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Detailed information of FLOPPY INFANT
FLOPPY INFANT
DEFINITION:
A subjective decrease to resistance to passive range of motion in
a newborn or infant.
EPIDEMIOLOGY:
- incidence: ?
- age of onset:
- risk factors:
- see differential diagnosis
DIFFERENTIAL DIAGNOSIS:
- Hypoxic-Ischemic Myelopathy
- Malformations
- Trauma
2. Lower Motorneuron
- SMA Type 1 - Werdnig-Hoffman Disease
- SMA Type 2
- SMA Type 3 - Kugelberg-Welander Disease
2. Polyneuropathy
- Congenital Hypomyelinating Polyneuropathy
- Familial Dysautonomia (Riley-Day Syndrome)
- Hereditary Sensory Neuropathy
3. Neuromuscular
- Congenital Myasthenia
- Transitory Neonatal Myasthenia Gravis
2. Infantile Botulism
4. Myopathies
- Central Core Disease
- Centronuclear Myopathy
- Congenital Muscle Fibre-Type Disproportion
- Minicore Disease
- Myotubular Myopathy (X-linked)
- Nemaline Rod Myopathy
2. Muscular Dystrophies*
- Congenital Muscular Dystrophy
- Congenital Myotonic Dystrophy
3. Metabolic Myopathies
- Glycogen Storage Diseases
- Type 1a - Von Gierke Disease
- Type II - Pompe's Disease
- Type III - Forbes Disease
- Type V - McArdle Disease
- Mitochondrial Disorders
5. Miscellaneous
- Achondroplasia
- Spondyloepiphyseal Dysplasia
- Thanatophoric Dwarfism
-
*most common causes of floppy infant
CLINICAL FEATURES:
- posture - square window - popliteal angle
- head lag - arm recoil - leg recoil
- ventral suspension - scarf sign - heel to ear
- ankle dorsiflexion
2. Evidence of Upper Motoneuron Lesion
- dysmorphic features
- seizures
- ocular problems
- no weakness (able to move limbs off bed)
- fisting of hands (after 6 weeks of age)
- scissoring on vertical suspension
- hyperreflexia
- malformation of other organs
3. Evidence of Lower Motoneuron Lesion
- weakness (unable to move limbs off bed)
- normal or decreased reflexes
- fatiguability
- fasciculations
- lack of muscle mass (atrophy)
- social and cognitively age appropriate
- elevated CPK
INVESTIGATIONS:
- CT scan
- Nerve Conduction Studies and EMG
- serum electrolytes, calcium, glucose, CPK
- blood culture, lumbar puncture
2. Second Line
- 'TORCH' screen
- karyotype
- serum amino acids
- urine amino acids and organic acids
- drug screen
- biopsy - muscle, liver
MANAGEMENT:
- treat underlying disorder
- respiratory and gastrointestinal support
2. Prognosis
- depends upon the underlying disorder
- while the differential diagnosis above has inferred an
organic cause to hypotonia, the etiology in many cases is
unknown
- even in cases where the etiology is unknown, hypotonia in
early infancy may be a marker of generalized central nervous
system dysfunction as a recent study by Dr. Andrew Morgan of the
U. of Illinois College of Medicine found that only 1/3 of
hypotonic babies were neurodevelopmentally normal by the time
there were 5-7 years old (24% minimally impaired, 43% abnormal)
and he recommends that all hypotonic infants be closely
monitered and if needed, enrolled in early intervention services
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Pediatric Database - FLOPPY INFANT
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