Arachnoid cyst overview: Difference between revisions
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== Classification == | == Classification == | ||
Arachnoid cysts may be classified according to cause into 2 subtypes/groups: primary or secondary, or according to symptoms into 3 groups. | Arachnoid cysts may be classified according to cause into 2 subtypes/groups: primary or secondary, or according to [[symptoms]] into 3 groups. | ||
== Causes == | == Causes == | ||
The exact cause of arachnoid cysts is not known. Researchers believe that most cases of arachnoid cysts are developmental malformations that arise from the unexplained splitting or tearing of the arachnoid membrane, being classified as primary. There are also arachnoid cysts that arise from secondary causes, such as trauma, surgery, intracranial hemorrhage and infection. | The exact cause of arachnoid cysts is not known. Researchers believe that most cases of arachnoid cysts are developmental [[malformations]] that arise from the unexplained splitting or tearing of the [[arachnoid membrane]], being classified as primary. There are also arachnoid cysts that arise from secondary causes, such as [[trauma]], [[Surgery operation|surgery]], [[intracranial hemorrhage]] and [[infection]]. | ||
== Epidemiology == | == Epidemiology == | ||
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== Natural History, Complications and Prognosis == | == Natural History, Complications and Prognosis == | ||
Prognosis of arachnoid cyst is generally excellent and is usually associated with a benign disease course, despite being symptomatic in a few patients. Most are found incidentally, and a few may, rarely, enlarge and complicate with the symptoms previously described such as hydrocephalus, seizures, hearing loss, visual changes and cervical myelopathy. | [[Prognosis]] of arachnoid cyst is generally excellent and is usually associated with a benign disease course, despite being symptomatic in a few patients. Most are found incidentally, and a few may, rarely, enlarge and complicate with the symptoms previously described such as [[hydrocephalus]], [[seizures]], [[hearing loss]], visual changes and cervical [[myelopathy]]. | ||
== History and Symptoms == | == History and Symptoms == | ||
Patients with arachnoid cysts will most likely never show symptoms, even in cases where the cyst is large. Therefore, while the presence of symptoms may provoke further clinical investigation | Patients with arachnoid cysts will most likely never show [[symptoms]], even in cases where the [[cyst]] is large. Therefore, while the presence of [[symptoms]] may provoke further clinical investigation. Symptoms independent of further data cannot, and should not be, interpreted as evidence of a cyst's existence, size or location. These symptoms usually are: | ||
* Headache; | *[[Headache]]; | ||
* Nausea/Vomiting; | *[[Nausea]]/[[Vomiting]]; | ||
* Seizures; | *[[Seizures]]; | ||
* Skull/spine deformation; | *[[Skull bones|Skull]]/[[spine]] deformation; | ||
* Developmental delays; | *[[Developmental delays]]; | ||
* Obstructive hydrocephalus; | *[[Obstructive hydrocephalus]]; | ||
* Hearing loss; | *[[Hearing loss]]; | ||
* Head bobbing; | * Head bobbing; | ||
* Visual changes. | * Visual changes. | ||
== Physical Examination == | == Physical Examination == | ||
Physical examination is generally not very useful as most cases of arachnoid cysts are diagnosed incidentally, but in larger cysts, depending of the affected region, there may be some findings such as: | [[Physical examination]] is generally not very useful as most cases of arachnoid cysts are diagnosed incidentally, but in larger cysts, depending of the affected region, there may be some findings such as: | ||
* Ataxia; | *[[Ataxia]]; | ||
* Hearing loss; | *[[Hearing loss]]; | ||
* Visual changes; | * Visual changes; | ||
* Protrusions from the head or spine; | * Protrusions from the head or spine; | ||
* Head bobbing; | * Head bobbing; | ||
* Endocrine issues, e.g. early onset of puberty. | *[[Endocrine]] issues, e.g. early onset of [[puberty]]. | ||
== CT == | == CT == | ||
On brain/spine CT scan, arachnoid cysts are characterized by cystic images with similar density to CSF and non-enhancing borders, mostly found in the middle cranial fossa while they only rarely occur in the spinal cord. | On [[brain]]/[[spine]] CT scan, arachnoid cysts are characterized by cystic images with similar density to [[CSF]] and non-enhancing borders, mostly found in the [[middle cranial fossa]] while they only rarely occur in the [[spinal cord]]. | ||
== MRI == | == MRI == | ||
On brain/spine MRI, arachnoid cysts are characterized by cystic images with similar density to CSF and non-enhancing borders, mostly found in the middle cranial fossa while they only rarely occur in the spinal cord. MRIs are more adequate than CT scans for evaluating arachnoid cysts. | On [[brain]]/[[spine]] MRI, arachnoid cysts are characterized by cystic images with similar density to [[CSF]] and non-enhancing borders, mostly found in the [[middle cranial fossa]] while they only rarely occur in the [[spinal cord]]. MRIs are more adequate than [[CT-scans|CT]] scans for evaluating arachnoid cysts. | ||
== Other Diagnostic Studies == | == Other Diagnostic Studies == | ||
| Line 53: | Line 53: | ||
== Medical Therapy == | == Medical Therapy == | ||
There is no medical treatment for arachnoid cysts. Some medications may be used for treating its symptoms, such as analgesics for headache, sleep aids for insomnia and other medications for the dizziness/nausea. | There is no medical treatment for arachnoid cysts. Some medications may be used for treating its [[symptoms]], such as [[analgesics]] for [[headache]], [[sleep aids]] for [[insomnia]] and other medications for the [[dizziness]]/[[nausea]]. | ||
== Surgery == | == Surgery == | ||
There are a number of approaches in treating arachnoid cysts, the most common are: | There are a number of approaches in treating arachnoid cysts, the most common are: | ||
* Endoscopic fenestration and removal of the cyst wall (advances in neurosurgical techniques favor fenestration over shunt insertion as the preferred method for initial management). | *[[Endoscopic]] [[Fenestrations|fenestration]] and removal of the cyst wall (advances in neurosurgical techniques favor fenestration over [[shunt]] insertion as the preferred method for initial management). | ||
* Microsurgical fenestration; | * Microsurgical fenestration; | ||
* Craniotomy followed by shunting. | *[[Craniotomy]] followed by [[shunting]]. | ||
== Cost-effectivenes of Therapy == | == Cost-effectivenes of Therapy == | ||
Most patients won't demand treatment. The very few who do must be assessed regarding cyst size, location and symptoms. If symptomatic, it may be a significant cause of morbidity and the costs of neurosurgical procedures, which are mostly safe and effective, may be high. | Most patients won't demand treatment. The very few who do must be assessed regarding cyst size, location and symptoms. If symptomatic, it may be a significant cause of morbidity and the costs of [[neurosurgical]] procedures, which are mostly safe and effective, may be high. | ||
== Investigational Therapies == | == Investigational Therapies == | ||
Advances in neurosurgical techniques continue to improve the safeness and efficacy of the neurosurgical procedures in treating arachnoid cysts. | Advances in [[neurosurgical]] techniques continue to improve the safeness and efficacy of the [[neurosurgical]] procedures in treating arachnoid cysts. | ||
==References== | ==References== | ||
Revision as of 01:29, 30 June 2020
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Overview
Arachnoid cysts are cerebrospinal fluid cysts covered by arachnoidal cells and collagen. They develop between the arachnoid membrane and the surface of the brain. Arachnoid cysts are mostly a congenital disorder.
Classification
Arachnoid cysts may be classified according to cause into 2 subtypes/groups: primary or secondary, or according to symptoms into 3 groups.
Causes
The exact cause of arachnoid cysts is not known. Researchers believe that most cases of arachnoid cysts are developmental malformations that arise from the unexplained splitting or tearing of the arachnoid membrane, being classified as primary. There are also arachnoid cysts that arise from secondary causes, such as trauma, surgery, intracranial hemorrhage and infection.
Epidemiology
Arachnoid cysts occur in about 1.2% of the general population and are more frequently seen in men than in women.
Natural History, Complications and Prognosis
Prognosis of arachnoid cyst is generally excellent and is usually associated with a benign disease course, despite being symptomatic in a few patients. Most are found incidentally, and a few may, rarely, enlarge and complicate with the symptoms previously described such as hydrocephalus, seizures, hearing loss, visual changes and cervical myelopathy.
History and Symptoms
Patients with arachnoid cysts will most likely never show symptoms, even in cases where the cyst is large. Therefore, while the presence of symptoms may provoke further clinical investigation. Symptoms independent of further data cannot, and should not be, interpreted as evidence of a cyst's existence, size or location. These symptoms usually are:
- Headache;
- Nausea/Vomiting;
- Seizures;
- Skull/spine deformation;
- Developmental delays;
- Obstructive hydrocephalus;
- Hearing loss;
- Head bobbing;
- Visual changes.
Physical Examination
Physical examination is generally not very useful as most cases of arachnoid cysts are diagnosed incidentally, but in larger cysts, depending of the affected region, there may be some findings such as:
- Ataxia;
- Hearing loss;
- Visual changes;
- Protrusions from the head or spine;
- Head bobbing;
- Endocrine issues, e.g. early onset of puberty.
CT
On brain/spine CT scan, arachnoid cysts are characterized by cystic images with similar density to CSF and non-enhancing borders, mostly found in the middle cranial fossa while they only rarely occur in the spinal cord.
MRI
On brain/spine MRI, arachnoid cysts are characterized by cystic images with similar density to CSF and non-enhancing borders, mostly found in the middle cranial fossa while they only rarely occur in the spinal cord. MRIs are more adequate than CT scans for evaluating arachnoid cysts.
Other Diagnostic Studies
There are no other imaging findings associated with arachnoid cysts.
Medical Therapy
There is no medical treatment for arachnoid cysts. Some medications may be used for treating its symptoms, such as analgesics for headache, sleep aids for insomnia and other medications for the dizziness/nausea.
Surgery
There are a number of approaches in treating arachnoid cysts, the most common are:
- Endoscopic fenestration and removal of the cyst wall (advances in neurosurgical techniques favor fenestration over shunt insertion as the preferred method for initial management).
- Microsurgical fenestration;
- Craniotomy followed by shunting.
Cost-effectivenes of Therapy
Most patients won't demand treatment. The very few who do must be assessed regarding cyst size, location and symptoms. If symptomatic, it may be a significant cause of morbidity and the costs of neurosurgical procedures, which are mostly safe and effective, may be high.
Investigational Therapies
Advances in neurosurgical techniques continue to improve the safeness and efficacy of the neurosurgical procedures in treating arachnoid cysts.