Child neurology Flashcards
When does neurolation (formation of neural tube) occur
3-6 weeks’ gestation
What arises from:
Mesencephalon
Prosencephalon
Rhombencephalon
(in abc order here)
Rhombencephalon:
Medulla
Pons
Cerebellum
Mesencephalon:
Midbrain
Prosencephalon:
Diencephalon: thalamus and hypothalamus (and STN)
Telencephalon: Cerebral hemispheres including basal ganglia (also olfactory bulb)
(in low to high order here)
How does galactosemia present?
In addition to checking the enzyme directly, what is a lab finding?
Treatment?
Vomiting, diarrhea, and jaundice in first days of life, with lethargy and hypotonia (can lead to neurologica sequelae includin developmental delay, tremor, ataxia)
Reducing substances in urine
Dietary restriction of galactose and lactose
How does pyruvate dehydrogenase (PDH) deficiency present?
In addition to checking the enzyme directly, what is a lab finding?
Treatment?
Variable.
Severe forms with severe lactic acidosis and neonatal death.
Milder form with episodes of ataxia, lethargy, and weakness.
Lab: lactic acidosis with low lactate:pyruvate ratio
Treatment: ketogenic diet and supplementation (thiamine and potentially carnitine, CoQ10, biotin)
What are two possible mechanisms of HTN in NF1
Renal artery dysplasia
Pheochromocytoma
How does GLUT-1 deficiency present?
What is a lab finding?
Gene and inheritence?
Treatment?
Can be:
Severe: severe epilepsy, developmental delay, involuntary movements
Milder: later-onset with episodic involuntary movements
Lab: hypoglycorrhachia (low CSF glucose)
Gene is SLC2A1, autosomal dominant
Treatment: ketogenic diet
PKU:
Clinical presentation
Enzyme deficiency. What accumulates?
Treatment
Normal at birth but later developmental delay, cognitive impairment, seizures, hypotonia. Fair skin and eyes due to decreased melanin
Phenylalanine hydroxylase (converts phenylalanine to tyrosine). Phenylalanine accumulates, as does phenylacetic acid (musty odor)
Treatment: low-protein diet and phenylalanine-free formula (can add tetrahydrobioperin, a cofactor fro phenylalanine hydroxylase)
Maple syrup urine disease
Clinical presentation
Enzyme deficiency. What accumulates?
Treatment
Classic: 2-3 days of live with opisthonus and progressive encephalopathy
Intermediate: developmental delay, FTT, ataxia, and sz in late infancy
Intermittent: AMS and ataxia with sressors, normal between
Enzyme: Branched-chain alpha-ketoacid deydrogenase complex.
Branched amino acids and their ketacids accumulate: leucine, isoleucine, and valine
Treatment: low-protein diet with branched-chain amino acid restrictions, and thiamine.
(Liver transplant can be performed in some cases)
Facial angiofibromas
Tuberous sclerosis
Ash leaf spots
Tuberous sclerosis
Brain tumors associated with tuberous sclerosis
- Cortical tubers
- Giant cell astrocytoma (can lead to obstructive hydrocephalus)
- Subependymal nodules (in ventricle walls)
Genetic cause of tuberous sclerosis
AD, mutations in hamartin (type 1) or tuberin (type 2)
Tumors in tuberous sclerosis outside the CNS
Cardiac rhabdosarcomas (common, usually seen in infancy and most but not always regress)
Renal angiomyolipimas (common)
RCC (relatively rare, 2-3%)
Ungual fibromas
Tuberous sclerosis
Presentation of proprionic aciemia
Cause
Treatment
Normal at birth, later present with hypotonia and difficulty feeding with attacks of metabolic acidosis with ketosis and hyperammonemia, potentially with seizures and coma. Also risk of bleeding including IPH
(On newborn screen)
AR, mutation in proprionyl-CoaA carboxylase
Treat with low protein diet and carnitine and biotin supplementation (cofacros)
Lesch-Nyhan:
Presentation
Genetic cause
Lab abnormality
Treatment
Variable severity, can include spasticity, dystonia, seizure, intellectual impairment. Aggressive behavior and self mutilation are hallmarks. Kidney stones from uric acid can occur.
X-linked recessive, HPRT1 gene, hypoxanthine guanine phosphoribosyltransferase (purine salvage pathway)
Lab: elevated uric acid (purine metabolite)
Treat: Purine restriction, allopurinole (decrease uric acid), hydration
Aggressive behavior and self-injurious behavior
Lesch-Nyhan
AEDs particularly associated with neural tube defects
- VPA
- Carbamazepine
Niemenn-Pick types
Type A: CNS involvement (feeding difficulty, hypotonia, psychomotor regression, cherry red macula) as well as visceral (hepatosplenomegaly)
Type B: purely visceral (hepatosplenomegaly and ILD)
Type C: CNS involvement (ataxia, oculomotor abnormalities, spasticity, seiuzures), as well as hepatosplenomegaly.
Type A and B are sphingomyelinase deficiency, lysosomal storage disease
Type C is due to defect in intracellular cholesterol circulation
Metabolic diseases associated with cherry-red macula
- Tay-Sachs (GM2 gangliosidosis type 1, hexosaminidase A deficiency)
- GM2 gangliosidosis type 2 or Sandhoff disease (beta-hexosaminidases A and B deficiency, similar to Tay-Sachs)
- Niemann-Pick disease (sphingomyelinase deficiency in A and B)
- GM1 gangliosidosis type 1 (Acid Beta Galactosidase deficiency)
- Sialidosis or mucolipidosis type 1 (alpha-neuraminidase deficiency)
- Farber disease (Ceramidase deficiency)
- Metachromatic leukodystrophy (arylsulfatase A deficiency)
- Galactosialidosis (neuraminidase deficiency with beta-galactosidase deficiency)
Niemann-Pick type A and B: deficiency
Sphingomyelinase
What is elevated in amniotic fluid in neural tube defects?
- AFP
- Acetylcholinesterase
Periventricular and subcortical white matter changes sparing U fibers
Genetic cause?
Metachromatic leukodystrophy (AR, arylsulfatase A deficiency)
Chiari I and Chiari II malformations
Chiari I: cerbellar tonxils through the foramen magnum, may be asymptomatic or symptomatic (headaches, ataxia, brainstem symptoms)
Chiari II: displacement of cerebellar vermis and tonsils associated with myelomeningocele, leads to brainstem function and hydrocpehaly
(Chiari III is cerebellar herniation into a cervical or occipital encephalocele)
Sialidosis
Presentation
Cause
Lab test other than enzyme deficiency
Type 1: Cherry-red spot myoclonus syndrome. Adolescent onset with myoclonic epilepsy and vision loss
Type 2: childhood onset, above plus severe neurological abnormalities and psychomotor retadation
Cause: alpha-N-acetyl neuraminidase (sialidase) deficiency (a glycoproteinosis lysosomal storage disease)
Lab test: urinary excretion of oligosaccharides and glycopeptides
Cherry-red spot and myoclonic seizures
Sialidosis
( alpha-N-acetyl neuraminidase (sialidase) deficiency (a glycoproteinosis lysosomal storage disease))
Molar tooth sign on imaging, classic association
Abnormal cerebellar peduncles and enlarged 4th ventricle, appearance of molar tooth.
Classically associated with Joubert’s syndrome (developmental delay, ataxia and EOM abnormalities, respiratory difficultyies)
(AR genetic disease due to many genes with cerebellar malformation)
Small fiber neuropathy, angiokeratomas, cardiac and renal disease, potentially stroke due to vascular ectasia
Gene?
Fabry disease
X-linked, alpha-galactosidase deficiency, accumulation of ceramide trihxeoside
AR disorders with progressive psychomotor retardation, seizures, and blindness, with accumulation of either saposins A and D or subunit C of ATP synthase
What accumulates?
Neuronal ceroid lipofuscinosis
Saponins A and D accumulate in infantile forms
Subunit C of ATP synthase accumulates in other forms
Genetically and clinically heterogenous, all AR
Leukodystrophy syndrome with dysmorphic features, cataracts, retinal dystrophy, SNHL, hypotonia, intellectual imairment, and seizures, potentially with polymicrogyria associated with liver and kidney failure and chondrodysplasia punctata with bony stippling of the patella.
Genetic cause
What accumulates
Zellweger’s syndrome
AR, multiple genes involved in peroxisome assembly which are all PEX genes
Peroxisomal storage disease, elevation of VLCFA
(Other peroxisomal storage disease are neonatal adrenoleukodystrohy and infantile Refsum’s disease)
Severe photosensitivity of skin as well as CNS manifestations including seizures and intellectual disability
Genetic cause
Xeroderma pigmentosa
AR, can be multiple genes involved in nucleotide excision repair
Cerebral AVMs, pulmonary AVMs, and telangiectasias in skin, mucus membranes, retina, and GI tract.
Genetic cause
Hereditary hemorrhagic telengiectasia (aka Osler-Weber-Rendu syndrome)
AD, mutation in HHT1 or HHD2
Malformations with hypoplastic or abent septum pellucidum, optic nerve/chiasm hypoplasia, dysgenesis of corpus callosum and anterior commisure, and fornix detachmen from corpus callosum
Septo-optic dysplasia
(Can have vision loss, endocrine dysturbances, ataxia, and sometimes hydrocephalus)
Leukodystrophies that may enhance on MRI
X-linked adrenoleukodystorphy (rim of enhancement, spares U fibers)
Alexander disease (front-to-brack progression, early U fiber sparing but later involvement)
Abnormal labs in adrenoleukocystrophy
- Increased VLCFA
- Elevated ACTH (due to adrenal insufficiency)
Progressive external ophthalmoplegia with onset before age 20, plus one of short stature pigmentary retinopathy, cerebellar ataxia, heart block, or increased CSF protiein
Genetic cause
Kerns-Sayre syndrome
Mitochondrial deletion (or less commonly duplication)
Multisystem disease including CNS and PNS malformations associated with lipodystrophy with prominent fat pads in buttocks and suprapubic area as well as inverted nipples
Genetic cause
Lab finding
Congenital disorders of glycans (CDG), type 1a
AR, due to abnormal glycan synthesis
(There are a variety of other CDGs, related to synthesis (type I) or processing (type II) of glycans)
CSF: presence of carbohydrate deficient transferrin in serum and CSF
Abnormalities in what embryonic structure called corpus callosal abormalities?
Over what gestational period does this develop?
Commisural plate
Commisural plate develops in week 5 of gestaion, corpus callosum fully developedby week 17
Mulitiple retinal, cerebellar, and spinal hemangioblastoma, benign hemangiomas and cysts in various body parts, and RCC
Genetic cause
Van Hippel-Lindau disase
AD, VHL gene
Exam finding frequently associated with hemimegalencephaly
Contralateral hemiparesis
Lissencephaly
Gross abnormality?
Microscopic abnormality?
Reduced or absent gyri
4 or fewer cortical cell layers (rather than usual 6)
(Multiple genetic forms)
Neurocutaneous disorder with multiple hypopigmented streaks or patches that may follow skin lines (e.g. V shape in back or linear lines over limbs) associated with intellectual impairment and seizures in many cases
Hypomelanosis of ito (HI)
(Also microphthalmia, cataracts, optic atrophy, retinal detachment)
Various genetic causes
(HypERpigmented streaks/patches along skin lines seen in incontinentia pigmenti)
Neurocutaneous disorder with skin changes initially vesicobullous lesions at birth, then verrucous at 6 weeks, then hyperigmented lesions following skin lines (Blaschko lines), associated in some cases with intellectual impairment, pyramidal tract findings, and ocular abnormalities
Genetic cause
Incontinentia pigmenti
X-linked dominant (so only seen in females - fatal in males), NEMO mutation (NF kappa B pathway)
(HypOpigmented streaks/patches along skin lines seen in hypomelanosis of Ito)
Cafe au lait spots
NF1
Axillary freckling
NF1
Lisch nodule
NF1 (aka iris hamartoma)
What nervous system lesion is part of criteria for NF1?
Optic pathway glioa
CNS tumors seen in NF1
PNS tumors seen in NF1
CNS:
- Optic pathway glioma
- Astrocytoma
PNS:
- Neurofibromas (plexiform and solitary)
- Schwannomas
Cobblestone malformations / type II lissencephaly are seen in…
Dystroglycanopathy congenital muscular dystrophies (Walker-Warburg, Fukuyama muscular dystrophy, muscle-brain-eye disease)
Marfinoid habitus, downward lens dislocation, intellectual disability
Cause
Treatment
Homocystinuria
Cystathionine-beta-synthase deficiency (AR)
Treatment: B6 supplementation, low-protein diet (especially low methionine with cystine supplementation), and potentially betaine (converts homocystein to methionine), folate, and B12.
(Some are B6 responsive, some are not, but treat all)
Levels of plasma homocystein, urine homocystine, and plasma methionine in:
- Homocysinuria (Cystathionine-beta-synthase deficiency)
- Methylene tetrahydrofolate reductase deficiency
- Methionine synthase deficiency
Homocystinuria: Serum homocysteine, plasma homocystein, and methionine all elevated
Others: Homocysteine elevated, but methionine low
Genetic cause of many cases of periventricular nodular heterotopi
FLNA (Filamin A), on x-chromosome
(X-linked dominant seen in females, almost always fatal in males)
Primary cell types in plexiform neurofibromas
Schwann cells and fibroblasts (also mast cells)
Most common cause of urea cycle disorders
Ornithine transcarbamylase (OTC) deficiency, X-linked recessive
(Other urea cycle disorders are autosomal recessive)
- Encephalopathy
- Hyperammonemia
- Respiratory alkalosis
Treatment?
Urea cycle disorders (most common is ornithine transcarbamylase (OTC) deficiency, X-linked recessive, others are AR)
Low-protein diet with low-nitrogen and administration of essential amino acids (including arginine, except in arginase deficiency)
(During acute attacks, treat with sodium benzoate and sodium phenylacetic acid, sometimes dialysis)
Difference between schizencephaly and porencephaly
Schizencephaly: uniformally lines with gray matter
Porencephaly: not line with gray matter, but instead white matter or gliosis
Schizencephaly can be genetic or associated with in utero insults, and is frequencly associated with other malformations (septo-optic dysplasia, gray matter heterotopia, absent septum pallucidum, dygenesis of corpus callosum).
Porencephaly is residual from insult like in utero infarction, generally after
Insults earlier in pregnancy (before gray matter migration completes, before 24 weeks) will be schizencephaly.
Insults later in pregnancy (after gray matter migration) will be porencephaly.
Autism-like syndrome with hand wringing/motor sterotypies and regression and other neurological abnormalities
Cause
Rett’s syndrome
X-linked dominant mutations in MECP2 (methyl CpG binding protein 2)
Subependymal giant cell astrocytomas (SEGA) seen in…
Tuberous sclerosis
Intellectual disability with enlarged testes
Fragile X syndrome
(FMRI1 gene, CGG repeat - Child with Giant Gonads)
What are the two 15q11-q13 microdeletion syndromes?
What causes one or the other to occur
Prader-Willi: paternal inheritance
Angelman syndrome: maternal inheritence
(Different imprinting)
Global delay, short stature, hypogonadism, and hyperphagia
Genetic cause
Prader-Will syndrome
Paternally-inheritent 15q11-q13 microdeletion
(Maternally-inheritent 15q11-q13 microdeletion leads to Angelman’s syndrome)
“Happy puppet” with intellectual disability, epilepsy, and ataxia
Genetic cause
Angelman’s syndrome
Maternally-inheritent 15q11-q13 microdeletion
(Paternally-inheritent 15q11-q13 microdeletion leads to Prader-Willi syndrome)
Intellectual disability with high-pitched cry and abnormal facies (epicanthal folds, wide-spaced eyes, micrognathia)
Genetic cause
Cri-du-chat
Chromosome 5p deletion
Methylmalonic acidemia
Genetic cause
What accumulates
Lab abnormalities
Treatment
AR mutation in methylmalonyl-CoA mutase (most commonly)
Methylmalonic acid, propionic acid, and propionyl-CoA accumulate
Metabolic acidosis, hyperglycinemia, hyperammonemia
Treatment: Protein restiction, parenteral B12, carnitine supplementation.
Multisystem neurological isease associated with alopeceia, and lab with ketoacidosis, hyperammonemia, and organic aciduria
Cause
Treatment
Biotinidase deficiency
AR mutation in biotinidase, which is involved in making biotin
Treat with biotin
Betz cells
Upper motor neuron type, pyramidal cells in layer V of motor cortex
Gaucher disease
Presentation
Cause
Treatment
Type 1: spares CNS early, hepatosplenomegaly, thromocytopenia, but increased risk of parkinson’s.
Type 2: Earlier onset with spasticity, choreathetosis, EOM abnormalities, psychomotor, death by 2-4
Type 3: Like 2 but later onset and more slowly progressive
Glucocerebrosidase defiiency (AR); glucocerebrosides accumulate (lysosomal storage ds)
Treat with enzyme replacement among others
What are the two GM2 gangliosidoses?
What causes each?
What clinically differentiates them?
Tay-Sachs: AR HEXA mutation leading tohexosaminidase A deficiency
Sandhoff’s: AR HEXB mutation leading to hexosaminidase A and B dficiency
Sandhoff’s has visceral involvement (e.g. hepatosplenomegaly), Tay-Sachs does not.
Cherry red macula, exaggerated startle, and psychomotor regression…
with hepatosplenomegaly?
without hepatosplenomegaly?
With hepatosplenomegaly: Sandhoff’s syndrome (AR HEXB mutation, deficiency of hexosaminidase A and B)
(GM1 gangliosidosis is similar presentation)
WithOUT hepatosplenomegaly: Tay-Sachs (AR HEXA mutation, deficiency of hexosaminidase A only so spares viscera)
Subependymal nodules
Tuberous sclerosis
Early childhood global neurological delay including poor vision with megalencephaly, diffuse symmetric white matter T2 hyperintensities with U-fiber involvement.
Cause
Lab finding
Treatment
Canavan’s disease
AR, deficiency of aspartoacylase
N-acetylaspartic acid elevated in urine (also accumulates in brain, can be seen on MR spec)
No treatment other than supportive
Cause of gyral calcifications in Sturge-Weber
Angiomatosis of the leptomeninges and brain
What pattern of port-wine stain suggests higher likelihood of CNS invovlement in Sturge-Weber syndrome
Port-wine stain on face, especially involving V1 region
Somatic mutation in what gene related to Sturge-Weber
GNAQ
Tram-track apperaance of gyral calcifications
Sturge-Weber
Cause of NF1 and NF2
NF1: AD mutation in neurofibromin (chr 17)
NF2: AD muation in MERLIN (chr 22)
Glycine encephalopathy:
Presentation
Genetic cause
Imaging and lab findings
EEG findings
Netbowrns with hypotonia, myoclonic seizures, and respiratory failure requiring intubation; if they surgive, will have profound intellectual disability, spasticity, and intractible epilepsy
Cause: AR mutations in one of 3 proteins in the micochondrial glycine cleavage system (glycine decarboxylase, aminomethyltransferase, rarely GCSH)
MRI: hypoplastic or absent corpus gallosum, gyral malformations, cerebellar hypolasia
Lab: high serum and CSF glycine, with high CSF/serum glycine ratio n( >0.6,normally <0.4)
EEG in acute phase: burst suppression and hypsarrhythmia
Leukodystrophy sparing U fibers with clusters of globoid cells on CNS pathology, and demyelinating neuropathy
Syndrome name
Cause
Accumulation
Krabbe’s disease
AR, galactocerebrocidase deficiency (“galactic crab”)
Galactocerebrosides accumulation in white matter macrophages, which form globoid cells
Eye finding associated with NF2
Posterior subcapsular lenticular opacities
Cherry red macula, regression and seizures, hepatosplenomegaly, with normal hexosaminidase function
Cause
Accumulation
GM1 gangliosidosis
AR, Beta-galactosidase deficiency (GLB1 gene)
(Hexosaminidase is low in Tay-Sachs and Sandhoff’s)
Accumulion: GM1 gangliosides, keratan sulfate, and glycoproteins
“Tadpole sign” due to thinning of upper cervical cor
Adult-onset Alexander’s disease (due to GFAP mutation)
Leukodystrophy associated with eosinophilic Rosenthal fibers on biopsy
Genetic cause?
Alexander’s disease
GFAP mutation (disease of astrocytes)
(Rosenthal fibers are abormal clumps of protein that accumulate in astrocytes)
Leukodystrophy due to astrocyte dysfunction
Alexander disease (GFAP mutation)
Leukodystrophy with prominent nystagmus, ataxia, and pyramidal disease, with “tigroid” pattern of demyelination sparing U fibers
Cause
Pelizaeus-Merzbacher disease
X-linked recessive mutation in PLP1 (proteolipid protein 1)
(Tigroid pattern seen if there is patchy involvement and some islands of white mattern)t
What are two X-linked leukodystrophies?
- X-linked adrenoleukodystrophy
- Pelizaeus-Merzbacher disease (PLP1 mutation “tigroid” appearance to white matter changes on MRI)
Clinical difference between Hunter’s and Hurler’s
Cause of each?
Hurler’s: corneal clouding.
AR due to alpha-L-iduronidase deficiency
Hunter’s: nodular ivory-coloed sin lesions
X-lined recessive due to iduronate sulfatase
What are mucopolysaccharadoses types 1 and 2. What acumulates
Type 1: Hurler’s
Type 2: Hunter’s
Dermatan sulfate and heparan sulface occur in both
Syndrome of skeletal dysplasia with reduced joint ROM, hearing loss, macroglossia, viesceromegaly, and prominent intellectual disability….
- With corneal clouding?
- With nodular ivory-covered skin lesions
- Hurler’s (AR)
- Hunter’s (XLR)
Both are mucopolysaccharidoses with accumulation of dermatan and hearan sulfate
Aminolevulinic acid (ALA) and porphobilinogen (PBG) are elvated in
porphyria - these may only be elevated during attacks
Cause of AIP
Prophobilinogen (PBG) deaminase deficiency,
Autosomal DOMINANT but with incomplete penetrance
Attacks of visceral and neurological symptoms
Porphyria, particularly AIP if normal in between
Seizure medications that appear safe in porphyria
Particularly unsafe:
Safe:
1. Clonazepam
2. Lamotrigine
3. Gabapentin
Particularly unsafe:
1. Barbituates
2. Phenytoin
Peripheral neuropathy and orange tonsils
Cause?
Lab findings?
Tangier disease
AR mutation in ATP casstte transporter protein, ABCA1 gene
Labs: High TG< lowl HDL and cholesterol
CNS manifestasions including seizures, delay, vasculopthy and SDH, associated with brittle hair and hyperelastic skin.
Cause
Menkes disease
Disorder of intracellular copper transport
(Also can lead to skeletal, GI, GU abnormalities)
SDH and fractures raise concern for nonaccidental trauma, but it’s not! It’s…
Menke’s disease
