Neurology VII-XVIII Flashcards
Selective neuronal necrosis - most common injury?
Hypoxic ischemic encephalopathy
Selective neuronal necrosis - pathogenesis and when to see change occur?
- Oxygen deprivation
- Potential role of excitatory AA - ASPARATATE + GLUTAMATE
- Change 24-36 hours after injury
Selective neuronal necrosis - distribution?
- Diffuse
- Cerebral cortex -> deep nuclear structures (BASAL GANGLIA, THALAMUS, GOLLUS PALLIDUS)
Selective neuronal necrosis - clinical outcome?
- Pyramidal cerebral palsy
- Mental deficiency, feeding difficulties, seizures, ataxia
Parasagittal cerebral injury - pathogenesis?
- Usually ischemic lesion in full term infants
- Disturbance in cerebral perfusion s/t systemic hypotension, hypoxemia, acidosis (severe perinatal depression)
Parasagittal cerebral injury - distribution?
- Border areas perfused by anterior, middle , posterior cerebral arteries (border areas susceptible to decreased in cerebral perfusion pressure)
- Usually bilateral and symmetrical, however one side can be more affected
- Parasagittal supermedial areas - posterior cerebral hemisphere more often involved
Parasagittal cerebral injury - clinical outcome?
- SPASTIC QUADRIPLEGIA (PROMIXAL LIMBS UPPER > LOWER)
- Weakness shoulder girdle
- If posterior artery affected - deficits in auditory, visual, spatial, language abilities
- Cognitive deficits
Focal or multifocal ischemia - distribution?
- Usually ischemic lesion in full term infants
- Unilateral 90% > bilateral 10%
- Left hemisphere most commonly affected - LEFT MIDDLE CEREBRAL ARTERY most common site
- left MCA 60% > right MCA 20% > bilateral MCA 10% > other arteries 5%
Focal or multifocal ischemia - etiology?
- Unknown 50% vs Perinatal asphyxia 33%
- Others 2% each - trauma, meningitis, polycythemia, hypernatremia/dehydration, postnatal hypotension, CHD, protein C def, protein S def, ATIII def, anti-PL Ab, intrauterine cocaine exposure
Focal or multifocal ischemia - neonatal presentation?
- Hypotonia vs hypertonia: PROXIMAL LIMBS UPPER > LOWER
- Seizures 12-24 hours of life; associated with apnea
- Decr level consciousness
- Periodic breathing or resp failure
- Intact pupillary response and oculomotor response
- Feeding dysfunction common - abnormal sucking, swallowing, tongue movements
Focal or multifocal ischemia - clinical outcome?
- Hemiplegia or quadriplegia
- Cognitive deficits
- Seizure disorder
Periventricular hemorrhage - risks?
Prematurity
IVH
Severe illness
Periventricular hemorrhage - location?
Usually large, asymmetric, mostly unilateral
Doral and lateral to external angle of lateral ventricles
Periventricular hemorrhage - pathogenesis?
- Caused by hemorrhagic necrosis of periventricular white matter
- Directly related to IVH because:
1. 80% associated large asymmetric IVH
2. Lesion usually same side as IVH
3. Develops after IVH occurs (PEAK TIME 4TH DAY OF LIFE)
IVH obstructs blood flow in terminal vein, leading to venous infarction in distribution of MEDULLARY VEINS (drain cerebral white matter into terminal vein)
Periventricular hemorrhage - how to diagnose?
Ultrasound d/t high sensitivity and resolution
Periventricular hemorrhage - clinical outcome?
Spastic hemiparesis or asymmetric quadriparesis UPPER = LOWER
Periventicular leukomalacia - risks?
Prematurity (rarely >32w)
Severe illness
IVH
Maternal fetal infection
Prolonged hypoxia (postnatal systemis hypotension)
Periventicular leukomalacia - pathogenesis?
- Caused by focal injury and necrosis of periventricular white matter
4 main physiologic features that predispose premature infants:
1) Periventricular vascular anatomic factors
2) CPP dependent on systemic BP
3) Increased vulnerability of actively differentiating or myelinating periventricular glial cells
4) Insult (vascular, inflammatory) leading to oligodendroglial cell death -> myelin deficiency
May develop lateral ventricular dilation in presence of myelin deficiency
Periventicular leukomalacia - how to diagnose?
Ultrasound - bilateral linear echodensities adjacent to external angles of lateral ventricles
US findings not evident until 1 month or later
Periventicular leukomalacia - clinical outcome?
SPASTIC DIPLEGIA (LOWER > UPPER) most common clinical sequela
Cognitive and visual deficits
Subdural hemorrhage - pathogenesis?
Uncommon
Full term > preterm
Caused by trauma and tearing of veins and venous sinuses
Subdural hemorrhage - clinical presentation?
Posterior fossa / Infratentorial:
- Severe hemorrhage with acute signs: stupor, lateral eye deviation, opisthotonos, apnea, death
- Insidious onset: can be silent for DAYS
Over convexities:
- Minimal or no symptoms
- Severe hemorrhage with acute signs: seizures, lateral eye deviation, nonreactive dilated pupil on side of hematoma, hemiparesis
- Insidious onset: can be silent for MONTHS
Subdural hemorrhage - how to diagnose?
- CT: safe, quick, details injury
- MRI: views of posterior fossa
- US: not effective
- Avoid LP, may provoke herniation
Subdural hemorrhage - prognosis?
Severe infratentorial: extremely poor px
Less severe infratentorial: variable
- if tx’d - 80-90% normal outcome
- 10-15% serious sequelae including hydrocephalus req shunt
- 5% mortality
Convexity: favorable; incr risk for focal cerebral signs and hydrocephalus
Subarachnoid hemorrhage
Premature > full term
Asymptomatic
Possible early onset refractory seizures on 2nd postnatal day
Dx CT
Px good
Cerebellar hemorrhage
Uncommon
Premature > full term
Serious; sx brainstem compression and irritation = Respiratory irregularities, apnea, bradycardia, lateral deviation eyes
Dx US, CT more definitive
Px long term neurodev deficits
Intraventricular hemorrhage - premature infants
Common
Premature 15% > full term
>32w severe IVH 5-6%
Location: germinal matrix, subependymal germinal matrix
Risks multifactorial (dev fragility, vulnerability and vascularity germinal matrix, fluctuating cerebral blood flow, incr CVP, impaired autoregulation CBF, coagulation disturbance)
Clinical: 50% occur in first 24h, 90% by 72h; variable presentation
Dx: serial US
Management: monitor for PHH and PVL
Px: depends on severity
Intraventricular hemorrhage - full term infants
Rare 2% full term infants
Location: germinal matrix, subependymal germinal matrix
Risks: trauma, asphyxia, majority no definable cause
Clinical: irritability, lethargy, apnea, seizures
Dx: US or CT
Management: monitor for PHH
Px: 55% neurologically normal; 40% severe neurologic sequelae, 50% shunt; 5% mortality
Caput succedaneum
Common
Hemorrhagic edema CROSSES SUTURE LINES
Soft, superficial, pitting
Vertex of head, associated with cranial molding
Spontaneously resolves over SEVERAL DAYS
Cephalohematoma
1-2% all births
Boys > girls, primiparous mother, delivery forceps
BLEEDING AT SUBPERIOSTEAL CONFINED BY SUTURE LINES
Firm, tense
Underlying skull fracture 10-25%
Spontaneously resolves FEW WEEKS TO MONTHS
Monitor hyperbilirubinemia
Subgaleal
Less common
BLEEDING OF EMISSARY VEINS BETWEEN SCALP AND DURAL SINUSES
BLEEDING BETWEEN SKULL PERIOSTEUM AND APONEUROSIS
Blood can dissect through subcutaneous tissue of neck and behind ear; up to 30% blood can be sequestered
Firm or fluctuant
Spontaneously resolves 2-3 WEEKS
Monitor hyperbilirubinemia
Extradural
Rare
SUPERIOSTEAL on INNER SURFACE OF SKULL
Caused by disruption MIDDLE CEREBRAL ARTERY OR VEIN and VENOUS SINUS
Linear skull fractures and cephalohematomas may co-exist
Early signs increased ICP
Dx: emergent CT shows CONVEX SHAPED hemorrhagic lesion
Management: evacuation aspiration or surgical
Brachial plexus injuries - which root most vulnerable?
Upper roots most vulnerable - first C5 then C6 and so on
90% unilateral right > left
Risks: LGA, complication labor and delivery process
Management: prevent contractures - PT, eval 3 months if no recovery
Px: 88% normal by 4 months, 92% normal by 1 year
- w/ full recovery: improvement by 2 weeks, recover by 6 months
- if residual impairment at 15 months, usually persists
- Potential morbidity: impaired function + strength, muscle atrophy, contractures, impaired growth
Erb-Duchenne Palsy
PROXIMAL C5-C7 injury
Most common 90%
“Waiter’s tip” = arm ADduction + internally rotated, extension elbow, pronation forearm, flexed wrist + fingers
Biceps reflex absent
Grasp reflex INTACT (diff Klumpke)
Shoulder moro absent
Hand moro PRESENT (diff Klumpke)
C4/C5 = phrenic nerve palsy
- Resp distress + decr diaphragm movement = CXR w/ elevated hemidiaphragm
C7 = flexion deformity of hand, winged scapula, sensory loss over deltoids + radial aspect upper arm, decr temp + perspiration
- Same moro + grasp reflex as above
Klumpke’s Palsy
DISTAL C8-T1 injury
Less common
Rare isolated injury, often upper roots involved -> total palsy
Flexors wrist + fingers weak = wrist + fingers extended in neutral position
Biceps reflex absent
Grasp reflex ABSENT (diff Erbs)
Complete moro ABSENT (diff Erbs)
T1 = unilateral Horner’s syndrome
- Miosis + ptosis + anhidrosis + decreased pigmentation of iris
Spinal cord injury
Traction + excessive rotation at delivery
Flaccid weakness LOWER > UPPER extremities
Sensory level at lower neck to upper trunk
Paradoxical respirations
Paralyzed abd muscles w/ rounded, distended appearance
Atonic anal sphincter
Distended bladder
Dx: US then MRI better delineate lesion
Facial nerve palsy
CN VII most common facial nerve injury during delivery
Caused by nerve compression w/ hemorrhage + edema of nerve sheath
Weakness lower + upper facial muscles, unilateral left 75% > right
Asymmetric cry
Lack of complete eyelid closure, inability to wink, flat nasolabial fold on paretic side
Px good, recover 1-3 weeks
Management: eyedrops, tape paralytic eyelid
Lower motor neuron disorders - major categories
- Anterior horn cell - ex. SMA Type 1 (Werdnig-Hoffman Disease)
- NMJ - ex. Acquired transient neonatal myasthenia graves, Congenital myasthenia graves
- Congenital myopathy
- Muscular dystrophy - ex. Congenital myotonic dystrophy
- Metabolic and multisystem disease
Spinal muscular atrophy type I - genetics, pathophysiology, history?
= Werdnig-Hoffman Disease
Genetics: AR, chromosome 5 (“S” = “5”)
Patho: Degeneration anterior horn cell
Hx: Decreased fetal movements, affected sibling
Spinal muscular atrophy type I - clinical presentation?
- Onset < 6 months
- Severe generalized hypotonia w/ marked head lag -> LEGS > ARMS; PROXIMAL > DISTAL
- Areflexia
- Bulbar weakness = poor suck and swallow, weak cry, TONGUE FASCICULATIONS
- Facial sparing- Classic “frog-leg” position
- Bell-shaped chest w/ abdominal breathing
- Upper extremities ABducted + rotated = “jug handle” appearance
- Normal extraocular movements, sensory exam, sphincter fxn, diaphragmatic fxn (vent support less likely)
Spinal muscular atrophy type I - diagnosis and prognosis?
Dx:
CPK normal
EMG nonspecific denervation, fasciculations, fibrillations
Muscle biopsy w/ atrophy of motor units
Nerve conduction velocity normal
Px: death < 2 years
Acquired transient neonatal myasthenia gravis - epidemiology and pathophysiology?
Epi: 10-20% infants born to mothers w/ MG (no correlation to severity and duration of maternal disease
Patho: immune process involving NMJ
- TRANSIENT
- neonate affected by maternally transmitted anti-Ach R Ab from mother with MG
Acquired transient neonatal myasthenia gravis - clinical presentation, duration?
- Intrauterine hypotonia and weakness -> decreased fetal movement, arthrogryposis, polyhydramnios, pulmonary hypoplasia
- Facial weakness, swallowing difficulties, feeding difficulties
- 2/3 resp failure, inability to management secretions
Duration: mean 18 days
Acquired transient neonatal myasthenia gravis - diagnosis and treatment?
Dx:
- Maternal history
- CPK normal
- EMG progressive decline amplitude w/ repetitive nerve stimulation, then return to baseline after period of rest or neostigmine
- Muscle biopsy normal
- Nerve conduction velocity normal
Tx: anticholinesterase therapy = neostigmine
Congenital neonatal myasthenia gravis - pathogenesis and types?
genetic defect in NMJ
NOT TRANSIENT
2 types:
1) Congenital myasthenia
2) Familial infantile myasthenia
Congenital myasthenia - pathophysiology, clinical presentation, diagnosis?
Genetics: AR
Path: deficiency of ENDPLATE acetylcholine R
Clinical:
- Less severe than familial infantile
- Sx by few weeks of life
- Ptosis, ophthalmoplegia, facial weakness, poor suck and cry
Dx: Similar to acquired transient MG
- CPK normal
- EMG progressive decline amplitude w/ repetitive nerve stimulation, then return to baseline after period of rest or neostigmine
- Muscle biopsy normal
- Nerve conduction velocity normal