Pediatric Neurology Flashcards
Brain etiologies of floppy baby
1) Hypoxic ischemic encephalopathy
2) Trisomy and other chromosomal alterations
3) Benign congenital hypotonia
4) Cerebral malformation
5) Neonatal adrenoleukodystrophy
6) Pelizaeus-Merzbacher disease
7) Prader-Willi syndrome
8) Zellweger Syndrome
Spinal cord etiologies of floppy baby
1) Hypoxic ischemic myelopathy
2) Traumatic spinal cord injury
Anterior horn etiologies of floppy baby
1) Spinal muscular atrophy
2) Vaccine related poliomyelitis
3) GM2 gangliosidosis
4) Coxsackie
Peripheral nerve etiology of floppy baby
1) Dejerine-Sottas
2) Congenital hypomyelinating polyneuropathy
3) CMT1 and 2
4) AIDP/CIDP
5) MLD
6) Guillen Barre
NMJ etiology of floppy baby
1) Familial infantile myasthenia
2) Infantile botulism
3) Transitory myasthenia gravia
Muscle etiology of floppy baby
1) Acid maltase deficiency
2) Central core myopathy
3) Congenital myotonic dystrophy
4) cytochrome c oxidase deficiency
5) Fukuyama MD
6) Infantile myositis
7) Merosin deficiency
8) Myotubular myopathy
9) Nemaline rod myopathy
10) Phosphofructokinase deficiency
11) Phosphorylase deficiency
12) Congenital fiber type disproportion myopathy
Look for CPK abnormalities!
Signs of brain etiology for floppy baby
Alertness: impaired
CNs: intact
Muscle tone: mixed
Muscle strength: normal
Muscle bulk: normal
DTRs: decreased then increased
Sensation: variable
Signs of SC etiology for floppy baby
Alertness: Normal
CNs: Intact
Muscle tone: Mixed
Muscle strength: Mixed
Muscle bulk: Normal
DTRs: Mixed
Sensation: Sensory level
Signs of anterior horn body etiology for floppy baby
Alertness: Normal
CNs: Tongue fasciculations
Muscle tone: Low
Muscle strength: Low
Muscle bulk: Low
DTRs: Low or absent
Sensation: Normal
Signs of peripheral nerve etiology for floppy baby
Alertness: Normal
CNs: Normal
Muscle tone: Low
Muscle strength: Low
Muscle bulk: Low
DTRs: Absent
Sensation: Diminished
Signs of NMJ etiology for floppy baby
Alertness: Normal
CNs: Facial weakness, oculomotor abnormal, bulbar weakness
Muscle tone: Low
Muscle strength: Low
Muscle bulk: Normal
DTRs: Low
Sensation: Normal
Signs of muscle etiology for floppy baby
Alertness: Normal
CNs: Facial weakness
Muscle tone: Low
Muscle strength: Low
Muscle bulk: Low to normal
DTRs: Low
Sensation: Normal
Spinal muscular atrophy
Autosomal recessive
Carrer frequency of 1 in 50. 1 in 10000 live births.
Caused by mutation in SMN1 gene on chromosome 5. Causes degeneration of the anterior horn motor neurons.
4 clinical subtypes
SMA type 1
Most common AKA Werdnig-Hoffman
Most severe form. Onset before 6 months
Death typically by age 2 years.
Pregnancy typically normal, one third note decreased fetal movements.
Normal cerebral function and alertness
Facial muscles normal
Tongue fasciculations in 50%
Poor suck/swallow
Weak cry
Profound hypotonia and flaccid weakness. Frog-legged posture. Distal strength better than proximal.
No head control
Never sit
DTRs usually absent
Sensation normal
Diaphragm spared (paradoxical breathing)
Respiratory distress
SMA II
Intermediate severity.
Onset between 7 and 18 months
Eventually sit but never walk on own
Kyphoscoliosis
Weak swallow - poor weight gain - freq aspiration
Respiratory insufficiency is freq cause of death during adolescence
SMA III
Mild but broad phenotype
Onset between 7 and 18 months
All walk on own but some may need wheelchair assistance. Others only have mild weakness
Scoliosis is common
Diagnosing SMA
SMN1 gene testing
EMG - Abnormal spontaneous activity with fibrillations and positive sharp waves
NCS - usually normal
CK - normal to slightly elevated
Muscle bx - groups of atrophied type 1 and 2 muscle fibers interspersed with hypertrophic type 1 fibers
NF1 diagnosis
At least 2 of the following:
1) 6 or more cafe spots greater than 5mm before puberty and 15mm after.
2) 2 or more neurofibromas or 1 plexiform neurofibroma
3) Axillary or inguinal freckling
4) Optic glioma
5) 2 or more Lisch nodules (on fundoscopic exam)
6) osseous lesion such as sphenoid dysplasia or pseudoarthrosis
7) 1st degree relative with NF1 (auto dominant)
Malignant Peripheral Nerve Sheath Tumors
If NF1 features plexiform neurofibromas, there is a risk of conversion to this
Lifetime risk 10%
5yr survival 19%. Overall 28%
Presents with rapid growth of a preexisting nodule within a plexiform neurofibroma
Higher incidence of rhabdomyosarcoma
Infantile spasm clinical features
Another peds seizure syndrome
includes spasm plus typical EEG pattern of hypsarrhythmia (chaotic) and in early childhood. EEG pattern seen at all times, not just during spasm.
Age range 1day to 4y with peaks at 2-8m. Almost all before 1 y.
“West Syndrome” = IS, hypsarrhythmia, psychomotor regression
Symptomatic in 67%. Due to metabolic conditions, perinatal asphyxia, Down syndrome, cerebral infarct, structural malformations, tuberous sclerosis
Cryptogenic in 33%. We don’t know etiology.
Strong association with mental retardation. 75-93% of affected children
High mortality: 11-33%
Refractory to normal seizure treatments
Sometimes X linked with ARX gene (homeobox)
The spasms of IS
Usually involve the muscles of neck, trunk, extremities. Contraction phase is less than 2 seconds then a tonic phase that’s 2-10s. Can have very brief contraction with no tonic phase. Can have periods of lower responsiveness after a spasm up to 90s.
About half have some eye deviation or nystagmoid movements. Often cry after. Most occur in clusters. Tend to occur following arousal. Not triggered by startling stimuli.
Hypsarrhythmia
Very high voltage, random, slow spikes and waves, diffusely
Multiple foci
Very disorganized/chaotic
Ictal EEG shows high voltage slow wave followed by attenuation
Treatment of IS
ACTH
Vigabatrin
Ketogenic diet
B6
Other AEDs - Topamax, Zonisamide, VPA
ACTH as treatment in IS
Mechanism of anti-convulsant effect unknown.
Works better than steroids. 50-86% effectiveness in eliminating spasms.
Side effects: HTN, susceptible to infection, cerebral atrophy, obesity, edema, gastric ulceration and hemorrhage, hyperphagia, glaucoma, irritability**
Must give GI ppx
Follow BPs, DS, Na/K
Mortality can be as high as 5%
Expensive
