Neurology

Question 0

Life-threatening causes of hypotonia?

Answer 0

Sepsis, meningitis, acute metabolic disorder

Question 1

Central hypotonia versus peripheral hypotonia?

Answer 1

Altered LOC, increased DTRs, ankle clonus

versus

normal consciousness, decreased DTRs and muscle bulk

Question 2

Tests if central hypotonia is suspected?

Tests if peripheral hypotonia is suspected?

Answer 2

1. Head CT to rule out acute CNS injury or no infarction
2. Electrolytes to rule out metabolic disorders
3. Chromosome studies and FISH for genetic disorders
4. CK levels
5. EMG and muscle biopsy
6. DNA tests

Question 3

Causes of peripheral hypotonia?

Answer 3

1. Spinal cord – Spinal muscular atrophy
2. Peripheral nerves – familial dysautonomia
3. Neuromuscular junction – botulism, magnesium toxicity, neonatal myesthenia
4. Muscle – Muscular dystrophy, metabolic myopathy, structural myopathy

Question 4

Second most common inherited neuromuscular disorder? Inheritance? Gene/Chromosome? Degeneration of? Clinical features? Diagnosis? Management? Prognosis?

Answer 4

Spinal muscular atrophy; autosomal recessive; survival motor neuron gene on chromosome 5

Degeneration/loss of anterior horn motor neurons

1. Weak cry, tongue fasciculations, difficulty sucking
2. Bell shaped chest
3. Frog leg posture, hypotonia, no reflexes

DNA testing and muscle biopsy

Supportive treatment – G-tube feedings, physical therapy

Death within one year

Question 5

Infant botulism – onset of symptoms? Classic first symptom?

Neurological symptoms? Diagnosis? Treatment? Contraindicated treatment?

Answer 5

12-48 hours after ingestion; constipation

Weak cry/suck, loss of motor milestones, ophthalmoplegia, hyporeflexia

EMG shows brief, small amplitude muscle potentials with incremental response during high-frequency stimulation

Supportive with botulism immune globulin

Antibiotics are contraindicated

Question 6

Congenital myotonic dystrophy – inheritance? Type of mutation? Chromosome? Clinical features as neonate, child, adult? Diagnosis? Treatment? Prognosis?

Answer 6

Trinucleotide repeat disorder with autosomal dominant inheritance, chromosome 19

1. as neonate – Facial diplegia, hypotonia, multiple joint contractures, feeding and respiratory problems
2. Myotonia (inability to relax muscles) developed by five years
3. Adulthood – myotonic faces, ptosis, inability to release grip after handshaking
4. Mental retardation, cataracts, arrhythmias, infertility

DNA testing

Supportive

40% mortality. Also survivors have mental retardation

Question 7

Hydrocephalus – noncommunicating versus communicating versus X vacuo?

Answer 7

Enlarged ventricles caused by CSF flow obstruction

Enlarged ventricles due to increased production/decreased absorption of CSF

Ventricular enlargement caused by brain atrophy (not true hydrocephalus)

Question 8

Congenital causes of hydrocephalus?

Answer 8

1. Chiari type II malformation – cerebellum/medulla downwardly displaced through foramen Magnum, blocking CSF flow. Associated with lumbosacral myleomeningocele
2. Dandy-Walker – absent cerebellar vermis and cystic enlargement of fourth ventricle, blocking flow of CSF
3. Congenital Aqueductal stenosis

Question 9

Acquired causes of hydrocephalus?

Answer 9

Intraventricular hemorrhage
Bacterial meningitis
Brain tumors

Question 10

Clinical features of hydrocephalus? Evaluation? Management?

Answer 10

1. Head circumference crossing isobars
2. Large fontanelles and split sutures
3. Sunset sign – downward deviation of eyes caused by enlarged ventricles on the upward gaze center
4. Headache, nausea vomiting
5. Papilledema
6. Unilateral sixth nerve palsy

Head CT

Ventriculoperitoneal shunt

Question 11

Hydrocephalus prognosis –

Best cognitive outcome with? Low normal intelligence and language disorder with? Severe mental retardation with?

Answer 11

Aqueductal stenosis

Chiari type II malformation

X-linked hydrocephalus

Question 12

Myelomeningiocele versus meningiocele versus spina bifida occulta

Diagnosis?

Prognosis?

Answer 12

Herniation of spinal cord and meninges (most common) versus herniation of meninges only (no neural deficits) versus no herniation

Physical exam versus MRI versus spinal radiographs

Handicapped (wheelchair, incontinence, retardation) versus excellent prognosis in others

Question 13

Spina bifida – caused by what drugs?

Answer 13

Decreased folate, phenytoin colchicine, vincristine, azathioprine methotrexate

Question 14

Spina bifida associated with what clinical features?

Answer 14

1. Hydrocephalus
2. Cervical hydrosyringomyelia (Fluid within the central spinal cord canal)
3. Defects in neuronal migration (Agenesis of corpus callosum)
4. Orthopedic problems (rib, lower extremity abnormalities)

Question 15

The following abnormal respiratory responses suggest?

1. Hypoventilation
2. Hyperventilation
3. Cheyne-Stokes breathing
4. Apneustic breathing
5. Ataxic/agonal breathing

Answer 15

1. Opiates/sedative overdose
2. Metabolic acidosis, neurogenic pulmonary edema, mid brain injury
3. Alternating apneas and hyperapneas – Bilateral cortical injury
4. Pausing at full inspiration – Pontine damage
5. Irregular respirations with no pattern – Medullary injury and impending bring death

Question 16

Suggested by these findings:

1. Unilateral dilated nonreactive pupil
2. Bilateral dilated nonreactive pupils
3. Bilateral constricted reactive pupils

Answer 16

1. Uncal herniation
2. Postictal state, irreversible brainstem injury, topical dilating agent
3. Opiate ingestion or Pontine injury

Question 17

Brainstem reflexes assessed during comas?

Answer 17

1. Oculocephalic maneuver (Doll’s size)
2. Caloric irrigation (cold water irrigation of the ears causes eye to deviate towards irrigated side)
3. Abnormal corneal/gag reflex