Infant usually constipated, poor feeding, weak, ptosis, decreased eye movements, and areflexic. May have respiratory failure and need ventilatory support. Aminoglycosides and hypomagnesium may interfere with the release of acetylcholine. There are many forms of myopathies that present in the neonatal period. They are hypotonic and hyporeflexic.
Diagnosis is made by muscle biopsy.
It is a rule out diagnosis after eliminating other causes of hypotonia. Hypotonia in Infants Pediatrics in Review.