some positive results. This technique when used with rehabilitative training, may be useful. Through this technique and different stimulation settings, inhibitory or excitatory influences are exerted on cortical excitability or plasticity. The synergistic approach using this technique prior to rehabilitative training, not only increases the efficacy, but it also increases the sustainability of the improvement seen. Some examples of non-invasive brain stimulation techniques which have been used in some neurological conditions with some improvement in the cognitive function components of the disease can be tried-
OR
**Transcranial direct current stimulation (tDCS)-low-level continuous electric current is delivered to influence plasticity and excitabililty of the cortex. In this, anodal tDCS works in excitatory ways, and cathodal tDCS in inhibitory ways.
**single-pulse or rTMS- It can be delivered in either low frequency (0.2–1 Hz) for inhibitory mode, or in high frequency (≥5 Hz) for excitatory mode.
**theta-burst stimulation (TBS)-It is also a magnetic stimulation method like rTMS, but it shows equal efficacy even with shorter stimulation period.
**paired associative stimulation (PAS)- This stimulation technique can be used to tackle physiological mechanisms underlying memory using long-term depression (LTD), and long-term potentiation (LTP).<br />


===Medical Therapy===
Empiric therapy for [disease name] depends on [disease factor 1] and [disease factor 2].
===Interventions===
There are no specific recommended therapeutic interventions for the management of Apraxia.


Apraxia is believed to have an adverse impact on the Activity of Daily Living independence<ref><nowiki><ref name="Hagmann1998"></nowiki>{{cite journal|last1=Hagmann|first1=Georg Goldenberg Sonja|title=Therapy of Activities of Daily Living in Patients with Apraxia|journal=Neuropsychological Rehabilitation|volume=8|issue=2|year=1998|pages=123–141|issn=0960-2011|doi=10.1080/713755559}}</ref>. There are limited information and research available regarding various treatments<ref><nowiki><ref name="pmid18254038"></nowiki>{{cite journal| author=West C, Bowen A, Hesketh A, Vail A| title=Interventions for motor apraxia following stroke. | journal=Cochrane Database Syst Rev | year= 2008 | volume=  | issue= 1 | pages= CD004132 | pmid=18254038 | doi=10.1002/14651858.CD004132.pub2 | pmc=6464830 | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=18254038  }}</ref><nowiki></ref></nowiki>. Various interventions include:
OR


*Daily living doings training: this method explains internal and external compensatory approaches that permit a functional mission to be accomplished<ref><nowiki><ref name="van HeugtenDekker2016"></nowiki>{{cite journal|last1=van Heugten|first1=C M|last2=Dekker|first2=J|last3=Deelman|first3=B G|last4=van Dijk|first4=A J|last5=Stehmann-Saris|first5=J C|title=Outcome of strategy training in stroke patients with apraxia: a phase II study|journal=Clinical Rehabilitation|volume=12|issue=4|year=2016|pages=294–303|issn=0269-2155|doi=10.1191/026921598674468328}}</ref>.
Patients with [disease subclass 1] are treated with [therapy 1], whereas patients with [disease subclass 2] are treated with [therapy 2].
*Sensory Stimulation: Including deep pressure stimulation, soft and sharp touch are useful to the patients' limbs<ref><nowiki><ref name="Butler2016"></nowiki>{{cite journal|last1=Butler|first1=Jenny|title=Intervention Effectiveness: Evidence from a Case Study of Ideomotor and Ideational Apraxia|journal=British Journal of Occupational Therapy|volume=60|issue=11|year=2016|pages=491–497|issn=0308-0226|doi=10.1177/030802269706001109}}</ref>.
*Chaining (forward or backward): This method is fragmented down into its sections. The task is done with assistance from the therapist separately from the final element through backward chaining, which the patient performs out unassisted. If positive next time, additional steps are presented. Forward chaining is the opposite of backward chaining;
*Proprioceptive stimulation: The patient props on and puts his weight through their upper and lower extremities;
*Cueing, physical or verbal stimuli: This technique enables each phase of the task to be completed;


===Surgery===
Surgery
Surgical intervention is not recommended for the management of Apraxia.
Surgical intervention is not recommended for the management of [disease name].


===Primary Prevention===
OR
There are no established measures for the primary prevention of Apraxia. Some steps can be used which include<ref><nowiki><ref name="pmid2799873"></nowiki>{{cite journal| author=| title=Stroke--1989. Recommendations on stroke prevention, diagnosis, and therapy. Report of the WHO Task Force on Stroke and other Cerebrovascular Disorders. | journal=Stroke | year= 1989 | volume= 20 | issue= 10 | pages= 1407-31 | pmid=2799873 | doi=10.1161/01.str.20.10.1407 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=2799873  }}</ref>.


*Exercise regularly.
Surgery is not the first-line treatment option for patients with [disease name]. Surgery is usually reserved for patients with either [indication 1], [indication 2], and [indication 3]
*Eat a healthy diet.
*Limit how much alcohol you drink.
*Quit smoking
*Check your blood pressure often.


===Secondary Prevention===
OR
Effective measures for the secondary prevention of Apraxia include secondary prevention of stroke<ref><nowiki><ref name="pmid26300647"></nowiki>{{cite journal| author=Esenwa C, Gutierrez J| title=Secondary stroke prevention: challenges and solutions. | journal=Vasc Health Risk Manag | year= 2015 | volume= 11 | issue=  | pages= 437-50 | pmid=26300647 | doi=10.2147/VHRM.S63791 | pmc=4536764 | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=26300647  }}</ref>:


*Aspirin, clopidogrel, extended-release dipyridamole, ticlopidine
The mainstay of treatment for [disease name] is medical therapy. Surgery is usually reserved for patients with either [indication 1], [indication 2], and/or [indication 3].
*Anticoagulants (apixaban, dabigatran, edoxaban, rivaroxaban, warfarin)
*Blood pressure-lowering medications.
*Diabetes Control
*Low-fat diet
*Cholesterol-lowering medications, Cessation of cigarette smoking, carotid revascularization


*Weight loss and Exercise
OR


==Overview==
The feasibility of surgery depends on the stage of [malignancy] at diagnosis.
'''Apraxia''' is a [[neurological disorder]] characterized by loss of the ability to execute or carry out learned purposeful movements, despite having the desire and the physical ability to perform the movements. It is a disorder of motor planning which may be acquired or developmental, but may not be caused by incoordination, sensory loss, or failure to comprehend simple commands (which can be tested by asking the person tested to recognize the correct movement from a series). The root word of '''Apraxia''' is ''praxis'', [[Greek language|Greek]] for an act, work, or deed. It is preceded by a privative a, meaning 'without'.


==Types==
OR
There are several types of apraxia including:
* ''ideomotor'' (inability to carry out a motor command, for example, "act as if you are brushing your teeth" or "salute") - the form most frequently encountered by [[physician]]s,
** ''limb apraxia'' when movements of the arms and legs are involved,
** ''nonverbal-oral'' or ''buccofacial'' (inability to carry out facial movements on command, e.g., lick [[lips]], [[whistle]], [[cough]], or [[wink]]),
* ''ideational'' (inability to create a plan for or idea of a specific movement, for example, "pick up this pen and write down your name"),
* ''limb-kinetic'' (inability to make fine, precise movements with a limb),
* ''verbal'' (difficulty planning the movements necessary for [[Speech communication|speech]]), also known as Apraxia of Speech (see below)
* ''constructional'' (inability to draw or construct simple configurations),
* ''oculomotor'' (difficulty moving the [[eye]])


Each type may be tested at decreasing levels of complexity; if the person tested fails to execute the commands, you can make the movement yourself and ask that the person mimic it, or you can even give them a real object (like a tooth brush) and ask them to use it.
Surgery is the mainstay of treatment for [disease or malignancy].


Apraxia may be accompanied by a [[language disorder]] called [[aphasia]].
Primary Prevention
There are no established measures for the primary prevention of [disease name].


===Apraxia of speech===
OR
Developmental Apraxia of Speech (DAS) presents in children who have no evidence of difficulty with strength or range of motion of the articulators, but are unable to execute speech movements because of motor planning and coordination problems. This is not to be confused with phonological impairments in children with normal coordination of the articulators during speech.


Symptoms of Acquired Apraxia of Speech (AOS) and Developmental Apraxia of Speech (DAS) include inconsistent articulatory errors, groping oral movements to locate the correct articulatory position, and increasing errors with increasing word and phrase length. AOS often co-occurs with Oral Apraxia (during both speech and non-speech movements) and Limb Apraxia.
There are no available vaccines against [disease name].


==Causes==
OR
Ideomotor apraxia is almost always caused by lesions in the language-dominant (usually left) hemisphere of the [[brain]], and as such these patients often have concomitant [[aphasia]], especially of the [[Expressive aphasia|Broca]] or [[Conduction aphasia|conduction]] type. Left-side ideomotor apraxia may be caused by a lesion of the [[anterior]] [[corpus callosum]].


Ideational apraxia is commonly associated with confusion states and dementia.
Effective measures for the primary prevention of [disease name] include [measure1], [measure2], and [measure3].


==Treatment==
OR
Generally, treatment for individuals with apraxia includes [[physical therapy]], [[occupational therapy]] or [[speech therapy]], or Oral Motor Therapy and [[IVIG]]. If apraxia is a symptom of another disorder (usually a [[Neurology|neurologic]] disorder), the underlying disorder should be treated.


==Prognosis==
[Vaccine name] vaccine is recommended for [patient population] to prevent [disease name]. Other primary prevention strategies include [strategy 1], [strategy 2], and [strategy 3].
The prognosis for individuals with apraxia varies. With therapy, some patients improve significantly, while others may show very little improvement. Some individuals with apraxia may benefit from the use of a [[Augmentative and alternative communication|communication aid]].


==Related Chapters==
Secondary Prevention
*[[Dyspraxia]]
There are no established measures for the secondary prevention of [disease name].


==References==
OR
*{{cite book
  | last = Epstein
  | first = O.
  | authorlink =
  | coauthors = D. Perkin, J. Cookson, D.P. de Bono
  | title = Clinical Examination
  | publisher = Mosby
  | date = 2003
  | location = London
  | pages = 294
  | url = http://www.fleshandbones.com/bookshop/title.cfm?ISBN=0723432295
  | doi =
  | id = ISBN 0-7234-3229-5 }}
* Kasper DL, Braunwald E, Fauci AS, Hauser SL, Longo DL, Jameson JL. ''Harrison's Principles of Internal Medicine''. New York: McGraw-Hill, 2005. ISBN 0-07-139140-1.


{{Symptoms and signs}}
Effective measures for the secondary prevention of [disease name] include [strategy 1], [strategy 2], and [strategy 3].




[[Category:Neurology]]
==References==
{{Reflist|2}}


==External Links==
* [http://rad.usuhs.edu/medpix/medpix_image.html?pt_id=0&imageid=17922&quiz=no#top Brain Herniation Diagrams]


[[es:Apraxia]]
{{CNS diseases of the nervous system}}
[[fr:Apraxie]]
[[pt:Apraxia]]
[[ru:Апраксия]]


[[Category:Neurotrauma]]
[[Category:Neurology]]


{{WikiDoc Help Menu}}
[[de:Einklemmung]]
{{WH}}
{{WS}}
{{WS}}
<references />

Latest revision as of 17:31, 31 August 2020

This page is for your practice!


Brain herniation
ICD-10 G93.5
ICD-9 348.4
MedlinePlus 001421

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Associate Editor(s)-in-Chief: Parul Pahal, M.B.B.S[2]

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Keywords and synonyms: Cerebral herniation, cerebellar herniation, uncal herniation, central herniation, supratentorial herniation, infratentorial herniation, transtentorial herniation, tonsillar herniation, cingulate herniation, transcalvarial herniation

Overview

Herniation, a deadly side effect of very high intracranial pressure, occurs when the brain shifts across structures within the skull. The brain can shift by such structures as the falx cerebri, the tentorium cerebelli, and even through the hole called the foramen magnum in the base of the skull (through which the spinal cord connects with the brain). Herniation can be caused by a number of factors that increase intracranial pressure such as traumatic brain injury. Because herniation puts extreme pressure on parts of the brain, it is often fatal. Therefore, extreme measures are taken in hospital settings to prevent the condition by reducing intracranial pressure.

Historical Perspective

In 1783, a medical educator and anatomist from Scotland, Alexander Monro, first proposed the concept of Intracranial pressure in his paper 'Observations on the Structure and Functions of the Nervous System'. In this paper, he stated his observations about brain, cranial cavity, and cranial blood flow. He mentioned that the cranial cavity is rigid and it encloses the incompressible brain. He hypothesized that the blood volume is constant in the cranial cavity at all times. There is a continuous balance between outflowing venous and incoming arterial blood.

This hypothesis was supported by George Kellie's (Monore's former student) experiments, and 'Monro–Kellie hypothesis' came into existence. According to this, the sum of brain volume, cerebrospinal fluid, and intrcranial blood flow is constant.[1]

Classification

There are two major classes of herniation: supratentorial and infratentorial.[2]. Depending on which structures of the brain have been displaced, herniation is further sub-classified.[3]

Tentorium Cerebelli is one of the four duramater folds (Extention of outermost meningeal layer, duramater). It serves as a landmark and divides the cranial cavity structures into supra and infra tentorial. This dural extention has a fixed and free margin. The free margin of tentorium cerebelli is called as 'Tentorial notch".[4]

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Brain Herniation
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Supratentorial Herniation
occurs above
the tentorial notch
 
 
 
 
 
 
 
 
 
 
 
Infratentorial Herniation
occurs below
the tentorial notch
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Uncal
 
Central
or transtentorial
 
Cingulate
or subfalcine
(most common type)
 
Transcalvarial
or
External herniation
 
 
 
Upward
transtentorial
or
Upward
Cerebellar
 
Tonsillar
or
Downward
Cerebellar


Central herniation

In central herniation, (also called "transtentorial herniation") the diencephalon and parts of the temporal lobes of both of the cerebral hemispheres are squeezed through a notch in the tentorium cerebelli.[3][5] Downward herniation can stretch branches of the basilar artery (paramedian artery), causing them to tear and bleed, known as a Duret hemorrhage. The result is usually fatal.[5]

Uncal herniation

In uncal herniation, a common subtype of transtentorial herniation, the innermost part of the temporal lobe, the uncus, can be squeezed so much that it goes by the tentorium and puts pressure on the brainstem.[3] The tentorium is a structure within the skull formed by the meningeal layer the dura mater. Tissue may be stripped from the cerebral cortex in a process called decortication.[6] The uncus can squeeze the third cranial nerve, which controls parasympathetic input to the eye on the side of the affected nerve. This interrupts the parasympathetic neural transmission, causing the pupil of the affected eye to dilate and fail to constrict in response to light as it should, so a dilated unresponsive pupil is an important sign of increased intracranial pressure.[5] Pupillary dilation often precedes a later finding of cranial nerve III compression, which is deviation of the eye to a "down and out" position due to loss of innervation to all ocular motility muscles except for the lateral rectus (innervated by cranial nerve VI) and the superior oblique (innervated by cranial nerve IV). Cranial arteries may be compressed during the herniation. Compression of the posterior cerebral artery may result in loss of the contralateral visual field. A later important finding, the false localizing sign, results from compression of the contralateral cerebral crus, which contains descending corticospinal fibers. This leads to ipsilateral (to herniating uncus) hemiparesis of the body. This type of herniation can also damage the brain stem, causing lethargy, slow heart rate, respiratory abnormalities, and pupil dilation.[6] Uncal herniation may advance to central herniation.[2]

Cerebellar herniation

Increased pressure in the posterior fossa can cause the cerebellum to move up through the tentorial opening in upward, or cerebellar herniation.[3] The midbrain is pushed through the tentorial notch. This also pushes the midbrain down.

Tonsillar herniation

In tonsillar herniation, also called downward cerebellar herniation,[2] the cerebellar tonsils move downward through the foramen magnum possibly causing compression of the lower brainstem and upper cervical spinal cord as they pass through the foramen magnum.[3] Increased pressure on the brainstem can result in dysfunction of the centers in the brain responsible for controlling respiratory and cardiac function.

Tonsillar herniation of the cerebellum is also known commonly as a Chiari Malformation (CM) which previously was called an Arnold Chiari Malformation (ACM). There are at least three types of Chiari malformation that are widely recognized, and they represent very different disease processes with different symptoms and prognosis. These conditions can be found in asymptomatic patients, as an incidental finding, or can be so severe as to be life-threatening. This condition is now being diagnosed more frequently by radiologists as more and more patients undergo MRI scans of their heads. Cerebellar ectopia is a term used by radiologists to describe cerebellar tonsils that are "low lying" but that do not meet the radiographic criteria for definition as a Chiari malformation. The currently accepted radiographic definition for a Chiari malformation are cerebellar tonsils that lay at least 5mm below the level of the foramen magnum. Some clinicians have reported that some patients appear to experience symptoms consistent with a Chiari malformation without radiographic evidence of tonsillar herniation. Sometimes these patients are described as having a 'Chiari 0'.

There are many suspected causes of tonsillar herniation including (but not exclusively)- Spinal cord tethering or occult tight filum terminale (pulling down on the brainstem and surrounding structures); decreased or malformed posterior fossa (the lower, back part of the skull) not providing enough room for the cerebellum; hydrocephalus or abnormal CSF volume pushing the tonsils out; connective tissue disorders, such as Ehlers Danlos Syndrome, can be associated as well.(These may affect the ability of the brain, as well as the supporting joints, to maintain proper position/strength; in pediatric cases, ACM is often an 'incidental' finding while doing a work up for scoliosis, which is usually associated with certain connective tissue disorders).

For further evaluation of tonsillar herniation, CINE flow studies are suggested. This type of MRI will look at the flow of CSF at the cranio-cervical joint. For persons experiencing symptoms with seemingly minimal herniation, especially if the symptoms are better in the suppine position and worse upon standing/upright, an upright MRI may be useful.

Cingulate herniation

In cingulate or subfalcine herniation, the most common type, the innermost part of the frontal lobe is scraped under part of the falx cerebri, the dura mater at the top of the head between the two hemispheres of the brain.[3][7] Cingulate herniation can be caused when one hemisphere swells and pushes the cingulate gyrus by the falx cerebri.[2] This does not put as much pressure on the brainstem as the other types of herniation, but it may interfere with blood vessels in the frontal lobes that are close to the site of injury (anterior cerebral artery), or it may progress to central herniation.[3] Interference with the blood supply can cause dangerous increases in ICP that can lead to more dangerous forms of herniation.[8] Symptoms for cingulate herniation are not well defined.[8] Usually occurring in addition to uncal herniation, cingulate herniation may present with abnormal posturing and coma.[2] Cingulate herniation is frequently believed to be a precursor to other types of herniation.[8]

  • Subfalcine-herniation

    Subfalcine-herniation

Transcalvarial Herniation

In transcalvarial herniation, the brain squeezes through a fracture or a surgical site in the skull.[2]

Natural History, Complications and Prognosis

The patient may become paralyzed on the same side as the lesion causing the pressure, or damage to parts of the brain caused by herniation may cause paralysis on the side opposite the lesion.[5] Damage to the midbrain, which contains the reticular activating network that regulates consciousness will result in coma.[5] Damage to the cardio-respiratory centers in the medulla will cause respiratory and cardiac arrest.[5]


Pathophysiology

The exact pathogenesis of [disease name] is not fully understood.

OR

It is thought that [disease name] is the result of / is mediated by / is produced by / is caused by either [hypothesis 1], [hypothesis 2], or [hypothesis 3].

OR

[Pathogen name] is usually transmitted via the [transmission route] route to the human host.

OR

Following transmission/ingestion, the [pathogen] uses the [entry site] to invade the [cell name] cell.

OR


[Disease or malignancy name] arises from [cell name]s, which are [cell type] cells that are normally involved in [function of cells].

OR

The progression to [disease name] usually involves the [molecular pathway].

OR

The pathophysiology of [disease/malignancy] depends on the histological subtype.

Causes

Conditions that lead to elevation of inracranial pressure increase the risk of brain herniation. These include-

Localized or generalized swelling of the brain Space-occupying lesions Increase intracranial venous blood pressure (venous sinus thrombosis, Heart failure, jugular venous obstruction) Obstruction of Cerebro-spinal Fluid flow

Traumatic (bRAIN HEMORRHAGES, CONTUSION) Space-occupying lesions (eg, brain tumor, edema, or abscess; contusions; hematomas) Generalized swelling or edema of the brain (eg, due to acute liver failure or hypertensive encephalopathy) Increased venous pressure (eg, due to heart failure, obstruction of superior mediastinal or jugular veins, or venous sinus thrombosis) Obstruction of the CSF flow (eg, due to hydrocephalus or extensive meningeal disease) There are multispectral factors that can predispose to raised intracranial pressure and brain herniation syndrome such as[1]:

Hematoma (traumatic epidural and subdural hematoma, contusions, intracerebral hemorrhage) Malignant infarction Tumors Infections (abscess, empyema, hydatid cyst) Hydrocephalus Diffuse subarachnoid hemorrhage Pneumocephalus (traumatic or postoperative) CSF over drainage Metabolic-hepatic encephalopathy


Disease name] may be caused by [cause1], [cause2], or [cause3].

OR

Common causes of [disease] include [cause1], [cause2], and [cause3].

OR

The most common cause of [disease name] is [cause 1]. Less common causes of [disease name] include [cause 2], [cause 3], and [cause 4].

OR

The cause of [disease name] has not been identified. To review risk factors for the development of [disease name], click here.

Diagnosis

Diagnostic Study of Choice

The diagnosis of [disease name] is made when at least [number] of the following [number] diagnostic criteria are met: [criterion 1], [criterion 2], [criterion 3], and [criterion 4].

OR

The diagnosis of [disease name] is based on the [criteria name] criteria, which include [criterion 1], [criterion 2], and [criterion 3].

OR

The diagnosis of [disease name] is based on the [definition name] definition, which includes [criterion 1], [criterion 2], and [criterion 3].

OR

There are no established criteria for the diagnosis of [disease name].

History and Symptoms

The majority of patients with [disease name] are asymptomatic.

OR

The hallmark of [disease name] is [finding]. A positive history of [finding 1] and [finding 2] is suggestive of [disease name]. The most common symptoms of [disease name] include [symptom 1], [symptom 2], and [symptom 3]. Common symptoms of [disease] include [symptom 1], [symptom 2], and [symptom 3]. Less common symptoms of [disease name] include [symptom 1], [symptom 2], and [symptom 3].

Physical Examination

Patients with [disease name] usually appear [general appearance]. Physical examination of patients with [disease name] is usually remarkable for [finding 1], [finding 2], and [finding 3].

OR

Common physical examination findings of [disease name] include [finding 1], [finding 2], and [finding 3].

OR

The presence of [finding(s)] on physical examination is diagnostic of [disease name].

OR

The presence of [finding(s)] on physical examination is highly suggestive of [disease name].

Laboratory Findings

An elevated/reduced concentration of serum/blood/urinary/CSF/other [lab test] is diagnostic of [disease name].

OR

Laboratory findings consistent with the diagnosis of [disease name] include [abnormal test 1], [abnormal test 2], and [abnormal test 3].

OR

[Test] is usually normal among patients with [disease name].

OR

Some patients with [disease name] may have elevated/reduced concentration of [test], which is usually suggestive of [progression/complication].

OR

There are no diagnostic laboratory findings associated with [disease name].

Electrocardiogram

There are no ECG findings associated with [disease name].

OR

An ECG may be helpful in the diagnosis of [disease name]. Findings on an ECG suggestive of/diagnostic of [disease name] include [finding 1], [finding 2], and [finding 3].

X-ray

There are no x-ray findings associated with [disease name].

OR

An x-ray may be helpful in the diagnosis of [disease name]. Findings on an x-ray suggestive of/diagnostic of [disease name] include [finding 1], [finding 2], and [finding 3].

OR

There are no x-ray findings associated with [disease name]. However, an x-ray may be helpful in the diagnosis of complications of [disease name], which include [complication 1], [complication 2], and [complication 3].

Echocardiography or Ultrasound

There are no echocardiography/ultrasound findings associated with [disease name].

OR

Echocardiography/ultrasound may be helpful in the diagnosis of [disease name]. Findings on an echocardiography/ultrasound suggestive of/diagnostic of [disease name] include [finding 1], [finding 2], and [finding 3].

OR

There are no echocardiography/ultrasound findings associated with [disease name]. However, an echocardiography/ultrasound may be helpful in the diagnosis of complications of [disease name], which include [complication 1], [complication 2], and [complication 3].

CT scan

There are no CT scan findings associated with [disease name].

OR

[Location] CT scan may be helpful in the diagnosis of [disease name]. Findings on CT scan suggestive of/diagnostic of [disease name] include [finding 1], [finding 2], and [finding 3].

OR

There are no CT scan findings associated with [disease name]. However, a CT scan may be helpful in the diagnosis of complications of [disease name], which include [complication 1], [complication 2], and [complication 3].

MRI

There are no MRI findings associated with [disease name].

OR

[Location] MRI may be helpful in the diagnosis of [disease name]. Findings on MRI suggestive of/diagnostic of [disease name] include [finding 1], [finding 2], and [finding 3].

OR

There are no MRI findings associated with [disease name]. However, a MRI may be helpful in the diagnosis of complications of [disease name], which include [complication 1], [complication 2], and [complication 3].

Other Imaging Findings

There are no other imaging findings associated with [disease name].

OR

[Imaging modality] may be helpful in the diagnosis of [disease name]. Findings on an [imaging modality] suggestive of/diagnostic of [disease name] include [finding 1], [finding 2], and [finding 3].

Other Diagnostic Studies

There are no other diagnostic studies associated with [disease name].

OR

[Diagnostic study] may be helpful in the diagnosis of [disease name]. Findings suggestive of/diagnostic of [disease name] include [finding 1], [finding 2], and [finding 3].

OR

Other diagnostic studies for [disease name] include [diagnostic study 1], which demonstrates [finding 1], [finding 2], and [finding 3], and [diagnostic study 2], which demonstrates [finding 1], [finding 2], and [finding 3].

Treatment Medical Therapy

Brain Herniation is a medical emergency and requires prompt management. Cautious adjustment of intracranial pressure should be done in all patients who develop displacement of the brain tissue. Based on Monroe-Kellie hypothesis, balance in brain volume, CSF volume and intracranial blood

OR

The mainstay of treatment for [disease name] is [therapy].

OR The optimal therapy for [malignancy name] depends on the stage at diagnosis.

OR

[Therapy] is recommended among all patients who develop [disease name].

OR

Pharmacologic medical therapy is recommended among patients with [disease subclass 1], [disease subclass 2], and [disease subclass 3].

OR

Pharmacologic medical therapies for [disease name] include (either) [therapy 1], [therapy 2], and/or [therapy 3].

OR

Empiric therapy for [disease name] depends on [disease factor 1] and [disease factor 2].

OR

Patients with [disease subclass 1] are treated with [therapy 1], whereas patients with [disease subclass 2] are treated with [therapy 2].

Surgery Surgical intervention is not recommended for the management of [disease name].

OR

Surgery is not the first-line treatment option for patients with [disease name]. Surgery is usually reserved for patients with either [indication 1], [indication 2], and [indication 3]

OR

The mainstay of treatment for [disease name] is medical therapy. Surgery is usually reserved for patients with either [indication 1], [indication 2], and/or [indication 3].

OR

The feasibility of surgery depends on the stage of [malignancy] at diagnosis.

OR

Surgery is the mainstay of treatment for [disease or malignancy].

Primary Prevention There are no established measures for the primary prevention of [disease name].

OR

There are no available vaccines against [disease name].

OR

Effective measures for the primary prevention of [disease name] include [measure1], [measure2], and [measure3].

OR

[Vaccine name] vaccine is recommended for [patient population] to prevent [disease name]. Other primary prevention strategies include [strategy 1], [strategy 2], and [strategy 3].

Secondary Prevention There are no established measures for the secondary prevention of [disease name].

OR

Effective measures for the secondary prevention of [disease name] include [strategy 1], [strategy 2], and [strategy 3].


References

  1. ↑ Mokri, B. (2001). "The Monro-Kellie hypothesis: Applications in CSF volume depletion". Neurology. 56 (12): 1746–1748. doi:10.1212/WNL.56.12.1746. ISSN 0028-3878.
  2. ↑ 2.0 2.1 2.2 2.3 2.4 2.5 Orlando Regional Healthcare, Education and Development. 2004. "Overview of Adult Traumatic Brain Injuries." Retrieved on February 6, 2007
  3. ↑ 3.0 3.1 3.2 3.3 3.4 3.5 3.6 Shepherd S. 2004. "Head trauma." Emedicine.com. Retrieved on January 28, 2007.
  4. ↑ Rai, Rabjot; Iwanaga, Joe; Shokouhi, Gaffar; Oskouian, Rod J; Tubbs, R. Shane (2018). "The Tentorium Cerebelli: A Comprehensive Review Including Its Anatomy, Embryology, and Surgical Techniques". Cureus. doi:10.7759/cureus.3079. ISSN 2168-8184.
  5. ↑ 5.0 5.1 5.2 5.3 5.4 5.5 Cornell. 1998. Introduction to neuropathology. Reaction to injury: Brain histology." Cornell University Medical College.
  6. ↑ 6.0 6.1 McCaffrey P. 2001. "The neuroscience on the web series: CMSD 336 neuropathologies of language and cognition." California State University, Chico. Retrieved on August 7, 2007.
  7. ↑ Dawodu ST. 2007. Traumatic brain injury: Definition, epidemiology, pathophysiology. Emedicine.com. Retrieved on January 28, 2007.
  8. ↑ 8.0 8.1 8.2 Kristi Hudson. 2006. Brain Herniation Syndromes - 2 Nursing CEs. Dynamic Nursing Education. Retrieved on September 6, 2007.

External Links

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