Neurology



Neurology


Casey Olm-Shipman

M. Zelime Ward

Verne S. Caviness



Simple febrile seizure


Definition

(Pediatrics 2008;121:1281; Pediatr Rev 2007;28:363)



  • Simple febrile szr: Brief (<15 min), generalized szr (nonfocal) occurring once in a 24 hr period in a febrile child. Usually limited and no further workup required.


  • Complex febrile seizure: Prolonged (>15 min), and/or focal component, can occur > once in 24 hr. Often requires ancillary workup/neuroimaging studies to r/o focal etiology.


Epidemiology

(J Child Neurol 2002;17:S44)



  • Most common szr disorder in children, affects ∼2%–5% btw age 6–60 mo


  • Risk factors: 1st-/2nd-degree relative w/ h/o febrile szr; peak temp & rate of rise


Pathophysiology

(J Child Neurol 2002;17:S44; Trends Neurosci 2007;30:490)



  • Mechanism unclear, possibly related to rate of rise of fever, actual peak temp (most szr’s occur w/ temps >102). Possible cytokine & temp effect on neuronal tissue


Diagnostic Studies

(Pediatrics 1996;97:769; Pediatr Rev 1999;20:285)



  • In general, focus should be on fever workup, not workup of seizure itself.


  • Lumbar puncture: Strongly consider LP in infants <12 mo (sx’s of meningitis frequently absent). Consider LP in infants 12–18 mo (signs of meningitis can be subtle).



    • LP not routinely warranted in pts >18 mo, recommended if meningeal/intracranial signs present or if child recently Rx’d w/ antibiotics (risk of partially Rx’d meningitis).


  • EEG: Not recommended in eval of neurologically nml pts w/ 1st simple febrile szr.



    • No assoc btw abn EEG & future febrile szr or development of epilepsy.


  • Laboratory studies: No evidence that routine blood studies (Chem7, Ca, Mg, Phos, CBC, or blood glucose) are of benefit in first simple febrile seizure


  • Neuroimaging: Not recommended in routine eval of first simple febrile seizure.


Treatment

(Pediatrics 2008;121:1281; Pediatr Rev 2007;28:405)



  • Most febrile seizures require no intervention and end within <10 min.


  • Rectal diazepam (0.3–0.5 mg/kg) can be used in outpt setting to stop febrile seizure.


  • Long-term anticonvulsant therapy not recommended for children w/ simple febrile seizures. If complex febrile, generally we do give prophylactic AED.


  • Antipyretics have not been shown to ↓ risk of recurrence of simple febrile seizures.


  • Administer antipyretic (Tylenol/ibuprofen) during fever for pts w/ recurrent febrile seizures.


Complications

(Pediatrics 2008;121:1281; J Child Neurol 2002;17:S44)



  • Almost all w/ excellent prognosis; no evidence that febrile szr causes IQ decline, no known deaths 2/2 simple febrile seizure. Still, can progress to status epilepticus.


  • Minimal ↑ risk of developing epilepsy. Simple febrile seizure carries 1% risk, same as compared to general pop. ↑ to 2.4 % if multiple simple febrile seizures, <12 mo at the time of the 1st febrile seizure, and + family history of epilepsy.


  • Febrile szr’s frequently recur. Risk ∼30% if 1st szr occurs >12 mo. Risk ∼50% if 1st szr occurs <12 mo. Recurrence risk also ↑ if + FHx febrile szr, lower peak temp w/ 1st szr, and shorter duration of fever w/ first febrile szr.


First Nonfebrile Seizure in Children


Definition

(Neurology 2000;55:616)



  • 1 or more afebrile or otherwise unprovoked seizures (i.e. not seizures 2/2 febrile illness, trauma, or other acute medical condition). Excludes children w/ previous dx of epilepsy.


Epidemiology

(Neurology 2000;55:616)



  • 25,000–40,000 children have 1st nonfebrile szr each yr



Diagnostic Studies

(Neurology 2000;55:616; Pediatr Rev 2007;28:363)



  • Detailed history/PE: Determine if episode is seizure vs. seizure-like episode.



    • Preictal sx’s include aura, mood, or behavior Δ’s, vocal sx’s (cries, gasps, slurred words, garbled speech), motor sx’s (head or eye turning, eye deviation, posturing, rhythmic jerking, stiffening, automatisms, generalized or focal mvmt’s), resp sx’s (Δ’s breathing pattern, apnea, cyanosis), autonomic sx’s (pupil dilation, drooling, Δ in RR or HR, incontinence, pallor, vomiting, LOC, inability to understand or speak)


    • Ictal sx’s: preserved or altered consciousness (simple vs. complex), unilat or bilat (generalized) involv, ↑ tone (tonic), rhythmic or sporadic jerking (clonic, myoclonic), loss of tone (atonic), or other sx’s (sensory, autonomic or psychic).


    • Postictal symptoms include amnesia for events, confusion, lethargy, sleepiness, HA’s and muscle aches, transient focal weakness (Todd paralysis), N/V


  • Seizurelike episodes: Breath-holding, syncope, GERD, pseudoseizure, panic attacks, parasomnias, TIAs, vestibular d/o, paroxysmal choreoathetosis, psychotic hallucinations/delusion, migraine, tics, benign myoclonus of infancy, and other nonepileptic events.


  • Determine cause of seizure: Provoked vs. unprovoked



    • Provoked seizure: 2/2 acute condition, fever, stress, hypoglycemia, toxic ingestion, intracranial infxn, trauma, alcohol, recreational drug use or w/d, antiepileptic drug abrupt withdrawal related to compliance, other precipitating factors.


    • Unprovoked: W/o underlying condition. Idiopathic or 2/2 remote brain insult.


Laboratory Studies



  • Consider tox studies if any question of exposure or substance abuse


  • Tests ordered based on individual H&P. Routine labs in child >6 mo who returns to baseline and whose Hx nonsuggestive is generally not necessary.


  • Lumbar puncture: Consider LP if concern for possible meningitis/encephalitis.


  • EEG: EEG std of care. EEG most sensitive w/i 24 h of sz. EEG (or long-term monitoring) can be performed as outpt. Sleep deprivation ↑ sensitivity.


  • Neuroimaging studies: Emergent if prolonged postictal deficit or not to baseline w/i few hr



    • Consider non-urgent imaging if cognitive or motor impairment of unknown etiology, abn neuro exam, focal szr presentation, abn/nonbenign EEG, or pts <1 yo.


  • Note that MRI is preferred over CT if possible.


Treatment

(Neurology 2003;60:166)



  • Rx w/ AEDs generally not indicated after a 1st nonfebrile seizures, and not shown to improve prognosis for long-term seizure remission if started after 1st vs. 2nd szr.


Complications

(Neurology 2003;60:166)



  • Majority children w/ 1st unprovoked afebrile szr have no or few recurrences (30%–50% recurrence w/i 2 yr after idiopathic 1st szr). Risk ↑ w/ abn EEG findings, h/o remote brain injury (recurrence risk often >50%).


Epilepsy


Definition

(Pediatr Rev 2007;28:363)



  • 2 or more seizures w/o clear underlying cause. Legal definition emphasize matter of recurrent seizures. Acute underlying cause may be ambiguous.


  • Partial szr’s: Categorized as simple (w/o LOC) or complex (with loss of consciousness).



    • Szr’s originate from focus of abn neurons and hence motor manifestations focal.


    • Focus often spreads, causing global excitation/generalized seizure.


  • Associated syndromes



    • Benign partial epilepsy (benign rolandic): Presents 3–13 yo. Tonic or clonic mvmt’s, often unilateral paresthesias of lower face. Typical electrical correlate in sleep.


    • Temporal lobe epilepsy: P/i childhood, may remit in adol, return in adulthood. Often w/ aura, psychic sx’s, and automatisms. May/may not arise from temporal lobe.


    • Frontal lobe epilepsy: Frequently occurs in nighttime clusters. Often involves auras and bizarre automatisms (e.g., bicycle pedaling, pelvic thrusting).


    • Other: Parietal lobe epilepsy (w/ somatosensory sx’s, including paresthesia and detailed visual hallucinations); occipital lobe (w/ vague visual sx’s flashes of light/colors).



  • Generalized szr’s: Global excitation. Motor manifestations bilat, often synchronous


  • Associated syndromes and seizure subtypes



    • Infantile spasms: Usually presents 5–12 mo, remitting by ∼3 yo. Assoc w/ poor neurocog outcomes and Lennox-Gastaut syndrome. Freq ranges from few to 100s of szr’s qd. Manifests as symmetric, bilateral, brief, and sudden contractions of axial muscle groups.


    • Lennox-Gastaut: Usually presents 2–8 yo. Characterized by mental retardation and multiple generalized seizure subtypes. Typical EEG correlate.


    • Absence seizures: “Staring spells.” Manifests as sudden brief LOC, +/- eye flickering. Ictal EEG shows 3 Hz spike/wave pattern. Activated by hyperventilation.


    • Myoclonic seizures: Manifests as sudden muscle contractions.


    • Clonic seizures: Manifests as jerking that is often asymmetric/irregular.


    • Tonic szr’s: Sust contraction w/o clonic phase. Assoc w/ diffuse cerebral damage.


    • Tonic-clonic seizures: Manifests with tonic, clonic, and postictal phases.


Epidemiology



  • Prevalence of epilepsy ∼1%. (Pediatr Rev 2007;28:363)


Etiology

(Pediatr Rev 2007;28:363)



  • 65%–70% szr’s idiopathic. Considered “symptomatic” if 2/2 identifiable abnormality impacting brain function. Symptomatic seizures etiologies include:


  • Inherited/genetic: Channelopathies, chromosomal abnormalities, mitochondrial DNA disorder, metabolic disorder, hereditary neurocutaneous disorders


  • Congenital: Cortical malform, cerebral tumor, vascular malform, prenatal injury


  • Acquired: Trauma, neurosurgery, infection, vascular disease, hippocampal sclerosis, tumors, neurodegenerative disorders, metabolic disorders, toxic disorders


Diagnosis

(Pediatr Rev 2007;28:405)



  • EEG: Nml in 10%–20%. Can induce szr’s w/ hypervent, photic stim, sleep depriv.


  • Brain Imaging: Recommended in pts w/ partial szr’s. Not needed in kids w/ generalized szr’s w/ nml neurodev, <2% w/ abnormality on scan. MRI is preferred modality.


  • Neuropsych eval: Better qualify learning diff assoc w/ epilepsy; target interventions.


Treatment

(Pediatr Rev 2007;28:405; Clin Pediatr (Phila) 2005;44:383; Pediatrics 2007;119:535)



  • Behavior modification/family education



    • Avoid common triggers (sleep depriv, hypervent, drugs/EtOH, photic light stim).


    • Teach szr 1st aid. Put pt in swimmers ¾ prone position; keep pt’s mouth clear.


    • Basic safety precautions (e.g., water safety, helmet safety) and driving restrictions


  • Antiepileptic drugs (AEDs): Based on szr type in consultation w/ Neurologist



    • Regular monitoring of AED blood conc to assess for dose-related toxicity, compliance, and potential drug-drug interactions. Blood levels not useful in all.


    • Principally phenobarb, Dilantin, valproate, carbamazepine.


    • Several AEDs affect liver metab. Carbamazepine, phenytoin, and phenobarbital are cytochrome p450 inducers can ↑ metabolism of other AEDs and meds (e.g., OCPs, steroids, warfarin). Valproic acid is a cytochrome p450 inhibitor.


  • Ketogenic diet: High-fat, low-carb; assoc w/ imp szr control & awareness level.



    • Long-term adverse effects; renal stones, growth inhib, hyperlipid, Vit def, constipation


  • Surgery: Must have localizable seizure focus


  • Vagus nerve stimulator: Adjunctive therapy for intractable partial seizures. Electric impulse to L vagus nerve.


Adverse Effects and Therapeutic Serum Levels of AEDs

(Pediatr Rev 1997;18:39; Pediatr Rev 2007;28:405)











































Drug Therapeutic Level mcg/mL Selected Adverse Effects
Carbamazepine 4–12 Dizziness, drowsiness, ataxia, diplopia, rash, liver dysfxn, blood dyscrasia
Clonazepam 6.3–56.8 Drowsiness, hyperactivity
Ethosuximide 40–160 Drowsiness, blood dyscrasia
Gabapentin <2 Ataxia, fatigue, dizziness, HA, vomiting, nystagmus
Lamotrigine 1–4 Severe rash, ataxia, drowsiness, insomnia, headache
Phenobarbital 15–40 Cognitive impairment, drowsiness, rash
Phenytoin 10–20 Hirsuitism, gum hypertrophy, ataxia, rash, Stevens-Johnson, nystagmus,
Sodium valproate 50–100 Weight gain, alopecia, tremor, liver dysfxn, osteopenia, ↑NH3, ↓plts
Vigabatrin 1.4–14 Agitation, drowsiness, weight gain, dizziness, HA, ataxia, retinal degen


Status Epilepticus (SE)


Definition

(Neurology 2006;67:1542)



  • 30 min szr (not univ accepted) or ≥2 sequential szr’s w/o consciousness btw szr’s.


  • As a practical measure, respond urgently even if only 10–15 min if pt under obs.


Epidemiology



  • Incid 10–58/100,000. W/ epilepsy, risk ↑: 9.1%–27%. (Neurology 2006;67:1542)


Etiology



  • Acute symptomatic: More common in younger kids/infants. During acute illness.



    • Etiology; meningitis, encephalitis, electrolyte abn, sepsis, hypoxia, trauma, intox.


  • Remote symptomatic: Occurs w/o acute trigger and in pt w/ prior CNS insult.



    • Etiology includes CNS malform, previous traumatic brain injury or insult, chromosomal disorder.


  • Febrile: Only provocation is febrile illness.


  • Progressive encephalopathy: Underlying progressive CNS disorder. Includes mitochondrial disorders, CNS lipid storage diseases, amino/organic acidopathies.


  • Idiopathic: No definable cause.


Diagnostic workup

(Neurology 2006;67:1542; Pediatr Rev 2007;28:405)



  • Labs: Finger glucose, CBC, Chem10, urine and blood cx’s, toxicology (serum and urine), and consider LP. (Always LP if suspicion of CNS infxn). Check AED levels pts w/ epilepsy on AED prophy. Consider studies for inborn errors of metabolism, genetic testing.


  • EEG: If child p/w new onset SE, consider EEG if nonconvulsive status epilepticus.


  • Neuroimaging: Consider if suspect ↑ ICP, focal deficits or if unknown etiology.


Treatment

(Pediatr Rev 2007;28:405)



  • ABCs: O2 by mask, CV monitor. IV. Correct metabolic abn.


  • Administer medication to stop seizure:



    • Step 1: Lorazepam: 0.1 mg/kg (max 4 mg). Rpt at same dose if szr not stopped after 5 min. If no IV access, then give diazepam PR (0.5 mg/kg if 2–5 yo, 0.3 mg/kg 6–11 y/o, 0.2 mg/kg if >11 y/o). Rpt at same dose if szr has not stopped after 5 min. Monitor for resp depression.


    • Lorazepam has longer anticonvulsant effect & less resp depression vs. diazepam.


    • Step 2: If lorazepam does not stop szr, give phenytoin or fosphenytoin 20 mg/kg IV (max 1250 mg). Usually ineffective in febrile SE. May also use phenobarbital 10–20 mg/kg (max 300 mg). Monitor for respiratory depression. May need intubation


    • Step 3: If szr persists, induce “barbiturate coma” and intubate (anesthesiology present). Neuro should be involved w/ all cases of SE.


Complications



  • Mortality ∼5%; excess metab demand → O2 insuff and neuronal damage/necrosis.



Dyskinesias/Movement Disorders


Definitions

(J Child Neurol 2003;18:S1)



  • Tics: Sudden, “brief” involuntary (but suppressible), stereotyped mvmt’s/vocalizations


  • Tremor: Involuntary, usually regular, oscillatory mvmt’s; may be limited to an extremity, may involve entire body including tongue


  • Chorea: Hyperkinetic, invol, arrhythmic, nonrepetitive, random jerking mvmt. Typically expressed distally may involve entire body or extremities; may flow into a voluntary movement and possess a dancing quality


  • Ballism: Violent, involuntary, generally high amplitude flailing movements


  • Athetosis: Involuntary, writhing mvmt’s typically accentuate in distal extremities and perioral muscles but may involve entire body including tongue (not eyes).


  • Dystonia: Tonic fixation of posture, not dependent upon contracture (not a mvmt)


  • Myoclonus: Involuntary asym brief shock-like w/ recovery, muscle jerk may be limited to distal extr or involve entire body, sym in phase or multifocal and asym.


Etiology



  • Tics: Tourette syndrome, transient tic of childhood, drug-induced


  • Tremor: Hyperthyroid, hypoglycemia, essential tremor, drugs (AEDs, amphetamines, bronchodilators, antidepressants, caffeine, steroids), CP, Wilson dz, juvenile Huntington dz, and multiple other (esp of cerebellar and other central motor system relays and tracts)


  • Chorea: Sydenham chorea, CP, drugs (AEDs, antidepressants, antihistamines, OCP, CCBs, digoxin), SLE, Wilson dz, post-pump cardiac surgery. PANDAS


  • Ballism: Subthalamic nucleus damage/hemiballismus typically hypertensive small vessel infarct but other small causes of small focal disease rarely


  • Athetosis: CP, host of degenerative infectious, metabolic disorders, ischemia, trauma


  • Dystonia: Neuroleptic-induced, dopa-responsive dystonia (Segawa), Sandifer syndrome, dystonia musculorum deformans, CP, drugs (AEDs, antipsychotics, antihistamines, CCBs), Wilson dz, perinatal hypoxia, brain tumors, trauma


  • Myoclonus: Benign neonatal sleep myoclonus/“sleep starts,” epilepsy, drugs (AEDs, antidepressants), infxn’s (SSPE, HSV, HIV, Creutzfeldt-Jakob), autoimmune (MS), neoplastic/tumors, paraneoplastic (neuroblastoma), metabolic (most prevalent; renal failure, hyperglycemia), hypoxia


Abnormal Gait/Ataxia

(J Child Neurol 2003;18:309; Pediatr Rev 2001;22:177)


Definitions



  • Abnormal coordination of balance and movement


  • May result from dysfunction in the cerebellum, sensory or motor pathways


  • Classified as genetic vs. acquired; also acute, episodic, or chronic/progressive


  • Dysmetria; disturbance of metric/rhythmic aspect of mvmt; incoord of volunt mvmt


  • Dysdiadochokinesia; dysfunction of rapid alternating movements


  • Can also see: Scanning speech: ↑ length btw syllables; titubation- ataxic, to-and-fro mvmt trunk and/or head


Clinical Manifestations



  • Cerebellar ataxia: Wide-based swerving gait, sx’s unΔ w/ eyes open or closed, pendular DTRs, dysmetria, dysdiadochokinesia, over/undershoot finger-nose test, scanning speech w/ fluctuation invol may be assoc w/ intention tremor (oscillatory, to-and-fro)


  • Sensory ataxia: Broad-based (high-step) gait, + Romberg (sx’s worse w/ eyes shut)


Etiology



  • Acute ataxia: Most common: Postinfectious cerebellitis (varicella up to 26%) and acute postinfectious demyelinating encephalomyelitis, drug ingestions/intox (AED, benzos, antihistamines, PCP, mercury, lead, thallium, alcohol, ethylene glycol)



    • Other: Trauma (vertebral artery dissect and postconcussion syndr), hydrocephalus, mass lesions, vascular events, labyrinthitis, Miller-Fisher/Guillain Barré (sensory ataxia)


  • Episodic ataxia: Basilar migraine, nonconvulsive szr’s, metabolic d/o (pyruvate decarboxylase def, Hartnup dz, maple syrup urine dz), genetic episodic ataxias


  • Chronic/progressive ataxia: Most common: Brain tumors and spinocerebellar deg (AD) other (Ataxia-telangiectasia, Friedreich ataxia, a-β-lipoproteinemia)



Pathophysiology



  • Postinfectious cerebellitis: Sx’s occur during recovery from viral infxn; autoimmune demyelination by Ab; less commonly from direct cerebellar infxn


  • Acute postinfectious demyelinating encephalomyelitis: Similar to postinfectious cerebellitis, but demyelination multifocal → different clinical manifestations


  • Paraneoplastic/neuroblastoma: Autoimmune


Clinical Manifestations

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Aug 18, 2016 | Posted by in PEDIATRICS | Comments Off on Neurology

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