Neurology Flashcards
What is hypotonia?
How is this different from weakness?
- Decreased resistance of movement during passive stretching of muscles
- Weakness is the decreased or less than normal force generated by the active contraction of muscles
Central vs. Peripheral Hypotonia
-
Central hypotonia
- Dysfunction of the upper motor neurons
- Cortical pyramidal neurons & their descending corticospinal pathways
-
Peripheral hypotonia
- Dysfunction of the lower motor neurons
- Spinal motor neurons & distally to muscle fibers
History in a hypotonic infant may reveal….
- Antenatal or neonatal problems
- Peripheral hypotonia: decreased fetal movements & breech presentation
- Central hypotonia: seizures in the neonatal period
What are the physical exam findings in hypotonia?
- Weak cry, decreased spontaneous movement, frog-leg posture, muscle contractures
-
Central hypotonia
- Altered level of consciousness
- Decreased DTRs, ankle clonus
-
Peripheral hypotonia
- Consciousness unaffected
- Muscle bulk & DTRs decreased
-
Congenital neuromuscular disorder pts
- Bilateral ptosis, ophthalmoplegia, flat mid-face, fish-shaped mouth, high-arched palate, chest wall abnormalities (bell-shaped chest, pectus excavatum, carinatum), bilateral cryptorchidism
What is the etiology of hypotonia?
- Systemic pathology
- Sepsis, electrolyte abnormalities, hepatic or renal encephalopathy
- Neural pathology
What is the differential diagnosis of central hypotonia?
-
Acquired
- Electrolyte abnormality
- Hypoxic-ischemic injury
- Infection
- Sepsis vs. Meningitis
- Intracranial hemorrhage
- Trauma (cerebral, cervical)
-
Congenital
- Cerebral malformation
- Chromosomal disorder
- Down syndrome
- Prader-Willi syndrome
- Metabolic disorder
- Urea cycle defects
What is the differential diagnosis of peripheral hypotonia?
-
Spinal cord
- Spinal muscular atrophy
-
Peripheral nerves
- Familial dysautonomia
-
Neuromuscular junction
- Botulism
- Neonatal myasthenia
- Magnesium toxicity
-
Muscle
- Congenital muscular dystrophy
- Congenital myotonic dystrophy
- Metabolic myopathy
- Pompe’s disease
- Phosphofructokinase deficiency
- Structural myopathy
- Central core disease
- Nemaline rod myopathy
When evaluating hypotonia, _______________ must be ruled out.
- acute life-threatening causes
- sepsis, meningitis, acute metabolic disorder
When central hypotonia is suspected, what 3 things need to be done?
-
Head CT scan
- Rule out acute CNS injury or congenital malformation
-
Serum electrolytes
- Ca, Mg, ammonia, lactate, pyruvate
- Rule out metabolic disorders
-
High-resolution chromosome studies
- FISH tests for suspected genetic disorders
- ex: Prader-Willi syndrome
When peripheral hypotonia is suspected, what 4 things need to be done?
- Serum creatinine kinase (CK) levels
- DNA tests for spinal muscular atrophy
- EMG: nerve conduction studies crucial to identify myasthenic disorders
- Muscle biopsy
Spinal muscular atrophy (SMA)
- definition
- epidemiology
- Anterior horn cell degeneration
- Hypotonia, weakness, tongue fasciculations
- 1 in 10,000-25,000 live births
- 2nd most common hereditary neuromuscular disorder after Duchenne’s
What is the classification system for spinal muscular atrophy?
-
Type I
- Infantile form
- Onset <6 mo
- Werdnig-Hoffman disease
-
Type II
- Intermediate form
- 6-12 mo
-
Type III
- Juvenile form
- >3 YO
What is the etiology of spinal muscular atrophy?
- Autosomal recessive
- Mutations in survival motor neuron gene (SMN1) on chromosome 5
- Pathology of spinal cord
- Degeneration & loss of anterior horn neurons
- Infiltration of microglia & astrocytes
What are the clinical features of spinal muscular atrophy?
-
Weak cry, tongue fasciculations
- Difficulty sucking & swallowing
- Bell-shaped chest
-
Frog-leg posture when in supine position
- Generalized hypotonia, weakness, areflexia
- Normal extraocular movements & normal sensory exam
How is spinal muscular atrophy diagnosed?
-
DNA testing
- Diagnostic >90% of cases
-
Muscle biopsy
- Atrophy of groups of muscle fibers that were innervated by damaged axons
What is the management & prognosis of spinal muscular atrophy?
-
Treatment is supportive
- Gastrostomy tube feeding
- Diligent surveillance & therapy of respiratory infections
- Physical therapy to maintain ROM
- No cure
-
Prognosis
- SMA type I: survival >1 YO unusual
- Death: respiratory insufficiency or pneumonia
- SMA types II & III: survival until adolescence & adulthood
- SMA type I: survival >1 YO unusual
What is the definition of infantile botulism?
What is the etiology?
- Bulbar weakness & paralysis during 1st yr
- Secondary to ingestion of Clostridium botulinum species & absorption of botulism toxin
- Source
- Infected foods: honey, spores
- Toxin prevents presynaptic release of ACh
What are the clinical features of infantile botulism?
- Onset of symptoms 12-48 hrs after ingestion
- Classic first symptom: constipation
-
Neurologic symptoms
- Weak cry & suck
- Loss of previously obtained motor milestones
- Opthalmoplegia, hyporeflexia
-
Paralysis: symmetric & descending
- Diaphragmatic paralysis can occur
How is infantile botulism diagnosed?
- Suggestive hx, neuro exam, toxin in stool
-
EMG: brief, small-amplitude muscle potentials
- Incremental response during high-frequency stimulation
How is infantile botulism managed?
- Treatment is supportive
- Nasogastric feeding
- Assisted ventilation
- Botulism immune globulin
- Antibiotics CONTRAINDICATED
What is congenital myotonic dystrophy?
What is the epidemiology?
- Myotonia: inability to relax contracted muscles
- Autosomal dominant muscle disorder
- Presents in newborn period
- Weakness & hypotonia
- 1 in 30,000 live births
What is the etiology of congenital myotonic dystrophy?
- Trinucleotide repeat disorder
- Autosomal dominant, variable penetrance
- Chromosome 19
- Transmission through infected mothers (>90%)
- Earlier onset in mother, more likely will transfer
Congential myotonic dystrophy
- antenatal hx
- neonatal hx
- physical exam
- adulthood
- additional problems
- Antenatal hx
- Polyhydramnios: poor swalling in utero & decreased fetal movements
- Neonatal hx
- Feeding & respiratory problems
- Physical exam
- Facial diplegia (bilateral weakness), hypotonia, areflexia, arthrogryposis (multiple joint contractures)
- Myotonia not always present in newborn
- Later, by 5 YO
- Adulthood
- Myotonic facies (atrophy of masseter & temporalis muscles), ptosis, stiff straight smile, inability to release grip after hand shaking (myotonia)
- Additonal problems
- Mental retardation, cataracts, cardiac arrhythmias, infertility
How is congenital myotonic dystrophy diagnosed?
- Should be suspected in all infants w/ hypotonia
- Mother should also be examined
- DNA testing
- EMG & muscle biopsy no longer indicated
Congential Myotonic Dystrophy
management
prognosis
-
Treatment is supportive
- Infants may require assisted ventilation & gastrostomy tube feedings
- Outlook is guarded
- Infant mortality up to 40% (resp problems)
- All survivors have mental retardation
- Average IQ 50-65
- Feeding problems subside w/ time
What is Hydrocephalus?
- Increased CSF under pressure w/i ventricles
- Results from:
- Blockage of CSF flow
- Decreased CSF absorption
- Increased CSF production (rare)
What are the 3 types of hydrocephalus?
-
Noncommunicating hydrocephalus
- Enlarged ventricles
- Obstruction of CSF flow through ventricles
- ex: aqueductal stenosis
-
Communicating hydrocephalus
- Enlarged ventricles
- Increased production of CSF (tumors)
- Decreased absorption of CSF (bacterial meningitis)
-
Hydrocephalus ex vacuo
-
Ventricular enlargement caused by brain atrophy
*
-
Ventricular enlargement caused by brain atrophy
What are the congenital causes of hydrocephalus?
- Chiari Type II malformation
- Dandy-Walker malformation
- Congenital acqueductal stenosis
What are the acquired causes of hydrocephalus?
- Intraventicular hemorrhage (preterm infants)
- Bacterial meningitis
- Brain tumors
What is Chiari type II malformation?
- Downward displacement of the cerebellum & medulla through the foramen magnum
- Blocks CSF flow
- Associated w/ lumbosacral myelomeningocele
What is Dandy-Walker malformation?
- Absent or hypoplastic cerebellar vermis
- Cystic enlargement of the 4th ventricle
- Blocks flow of CSF
What is Congenital Aqueductal Stenosis?
- X-linked trait
- Thumb abnormalities
- CNS abnormalities: spina bifida
The main clinical feature of hydrocephalus is _____.
increasing head circumference
>97% for age
What are the clinical features of hydrocephalus for infants?
- Infants w/ open cranial sutures
- Large anterior & posterior fontanelles & split sutures
-
Sunset sign
- Tonic downward deviation of both eyes
- Pressure from enlarged 3rd ventricles on the upward gaze center in the midbrain
What are the clinical features of hydrocephalus for older children?
- Closed cranial sutures
-
Increased ICP
- Headache
- Nausea & vomiting
- Unilateral 6th nerve palsy
- Papilledema
- Brisk DTRs but w/ a usually downward plantar response
How is hydrocephalus evaluated & managed?
- Increasing head circumference & signs/symptoms of increased ICP
- Urgent head CT scan
- Surgical placement of ventriculoperitoneal shunt
- Divert flow of CSF
- Complications: shunt infection/obstruction
What is the prognosis of hydrocephalus?
-
Pts w/ aqueductal stenosis
- Best cognitive outcome
-
Pts w/ Chiari type II malformation
- Low-normal intelligence
- Language disorders
-
Pts w/ X-linked hydrocephalus
- Severe mental retardation
What is spina bifida?
Any failure of bone fusion in the posterior midline of the vertebral column
Definitions
- Neural tube defects
- Myelomeningocele
- Meningocele
- SB occulta
-
Neural tube defect
- All forms of failure of neural tube closure
- Anencephaly to sacral meningocele
-
Myelomeningocele
- Herniation of spinal cord tissue & the meninges through a bony cleft
- Commonly the lumbosacral region
- 20X more than meningocele
-
Meningocele
- Herniation of the meninges only
- Not associated w/ neural deficits
-
SB occulta
- No herniation of tissue through vertebral cleft
The highest incidence of neural tube defects is in _______ and the lowest is in _____.
Ireland (1 in 250 live births)
Japan (1 in 3,000 live births)
What is the etiology of neural tube defects?
- Multifactorial
- Environmental
- Genetic
- Nutritional
- Teratogenic factors
- Mothers taking folic acid have decreased incidence of spina bifida
-
Teratogens that cause SB
- Valproate, phenytoin, colchicine, vincristine, azathioprine, methotrexate
What are the clinical features of SB occulta?
- Skin on the back epithelialized
- Hairy patch or dimple covers the area
- Usually lumbosacral region
- No neurologic defects
What are the clinical features of Meningocele?
- Fluctuant midline mass overlying the spine
- Filled w/ CSF, transluminated
- Neurologic deficits mild/absent
What are the clinical features of Myelomeningocele?
- Fluctuant midline mass anywhere along spine
- Commonly lumbosacral region
-
Neurologic defects present
- Depend on level of lesion
- Complete paraplegia (above L3) to preserved ambulation & variable bladder or bowel incontinence (S3 & below)
What are the 5 associated abnormalities & complications of Myelomeningocele?
-
Hydrocephalus
- 90% of lumbosacral associated w/ Chiari type II malformations & hydrocephalus
-
Cervical hydrosyringomyelia
- Accumulation of fluid w/i the central spinal cord canal & within the cord itself
-
Defects in neuronal migration
- Gyral anomalies
- Agenesis of corpus callosum
-
Orthopedic problems
- Rib abnormalities, deformities of LE, LE fractures from loss of sensation
- GU defects
How is spina bifida diagnosed prenatally?
-
Alpha fetoprotein
- Elevated in amniotic fluid & maternal serum
- At 16-18 wks gestation, detects 80% of spinal defects
-
Fetal sonography
- Highly sensitive
How is spina bifida diagnosed after birth?
-
SB occulta
- Skin abnormality overlying the spine
- Confirmed by spinal radiographs
-
Meningocele
- Physical exam findings
- Confirmed by MRI of spinal cord & spine
-
Myelomeningocele
- Physical exam
How is spina bifida managed?
- SB occulta doesn’t require treatment
- Meningocele: surgical repair
- Myelomeningocele
- Urgent surgical repair w/i 24 hrs of birth
- Reduce morbidity & mortality from infection
- Prevent further trauma to exposed neural tissue
What is the prognosis of spina bifida?
-
SB occulta & meningocele
- Excellent prognosis
-
Myelomeningocele
- 90% of pts survive to adolescence
- Many handicapped
- Associated problems:
- Wheelchair dependency
- Bladder/bowel incontinence
- Mental retardation
- Seizures
- Precocious puberty
- Pressure sores
- Fractures
What is the definition of a coma?
- State of unawareness of self & environment
- Patient lies w/ eyes closed
- Unarousable by external stimuli
What is the etiology of a coma?
Young vs. old children?
-
Children <5 YO
- Nonaccidental trauma
- Near-drowning
-
Older children
- Drug overdose
- Accidental head injury
What are the etiologies of focal lesions that lead to a coma?
Abnormal neuroimaging studies
-
Supratentorial lesions
- Vascular: subarachnoid hemorrhage, multiple infarcts, thalamic infarct
- Trauma: subdural hematoma, nonaccidental trauma
- Tumors
- Demyelination (postinfectious encephalitis)
-
Infratentorial lesions
- Vascular: cerebellar hemorrhage
- Trauma
- Tumors
What are the etiologies of diffuse lesions that lead to a coma?
Normal neuroimaging studies
-
Ingestion
- Drugs: atropine, scopolamine, benzodiazepines, barbiturates, ethanol, lithium, opiates, TCAs
- Toxins: lead, mercury
- Infection: encephalitis
- Hypoxemia: near-drowning, CO
-
Abnormal metabolites
- Metabolic: hypo/hyperglycemia, hypo/hypernatremia, thiamine deficiency
- Endocrine: hypo/hyperthyroidism, hypo/hypercortisolism
-
Organ failure
- Cardiac arrest, hepatic failure, uremia
-
Seizures
- Nonconvulsive status epilepticus
- Reye syndrome
What is the goal in the assessment of the comatose patient?
- Determine the depth of the coma
- Identify the neurologic signs that indicate the site & cause of the coma
- Monitor the patient’s recovery
What are 6 ways to assess a comatose patient?
- Glascow Coma Scale
- Head & neck exam
- Abnormal motor responses
- Abnormal respiratory responses
- Pupillary size & reactivity
- Other brainstem reflexes
What is the Head & Neck exam for a comatose patient?
- Scalp injuries
- Breath odors (alcohol intoxication, DKA)
- Nuchal rigidity (meningitis)
- CSF or blood draining from auditory canal
- Indicates a basilar skull fracture
What are some abnormal motor responses that can indicate brain damage in a comatose patient?
-
Flaccidity or no movement
- Severe spinal/brainstem injury
-
Decerebrate posturing (extension of arms/legs)
- Subcortical injury
-
Decorticate posturing (flexion of arms & extension of legs)
- Bilateral cortical injury
-
Asymmetric responses
- Hemispheric injury
What are some abnormal respiratory responses that can indicated injury in a comatose patient?
-
Hypoventilation
- Opiate or sedative overdose
-
Hyperventilation
- Metabolic acidosis (Kussmaul respirations)
- Neurogenic pulmonary edema
- Midbrain injury
-
Cheyne-Stokes breathing
- Alternating apneas & hyperpneas
- Bilateral cortical injury
-
Apneustic breathing
- Pausing at full inspiration
- Pontine damage
-
Ataxic or agonal breathing
- Irregular respirations w/ no pattern
- Medullary injury
- Impending brain death
How do pupillary size & reactivity provide clues to brain injury in a comatose patient?
-
Unilateral dilated nonreactive pupil
- Uncal herniation
-
Bilateral dilated nonreactive pupils
- Topical application of a dilating agent
- Postictal state
- Irreversible brainstem injury
-
Bilateral constricted reactive pupils
- Opiate ingestion
- Pontine injury
What is the Oculocephalic maneuver (doll’s eyes)?
- When turning the head of an unconscious patient, the eyes normally look straight ahead & then slowly drift back to the midline position
- Intact vestibular apparatus senses a change in position
-
Injured brainstem
- Movement of the head does not evoke any eye movement
- Negative oculocephalic maneuver
- “negative doll’s eyes”
What is Caloric Irrigation?
- Performed when oculocephalic response negative or can’t be performed
- Angle the head at 30o
- Irrigate each auditory canal w/ 10-30 mL of ice water
-
Intact (normal) cold caloric response
- Eye deviation to the irrigated side
-
Abnormal response
- Pontine injury
Abnormal _____ & _____ reflexes indicate significant brainstem injury.
corneal, gag
How is a comatose patient diagnostically worked up?
- Glucose check immediately
- Urine toxicology screen, serum electrolytes, metabolic panel
- Head CT scan
- Identify mass lesions or trauma
- Lumbar puncture
- Rule out meningoencephalitis if CT neg
- Urgent EEG
What is a seizure?
- Transient, involuntary alteration of consciousness, behavior, motor activity, sensation or autonomic function
- Excessive discharge from population of cerebral neurons
What is epilepsy?
What is status epilepticus?
-
Epilepsy
- 2 or more spontaneous seizures
- No obvious precipitating cause
-
Status epilepticus
- Seizure _>_30 min
- Pt doesn’t regain consciousness
____% of children have a single afebrile seizure before 16 years of age.
Fewer than ____ of children who have a single seizure go on to develop epilepsy.
Epilepsy has an incidence of _____% during childhood.
4-6%
1/3
0.5-0.8%
What is the etiology of seizures?
- Imbalance btwn excitatory & inhibitory input within the brain
- Abnormalities in the membrane properties of individual neurons
- In some children, cause of seizures is known
- 60-70% of cases, cause is unknown
What are the 7 causes of acute seizures during childhood?
What are some examples of each?
-
Head trauma
- Cerebral contusion, subdural hematoma
-
Brain tumor
- Astrocytoma, meningioma
-
Toxins
- Amphetamines, cocaine
-
Infections
- Meningitis, encephalitis, brain abscess, neurocysticercosis
-
Vascular
- Cerebral infarction, intracranial hemorrhage
-
Metabolic disturbances
- Hypocalcemia, hypoglycemia, hypomagnesemia, hypo/hypernatremia, pyridoxine deficiency
-
Systemic diseases
- HTN, hypoxic-ischemic injury, inherited metabolic disorder, liver disease, renal failure, neurocutaneous disorders (tuberous sclerosis)
What are the criteria for the classification of seizures?
- Presence or absence of fever
- Extent of brain involvement
- Whether consciousness is impaired
- Nature of the movements
What is the classification of seizures?
-
Febrile
- Simple
- Complex
-
Afebrile
- Partial (one hemisphere)
- Simple: consciousness not impaired
- Complex: consciousness impaired
- Generalized (both hemispheres)
- Tonic-clonic
- Tonic
- Clonic
- Myoclonic
- Absence
- Atonic
- Partial (one hemisphere)
What are tonic-clonic seizures?
- Most common type of generalized seizure
- Characterized by:
- Increased thoracic & abdominal muscle tone, followed by clonic movements of the arms & legs
- Eyes rolling upward
- Incontinence
- Decreased consciousness
- Postictal state of variable duration
What are absence seizures?
- Brief staring spells
- Occur w/o loss of posture
- Minor motor manifestations
- Eye blinking or mouthing movements
- <15 seconds
- No postictal state
What are partial (focal) seizures?
What are the symptoms?
- Discharge of group of neurons in one hemisphere
- Motor, sensory, psychomotor features
-
Simple partial seizures
- Consciousness not impaired
-
Complex partial seizures
- Consciousness decreased
How is epilepsy classified?
- Predominant seizure type
- Site of origin of epileptic discharge
What is the differential diagnosis of seizure-like events?
- Breath-holding spells (infants)
- GERD (Sandifer syndrome)
- Syncope
- Migraine
- Vertigo
- Movement disorder (tics, chorea)
- Sleep disturbances (night terrors, somnambulism)
- Transient ischemic attack
- Rage attacks
- Psychogenic seizures
How are seizures diagnosed?
-
EEG
- Identifies focus & pattern of epilepsy
- Abnormal EEG not required for diagnosis
-
Video-EEG monitoring
- Useful when clinical info inadequate
- Pts <3 YO, sleep seizures, poor historians
-
Neuroimaging studies
- Should be performed in all children except those w/ absence seizures or benign rolandic epilepsy
What are the steps in evaluating a seizure patient?
What are some important labs?
- ABCs
- Laboratory studies
-
Afebrile seizures
- 1st time in healthy child w/ normal neuro exam is fine
- Serum electrolytes & neuroimaging in child w/ prior afebrile seizures
-
Febrile seizures
- CNS infection MUST be ruled out
- Examination of CSF
- CBC, CXR, urine & blood cultures
-
Afebrile seizures
How is status epilepticus treated?
- IV anti-convulsants
-
Short-acting benzodiazepine
- Lorazepam, diazepam
- Loading dose of phenobarbital or phenytoin
How is epilepsy treated?
- Pharmacotherapy
- Single drug therapy
- Generalized epilepsy: valproic acid or phenobarbital
- Absence epilepsy: ethosuximide
- Partial epilepsy: carbamazepine or phenytoin
- Surgery
- Medically intractable epilepsy: surgery to remove epileptic tissue
- Best prognosis: temporal lobe lesions (75% complete control/remission)
What are some treatment alternatives for epilepsy? (besides drugs/surgery)
-
Vagal nerve stimulator
- Pacemaker-sized device that sends electrical impulse to the vagus nerve
- Side effect: hoarseness
-
Ketogenic diet
- High fat, low carb diet
- State of ketosis suppresses seizure activity
What is the prognosis of epilepsy?
- Epilepsy is not a lifelong disorder
- 70% of children can be weaned off their meds
- After 2 yr seizure free period & normalization of EEG
Febrile Seizures
- definition
- epidemiology
- etiology
- Any seizure accompanied by a fever owing to a non-CNS cause in patients 6 mo to 6 YO
- Common, 3% of all children
- Pathophysiologic mechanism unknown
- Can be inherited (several gene mutations found)
Simple vs. Complex Febrile Seizures
-
Simple febrile seizure
- <15 min, generalized
-
Complex febrile seizure
- >15 min, focal, recurs w/i 24 hrs
How are febrile seizures diagnosed?
- History, normal neurologic exam, exclusion of any CNS infection
- Lumbar puncture only if meningitis suspected
- Neither neuroimaging or EEG needed unless neurologic exam abnormal
How are febrile seizures managed?
-
First-time or occasional
- Not treated
- Aggressive anti-pyretic treatment of subsequent febrile illnesses may help prevent febrile seizures
-
Frequent, recurrent
- Daily anticonvulsant prophylaxis
- Valproic acid, phenobarbital
- Abortive treatment w/ rectal diazepam
- Daily anticonvulsant prophylaxis
Approximately ____% of pts w/ one febrile seizure will have a recurrence. Recurrence risk _____ with increasing patient age. The risk of epilepsy is ____%.
30%, decreases, 2% (low)
What are epileptic syndromes?
How are they classified?
- Epileptic conditions characterized by a specific age of onset, seizure characteristics, EEG abnormality
- 3 of the most common
- Infantile spasms
- Absence epilepsy of childhood
- Benign rolandic epilepsy
Infantile spasms (West syndrome)
age of onset
etiology
- Age of onset: 3-8 mo (rare in children >2 YO)
-
Tuberous sclerosis is the most commonly identified cause of infantile spasms
- PKU, hypoxic-ischemic injury, intraventricular hemorrhage, meningitis, encephalitis
What are the clinical features of infantile spasms?
How is it diagnosed?
- Brief, myoclonic jerks, lasting 1-2 sec each
- Clusters of 5-10 seizures over 3-5 min
-
Sudden arm extension or head & trunk flexion
- “jackknife seizures”, “salaam seizures”
- EEG
- Hypsarrhythmia pattern
- Highly disorganized pattern of high amplitude spike & waves in both cerebral hemispheres
How are infantile spasms managed?
What is the prognosis?
-
ACTH IM injections
- 4-6 wks, effective in >70% pts
-
Valproic acid
- Second-line drug of choice
-
Vigabatrin
- Most effective for those w/ tuberous sclerosis
- Outlook is poor
- Moderate-severe mental retardation
Absence epilepsy of childhood
age of onset
etiology
- Age of onset: 5-9 YO
- Female:Male = 3:2
- Autosomal dominant inheritance
- Age-dependent penetrance
What are the clinical features of absence epilepsy of childhood?
- Absence seizures 5-10 sec
- Frequent, tens to hundreds of times per day
- Accompanied by automatisms
- Eye blinking, incomprehensible utterances
- Loss of posture, urinary incontinence, postictal state do NOT occur
Absence epilepsy of childhood
- diagnosis
- management
- prognosis
- EEG
- Generalized 3 Hz spike & wave discharge
- Both hemispheres
- Treatment
- Ethosuximide (1st line) or valproic acid
- Outlook is very good
- Seizures resolve in adolesence
- No cognitive impairment
Benign rolandic epilepsy
(benign centrotemporal epilepsy)
- definition
- epidemiology
- etiology
- Involves nocturnal partial seizures w/ secondary generalization
- Most common partial epilepsy during childhood
- 15% of epilepsy
- Presents at 3-13 YO
- Peak incidence: 6-7 YO
- Boys > girls
- Autosomal dominant, variable penetrance
What are the clinical features of benign rolandic epilepsy?
- Seizures in early morning hours
-
Oral-buccal manifestations
- Moaning, grunting, pooling of saliva
- Seizures spread to face & arm
- Generalize to tonic-clonic seizures
Benign rolandic epilepsy
- diagnosis
- management
- prognosis
- EEG
- Biphasic spike & sharp wave disturbance in the mid-temporal & central regions
- Treatment
- Valproic acid (1st line), carbamazepine
-
Outcome is excellent
- Seizures remit spontaneously during adolescence, no effects on development
What are the intracranial causes of a headache?
-
Primary headaches
- Primary dysfunction of neurons
- Migraine headache
- Primary dysfunction of muscles
- Tension headache
- Primary dysfunction of neurons
-
Secondary headaches
- Increased ICP
- Hydrocephalus, brain tumor, subdural hematoma
- Meningeal irritation
- Meningitis, subarachnoid hemorrhage
- Increased ICP
What are the extracranial causes of a headache?
-
Local causes
- Ears: otitis media
- Eyes: refractive rror, glaucoma
- Nose: sinusitis
- Mouth: toothache, abscess
- TMJ dysfunction
-
Systemic causes
- Anemia (children)
- Depression (adolescents)
- Hypoglycemia (children)
- HTN (adolescents)
- Psychogenic
- CO poisoning
What are the 4 pieces of clinical information that help determine the cause of a headache?
-
Quality of pain
- Migraine: throbbing/pounding
- Tension: aching/pressure
-
Site & radiation
- Migraine: unilateral, periorbital to forehead & occiput
- Tension: generalized/bitemporal
-
Time of onset
- Tension: end of day
- Increased ICP: morning
-
Duration
- Shorter duration, less likely serious
What is a migraine?
- Prolonged (>1 hr), unilateral headaches
- Nausea, vomiting, visual changes
- Caused by changes in cerebral blood flow
Migraines are the most common cause of headaches in children & adolescents, occuring in up to ___% of school-age children.
Age of onset is younger than ____yrs in _____%.
Before puberty, (M/F) dominant.
After puberty, (M/F) dominant.
5%
5 years, 20%
M>F
F>M
What is the etiology of migraines?
-
Autosomal dominant
- >80% of children have at least 1 affected parent
- Changes in cerebral blood flow secondary to release of serotonin (5-HT), substance P & VIP from changes in neuronal activity
How are migraines classified?
-
Migraine w/o aura
- Most common form in children
- No warning symptoms
-
Migraine w/ aura
- Preceded by transient visual changes
- Blurred vision, small areas of decreased vision (scotomata), streaks of light, hemianopsia, unilateral pressure/weakness
-
Migraine equivalent
- Young children, headache absent
- Prolonged, transient alteration of behavior
- Cyclic vomiting, cyclic abd pain, paroxysmal vertigo
Migraines are associated w/ what focal neurologic signs?
-
Ophthalmoplegic migraine
- Unilateral ptosis or cranial nerve III palsy
-
Basilar artery migraine
- Vertigo, tinnitus, ataxia, dysarthria
What are the precipitating factors in migraines?
- No obvious precipitating cause
- Many sufferers sensitive to vasoactive substances in certain wines, cheeses, preserved meats & chocolate
- Some patients have headaches induced by stress, fatigue, menstruation, exercise
What are the 7 main clinical features of migraines?
-
Prolonged, throbbing, unilateral headache
- Supraorbital area & radiates to occiput
- Young children: bifrontal
-
Nausea & vomiting
- Motion sickness common
-
Visual disturbances
- Blurred vision, scotomata, jagged streaks of light that outline old forts (fortifications)
-
Photophobia or phonophobia
- Treat by lying in dark, quiet room
- Over-the-counter analgesics ineffective
- Symptoms improved by sleep
- Neurologic exam normal
Migraines
- diagnosis
- management
- prognosis
- Hx & normal neuro exam
- Rest & elimination of known triggers
- Abortive treatment
- Sumatriptan: selective 5-HT agonist
- Injectable, intranasal, oral
- Prophylaxis
- Propranolol
- Lifelong disorder w/ waxing & waning course
What is a tension headache?
What age is most common?
- Bifrontal or diffuse, dull, aching headaches
- Associated w/ muscle contraction
- Unusual during childhood
- Extremely rare in children <7 YO
What are the clinical features of a tension headache?
- Dull, aching, rarely throbbing
- Increases in intensity during the day
- Pain usually bifrontal, can be diffuse
-
Isometric contraction
- Temporalis, masseter, trapezius
- No vomiting, visual changes, paresthesias
How are tension headaches diagnosed?
How are they managed?
- Tension headaches are very rare in childhood
- Other diagnoses (migraines) should be preferentially considered
- Treatment
- Reassurance & pain control
- Acetaminophen, ibuprofen
- Stress & anxiety reduction
What is a cluster headache?
What are the clinical features?
How is it treated?
- Extremely rare during childhood
-
Unilateral frontal or facial pain
- Conjunctival erythema
- Lacrimation
- Nasal congestion
- <30 minutes, several times a day
- May not occur for wks-mo
- Treatment
- Abortive therapy: oxygen, sumatriptan
- Prophylaxis: Ca2+ blockers, valproic acid
What is ataxia?
- Inability to coordinate muscle activity during voluntary movement
- Involves trunk or limbs
- Caused by cerebellar or proprioceptive dysfunction
What is the differential diagnosis of unsteady gait?
-
Cerebellar dysfunction
- Unsteady wide-based stance
- Irregular steps & veering to one side/other
-
Weakness
- Muscle weakness: spinal cord lesions, acute disorders of motor unit (Guillain-Barre)
-
Encephalopathy
- Infection, drug overdose, recent head trauma (decreased consciousness)
-
Seizures
- During a seizure or postictal period
- Vision problems
-
Vertigo
- Migraines, acute labyrinthitis, brainstem tumors
What is the differential diagnosis of cerebellar ataxia?
-
Brain tumors
- Cerebellar astrocytoma
- Cerebellar primitive neuroectodermal tumor (medulloblastoma)
- Neuroblastoma
-
Trauma
- Cerebellar contusion
- Subdural hematoma
-
Toxins
- Ethanol
- Anticonvulsants
-
Vascular
- Cerebellar infarction/hemorrhage
-
Infections
- Meningitis
- Encephalitis
-
Inflammatory
- Acute cerebellar ataxia of childhood
-
Demyelination
- Acute disseminated encephalomyelitis
- Multiple sclerosis
What is Acute Cerebellar Ataxia of Childhood?
What is the age of onset & etiology?
- Unsteady gait secondary to a presumed autoimmune or postinfectious cause
- Most common cause of ataxia in children
- Age of onset: 18 mo to 7 yrs
- Rarely in children >10 YO
- Etiology
- Varicella, influenza, EBV, mycoplasma
- Ataxia follows viral illness by 2-3 wks
- Immune complex deposition in the cerebellum
What are the clinical features of acute cerebellar ataxia of childhood?
-
Truncal ataxia
- Deterioration of gait
- Young children refuse to walk (fear of fall)
-
Slurred speech & nystagmus
- Hypotonia & tremors less common
- Fever is absent
How is acute cerebellar ataxia of childhood diagnosed?
- Hx & physical exam
- Exclusion of other causes of ataxia
-
Urgent neuroimaging study necessary in all pts
- Rule out life-threatening causes
- Tumors/hemorrhage in posterior fossa
- Head CT scan is normal
How is acute cerebellar ataxia of childhood managed?
- Treatment is supportive
- Complete resolution of symptoms: 2-3 mo
- Physical therapy may be useful
Guillain-Barre Syndrome
(acute inflammatory demyelinating polyneuropathy)
- definition
- etiology
- Demyelinating polyneuritis
- Ascending weakness, areflexia, normal sensation
-
Campylobacter jejuni
- Prodromal gastroenteritis
- CMV, EBV, HSV, influenza, varicella, Coxsackie virus
What is the pathophysiology of Guillain-Barre Syndrome?
- Principal sites of demyelination
- Ventral spinal roots
- Peripheral myelinated nerves
- Cell-mediated immune response to infectious agent that cross-reacts to antigens on the Schwann cell membrane
What are the 4 main clinical features of Guillain-Barre Syndrome?
-
Ascending, symmetric paralysis
- May progress to respiratory arrest
-
No sensory loss occurs
- Low back or leg pain (50%)
-
Cranial nerve involvement
- Facial weakness (40-50%)
-
Miller-Fischer syndrome (variant)
- Ophthalmoplegia
- Ataxia
- Areflexia
How is Guillain-Barre Syndrome diagnosed?
-
Lumbar puncture
- Albuminocytologic dissociation
- Increased CSF protein in the absence of an elevated cell count
- 1 wk after symptom onset
-
EMG
- Decreased nerve conduction velocity or conduction block
-
Spinal MRI
- Children <3 YO
- Rule out compressive lesions of spinal cord
How is Guillain-Barre Syndrome managed?
What is the prognosis?
-
IVIG
- 2-4 days
- Preferred treatment for children
-
Plasmapheresis
- 4-5 days
- Removes patient’s plasma along w/ presumed anti-myelin Ab
-
Complete recovery is the rule in children
- Physical therapy may be necessary
What is Sydenham chorea?
(St. Vitus’ dance)
- Self-limited autoimmune disorder
- Associated w/ rheumatic fever
- Presents with:
- Chorea
- Uncontrolled, restless proximal limb movements
- Emotional lability
- Chorea
Sydenham chorea occurs in approximately ___% of patients w/ rheumatic fever.
Onset is common btwn ___ & ___ yrs of age.
25%, 5-13 YO
What is the pathophysiology of Sydenham chorea?
Ab cross-react w/ membrane antigens on both group A ß-hemolytic streptococcus & basal ganglia cells
What are the 8 clinical features of Sydenham chorea?
- Immunologic response (2-7 mo)
-
Children appear restless
- Face, hands, arms
- Movements continuous, quick, random
- Speech jerky or indistinct
-
Chameleon tongue
- Patients unable to sustain protrusion of the tongue
-
Choreic hand
- Wrist flexed & hyperextended at the metacarpal joints
-
Milkmaid’s grip
- Pts unable to maintain grip on examiner’s fingers
- Emotional lability
- Gait & cognition not affected
What is the differential diagnosis of Sydenham chorea?
- Other conditions may cause chorea
- Acquired & congenital conditions
- Encephalitis
- Kernicterus
- SLE
- Huntington’s disease
- Wilson’s disease
How is Sydenham chorea diagnosed?
- No single confirmatory test
-
Elevated ASO or anti-DNase B titer
- Recent strep infection
- Neuroimaging
-
Head MRI
- Increased signal intensity in the caudate & putamen on T2 weighted
- Single-photon emission computed tomography (SPECT)
- Increased perfusion to thalamus & striatum
-
Head MRI
How is Sydenham chorea managed?
What is the prognosis?
- Haloperidol, valproic acid, phenobarbital
- Symptoms: several months to 2 yrs
- Generally, all patients recover
What is Tourette Syndrome?
What is the prevalence?
What is the etiology?
- Chronic, lifelong movement disorder
- Motor & phonic tics <18 YO
- Tics are brief, stereotypical behaviors that are initiated by an unconscious urge that can be temporarily suppressed
- 1 in 1,000 live births; 3% of children
- Cause is unknown
What are the clinical features of Tourette syndrome?
-
Motor tics
- Simple: eye blinking, head/shoulder shaking
- Complex: bouncing, jumping, kicking
-
Phonic tic
- Simple: cough, groan, bark
- Complex: echolalia (repetition of heard words/phrases)
- Tics present _>_1 yr
- Absence of signs of neurodegenerative disorder
-
Coprolalia
- Utterance of obsence words (15%)
-
Associated findings
- Learning disabilities
- Attention deficit/hyperactivity disorder
- Obsessive compulsive traits
What is the differential diagnosis of Tourette syndrome?
- Disorders that may cause tics
- Wilson’s disease
- Sydenham chorea
- Partial seizures
- Pediatric autoimmune neuropsych disorders associated w/ streptococcal infection (PAN-DAS)
- Simple habits
- Habits are situation-dependent & under voluntary control
How is Tourette syndrome diagnosed?
- Clinical diagnosis: hx & neuro findings
- No lab or imaging tests
How is Tourette syndrome managed?
What is the prognosis?
-
Pimozide (drug of choice)
- Effective, minimal extrapyramidal SE
-
Clonidine
- Less effective than pimozide
- Major SE: sedation
-
Haloperidol
- Risk of tardive dyskinesia
-
Hyponotherapy
- Effective in some patients
-
Tics decrease in adulthood
- Pharmacotherapy successful, SE limiting
Duchenne & Becker Muscular Dystrophies
- definition
- epidemiology
- etiology
- Progressive, X-linked myopathies
- Myofiber degeneration
- DMD more severe than BMD
- Deletion in dystrophin gene
- All ethnic groups
- 1 in 25,000 live births
- Onset 2-5 YO
What is the pathophysiology of DMD & BMD?
- Dystrophin
- High molecular weight cytoskeletal protein
- Associates w/ actin & other structural membrane elements
- Absence of dystrophin
- Weakness & rupture of plasma membrane
- Injury & degeneration of muscle fibers
How do DMD & BMD appear on light microscopy?
- Degeneration & regeneration of muscle fibers
- Infiltration of lymphocytes into the injured area & replacement of damaged muscle fibers w/ fibroblasts & lipid deposits
What are the clinical features of DMD & BMD?
What are the similarities/differences?
- Slow, progressive weakness (legs first)
- Loss of ability to walk
- DMD: 10 YO
- BMD: _>_20 YO
-
Psuedohypertrophy of calves
- Excess accumulation of lipids
- Replace degenerating muscle fibers
- DMD > BMD
-
Gower’s sign
- Weakness of pelvic muscles
- Pts extend each leg & “climb up” each thigh
-
Cardiac involvement (50%)
- Cardiomegaly, tachycardia, cardiac failure
-
Cognition
- DMD: mild cognitive impairment
- BMD: normal intelligence
How are DMD & BMD diagnosed?
- Presence of enlarged calf muscles in a young boy w/ muscle weakness suggests diagnosis
- CK level elevated
-
EMG
- Small, polyphasic muscle potentials
- Normal nerve conductions
-
Muscle biopsy
- Typical dystrophic pattern
-
Absent/decreased dystrophin levels
- IHC, Western blot
-
DNA testing
- Gene deletion (90%)
How are DMD & BMD managed?
- No cure
- Oral steroids improve strength transiently
- Not successful in clinical trials
- Gene replacement
- Myoblast transplantation
- Dystrophin replacement
What is the prognosis of DMD? BMD?
-
DMD
- Wheelchair dependent by 10 YO
- Die in late teens from respiratory failure
- Assisted ventilation may help
-
BMD
- Wheelchair dependent in 20s
- Life expectancy in 50s
Myasthenia Gravis
- definition
- etiology
- boys vs. girls
- Autoimmune disorder
- Progressive weakness or diplopia
- Ab against ACh receptor at NMJ
- Girls 2-6X more than boys
What is the classification system of Myasthenia Gravis?
-
Neonatal myasthenia
- Transient weakness in the newborn period
- Secondary to transplacental transfer of maternal AChR ab from the mother with myasthenia gravis
-
Juvenile myasthenia
- Presents in childhood
- Secondary to AChR ab formation
What are the clinical features of myasthenia gravis?
-
Neonatal myasthenia
- Hypotonia, weakness, feeding problems
-
Juvenile myasthenia
- Bilateral ptosis (most common)
- Characteristic increasing weakness later in the day w/ sustained muscle activity
- Diplopia secondary to decreased extraocular movements
- DTRs preserved
- Other autoimmune disorders (JRA, DM, thyroid disease)
How is myasthenia gravis diagnosed?
-
Tensilon test
- IV injection of edrophonium chloride
- Rapidly acting cholinesterase inhibitor
- Transient improvement of ptosis
- Decremental response to low freq (3-10 Hz) repetitive nerve stimulation
- Presence of AChR ab titers
How is myasthenia gravis managed?
Neonatal vs. Juvenile?
-
Neonatal
- Treatment symptomatic
- Compromised respiration: cholinesterase inhibitors or IVIG
-
Juvenile
- Cholinesterase inhibitors
- Pyridostigmine bromide
- Immunotherapy
- Corticosteroids
-
Plasmapheresis lowers AChR ab
- When symptoms worse, respiratory effort compromised, pt unresponsive
- IVIG
- Thymectomy
- Cholinesterase inhibitors
What is the prognosis of Myasthenia Gravis?
-
Neonatal
- Symptoms mild & resolve 1-3 wks
-
Juvenile
- Remission after thymectomy (60%)