Add comprehensive articles on Vascular Dementia and Wallerian Degeneration
- Created a detailed article for Vascular Dementia covering key facts, terminology, imaging findings, differential diagnoses, pathology, clinical issues, and diagnostic checklist. - Developed an extensive article on Wallerian Degeneration including key facts, terminology, imaging features, differential diagnoses, pathology, clinical issues, and diagnostic checklist.
This commit is contained in:
Ross
@@ -0,0 +1,132 @@
|
||||
---
|
||||
title: "Epilepsy, Child"
|
||||
docid: "a342e5b5-5b98-4003-a437-6d42a483b40e"
|
||||
breadcrumbs:
|
||||
- "Brain"
|
||||
- "Differential Diagnosis"
|
||||
- "Brain Parenchyma, General"
|
||||
- "Clinically Based Differentials"
|
||||
- "Epilepsy, Child"
|
||||
---
|
||||
# ESSENTIAL INFORMATION
|
||||
|
||||
- ## Key Differential Diagnosis Issues
|
||||
|
||||
|
||||
- Generalized seizure disorders usually nonlocalizing
|
||||
- Partial complex (focal) epilepsy usually due to focal structural abnormality [i.e., focal cortical dysplasia (FCD)]
|
||||
- Correlate with EEG results
|
||||
- High-resolution & 3T MR helpful for subtle lesions
|
||||
- 1-mm isotropic T1 for gray matter evaluation
|
||||
- 3D FLAIR imaging helpful for identifying FCD
|
||||
- PET & SPECT are often complimentary to MR in identifying seizure focus prior to surgical intervention
|
||||
- PET: Decreased interictal metabolism in seizure focus
|
||||
- SPECT: Increased ictal blood flow in seizure focus
|
||||
- ## Helpful Clues for Common Diagnoses
|
||||
|
||||
|
||||
- **Idiopathic Epilepsy**
|
||||
- No structural cause found on MR
|
||||
- Generalized: May be inherited
|
||||
- Partial: Partial motor seizures, may resolve by puberty
|
||||
- **Acquired Causes**
|
||||
- Febrile seizure: Most common cause of seizure in children < 5 years
|
||||
- Simple febrile seizure < 15 minutes without recurrence does not require imaging
|
||||
- Trauma, remote stroke, or infection results in encephalomalacia &/or gliosis, which may cause epilepsy
|
||||
- Benign & malignant tumors
|
||||
- Toxic, metabolic, & drug abuse
|
||||
- **Vascular Malformation**: Arteriovenous & cavernous malformations with hemorrhage
|
||||
- **Mesial Temporal Sclerosis**
|
||||
- Most common cause of intractable temporal lobe epilepsy in adults
|
||||
- 2-hit hypothesis suggests initial injury with inherent vulnerability to neuronal injury
|
||||
- Hippocampal atrophy & gliosis
|
||||
- May see ipsilateral mammillary body & forniceal atrophy
|
||||
- Look for associated FCD, especially in the ipsilateral temporal lobe (FCD type IIIa)
|
||||
- **Migrational Anomalies**
|
||||
- **Focal cortical dysplasia**
|
||||
- Newest classification Blumcke et al 2011
|
||||
- Type I: Mild blurring of gray-white junction with mild increased T2 signal of subcortical white matter
|
||||
- More common in temporal lobes, difficult to detect
|
||||
- Type II: Moderate blurring of gray-white junction & increased T2 signal of subcortical white matter
|
||||
- Typically frontal lobes
|
||||
- Type IIb includes more dysmorphia & balloon cells: Highly associated with transmantle sign & easier to detect on MR
|
||||
- Transmantle sign: T2-hyperintense comet tail from ventricle to cortex; best seen on FLAIR
|
||||
- Type III: Associated with another lesion: Mesial temporal sclerosis, tumor, vascular malformation, acquired injury
|
||||
- **Polymicrogyria**
|
||||
- Small, pebbly, cobblestone, or micronodular-appearing gyri
|
||||
- Common migrational malformation with heterogeneous causes
|
||||
- TORCH infection (particularly CMV) is common cause of polymicrogyria & seizures
|
||||
- Diffuse or bilateral polymicrogyria more likely genetic/syndromic
|
||||
- **Heterotopic gray matter**
|
||||
- Gray matter nodules within deep white matter follow gray matter signal on all MR sequences
|
||||
- Subependymal most common location
|
||||
- Can be found incidentally in patients without seizures
|
||||
- Diffuse subependymal heterotopia is X-linked
|
||||
- **Schizencephaly**
|
||||
- Cleft extending from cortical surface to ventricular ependyma, gray matter lined
|
||||
- Outpouching or "dimpling" of lateral ventricular contour "points" to cleft
|
||||
- May be unilateral or bilateral
|
||||
- Open lipped: CSF in cleft; commonly bilateral
|
||||
- Closed lipped: No CSF with apposed walls, usually unilateral
|
||||
- **Septo-Optic Dysplasia Plus Syndrome**
|
||||
- Septum pellucidum absence + optic nerve hypoplasia ± pituitary dysfunction
|
||||
- When SOD is associated with schizencephaly &/or polymicrogyria, it is referred to as SOD Plus
|
||||
- **Tuberous Sclerosis Complex**
|
||||
- Burden of cortical dysplasias (i.e., tubers) correlates with seizure burden
|
||||
- T2-hyperintense cortical/subcortical tubers: Similar imaging to type IIb FCD
|
||||
- Cortical tubers also similar in histology to FCD type IIb with balloon cells
|
||||
- Subependymal nodules can enhance & calcify
|
||||
- 10-15% develop subependymal giant cell astrocytoma at foramen of Monro
|
||||
- ## Helpful Clues for Less Common Diagnoses
|
||||
|
||||
|
||||
- **Cortically Based Glioneuronal Tumors**
|
||||
- Associated cortical dysplasia with tumor common (type IIIb)
|
||||
- **Ganglioglioma**
|
||||
- Most common cause of tumor-associated temporal lobe epilepsy
|
||||
- Cystic/solid cortically based mass
|
||||
- Ca⁺⁺ (~ 50%); enhancement (~ 50%)
|
||||
- Temporal lobe most common site
|
||||
- **Dysembryoplastic neuroepithelial tumor**
|
||||
- Discrete T2-hyperintense "bubbly" cortical mass
|
||||
- Medial temporal lobe most common
|
||||
- Enhancement may occur (~ 10%) but is less common than ganglioglioma
|
||||
- **Holoprosencephaly**
|
||||
- Spectrum of failure of cleavage of midline cerebral hemispheres & telencephalon from diencephalon
|
||||
- Monoventricle due to absence of septum pellucidum
|
||||
- Complete to partial absence of other midline structures: Falx & corpus callosum
|
||||
- Fusion of fornices, thalami, & basal ganglia
|
||||
- Incomplete separation of frontal lobes
|
||||
- More severe cases may include large dorsal cyst
|
||||
- **Hemimegalencephaly**
|
||||
- Unilateral hemispheric overgrowth
|
||||
- Dysplastic enlarged ipsilateral ventricle
|
||||
- Associated with genetic/syndromic diseases
|
||||
- **Sturge****-****Weber Syndrome**
|
||||
- Unilateral trigeminal (V1 & V2) distribution facial port-wine stain
|
||||
- Ipsilateral malformation of cortical & pial veins = leptomeningeal enhancement
|
||||
- Ipsilateral enlarged choroid plexus, hemiatrophy late finding
|
||||
- Gyriform Ca⁺⁺ increases over time
|
||||
- **Status Epilepticus**
|
||||
- Seizure > 5 minutes or > 1 seizure within 5-minute period
|
||||
- Higher likelihood for irreversible brain damage
|
||||
- 1/2 are associated with known history of epilepsy
|
||||
- Increased T2 signal of predominantly cortex with swelling & possible decreased diffusion
|
||||
- ## Helpful Clues for Rare Diagnoses
|
||||
|
||||
|
||||
- **Lissencephaly Type 1: Subcortical Band Heterotopia**
|
||||
- "Smooth" brain lacking normal gyri; thick cortex
|
||||
- Can see subcortical smooth gray matter band in many cases
|
||||
- LIS1: Posterior predilection of lissencephaly
|
||||
- DCX (double cortex): X-linked
|
||||
- Females: Primarily diffuse band heterotopia
|
||||
- Males: Diffuse lissencephaly, more severe phenotype
|
||||
- **Lissencephaly Type 2**
|
||||
- Congenital muscular dystrophy: Walker-Warburg, Fukuyama, & muscle-eye-brain
|
||||
- Diffuse polymicrogyria (cobblestone lissencephaly) particularly frontal lobes & sylvian fissures
|
||||
- Cerebellar polymicrogyria, cysts, vermian hypoplasia, hypomyelination, & eye abnormalities can be seen
|
||||
- **Rasmussen Encephalitis**
|
||||
- Likely autoimmune inflammation of unilateral cerebral hemisphere
|
||||
- Typically at least mesial temporal lobe & insula affected
|
||||
- Hemiatrophy late
|
||||
Reference in New Issue
Block a user