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
Familial infantile myasthenia - pathophysiology, clinical presentation, diagnosis?
Genetics: AR rare
Path: deficiency in PRESYNAPTIC Ach synthesis or packaging into vesicles
Clinical:
- Can be severe
- Hypotonia, resp failure, apnea, severe feeding difficulties, facial weakness, ptosis
- Oculomotor less affected than congenital
- Improvement with age
Dx:
- EMG fatigue with prolonged stimulation of faster rates
Congenital myotonic dystrophy - genetics, risks, pathogenesis, history?
Genetics: AD, chromosome 19
- Trinucleotide repeat CTG, severity determined by number of repeats
- almost entirely inherited from MOTHER
Risks: more severe and earlier onset of mother -> greater risk
Path: altered protein in muscle -> dysfunctional Na and K channels
Mat hx: inability to open eyes completely after shutting tight, delayed release hand grip
Pregnancy hx: polyhydramnios (disordered fetal swallowing), prolonged labor (maternal uterine dysfunction, possibly only sign since mothers often misdiagnosed)
Congenital myotonic dystrophy - clinical presentation?
First hours to first days of life
Facial diplegia: “tent shaped” mouth, poor oral-motor fxn, resp failure, hypotonia, arthrogryposis, areflexia/hyporeflexia, muscle atrophy
Mental deficiency later in life
Neonatal mortality 40%
Congenital myotonic dystrophy - diagnosis?
CPK normal
EMG “myotonic” changes “dive-bomber” sound
Muscle biopsy abnormal = small round muscle fibers w/ large nuclei and sparse myofibrils
Nerve conduction velocity normal
Riley-Day Syndrome or Familial Dysautonomia - genetics, pathophysiology?
Genetics: AR rare
- defect 9q31-33
- Ashkenazi Jewish
Path: disorder peripheral NS
- reduced number small unmyelinated nerves that carry pain, temp, taste, mediate autonomic fxn
- reduced number large myelinated afferent nerve fibers
Riley-Day Syndrome or Familial Dysautonomia - clinical presentation?
Sx first year of life
Poor suck and swallow with high risk aspiration
Emesis, abd distension, loose bowel movements, irritability
Pale, blotchy skin
Hypotonia, absent corneal reflexes, decreased or absent DTR, hypersensitive pupillary denervation
Decreased tongue papillae
Temp and BP instability
Riley-Day Syndrome or Familial Dysautonomia - diagnosis?
In normal patient exposed to metacholine eye drops or pilocarpine -> usually no response
In patient with FD / Riley-Day -> leads to miosis
No flare w/ intradermal histamine
Prader-Willi Syndrome - genetics and prenatal history?
Genetics:
- 70% paternal deletion 15q11.13
- 25% maternal uniparental disomy
- 5% maternal methylation at several loci within 15q11-13 region
Prenatal hx: decreased fetal movement, breech, or both
Prader-Willi Syndrome - clinical presentation?
Triad: hypotonia + cryptorchidism (or hypogonadism) + poor feeding
Other:
- Small hands and feet
- Almond shaped palpebral tissues
- Thin upper lip
- Light colored hair
- Mild to severe MR, dolichocephaly
- Incr risk scoliosis
- FTT during infancy then obesity from age 6 months to 6 years
Arthrogryposis multiplex congenita
Fixed joints with limited movements
Associated with other disorders that affects motor fxn
Management: stretching, serial casting, tendon or ligament release procedures
Seizures - etiology and treatment?
Hypoxia-ischemia
Intracranial hemorrhage
Metabolic - hyponatremia, hypoglycemia, hypocalcemia, metabolic disorders)
Infection
Developmental cerebral anomalies
Drug withdrawal (maternal heroin, methadone, barbiturates)
Treat underlying cause
- Use of anticonvulsants
- Pyridoxine for inherited deficiency
Subtle seizures
- Most common
- Oral, facial, ocular activity
- “swimming”, “pedaling” limb movements
Multifocal seizures
- Clonic activity, jittery of one limb with migration to another part of body non ordered fashion
- Full term
Focal clonic seizures
- Well-localized repetitive
- Poss associated with metabolic disorder
- Full term > preterm
Tonic seizures
- abrupt change in tone leads to change in posture “posturing” “stiffening” “rigidity”
- Can be decerebrate posturing
- Premature
Myoclonic seizures
- Rapid sudden shock like jerks of flexion or both arms +/- legs
- Individual or brief series
- Premature = term
Bumetanide
Antiepileptic
Diuretic
Inhibit Na-K-Cl tritransporter used to block Cl channel
Tx temporal lobe seizures
Topiramate
Antiepileptic
Enhances GABA-activated Cl channels
Inhibits excitatory neurotransmitter
Phenobarbital
Initial drug of choice
Acts on GABA-A R subunit -> increases time for Cl channels to remain open -> decreasing the cerebral metabolic rate
Therapeutic level 20-40 mg/L
Metabolism liver cytochrome P450
half life:
0-7 days = 100 hours
> 28 days = 0-70 hours
Oral or IV
Phenytoin
TERATOGEN
Block voltgate-gated Na channels -> block repetitive firing of action potentials
Therapeutic level 10-20 mg/L
Metabolism liver cytochrome P450 + excrete in urine
IV preferred
Oral not ideal - poor GI absorption
Monitor cardiac arrhythmias
Keppra
Binding to synaptic vesicle protein SV2A -> reduce rate of vesicle release
Midazolam
Increases GABA activity
Vein of Galen Malformation - pathogenesis?
Path: persistent median prosencephalic vein of Markowski
- in utero, this vein drains in to Vein of Galen, regress by 2 weeks)
Mechanism of injury:
1. Intracranial steal s/t diastolic run off
2. Hemorrhagic infarction after thrombosis of dilated vein
3. Cerebral ischemia by decr CO after high output CHF
4. Brain atrophy s/t compression
Vein of Galen Malformation - clinical presentation?
- 44% present neonatal period
- Greater size -> Greater amt blood shunted through lesion -> Earlier develop CHF
- CHF present few hours of life -> worse first 3 days of life, refractory to med mgt
- Continuous cranial bruit
- Hydrocephalus 15%: usually not neonatal period s/t aqueduct obstruction or elevated CVP
- Poss small aneurysm -> HA, focal neurologic deficits syncope later in life
Vein of Galen Malformation - diagnosis, management, prognosis?
Dx: US doppler, CT, or MRI + angiography
Mgt:
- Minimize CHF
- Embolization transvenous or transarterial, better survival compared to surgery
Px:
- Outcome dep severity CHF and degree brain injury
- Incr risk neurologic deficits
- Morbidity + mortality high
Sturge Weber Syndrome
Genetics: sporadic
- PORT-WINE STAIN = pink-purple flat hemangiomata unilateral in 1st division TRIGEMINAL NERVE (CN V) PRESENT AT BIRTH
- CNS ipsilateral “tramline” intracortical calcifications
- GLAUCOMA 30% + visual deficits
- Macrocephaly: hyperplasia of endothelium
- Seizures GRAND MAL at 2-7 months, mental deficiency
- Hemiparesis contralateral to facial lesion
- Worse w/ age
Tuberous Sclerosis
Genetics: AD
- Chrm 9, 16
- HYPOPIGMENTED “ASHLEAF” MACULES 50%: +Wood’s lamp, mostly at trunk and buttocks
- can also have cafe-au-laite spot and shagreen spot
- Cardiac rhabdomyomas
- CNS tumors
- Eye involvement
- Seizures, mental deficiency
- Enamel pits in teeth
- Worse w/ age
Neurofibromatosis
Genetics: AD
- Chrm 17
- CAFE-AU-LAIT SPOTS: do not cross midline, SHARP BORDERS, multiple >1.5 cm, RARELY AT BIRTH, 80% by 1 year, 100% by 4 years
- Freckling axilla, inguinal folds, perineum
- Macrocephaly, aqueduct stenosis
- Associated tumors: cutaneous neurofibromas, schwanoma, pheochromocytoma
- Mildly short stature
- Seizures, mental deficiency
McCune-Albright Syndrome
Genetics: sporadic
Triad:
1) IRREGULAR BROWN PIGMENTATIONS “Coast of Maine”
2) FIBROUS DYSPLASIA OF BONES
3) PRECOCIOUS PUBERTY
- Hyperthyroidism
- Hyperparathryoidism
- Pituitary adenomas
Von Hippel-Lindau Disease
Genetics: AD
- Chrm 3p (short arm)
Path: Overexpression TF hypoxia-inducible factor -> incr tumor growth
- CNS tumors: hemangioma (mostly cerebellum)
- Multiple systemic hemangiomata
- Retinal angiomas
- Pheochromocytoma
Cerebral Palsy - epidemiology?
Incidence: 2-3 / 1000
Incr incidence with decr GA + decr BW
Premature infant < 1500 g: 5-20%
24-26w: 6.9%
27-31w: 4.3%
32-34w: < 1%
36w: < 0.1%
Cerebral Palsy - risks?
Extreme prematurity - most common SPASTIC DIPLEGIA
Symptomatic congenital infection
Bilirubin encephalopathy - incr risk ATHETOID CP
Severe perinatal depression
APGAR poor indicator of infants at risk for brain damage:
- Majority term infants w/ CP had normal APGAR
- Risk of CP 1%, 9%, 57% if APGAR 0-3 at 5, 10, 20 min, respectively
Cerebral Palsy - Classification by extremities involved
Quadriplegia: all 4 limbs
Hemiplegia: one side (ex right arm + right leg)
Diplegia: legs only OR legs > arms
Cerebral Palsy - Classification by neurologic dysfunction
Spastic = Pyramidal
Athetoid = Dyskinetic = Extrapyramidal
Mixed
Ataxic
Spastic CP = Pyramidal CP
Most common 85-90% includes extreme prematurity
INCREASE TONE
INCREASE DTR
GROSS MOTOR AFFECTED
Fine motor not affected
Cognitive fxn not affected
Athetoid = Dyskinetic = Extrapyramidal CP
7% includes bilirubin encephalopathy
Repetitive uncontrolled involuntary movement
Mixed tone in SAME MUSCLE
GROSS AND FINE MOTOR AFFECTED
Cognitive fxn not affected
Hearing deficits
Speech abnl
2 types:
1) Dystonic
2) Choreoathetoid
Mixed CP
Mixed tone in VARIOUS MUSCLES
Ataxic CP = Atonic CP
Least common
DECREASED TONE, poor coordination
DECREASED DTR
SEVERE COGNITIVE DELAY
Cerebral Palsy - clinical presentation?
Hypotonia, no suck, weak cry > 24h of life Carry 10- to 20-fold incr risk CP
Hypertonia also possible
NON-PROGRESSIVE MOTOR DISORDER
Recognized at 6-18 months corrected age
Incr risk seizures, cognitive dysfunction, sensory impairment, orthopedic deformities, emotional and behavioral disorder
Cerebral Palsy - interventions?
PT, OT
Assistive devices
Ortho surgery, rhizotomy, brace, botulism toxin injections
Mental deficiency - epidemiology and onset?
3% population functions 2 standard dev below mean IQ of general population
= IQ < 70-75
Onset:
Prenatal
Perinatal
Postnatal
Mental retardation - Prenatal onset
Incidence: 60-80%
Single brain defect s/t:
- Microcephaly, hydrocephalus, hydranencephaly (absent cerebral hemispheres), NTD
Multiple defects incl brain s/t:
-Chrm disorder, genetic syndrome (T21, FRAGILE X), hypothyroidism
Infection
Toxin
Mental retardation - Postnatal onset
Incidence: 10%
Environmental - trauma, lead encephalopathy
Metabolic - hypernatremia, severe hypoglycemia, IEM
Infection - meningitis, encephalitis
Severe hypoxemia
Postnatal stroke
IVH
Mental retardation - Perinatal onset
Incidence: 8-12%
Trauma
Perinatal depression
Metabolic - kernicterus, severe neonatal hypoglycemia
Infection - meningitis
Intracranial hemorrhage
Stroke
Mental retardation - classification old vs new?
Old classification - based on IQ:
IQ = Degree of MR
52-68 = Mild
36-51 = Moderate
20-35 = Severe
<20 = Profound
New classification - based on level of support:
Intermittent = constant support not needed
Limited = ongoing support but varying intensity
Extensive = consistent ongoing and daily support
Pervasive = high support for all activities
Mental retardation - clinical presentation?
Low IQ
Limitations in social, language, self-adaptive fxns
Possible seizures, psych disorders, behavioral abnl
Often depression
Mental retardation - Management and prognosis?
Early intervention as soon as MR recognized
Family support+ counseling
Identify cause
Consult neuro, speech, SW, OT, PT
Education to max social + occupational skills
Determine support needed
Px: greater degree deficiency -> greater immobility and higher mortality
Hearing loss - epidemiology?
Profound bilateral 1/1000
Mild-mod 2/1000
Unilateral 1/1000 (LEFT > RIGHT affected)
Premature born < 32w -> incidence 2-4/100 w/ some degree of hearing loss
Hearing loss - etiology?
Genetic 50%
- 70% AR
- 15% AD
-15% other genetic transmission
- MOST COMMON GENETIC CAUSE HEARING LOSS: CONNEXIN 26 (Cx26) gene mutation 20-30%
- Alport, Pierre Robin, Usher, Pendred, Waardenburg, Treacher Collins, CHARGE, Klippel-Feil sequence, T8, Stickler, T21
Acquired 25%
- Injury intrapartum or permpartum
- S/t hypoxia, infections (meningitis), ischemia, severe hyperbili, complications r/t prematurity, ototoxic meds (gentamicin, vancomycin, furosemide)
- MOST COMMON NONHEREDITARY SENSORINEURAL HEARING LOSS: CONGENITAL CMV
Unknown 25%
Hearing loss - range
Hearing Category - Range (decibel)
Normal -10 to 20
Mild 21 to 40
Moderate 41 to 55
Moderate Severe 56 to 70
Severe 71 to 90
Profound >90
Conductive hearing loss
Path: interference in transmission of sound from external auditory canal to normal inner ear
S/t fluid in middle ear (MOST COMMON), microtia, canal stenosis, stapes fixation
Bone conduction good
AIR CONDUCTION POOR
Sensorineural hearing loss
Path: abnormal development or damage to cochlear hair cells or auditory nerve
BONE + AIR CONDUCTION POOR
Auditory dyssynchrony = Auditory neuropathy
Less common
Inner ear or cochlea receive songs appropriately, but auditory processing FROM COCHLEA TO AUDITORY NERVE abnormal
More severe sound and speech abnormalities than predicted by degree of hearing loss
Unknown cause
Central hearing loss
Auditory canal and inner ear intact with normal sensory and neural pathways, but auditory processing at HIGHER LEVELS WITHIN CNS abnormal
Hearing loss - diagnosis?
90% detected in newborn period
2 screening methods in newborn period: automated brain response (ABR) and evoked otoacoustic emissions (EOAE)
>= 35 dB = abnormal screen
Automated brain response (ABR)
> = 35 dB = abnormal screen
- Measures EEG waves generated by auditory system in response to clicks via 3 electrodes on scalp
- Reliable after 34 weeks
- Preferred initial screening method for NICU grad d/t ability to detect auditory dyssynchrony
Evoked otoacoustic emissions (EOAE)
> = 35 dB = abnormal screen
- Measures acoustic feedback from cochlea through ossicles to tympanic membrane and ear canal after click stimulus
- Quicker than ABR
- More likely affected by debris or fluid in external and/or middle ear -> higher referral rates
- Can’t detect some sensorineural hearing loss
Hearing loss - management?
- If fail EOAE -> consider ABR ptd
- If unable to perform ABR -> rescreen within 10 days of original test w/ ABR at auditory center with expanded dB ranges
If still positive for hearing loss:
- Otolaryngologist consult
- Genetic eval if no known cause
- Early intervention referral prior to 3 months PMA
- Ophthalmology to eval another sensory loss
- Determine ideal mode of assistance: amplification system, cochlear implant (esp if profound bilateral loss available as early as age 1 year)
Hearing loss - outcome?
2-7% infants initial screen will refer
Of referrals, 80% prescreen normal hearing; 20% true hearing deficit
Critical window of neuroplasticity during first 3 years
Earlier habilitation initiated -> greater chance achieving age-appropriate language and communication skills
Learning disability
Def: deficit psychological process w/ imperfect ability to listen, speak, read, write, spell, do math
- Significant discrepancy btw learning potential and actual academic achievement
- Must exclude mental deficiency, deafness, lack of opportunity
Epi: 2 peaks
1) Early elementary - reading, spelling, math
2) Late elementary - concept classes
Clinical:
Must be at least 1 std dev or 15-point difference btw scores on standardized intelligence test (higher) and standardized achievement test (lower)
Present any age
what is congenital hypoplasia of depressor angularis oris muscle ?
facial palsy. but only impact lower face.
What type of brain development occurs at 34 to 40 weeks?
Increase in cerebral volume
Increase in cortical surface area
Maturation of cell types - oligodendrocytes, microglia, astrocytes
GABA-nergic neurons migrate to cortex
At what gestational age does the fetus first respond to sound?
20 to 25 weeks
Congenital glaucoma - genetics, path, signs and symptoms?
Genetics: AR
Male > Female
Caused by abnormalities in drainage of aqueous humor in anterior eye -> increased ocular pressure
Presents within first 6 months of life
Signs and symptoms:
- Tearing
- Photophobia
- Enlarged globe (buphophthalmos)
- Corneal edema
- Corneal clouding -> irregular corneal light reflex (leukocoria) and dull red reflex
- Vision loss
- Conjunctival injection
What congenital infection presents with leukocoria?
Rubella -> bilateral cataracts
What congenital infection presents with chorioretinitis?
CMV
Toxoplasmosis (can also have cataract, like Rubella)
What are the language milestones at-
1 to 6 months?
4 to 6 months?
5 to 7 months?
10 months?
15 to 18 months?
1 to 6 months: Cooing “ooh” “aah”
4 to 6 months: Vocal play / expansion stage - consonant and vowel sounds
5 to 7 months: Babbling - forms sounds with “b” “m” “p”
*lack of babbling by 11 months warrants audiologic evaluation
10 months: Jargon / intonated babbling - well formed vowel syllables
15 to 18 months: Echolalia / repetitive sounds
What is the functional development of the eye at-
30 to 32 weeks?
Term?
2 months?
3 months?
6 months?
24 months?
30 to 32 weeks red reflex [tests afferent and efferent pathways of CN III (oculomotor)]
Term: conjugate HORIZONTAL gaze, visual fixation (well developed at 2 months of age)
2 months: conjugate VERTICAL gaze
3 months: well developed vision
6 months: visual evoked potentials reach adult levels
24 months: optic nerve myelination complete
What CN is responsible for ptosis?
CN III (oculomotor) - leading to abnormal function of levator palpebral muscle
Ptosis: inability of eyelid to rise to normal level leading to decreased vertical space btw upper and lower lids
- unilateral or bilateral
