Neurology VII-XVIII Flashcards
(115 cards)
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