Early myoclonic encephalopathy: Difference between revisions
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{{SI}} | |||
{{CMG}} ; | {{CMG}}; {{AE}} {{ADI}} | ||
{{SK}} | {{SK}} Neonatal myoclonic encephalopathy; infantile myclonic encephalopathy | ||
==Overview== | ==Overview== | ||
Early myoclonic encephalopathy | Early myoclonic encephalopathy is a seizure disorder that occurs in the [[neonatal]] period. This disorder presents with features such as partial or fragmentary erratic myoclonic [[seizure]]s, massive [[myoclonus]], partial motor seizures (jerking movements of one side), and tonic seizures. | ||
== | ==Classification== | ||
According to the International Classification of Epilepsies and Epileptic Syndromes, early myoclonic encephalopathy can be categorized as age related, and as generalized symptomatic epilepsy of a non specific etiology.<ref name="urlwww.ilae.org">{{cite web |url=http://www.ilae.org/visitors/Documents/21-appendix.pdf |title=www.ilae.org |format= |work= |accessdate=}}</ref> | |||
The two variants of early infantile epileptic encephalopathy are: | |||
* Early myoclonic encephalopathy | |||
* [[Ohtahara syndrome]] | |||
==Pathophysiology== | ==Pathophysiology== | ||
=== Genetics === | === Genetics === | ||
* In most cases the disease appears to be inherited | * In most cases, the disease appears to be inherited in an [[autosomal recessive]] fashion. | ||
===Associated Conditions=== | ===Associated Conditions=== | ||
* [[Non-ketotic | * [[Non-ketotic hyperglycinemia]] | ||
* [[D-glycemic acidemia]] | * [[D-glycemic acidemia]] | ||
* [[Methylmalonic acidemia]] | * [[Methylmalonic acidemia]] | ||
| Line 42: | Line 44: | ||
==Causes== | ==Causes== | ||
The cause of early myoclonic encephalopathy is unknown. | |||
==Differentiating Early myoclonic encephalopathy from other Diseases== | ==Differentiating Early myoclonic encephalopathy from other Diseases== | ||
Early myoclonic encephalopathy has to be differentiated from few other epilepsy syndromes due to similar | Early myoclonic encephalopathy has to be differentiated from a few other epilepsy syndromes due to similar presentation. | ||
These similar epileptic syndromes include: | |||
* [[Ohtahara syndrome]] | * [[Ohtahara syndrome]] | ||
* [[West syndrome]] | * [[West syndrome]] | ||
| Line 85: | Line 89: | ||
== Epidemiology and Demographics == | == Epidemiology and Demographics == | ||
Early myoclonic encephalopathy(EME) is a rare disease with only around 30 cases described so far. | Early myoclonic encephalopathy (EME) is a rare disease with only around 30 cases described so far. | ||
== Risk Factors == | == Risk Factors == | ||
Risk factors include: | |||
* Structural [[brain lesion]] | |||
* Metabolic disturbances | |||
* [[Small for gestational age]] | |||
* [[Sepsis]] | |||
* [[Bleeding into brain]]([[cerebral hemorrhage]]) | |||
== Screening == | == Screening == | ||
* There is no screening procedure set forth for detecting early myoclonic encephalopathy. | |||
* Every child with a presentation of [[seizure]] (partial or complete) must undergo an [[EEG]] evaluation. | |||
== Natural History, Complications, and Prognosis== | == Natural History, Complications, and Prognosis== | ||
===Natural History=== | |||
Symptoms may occur as early as a few hours after birth, and postnatal movements are sometimes reported by the mother to be of the same type as those felt at the end of pregnancy. Other types of [[seizures]], including partial seizures, massive myoclonia, and tonic spasms can also occur; usually around 3-4 months of age. | |||
===Complications=== | |||
* Severe neurological impairment | |||
* Mental retardation | |||
* Vegetative state | |||
===Prognosis=== | |||
The prognosis for early myoclonic encephalopathy is poor. Children survive in a persistent vegetative state or die within the first or second year of life. | |||
== Diagnosis == | == Diagnosis == | ||
=== Symptoms === | === Symptoms === | ||
* Recurrent seizures | |||
* Developmental delay | |||
===Family History=== | |||
* There is a high risk of familial recurrence since in most cases the disease appears to be inherited as an [[autosomal recessive#Autosomal recessive gene|autosomal recessive]] trait. | |||
* Consanguineous marriage of parents. | |||
=== | ===Birth History=== | ||
* | * History of complicated birth may be noticed | ||
* Post natal erratic movements | |||
* Poor sucking and swallowing | |||
=== Physical Examination === | === Physical Examination === | ||
==== Appearance of the Patient ==== | ==== Appearance of the Patient ==== | ||
* Floppy due to [[hypotonia]] | |||
==== Neurologic ==== | ==== Neurologic ==== | ||
* Erratic [[myoclonus]] of face or extremities | |||
* [[Seizures]] | |||
* Severe developmental delay | |||
* Altered mental status | |||
=== Laboratory Findings === | === Laboratory Findings === | ||
==== Biomarker Studies ==== | ==== Biomarker Studies ==== | ||
* [[Acidosis]] may be noticed if any metabolic derangements coexist. | |||
* Biochemical tests of [[calcium]], [[magnesium]] and [[glucose]] are needed to evaluate the cause of seizures. | |||
* High [[glycine]] levels may be detected if associated with [[Non-ketotic hyperglycinemia]] | |||
====CT ==== | ====CT and MRI==== | ||
* Identifying any structural brain lesions (malformations, tumors, bleeds) | |||
==== | ====Electroencephalogram (EEG)==== | ||
Characteristic features on the EEG include: | |||
* Suppression bursts | |||
** More apparent during sleep | |||
* Repetitive EEG recordings are necessary for the diagnosis of early myoclonic encephalopathy.<ref name="pmid16010070">{{cite journal |author=Ozyürek H, Turanli G, Aliefendioglu D, Coskun T |title=Repetitive EEG recordings are necessary for the diagnosis of early myoclonic encephalopathy |journal=Neurol India |volume=53 |issue=2 |pages=235–7 |year=2005 |month=June |pmid=16010070 |doi= |url=}}</ref> | |||
== Treatment == | == Treatment == | ||
=== Pharmacotherapy === | === Pharmacotherapy === | ||
* There are no clear guidelines for the treatment of seizures. | |||
* Conventional drugs like [[valproate]] , [[clobazam]] , and [[lamotrigine]] are ineffective. | |||
* Alternative therapies like [[ACTH]], a ketogenic diet, and [[zonisamide]] are beneficial for the treatment of [[Ohtahara syndrome]] | |||
* In patients with [[Non-ketotic hyperglycinemia]], oral administration of [[ketamine]], [[tryptophan]], and [[dextromethorphan]] in combination with [[benzoate]] have brought partial improvement in symptoms and EEG findings. | |||
====Genetic Counseling==== | ====Genetic Counseling==== | ||
* Genetic counseling may aid in the early diagnosis and prevention of EME to certain extent. | |||
==References== | ==References== | ||
Latest revision as of 13:44, 13 August 2012
| Early myoclonic encephalopathy | |
| ICD-10 | G 40.3 |
|---|---|
| MeSH | D004831 |
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Aditya Govindavarjhulla, M.B.B.S. [2]
Synonyms and keywords: Neonatal myoclonic encephalopathy; infantile myclonic encephalopathy
Overview
Early myoclonic encephalopathy is a seizure disorder that occurs in the neonatal period. This disorder presents with features such as partial or fragmentary erratic myoclonic seizures, massive myoclonus, partial motor seizures (jerking movements of one side), and tonic seizures.
Classification
According to the International Classification of Epilepsies and Epileptic Syndromes, early myoclonic encephalopathy can be categorized as age related, and as generalized symptomatic epilepsy of a non specific etiology.[1]
The two variants of early infantile epileptic encephalopathy are:
- Early myoclonic encephalopathy
- Ohtahara syndrome
Pathophysiology
Genetics
- In most cases, the disease appears to be inherited in an autosomal recessive fashion.
Associated Conditions
- Non-ketotic hyperglycinemia
- D-glycemic acidemia
- Methylmalonic acidemia
- Propionic acidemia
- Hyperammonemia due to carbamyl phosphate synthetase deficiency
Causes
The cause of early myoclonic encephalopathy is unknown.
Differentiating Early myoclonic encephalopathy from other Diseases
Early myoclonic encephalopathy has to be differentiated from a few other epilepsy syndromes due to similar presentation.
These similar epileptic syndromes include:
Differentiating features are:
| Features/Disease | Early myoclonic encephalopathy | West syndrome | Lennox-Gastaut syndrome |
| Age at presentation | Early infancy | Infancy | Early childhood |
| Diverse seizures | May or may not be present | Not present | Present |
| Tonic spasms | May or may not be present | Present | Not present |
| Response to ACTH [2] | Poor | Good | Poor |
| Interictal EEG | Suppression bursts | Hypsarrhythmia | Diffuse slow spike wave |
Differentiating Early myoclonic encephalopathy from Ohtahara syndrome:[3]
| Features/Disease | Early myoclonic encephalopathy | West syndrome |
| Etiology | Non structural or metabolic | Structural brain lesions |
| Clinical | Myoclonia and partial seizures | Tonic spasms |
| Suppression bursts(SB) | More apparent in sleep | Consistently seen in wakeful and sleep states |
| Course | SB's persist to childhood with transient transformation to hypsarrhythmia | Evolve to hypsarrhythmia and then to diffuse slow spike waves |
| Transformation | Persists for long period | Evolves to West syndrome and then to Lennox-Gastaut syndrome |
Epidemiology and Demographics
Early myoclonic encephalopathy (EME) is a rare disease with only around 30 cases described so far.
Risk Factors
Risk factors include:
- Structural brain lesion
- Metabolic disturbances
- Small for gestational age
- Sepsis
- Bleeding into brain(cerebral hemorrhage)
Screening
- There is no screening procedure set forth for detecting early myoclonic encephalopathy.
- Every child with a presentation of seizure (partial or complete) must undergo an EEG evaluation.
Natural History, Complications, and Prognosis
Natural History
Symptoms may occur as early as a few hours after birth, and postnatal movements are sometimes reported by the mother to be of the same type as those felt at the end of pregnancy. Other types of seizures, including partial seizures, massive myoclonia, and tonic spasms can also occur; usually around 3-4 months of age.
Complications
- Severe neurological impairment
- Mental retardation
- Vegetative state
Prognosis
The prognosis for early myoclonic encephalopathy is poor. Children survive in a persistent vegetative state or die within the first or second year of life.
Diagnosis
Symptoms
- Recurrent seizures
- Developmental delay
Family History
- There is a high risk of familial recurrence since in most cases the disease appears to be inherited as an autosomal recessive trait.
- Consanguineous marriage of parents.
Birth History
- History of complicated birth may be noticed
- Post natal erratic movements
- Poor sucking and swallowing
Physical Examination
Appearance of the Patient
- Floppy due to hypotonia
Neurologic
Laboratory Findings
Biomarker Studies
- Acidosis may be noticed if any metabolic derangements coexist.
- Biochemical tests of calcium, magnesium and glucose are needed to evaluate the cause of seizures.
- High glycine levels may be detected if associated with Non-ketotic hyperglycinemia
CT and MRI
- Identifying any structural brain lesions (malformations, tumors, bleeds)
Electroencephalogram (EEG)
Characteristic features on the EEG include:
- Suppression bursts
- More apparent during sleep
- Repetitive EEG recordings are necessary for the diagnosis of early myoclonic encephalopathy.[4]
Treatment
Pharmacotherapy
- There are no clear guidelines for the treatment of seizures.
- Conventional drugs like valproate , clobazam , and lamotrigine are ineffective.
- Alternative therapies like ACTH, a ketogenic diet, and zonisamide are beneficial for the treatment of Ohtahara syndrome
- In patients with Non-ketotic hyperglycinemia, oral administration of ketamine, tryptophan, and dextromethorphan in combination with benzoate have brought partial improvement in symptoms and EEG findings.
Genetic Counseling
- Genetic counseling may aid in the early diagnosis and prevention of EME to certain extent.
References
- ↑ "www.ilae.org" (PDF).
- ↑ Perheentupa J, Riikonen R, Dunkel L, Simell O (1986). "Adrenocortical hyporesponsiveness after treatment with ACTH of infantile spasms". Arch. Dis. Child. 61 (8): 750–3. PMC 1777931. PMID 3017239. Unknown parameter
|month=ignored (help) - ↑ Ohtahara S, Yamatogi Y (2006). "Ohtahara syndrome: with special reference to its developmental aspects for differentiating from early myoclonic encephalopathy". Epilepsy Res. 70 Suppl 1: S58–67. doi:10.1016/j.eplepsyres.2005.11.021. PMID 16829045. Unknown parameter
|month=ignored (help) - ↑ Ozyürek H, Turanli G, Aliefendioglu D, Coskun T (2005). "Repetitive EEG recordings are necessary for the diagnosis of early myoclonic encephalopathy". Neurol India. 53 (2): 235–7. PMID 16010070. Unknown parameter
|month=ignored (help)