Pediatric Neurology

Congenital Anomalies of the CNS

• Scope: NTDs, Chiari, Klippel-Feil, migrational defects, hydrocephalus, syringomyelia, CP, etc.

Neural Tube Formation & NTD Risk

• Milestones: neural plate day 19 → groove day 20 → closed tube day 22. 
• Closure sequence: cranial (ant.) neuropore \approx day 26, caudal (post.) neuropore ~ day 28. 
• Incidence: 1/1000 births (0.1 %).
• Screening: maternal serum \alpha-fetoprotein (MSAFP) 16{-}18 wk GA.
• Prevention: folic acid 0.4–0.8 mg/d for all females (start \ge1 mo pre-conception \rightarrow 12 wk GA). High-risk (prior NTD or on ASMs esp. valproate) \rightarrow 4 mg/d. 
• Teratogens: valproate \uparrow NTD 10–20× (0.1 % \rightarrow 1–2 %).

Spina Bifida Spectrum

• Occurs <28 d PC; vertebral defect.
• Types:
– Spina bifida occulta (10 % pop.; closed). 
– Meningocele (rare 1/5{,}000). 
– Myelomeningocele (1–2/1,000). 
• Occulta: skin-covered midline LS–S1 defect. Cutaneous stigmata (hair tuft, lipoma, dimple). Eval ⇒ spine MRI; surgically untether if symptomatic. Monitor neuro-urologic func.
• Meningocele: herniated meninges, cord normal. If intact skin & neuro-norm, delay repair; urgent repair if CSF leak/incomplete skin.
• Myelomeningocele: post. neuropore non-closure. 85 % w/ Chiari II \rightarrow hydrocephalus. Neuro deficits level-dependent (sacral ⇒ bowel/bladder only; high lumbar ⇒ flaccid LE paralysis). Mgmt: early closure + shunt; GU surveillance. Survival 85 %; 75 % NL IQ but LD common.

Encephalocele

• Brain/meningeal herniation through skull (75 % occipital). Incidence 1/10,000. Prognosis correlates w/ brain tissue. Dx: prenatal US/MSAFP, postnatal MRI. Tx: prompt surgery.

Anencephaly

• Ant. neuropore failure (day 24). Absent cerebral hemispheres, often absent cranial bones; lethal (1/10,000 live births). Prenatal US + high MSAFP.

Syringomyelia / Syringobulbia

• Paracentral spinal cavity; assoc. Chiari I, myelomeningocele. Sx: UE atrophy, loss of pain/temp (crossing fibers), trophic ulcers, sleep apnea. Dx MRI. Tx: shunt; posterior fossa decompression if Chiari I.

Hydrocephalus

• Definition: excess CSF w/ ventricular dilation. Etiologies: obstruction (non-comm.), impaired absorption (comm.), ↑ production (choroid plexus papilloma).
• CSF path: lat. ventricle > Foramen of Monro> 3rd V > Aqueduct of Sylvius > 4th V – foramina Luschka/Magendie > subarachnoid > arachnoid granulations > venous sinuses.
• Non-communicating sites: Monro, aqueduct, 4th V outlets. Communicating: arachnoid scarring (post-meningitis, SAH, IVH).
• Associations: Dandy-Walker, Chiari I/II, aqueductal stenosis (Ll CAM X-linked).
• S/S: ↑ICP—morning HA, vomiting, papilledema, CN III/VI palsy, setting sun, Cushing triad. Infants: macrocephaly, bossing.
• Imaging: cranial US (open fontanelle); CT/MRI older kids.
• Tx: VP (preferred) or VA shunt; ETV; treat infection (MC bug S. epidermidis).

Chiari Malformations

• Type I: cerebellar tonsils >5 mm below foramen magnum. May be asx; Sx—HA, ataxia, dysphagia, syringomyelia. Tx: none if asx; decompression if sx.
• Type II (Arnold-Chiari): 4th V, vermis, medulla displaced; almost all MMC; 85 % hydrocephalus. Present neonatally.
• Type III: cerebellar herniation through cervical SB defect; rare; surgical.

Klippel-Feil Syndrome

• Congenital fused cervical verts; triad: short neck, low posterior hairline, limited neck motion. AD/AR.

Neuronal Migrational Disorders

• Polymicrogyria (multiple small gyri) – 20 % cortical malformations; causes CMV, ischemia, genetics; Sx: dev delay, seizures.
• Lissencephaly (agyria): smooth cortex; CT/MRI thick mantle. Assoc. Miller-Dieker (del 17p13). Fatal <10 y.
• Schizencephaly: clefts in hemispheres; dx MRI; bilateral ⇒ severe; unilateral ⇒ focal epilepsy.
• Holoprosencephaly: failed forebrain cleavage; seen w/ trisomy 13, teratogens; midline facial anomalies incl. cyclopia.
• Agenesis corpus callosum: inherited X-linked dom/rec or AD; assoc. trisomy 8/18, maternal cocaine. MRI “racing car” vents. Aicardi triad (girls): ACC + infantile spasms + chorioretinal lacunae.

Cerebral Palsy (CP)

• Static encephalopathy – non-progressive motor tone/posture deficit from early CNS insult.
• Incidence 2{-}4/1000.
• Types (%): Spastic 70, Dyskinetic 15, Hypotonic 7, Ataxic 5, Mixed.
• Etiologies multifactorial: neonatal encephalopathy/HIE, LBW (<1500 g), congenital malformations, infections, genetic/metabolic, kernicterus.
• Spastic: UMN signs, diplegia (premature), hemi, quad.
• Dyskinetic: basal ganglia injury; choreoathetosis, dystonia (kernicterus).
• Hypotonic/Ataxic forms—cerebellar.
• Comorbidities: seizures 25–40 %, ID 25–75 %, visual/hearing issues.
• Dx: serial exams; brain MRI; r/o progressive disorders.
• Tx: PT/OT, baclofen, diazepam, botulinum toxin, SDR, antiseizure meds.

Chorea & Movement

• Chorea: rapid jerks; MC cause childhood = Sydenham (acute rheumatic fever). Others: SLE, drugs (OCP, metoclopramide), genetic. Dx labs (ASO, dsDNase-B, ANA). Tx underlying; dopamine blockers symptomatic.
• Narcolepsy tetrad: daytime sleepiness, cataplexy, hypnagogic hallucinations, sleep paralysis. HLA-DQ1B*0602; Dx PSG + MSLT. Tx modafinil, stimulants, sodium oxybate.

Cerebrovascular Disease (Stroke)

• Incidence children 3–25/100k/y; neonates highest.
• Ischemic 50 % (¾ arterial, ¼ sinovenous); hemorrhagic equal.
• Etiologies: cardiac (25 %), prothrombotic (APLS, F5 Leiden), sickle cell (10 %; silent MRI 20 %), Moyamoya (puff of smoke collaterals—revascularize), dissection, CNS vasculitis (post-varicella, meningitis), metabolic (Fabry, homocystinuria), neonatal embolic (MCA).
• Presentation age-dependent: fetal → early hand dominance; neonate → focal seizures; <2 y seizures + hemi; older kids focal deficit. • Imaging: MRI ± MRA; manage ABCs. tPA/thrombectomy evidence limited—consider if LVO, \ge6 NIHSS, large child. • SCD: transcranial Doppler >200 cm/s high risk; chronic transfusion.

Trauma to CNS & PNS

Scalp & Skull

• Scalp lac → profuse bleed; close ≤12 h. Galeal laceration >0.5 cm suture. Hematomas self-resorb; subgaleal huge.
• Skull fractures: >80 % linear (parietal). “Ping-pong” in infants; depressed may injure brain. Basilar signs: raccoon eyes, Battle, CSF otorrhea/rhinorrhea, pneumocephalus.
• Imaging: CT bone windows if <3 y with risk signs. Linear fxs observe; repeat XR 3 mo. Depressed >0.5 cm → neurosurg. Basilar w/ CSF leak → hosp obs; no ear/nose packing; watch meningitis.

Parenchymal Injury

• Contusion: coup/contrecoup; CT; monitor.
• Diffuse axonal injury: accel-decel MVC; MRI > CT; supportive.
• Epidural hematoma: arterial (MMA); lucid interval \rightarrow drowsy; CT biconvex; early herniation → ipsi blown pupil, contra hemiplegia. Emergent surgery.
• Subdural: bridging veins; infants (AHT); CT crescent crosses sutures; retinal hemorrhages suspicious. Surg if midline shift.

Spinal Cord

• SCIWORA in <3 y; need MRI. Spinal shock flaccid → spastic. No IV methylpred.
• Peripheral nerve birth injuries: 
– Erb (C5–6 ± 7): “waiter’s tip”, diaphragm palsy if phrenic. 90 % recover 3 mo.
– Klumpke (C8–T1): claw hand + Horner; worse prog.
– Sciatic IM injections.

Cranial Nerve Disorders

• Bell palsy: idiopathic/HSV; steroids ± acyclovir; eye care.
• Mobius: congenital CN VII±VI agenesis.
• Marcus Gunn jaw-winking: aberrant trigeminal–oculomotor; monitor for amblyopia, surg if severe.

Seizure Disorders

Classification & Key Types

• Generalized: tonic-clonic, absence (3 Hz spike-wave; ethosuximide), myoclonic (JME 8–20 y, morning jerks; valproate), atonic.
• Focal: aware, impaired awareness. Childhood benign rolandic epilepsy (centrotemporal spikes) nocturnal; often no treatment.
• Infantile spasms (West): “jackknife” clusters, hypsarrhythmia; etiologies—TS 30 %. Tx ACTH or pred; vigabatrin (TS) → vision risk.
• Lennox–Gastaut: multiple seizure types, slow 1.5–2.5 Hz spike-wave, ID; difficult control (valproate, lamotrigine, rufinamide, clobazam, CBD).
• Status epilepticus: ≥5 min seizure. ABCs → benzo (lorazepam 0.1 mg/kg) → fosphenytoin, levetiracetam, or valproate → anesthetic drip.
• Febrile seizures: 6–60 mo, temp, no CNS infx. Simple <15 min, generalized, single 24 h. No EEG/CT/ASM. LP if <12 mo unimmunized or meningeal signs. Recurrence risk ↑ if <1 yr, FHx, low temp, short fever duration.

Antiseizure Meds (selected)

• Valproate: broad; SE—\uparrow LFTs, thrombocytopenia, weight \uparrow, hyperammonemia; teratogenic NTD 1.5 %; avoid <3 y metabolic, avoid teen girls. Carnitine for toxicity.
• Carbamazepine/oxcarbazepine: focal; SE—leukopenia, SIADH hyponatremia; erythromycin ↑ levels. Oxcarbazepine less hepatic.
• Phenytoin: focal; zero-order kinetics; SE—gingival hyperplasia, hirsutism, ataxia, SJS; IV arrhythmia, tissue necrosis.
• Ethosuximide: absence only; GI, rash.
• Phenobarbital: neonates; sedation, cognition ↓.
• Lamotrigine: broad; SJS risk; slow titration.
• Levetiracetam: adjunct; irritability.
• Topiramate: broad, migraine Px; cog slowing, weight ↓, acidosis.
• Vigabatrin: infantile spasms/TS; permanent visual field loss.

Drug Monitoring & Special Issues

• Check levels for VPA, CBZ, PHT, PB, ethosuximide for toxicity/compliance. 
• ASM teratogenicity: cleft, NTD; folic acid 4 mg/d females. Breastfeeding OK (watch PB/primidone sedation).

Headache Disorders

• Types: tension (MC), migraine, cluster; organic (tumor, infection, IIH, bleed, CO). 
• Pediatric migraine criteria (ICHD-III): ≥5 attacks 2–72 h, ≥2 (bil/uni, pulsating, mod-severe, aggravated by activity), ≥1 (N/V or photophobia/phonophobia inferred). Aura rare.
• Abortive: ibuprofen; triptans (rizatriptan ≥6 y). Preventive when ≥4/mo: topiramate, propranolol, amitriptyline + CBT; avoid triggers.
• Cluster: unilateral severe, autonomic signs; O2 6 L/min + triptan; verapamil prophylaxis. • Organic red flags (need MRI): occipital HA, night/morning wake, neuro deficits, growth failure, papilledema, crescendo pattern, <3 y, Valsalva induced. • IIH: papilledema, ↑ opening P >25 cm H2O, normal imaging/CSF; risk—obesity, tetracycline, vit A, OCPs. Tx acetazolamide ± shunt/ON fenestration.

Neuromuscular Diseases

Spinal Muscular Atrophy

• SMN1 deletion, AR. Types 0–3. Tongue fascic., symmetric proximal weakness, areflexia. Tx: nusinersen (intrathecal), onasemnogene (gene therapy).

Duchenne/Becker Muscular Dystrophy

• X-linked dystrophin. DMD absent protein; onset 2–6 y, Gowers, pseudohypertrophy, \uparrow CK. Wheelchair ~12 y. Tx steroids, exon-skipping. Becker milder.

Myasthenia Gravis

• Types: transient neonatal (maternal Ab), congenital (genetic, no Ab), juvenile autoimmune (AChR Ab 80–90 %). Sx fatigable weakness, ptosis. Dx AChR/MuSK Ab, EMG. Tx pyridostigmine, steroids, IVIG/plasma exchange, thymectomy.

Guillain-Barré

• Post-infectious demyelinating polyradiculoneuropathy. Ascending paralysis, areflexia, albumin-cytologic dissociation (↑ protein, nl WBC). Monitor resp; IVIG or plasmapheresis.

Charcot-Marie-Tooth

• Hereditary sensorimotor neuropathy; pes cavus, stork legs; supportive.

Botulism

• C. botulinum toxin blocks ACh release. Infant: constipation, hypotonia, poor suck, ptosis, pupillary paralysis but alert. Dx stool/toxin. Tx human BIG <1 y; equine antitoxin >1 y; ICU resp support.

Transverse Myelitis

• Post-viral autoimmune inflammation spanning ≥3 seg; back pain → rapidly ascending paraparesis, sensory level, bladder dysfxn. MRI + LP. High-dose IV steroids.

Multiple Sclerosis (peds)

• Rare <10 y; optic neuritis, brainstem sx; MRI plaques; CSF OCB +. Steroid pulses for relapse.

Ataxia Causes & Highlights

• Acute work-up algorithm (see above). 
• Acute cerebellar ataxia: post-viral (1–3 yr), abrupt, benign; resolves 6–8 wk.
• Friedreich: AR, frataxin; ataxia + absent DTR, \uparrow Babinski, cardiomyopathy, DM.
• Ataxia-telangiectasia: AR ATM gene; progressive ataxia + oculomotor apraxia, telangiectasias, immunodef., ↑ AFP.