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L1: Seizures in Childhood

1. Definitions & Classifications
  • Seizure: Transient occurrence of signs/symptoms resulting from abnormal excessive or synchronous neuronal activity. Divided into Focal & Generalized.
  • Acute Symptomatic Seizure: Secondary to an acute problem (e.g., electrolyte disturbances, meningitis).
  • Remote Symptomatic Seizure: Secondary to a distant brain injury (e.g., old stroke).
  • Unprovoked Seizure: Without a precipitating cause.
  • Epilepsy: Enduring predisposition to generate seizures. Requires at least 1 unprovoked seizure with a second in >24 hr OR enough Electroencephalogram (EEG) / clinical info to predict recurrence.
  • Epileptic Encephalopathy: Severe EEG abnormality resulting in cognitive & other impairments.
  • Idiopathic Epilepsy: Genetic (presumed), no underlying disorder affecting development.
  • Symptomatic Epilepsy: Caused by a known underlying brain disorder.
  • Cryptogenic (Unknown) Epilepsy: Presumed underlying disorder, but cause is unknown.
  • Risk of Epilepsy: ~30% of patients with a first afebrile seizure develop epilepsy. Risk decreases to 20% if neurologic exam, Electroencephalogram (EEG), and Magnetic Resonance Imaging (MRI) are normal. Cumulative lifetime incidence is 3%.
2. Pathophysiology & Seizure Types
  • Pathology (4 sequential processes): 1. Underlying etiology. 2. Epileptogenesis. 3. Epileptic state of increased excitability. 4. Seizure-related neuronal injury (Prolonged Status Epilepticus → acute hippocampal swelling → long-term hippocampal atrophy with sclerosis on MRI).
  • Focal (Partial) Seizures (40% of childhood seizures): Sensory, motor, gelastic, hemiclonic. Aura (somatosensory, visual, olfactory) precedes complex partial seizures. Children <7 yr are less likely to report auras.
  • Simple Partial Seizure: Consciousness is NOT impaired. Jacksonian march possible (from face to arm to leg). Associated with adversive head/eye movement and Todd's Postictal Paralysis.
  • Complex Partial Seizure: Consciousness IS impaired. Lasts 1-2 min. Preceded by an aura. Accompanied by Automatisms (chewing, lip-smacking, shuffling).
  • Secondary Generalized Seizures: Start focal, spread rapidly. Often adversive eye/head deviation to contralateral side.
  • Generalized Seizures:
    • Typical Absence (Petit mal): Age 5-8 yr. Brief (few seconds). NO aura, NO postictal period. Hyperventilation for 3-5 mins precipitates it. Electroencephalogram (EEG) shows 3 Hz spike-and-slow wave discharges. Drug of choice: Ethosuximide (Alternatives: valproate, lamotrigine).
    • Atypical Absence: Myoclonic components, tone changes, precipitated by drowsiness. Electroencephalogram (EEG) shows 1-2 Hz spike-and-slow wave. Difficult to treat.
    • Generalized Tonic-Clonic: Most common type. Loss of consciousness, sudden cry, tonic (stiff) -> clonic (jerky). Associated with cyanosis, tongue biting, incontinence. Postictal period lasts 30 min to hours (sleepiness, headache). Drug of choice: Valproate. First aid: Position on side, do NOT force mouth open.
3. Epilepsy Syndromes
  • Benign Childhood Epilepsy with Centrotemporal Spikes (BCECTS): Most common. Child wakes up at night, buccal and throat tingling, drooling, inability to speak. Consciousness preserved. Electroencephalogram (EEG): Broad-based centrotemporal spikes markedly increased during drowsiness and sleep. MRI is normal.
  • Benign Epilepsy with Occipital Spikes: Panayiotopoulos type (early childhood, ictal vomiting), Gastaut type (late childhood, visual auras, migraine). Both outgrown within few years.
  • Temporal Lobe Epilepsy: Caused by Mesial Temporal Sclerosis (often preceded by febrile seizures). Characterized by atrophy and gliosis of hippocampus/amygdala. Most common surgically remediable partial epilepsy.
  • Rasmussen's Encephalitis: Chronic encephalitis, unilateral intractable partial seizures (epilepsia partialis continua), progressive hemiparesis. Treatment: Plasmapheresis, Intravenous Immunoglobulin (IVIG), Surgery.
  • Juvenile Myoclonic Epilepsy (JME / Janz Syndrome): Early adolescence, myoclonic jerks in the morning (dropping things). Triggered upon awakening. Linked to gene mutations. Treatment: Valproate, Topiramate.
  • West Syndrome (Infantile Spasms): Age 2-12 months. Triad: 1. Infantile spasms (clusters during drowsiness/arousal) 2. Developmental regression 3. Hypsarrhythmia on Electroencephalogram (EEG). Spasms often mistaken for colic. Medical Emergency. Treatment: Adrenocorticotropic Hormone (ACTH) 150 IU/m2/day or Vigabatrin (Drug of choice).
  • Lennox-Gastaut Syndrome: Age 2-10 years. Triad: Developmental delay, multiple seizure types (drop attacks), Electroencephalogram (EEG) 1-2 Hz spike-and-slow waves and polyspike bursts in sleep.
  • Landau-Kleffner Syndrome: Loss of language skills (acquired aphasia / auditory agnosia) in a previously normal child around 5.5 yrs. Often confused with autism. Hearing is normal. Electroencephalogram (EEG): Continuous spike waves in slow-wave sleep. Treatment: Valproate, Corticosteroids.
  • Severe Myoclonic Epilepsy of Infancy (Dravet Syndrome): Onset 1st year. Febrile and afebrile unilateral clonic seizures. Often linked to "Vaccine Encephalopathy" mutations. Lamotrigine may exacerbate seizures in Dravet.
4. Febrile Seizures (FS)
  • Definition: Most common seizures in childhood (2-5%). Age 6-60 months. Temperature ≥ 38.0°C. No Central Nervous System (CNS) infection or metabolic disturbance.
  • Simple FS: Generalized (tonic-clonic), ≤ 15 min, not recurrent within 24 hr. Do not carry risk of epilepsy or mortality.
  • Complex FS: Focal, or > 15 min, or recurs within 24 hr.
  • Risk Factors for Recurrence: Age < 1 yr, Fever 38-39°C, Fever duration < 24 hr (Major). Family history, complex FS, male, daycare, hyponatremia (Minor). Recurrence rate is 30% after first episode, higher with risk factors.
  • Risk for later Epilepsy: Complex FS, fever < 1 hr before FS, family history of epilepsy, neurodevelopmental abnormalities.
  • Management: Lumbar Puncture (LP) mandatory in infants < 6 months to rule out meningitis (especially if on antibiotics). Antipyretics reduce discomfort but do NOT reduce the risk of recurrent FS. Iron deficiency screening is appropriate. Intermittent Diazepam during fever can prevent recurrence in highly anxious cases. Early EEG is NOT predictive and should be deferred 2 weeks.
5. Antiepileptic Drugs (AEDs) & Status Epilepticus
  • Valproate: Drug of choice for generalized/unclassified. Side Effects (SE): Weight gain, alopecia, hyperammonemia, hepatic & pancreatic toxicity. (High risk of fatal hepatotoxicity in children < 2 yr with metabolic disorders - must check amino/organic acids first).
  • Phenobarbital: SE: Hyperactivity, behavioral changes, Stevens-Johnson syndrome. Steady state takes 2-4 weeks.
  • Carbamazepine: SE: Transient leukopenia, agranulocytosis, aplastic anemia, hyponatremia, tics. (Avoid combining with Phenytoin as both act on Na channels).
  • Phenytoin: SE: Gingival hyperplasia, hirsutism, rickets (decreased 25-OH Vitamin D), nystagmus, ataxia.
  • Ethosuximide: SE: Blood dyscrasias, GI upset.
  • Status Epilepticus (SE): Continuous seizure > 5 min. (Refractory if fails 2 meds). Management: ABCs first.
    • Step 1: Lorazepam Intravenous (IV) 0.05-0.1 mg/kg or Diazepam. (If no IV: buccal/intranasal midazolam or rectal diazepam). Trial of Pyridoxine in infants.
    • Step 2: Phenytoin / Fosphenytoin Intravenous (IV) loading dose (15-20 mg/kg).
    • Step 3: Phenobarbital Intravenous (IV) loading dose (prepare for intubation).
    • Step 4: Valproate Intravenous (IV).
    • Refractory SE: Midazolam/Propofol/Thiopental continuous drip with Electroencephalogram (EEG) monitoring to achieve burst suppression.
  • Discontinuation of AEDs: Consider when seizure-free for at least 2 years (6 months in benign syndromes). Must taper gradually over 3-6 months. Mandatory normal Electroencephalogram (EEG) before withdrawal. Relapse mostly in 1st 6 months.
  • Sudden Unexpected Death in Epilepsy (SUDEP): Most common epilepsy-related mortality. Risk factors: poorly controlled generalized seizures, polypharmacy, male gender.
💡 Quick Exam Hints: Seizures
  • Simple vs Complex Partial: Simple = Intact consciousness. Complex = Impaired consciousness + Automatisms + Aura.
  • Absence Seizures vs Complex Partial: Absence has NO aura, NO postictal state, lasts seconds, provoked by hyperventilation (3Hz EEG).
  • West Syndrome: Classic triad (Spasms + Regression + Hypsarrhythmia). Treatment is ACTH or Vigabatrin, NOT standard AEDs.
  • Febrile Seizures: Antipyretics do NOT stop recurrences. LP is mandatory if child is <6 months.
  • Status Epilepticus First Line: Always Lorazepam or Diazepam IV. If no IV, use rectal diazepam or buccal midazolam.
  • Valproate Toxicity: Beware in children < 2 years, causes fatal hepatotoxicity and hyperammonemia.
  • AED Withdrawal: Never withdraw abruptly. Must wait 2 years seizure-free AND have a normal EEG.

L2: Cerebral Palsy (CP)

Definition & Clinical Types
  • Definition: Static (but evolving) motor syndromes resulting from early brain development disorders. Mostly idiopathic/prenatal. Co-morbidities: Pain (75%), cognitive disability (50%), hip displacement, seizures (25%).
  • 1. Spastic Quadriplegia (20%): Most severe. All 4 extremities involved. Upper Motor Neuron (UMN) signs → Scissoring posture of legs → contracture deformities. Associated with severe mental retardation, epilepsy, and pseudo-bulbar palsy (swallowing difficulty → aspiration pneumonia).
  • 2. Spastic Diplegia (30%): Lower limbs more affected than upper. Often appears as Commando crawl in infants. Usually NOT associated with mental retardation or epilepsy.
  • 3. Spastic Hemiplegia (25%): Affects upper limb more than lower limb. Early hand preference. Distal limb growth arrest. Circumductive gait.
  • 4. Athetoid/Dyskinetic/Extrapyramidal (15%): Lesion in Basal Ganglia. Early hypotonia/head lag → later rigidity and dystonia. Absent UMN signs. Seizures uncommon. Intellect preserved, but severe speech/feeding issues (tongue thrusting, drooling).
  • Management & Prevention: Multidisciplinary. Prevention: Magnesium Sulfate for mother with premature labor, neonatal hypothermia for Hypoxic-Ischemic Encephalopathy (HIE) prevents CP.
  • Anti-Spasticity Drugs: Baclofen (oral/intrathecal), Benzodiazepines, Dantrolene. Botulinum toxin (Botox) for localized spasticity and reducing salivary drooling. Levodopa / Trihexyphenidyl for rigidity/dystonia. Reserpine / Tetrabenazine for choreoathetosis.
  • Surgical: Selective dorsal rhizotomy for severe spasticity. Orthopedic procedures for joint contractures.
💡 Quick Exam Hints: Cerebral Palsy
  • Spastic Quadriplegia is the most severe form, uniquely associated with pseudo-bulbar palsy (swallowing issues).
  • Spastic Diplegia spares intellect and is classically identified by a "Commando crawl".
  • Spastic Hemiplegia presents early as abnormal "Early hand preference" in infancy.
  • Athetoid CP is caused by basal ganglia lesions; intelligence is typically preserved, but severe speech/feeding issues exist. NO UMN signs.
  • Magnesium Sulfate given to mothers in premature labor helps prevent CP.

L3: Hydrocephalus & Microcephaly

Hydrocephalus
  • Physiology: Cerebrospinal Fluid (CSF) produced by Choroid Plexus (20 mL/hr, total volume 50mL in infants). Flow: Lateral → Foramen of Monro → 3rd Ventricle → Aqueduct of Sylvius → 4th Ventricle → Foramina of Luschka & Magendie → Basal cisterns → Arachnoid Villi (absorption).
  • Noncommunicating (Obstructive) Hydrocephalus: Obstruction WITHIN the ventricular system (e.g., Aqueductal stenosis, Dandy-Walker).
  • Communicating (Nonobstructive) Hydrocephalus: Obliteration of subarachnoid cisterns or malfunction of arachnoid villi (e.g., post-meningitis, subarachnoid hemorrhage).
  • Clinical Signs (Infant): Bulging fontanel, broad forehead, dilated scalp veins, Setting-sun eye sign (impingement of suprapineal recess on brainstem tectum). Upper Motor Neuron (UMN) signs in lower extremities. Macewen sign (cracked pot sound on percussion).
  • Head Shapes: Prominent occiput suggests Dandy-Walker malformation; foreshortened occiput suggests Chiari malformation.
  • Treatment: Medical (Acetazolamide, Furosemide - temporary relief by reducing CSF production). Surgical: Ventriculoperitoneal (VP) shunt or Endoscopic third ventriculostomy (avoids shunts).
  • Complications of shunts: Blockage or infection (infection rate <5% with prep, usually Staphylococcus epidermidis).
Microcephaly
  • Definition: Head circumference > 3 Standard Deviations (SD) below the mean for age/sex. Indicates early embryonic/fetal insult. Serial measurements more meaningful than single.
  • Primary (Genetic):
    • Familial Autosomal Recessive: Slanted forehead, normal cytoarchitecture is poorly differentiated.
    • Down Syndrome (Trisomy 21): Narrow superior temporal gyrus, early Alzheimer's.
    • Edward Syndrome (Trisomy 18): Rocker-bottom feet, micrognathia, congenital heart disease.
    • Cri-du-chat (5 p-): Characteristic cry, hyper-telorism.
  • Secondary (Nongenetic):
    • Congenital Infections (TORCH): Zika (ocular anomalies), Cytomegalovirus (CMV), Rubella, Toxoplasmosis (cerebral calcifications).
    • Drugs/Toxins: Fetal Alcohol Syndrome (absent philtrum, ptosis), Fetal Hydantoin.
    • Metabolic: Maternal diabetes, Maternal Hyperphenylalaninemia (Check asymptomatic mother's serum phenylalanine).
  • Diagnosis: Karyotype, Array CGH, Magnetic Resonance Imaging (MRI) (detects lissencephaly, pachygyria, polymicrogyria), TORCH titers.
💡 Quick Exam Hints: Hydrocephalus & Microcephaly
  • Setting-sun eye sign and Macewen sign (cracked pot) are classic clinical markers of infant hydrocephalus.
  • Dandy-Walker presents with a prominent occiput, while Chiari presents with a foreshortened occiput.
  • Staphylococcus epidermidis is the most common organism causing VP shunt infections.
  • Microcephaly is defined strictly as head circumference > 3 SD below the mean.
  • Always check maternal serum phenylalanine in unexplained secondary microcephaly cases.

L4: Neural Tube Defects

Spina Bifida Occulta & Occult Spinal Dysraphism
  • Etiology: Failure of neural tube closure between 3rd & 4th weeks in utero. Polygenic heredity. Linked to Valproic acid, malnutrition, low red cell folate, maternal obesity/diabetes.
  • Spina Bifida Occulta: Midline defect of vertebral arches/laminae (L5-S1) WITHOUT protrusion of spinal cord/meninges. Mostly asymptomatic. No neurological signs.
  • Occult Spinal Dysraphism: Closed spinal cord malformation indicated by cutaneous signs: Hemangioma, hairy patch (faun tail), dermal sinus, deep dimple, lipoma. Highly associated with tethered cord, syringomyelia. Best investigated with Magnetic Resonance Imaging (MRI) at any age.
Myelomeningocele
  • Pathology: Most severe open form (aperta). Neural placode exposed or covered by thin membrane. 75% lumbosacral.
  • Prevention: Folic acid supplementation before conception until 12th week reduces risk by 50%.
  • Clinical Manifestations: Flaccid paralysis of lower extremities, absent Deep Tendon Reflexes (DTRs), lack of pain response. Deformities: Clubfeet, hip subluxation, kyphotic gibbus.
  • Complications: Neurogenic bladder (constant dribbling or high-pressure with sphincter dyssynergy). Type II Chiari Malformation leading to Hydrocephalus in >80% of patients (unless fetal surgery done). Fecal impaction.
  • Management: Early surgical repair. Ventriculoperitoneal shunt for hydrocephalus. Clean Intermittent Catheterization (CIC) to maintain low bladder pressure and prevent pyelonephritis/renal failure. Latex-free environment strictly required from birth due to high risk of latex allergy.
  • Prognosis: Mortality 10-15% (most before 4 yrs). Renal dysfunction is a major determinant of mortality. At least 70% have normal intelligence, but higher risk of seizures/learning problems.
💡 Quick Exam Hints: Neural Tube Defects
  • Folic Acid must be taken BEFORE conception until the 12th week to reduce NTD risk by 50%.
  • A Hairy patch (faun tail) or deep dimple on the lower back strongly suggests Occult Spinal Dysraphism, necessitating an MRI.
  • Type II Chiari Malformation with Hydrocephalus occurs in >80% of myelomeningocele patients.
  • Latex-free environment is an absolute medical necessity for myelomeningocele patients to prevent severe allergies.
  • Renal failure (from neurogenic bladder) is the leading cause of mortality; prevented by Clean Intermittent Catheterization (CIC).

L5: Central Nervous System Infections

1. Acute Bacterial Meningitis
  • Epidemiology: Transmitted via respiratory droplets. Risk factors: asplenia, cochlear implants, complement defects.
  • Etiology by Age:
    • > 1 mo: Streptococcus pneumoniae (most common, peaks < 2 yrs), Haemophilus influenzae type b, Neisseria meningitidis (epidemics, serogroup A).
    • Neonates (< 3 mo): Listeria monocytogenes (T-cell defects), E. coli.
    • Shunt Infections: Coagulase-negative Staphylococci (S. epidermidis).
  • Pathophysiology: Increased Intracranial Pressure (ICP) due to cerebral edema (cytotoxic/vasogenic), hydrocephalus, Subdural effusion, Syndrome of Inappropriate Antidiuretic Hormone (SIADH). (Cerebral Perfusion Pressure = Mean Arterial Pressure - ICP).
  • Clinical: Sudden onset (shock, purpura, Disseminated Intravascular Coagulation (DIC)). Insidious (fever, nuchal rigidity, Kernig/Brudzinski signs - inconsistent in < 1.5 yr, bulging fontanel in infants). Cushing Triad (Hypertension, bradycardia, irregular respiration) indicates severe Increased Intracranial Pressure (ICP). Papilledema is UNCOMMON in uncomplicated cases (suggests abscess/venous sinus thrombosis).
  • Contraindications for immediate Lumbar Puncture (LP): Increased Intracranial Pressure (ICP) signs (coma, Cushing triad, papilledema - but NOT bulging fontanel alone), severe shock, skin infection at site, thrombocytopenia. Do blood culture and start empirical antibiotics.
  • Cerebrospinal Fluid (CSF) Profile: High pressure, High Leukocytes (PMNs predominant), High Protein (100-500 mg/dl), Low Glucose (< 40 mg/dl). Low WBC in CSF is a poor prognostic sign.
  • Treatment:
    • S. pneumoniae: Vancomycin + 3rd Gen Cephalosporin (Cefotaxime/Ceftriaxone).
    • H. influenzae / N. meningitidis: Cefotaxime or Ceftriaxone.
    • L. monocytogenes: Ampicillin.
    • Dexamethasone: Only proven effective for H. influenzae type b to reduce sensorineural hearing loss. Give 1-2 hours BEFORE antibiotics.
    • Increased ICP Tx: Head elevation, fluid restriction (if no shock), Mannitol, hyperventilation.
  • Complications & Prognosis: Sensorineural hearing loss (most common sequela, requires audiologic testing), Subdural effusion (bulging fontanel/fever, treat by aspiration), SIADH. Mortality highest with Pneumococcal.
  • Prevention: Rifampin prophylaxis for contacts of H. influenzae (20 mg/kg x 4 days) and N. meningitidis (2 days). Ceftriaxone/Cipro also work for N. meningitidis.
2. Viral Meningoencephalitis
  • Etiology: Enteroviruses are the most common cause. Parechoviruses severe in infants.
  • Herpes Simplex Virus (HSV-1): Severe focal temporal lobe encephalitis. Focal seizures, focal EEG/MRI findings. Untreated → coma/death. Drug of choice: Intravenous Acyclovir (10 mg/kg q8h for 2-3 wks).
  • Rabies: Affects basal ganglia. Always fatal.
  • Clinical: Headache, hyperesthesia, bizarre movements, flaccid paralysis (Enterovirus).
  • Cerebrospinal Fluid (CSF) Profile: Normal glucose, normal/mildly elevated protein, Lymphocyte predominant WBC.
  • Treatment: Supportive (rest, antipyretics, fluid management for SIADH). Acyclovir for HSV.
3. Tuberculous Meningitis
  • Pathology: Metastatic caseous lesion in cerebral cortex/meninges (basilar meningitis) → exudate causes CN III, VI, VII palsies and Communicating Hydrocephalus.
  • Stages: Stage 1 (nonspecific, developmental stagnation). Stage 2 (lethargy, cranial nerve palsies, vasculitis, hydrocephalus). Stage 3 (Coma, hemiplegia, decerebrate posturing).
  • Diagnosis: TST nonreactive in 50%. CXR normal in 20-50%. Cerebrospinal Fluid (CSF) Profile: High protein (100-3000), Low glucose, Lymphocyte predominance. Acid-fast stain requires large volume (5-10 mL) for yield.
  • Treatment: Prompt Anti-Tuberculosis drugs + Corticosteroids (imperative). VP Shunt for hydrocephalus.
  • Tuberculoma: Tumor-like mass. Central Nervous System (CNS) mass effect. TST positive, Chest X-Ray often normal. Ring-enhancing lesion on CT/MRI. Treat medically (Anti-TB + steroids), surgery rarely needed.
💡 Quick Exam Hints: CNS Infections
  • Dexamethasone is heavily tested: it MUST be given 1-2 hours BEFORE antibiotics to prevent hearing loss in H. influenzae meningitis.
  • Contraindications to LP: Cushing triad, papilledema, and severe shock. Bulging fontanel ALONE is NOT a contraindication.
  • Sensorineural hearing loss is the most common permanent complication of bacterial meningitis; audiologic testing is mandatory.
  • HSV-1 Encephalitis targets the Temporal Lobe (focal signs). Treat immediately with IV Acyclovir.
  • Tuberculous Meningitis CSF Profile: Very high protein, low glucose, Lymphocytes. Basilar enhancement on MRI.

L6: Duchenne Muscular Dystrophy (DMD)

Clinical Features & Diagnosis
  • Genetics: X-linked recessive. Most common hereditary neuromuscular disease (1 in 3600 boys). Mutation in dystrophin gene.
  • Clinical Manifestations:
    • Normal birth, delayed walking/gross motor.
    • Gowers' sign (using hands to push up on legs) by age 5-6.
    • Trendelenburg (waddling) gait due to gluteal weakness. Lordotic posture.
    • Loss of independent ambulation typically by age 10-14 years.
    • Calf Pseudohypertrophy: Enlarged calves due to fat infiltration and collagen proliferation, not muscle. (Tongue is 2nd most common).
    • Cardiomyopathy: Occurs in majority, progression typically AFTER loss of ambulation. Pulmonary failure (sleep apnea, weak cough) is a leading cause of death in teens/20s.
    • Intellectual impairment in majority (IQ < 70 in 20-30%). Extraocular and sphincter muscles preserved. Deep Tendon Reflexes: Ankle preserved late, knee lost early.
  • Labs/Diagnosis: Serum Creatine Kinase (CK) is consistently massively elevated (15,000 - 35,000) even at birth. A normal CK excludes DMD. Genetic testing (deletion/duplication analysis) is first-line. Muscle biopsy (absent dystrophin staining) if genetic test negative. EMG shows myopathic features (no denervation).
  • Treatment: No cure. Glucocorticoids (Prednisone, Deflazacort) slow muscle decline and prolong ambulation (start around age 4-6 when plateau occurs). Cardiac surveillance (Angiotensin-Converting Enzyme (ACE) inhibitors) every other year. Weight management. Avoid excessive vitamins. Watch for osteoporosis.
💡 Quick Exam Hints: Duchenne Muscular Dystrophy
  • Massively elevated CK (15,000+) is the hallmark lab finding. Normal CK rules out DMD.
  • Gowers' sign and Calf pseudohypertrophy (fat/collagen, not muscle) are classic physical signs.
  • Glucocorticoids are the only medical therapy proven to prolong ambulation and slow scoliosis.
  • Cardiomyopathy and Respiratory failure are the leading causes of death, typically progressing after the child becomes wheelchair-bound (10-14 yrs).
  • Genetics: X-linked recessive, defect in the dystrophin gene.

L7: Guillain-Barre Syndrome (GBS)

Etiology, Clinical & Treatment
  • Etiology & Pathogenesis: Autoimmune post-infectious polyradiculoneuropathy. Preceded (~10 days) by GI/respiratory infection (Campylobacter jejuni, H. pylori, Mycoplasma pneumoniae) or vaccines. Primarily demyelinating motor nerves, sometimes axonal.
  • Clinical Types:
    • Classic Landry Ascending Paralysis: Symmetrical ascending weakness starting in lower limbs → trunk → bulbar muscles (causes dysphagia, aspiration risk). Flaccid tetraplegia within 24 hrs. Areflexia.
    • Miller-Fisher Syndrome: Triad of Ataxia, Areflexia, Ophthalmoplegia (CN VI).
    • Chronic Relapsing Polyradiculoneuropathy: Unremitting for months/years.
  • Autonomic Dysfunction: Postural hypotension, arrhythmias (bradycardia/asystole), urinary retention.
  • Diagnosis:
    • Cerebrospinal Fluid (CSF): Cytoalbuminologic Dissociation (High Protein > 2x upper limit, with NORMAL WBC < 10/mm3). Diagnostic hallmark.
    • Nerve Conduction Velocity (NCV): Greatly decreased motor conduction.
    • Antiganglioside antibodies elevated in axonal variants. EMG shows acute denervation.
  • Treatment: Admit to ICU. Intravenous Immunoglobulin (IVIG) (0.4 g/kg/d x 5 days) OR Plasmapheresis. Corticosteroids are INEFFECTIVE in classic GBS. Strict respiratory monitoring (Peak Expiratory Flow Rate - PEFR) and cardiovascular monitoring (Pacemaker if needed).
  • Prognosis: Spontaneous recovery starts in 2-3 weeks. Tendon reflexes are first lost, last to recover. Poor prognosis if early max disability, CN involvement, or intubation.
💡 Quick Exam Hints: Guillain-Barre Syndrome
  • Cytoalbuminologic Dissociation in CSF (High Protein, Normal WBC) is the definitive diagnostic marker.
  • Ascending flaccid paralysis (Landry type) is the classic presentation, often preceded by Campylobacter jejuni.
  • Corticosteroids are completely INEFFECTIVE. Treatment relies on IVIG or Plasmapheresis.
  • Miller-Fisher Syndrome variant presents as Ataxia, Areflexia, and Ophthalmoplegia.
  • Respiratory failure and autonomic arrhythmias (bradycardia) are the main causes of mortality; ICU monitoring is critical.

L8: Poisoning

1. Lead Poisoning
  • Pathology: Pure toxicant. No safe level exists (toxicity occurs < 5 μg/dL). Blood Lead Level (BLL) is gold standard. 99% identified by universal screening. Venous sample preferred over capillary.
  • Clinical Manifestations:
    • GI: Anorexia, abdominal pain, constipation. (High risk if BLL > 20 μg/dL).
    • Central Nervous System (CNS): Cerebral edema, intracranial pressure. Seizures/coma/death rarely seen below 100 μg/dL, but encephalopathy reported at >70 μg/dL.
    • Renal: Reversible Fanconi syndrome at very high levels (>100 μg/dL).
    • Hematology: Red blood cell shortened survival, anemia (often co-exists with iron deficiency).
    • Peripheral neuropathy: Wrist drop and footdrop (older patients).
  • Treatment: Environmental elimination, behavior modification, dietary iron/calcium. Chelation indicated for Venous BLL ≥ 45 μg/dL. Drugs: DMSA (succimer) [oral], Penicillamine [oral], CaNa2EDTA [IV], BAL (dimercaprol) [IM]. Encephalopathic children require emergency chelation.
2. Hydrocarbon Aspiration
  • Pathology: Lower surface tension = higher aspiration risk (Gasoline, turpentine, naphthalene). Aspiration pneumonitis is the major risk. Ingestion >30mL increases risk.
  • Clinical: Respiratory distress, grunting, hypoxemia within 30 min. Chest X-Ray peaks in 48-72 hrs (pneumatoceles, pleural effusion).
  • Management: Gastric emptying is CONTRAINDICATED due to massive aspiration risk. Supportive care (Oxygen, fluids, ECMO). Gastric emptying ONLY considered if highly toxic components (CHAMP mnemonic: Camphor, Halogenated, Aromatic, Metals, Pesticides) and ingestion >30mL (use cuffed endotracheal tube if altered mental status).
3. Acetaminophen (APAP) Toxicity
  • Pathology: #1 cause of acute liver failure in USA. Acute toxic dose in children: > 200 mg/kg (or >7.5g in adults).
  • Diagnosis: 4 stages. Cannot rely on symptoms. Measure serum APAP at 4 hours post-ingestion (using the Rumack-Matthew Nomogram). Levels drawn < 4 hours are uninterpretable. Check Aspartate Aminotransferase (AST), Alanine Aminotransferase (ALT), INR.
  • Treatment Categories:
    • Prophylactic: Normal AST. APAP level falls on "possible/probable" toxicity line on nomogram → Start N-acetylcysteine (NAC).
    • Hepatic Injury: Elevated AST/ALT. Treat with NAC until AST normalizes and APAP is undetectable. Liver enzymes peak at 3-4 days.
    • Acute Liver Failure: King's College criteria for transplant (pH < 7.3, INR > 6, Creatinine > 3.4, Grade III/IV encephalopathy, Lactic acid > 3 mmol/L). Transaminase levels do NOT factor into transplant decision.
  • Antidote: N-Acetylcysteine (NAC) (Mucomyst Oral / Acetadote Intravenous).
4. Salicylate (Aspirin) Toxicity
  • Pathology: Found in aspirin, oil of wintergreen (highly toxic, 5g in 1 tsp). Acute toxic dose: > 150 mg/kg. Uncouples oxidative phosphorylation.
  • Clinical: Tinnitus, diaphoresis, hyperpnea, vomiting, hyperthermia. Severe: coma, seizures.
  • Lab Findings: Classically Primary Respiratory Alkalosis followed by Primary Elevated Anion Gap Metabolic Acidosis. Hyperglycemia (early) → Hypoglycemia (late). Done nomogram is of POOR value (do not use).
  • Management:
    • Activated charcoal for decontamination.
    • Aggressive fluid resuscitation.
    • Urinary Alkalinization (Sodium Bicarbonate infusion) to trap salicylate in renal tubules. Keep serum pH 7.45-7.55 and urine pH 7.5-8.0. Watch out for Hypokalemia (impairs alkalinization, add K+ to drip).
    • Hemodialysis indicated for severe acidemia, pulmonary/cerebral edema, seizures, or rising levels despite decontamination.
5. Organophosphorus Poisoning
  • Muscarinic Effects: DUMBELS (Salivation, lacrimation, bronchorrhea, bronchospasm, miosis, diarrhea).
  • Nicotinic Effects: Muscle fasciculation, weakness, respiratory failure (cause of death).
  • Diagnosis: Low plasma pseudocholinesterase and RBC cholinesterase.
  • Treatment:
    • Decontamination: Remove clothes, wash skin.
    • Atropine (0.01 mg/kg IV): Antagonizes muscarinic effects. Endpoint is satisfactory gas exchange (NOT pupil size).
    • Pralidoxime: Regenerates cholinesterase, treats NICOTINIC symptoms. Must be given with atropine.
💡 Quick Exam Hints: Poisoning
  • Acetaminophen: Never draw levels before 4 hours. Antidote is NAC. Toxicity > 200mg/kg.
  • Salicylates: Mixed acid-base disorder (Resp. Alkalosis + Metabolic Acidosis). Treat with Urinary Alkalinization (Bicarbonate + Potassium).
  • Hydrocarbons: Gastric emptying is absolutely contraindicated unless CHAMP criteria met due to aspiration pneumonitis risk.
  • Lead: Treat with Chelation (DMSA, EDTA) only if Venous BLL ≥ 45 μg/dL.
  • Organophosphates: Atropine endpoint is clear lungs/gas exchange, not pupil dilation. Pralidoxime is added for nicotinic (muscle) weakness.

📊 Comprehensive Comparisons

1. Simple vs. Complex Partial Seizures
Feature Simple Partial Seizure Complex Partial Seizure
Consciousness Preserved (Not impaired) Impaired
Aura Rare / Is considered the aura itself Often preceded by an aura
Clinical Signs Jacksonian march, focal motor/sensory signs Automatisms (chewing, lip-smacking)
Postictal State Todd's Paralysis (focal weakness) Confusion, sleepiness
2. Simple vs. Complex Febrile Seizures
Criteria Simple Febrile Seizure Complex Febrile Seizure
Type of Seizure Generalized (usually tonic-clonic) Focal (Partial)
Duration ≤ 15 minutes > 15 minutes
Recurrence Does NOT recur within 24 hours Recurs within 24 hours
Risk for future Epilepsy Very low (1%) Higher risk (6% to 29%)
3. Cerebrospinal Fluid (CSF) Profiles in CNS Infections
Condition Leukocytes (WBCs) Protein (mg/dL) Glucose (mg/dL) Comments
Normal < 5 (Lymphocytes) 20 - 45 > 50 (or 75% serum) Sterile
Acute Bacterial Meningitis 100 - 10,000 (PMNs/Neutrophils) Elevated (100 - 500) Decreased (< 40) Organisms on Gram stain/culture
Viral Meningoencephalitis Rarely > 1000 (Lymphocytes) Normal or mildly elevated (50-200) Normal Enteroviruses/HSV, detected by PCR
Tuberculous (TB) Meningitis 10 - 500 (Lymphocytes) Very High (100 - 3000) Decreased (< 50) AFB smear negative, needs large volume for culture
4. Types of Spastic Cerebral Palsy (CP)
Type of CP Limbs Affected Key Clinical Features Comorbidities
Spastic Quadriplegia All 4 extremities Scissoring posture, most severe UMN signs Mental retardation, Pseudo-bulbar palsy, Epilepsy
Spastic Diplegia Lower > Upper limbs Commando crawl Intellect usually preserved, NO epilepsy
Spastic Hemiplegia Unilateral (Upper > Lower) Early hand preference, circumductive gait Distal limb growth arrest
Athetoid (Dyskinetic) Variable Rigidity, dystonia, NO UMN signs, Basal ganglia lesion Preserved intellect, Severe speech/feeding issues
5. Primary vs. Secondary Microcephaly
Feature Primary (Genetic) Microcephaly Secondary (Nongenetic) Microcephaly
Etiology Autosomal recessive, Trisomy 21 (Down), Trisomy 18 (Edward), Cri-du-chat Infections (TORCH), Drugs (Alcohol, Hydantoin), Metabolic (Maternal PKU)
Classic Signs Slanted forehead, Rocker-bottom feet (Edward), early Alzheimer's (Down) Cerebral calcifications (Toxo/CMV), ocular anomalies (Zika), absent philtrum (Alcohol)
Diagnosis Karyotype, Array Comparative Genomic Hybridization (CGH) Maternal Phenylalanine, TORCH titers, Viral Cultures
6. Communicating vs. Non-communicating Hydrocephalus
Feature Non-communicating (Obstructive) Communicating (Non-obstructive)
Pathology Obstruction WITHIN the ventricular system (CSF cannot reach subarachnoid space) Obliteration of subarachnoid cisterns or malfunction of arachnoid villi (CSF reaches space but isn't absorbed)
Common Causes Aqueductal stenosis, Dandy-Walker complex, Tumors (mass effect) Post-meningitis (Arachnoid scar), Subarachnoid hemorrhage, Post-infectious
7. Acetaminophen vs. Salicylate Toxicity
Feature Acetaminophen (APAP) Toxicity Salicylate (Aspirin) Toxicity
Toxic Dose > 200 mg/kg > 150 mg/kg
Pathology Hepatocellular necrosis (Liver failure) Uncouples oxidative phosphorylation
Lab Findings Elevated AST/ALT, elevated INR, Lactic acidosis Primary Respiratory Alkalosis + Primary Metabolic Acidosis
Diagnosis Guide Rumack-Matthew Nomogram (drawn at 4 hours) Done Nomogram (Poor value, do NOT use)
Antidote / Treatment N-Acetylcysteine (NAC) Urinary Alkalinization (Sodium Bicarbonate + Potassium), Hemodialysis
8. Quick Antidotes Reference
Poison / Toxin Specific Antidote
Acetaminophen N-Acetylcysteine (NAC)
Anticholinergics Physostigmine
Benzodiazepines Flumazenil (Avoid in unknown ingestions due to seizure risk)
Beta Blockers Glucagon
Calcium Channel Blockers Insulin / Calcium salts
Organophosphates Atropine (for Muscarinic) + Pralidoxime (for Nicotinic)
Lead / Heavy Metals DMSA (Succimer), BAL (Dimercaprol), Calcium disodium EDTA
Iron Deferoxamine
Isoniazid (INH) Pyridoxine (Vitamin B6)
Ethylene Glycol / Methanol Fomepizole