Hypotonia in Infants

Abstract

Neonatal hypotonia can have many different etiologies. Floppiness in an infant can be caused at various levels of the nervous system from disorders of the brain to spinal cord lesions, neuropathies, neuromuscular junction disorders, and myopathies. A variety of diagnostic tools are available for defining the source of the hypotonia, but before any serum values, muscle biopsies, electromyelograms (EMGs), or nerve conduction studies are ordered, a thorough neurologic examination is essential for determining the diagnosis. The first goal in diagnosing the source of neonatal hypotonia is to ascertain if it is central on peripheral. Infants who have central hypotonia from a brain source usually have other central deficits.