Affiliations: Department of Pediatrics, King Abdulaziz University
Hospital, and Department of Neurosciences, King Faisal Specialist Hospital
& RC, Jeddah, Saudi Arabia
Note: [] Correspondence: Mohammed M.S. Jan, Professor and Consultant of
Pediatric Neurology, Department of Pediatrics (Neurology), King AbdulAziz
University Hospital, P.O. Box 80215, Jeddah 21589, Kingdom of Saudi Arabia.
Tel.: +996 2 6401000 (ext. 20208); Fax: +996 2 6403975; E-mail:
mohammedmsjan@yahoo.com
Abstract: Hypotonia in infants can be a confusing clinical presentation
leading to inaccurate evaluation and unnecessary investigations. Hypotonia can
result from a variety of central or peripheral causes. Therefore, hypotonia is
a phenotype of many clinical conditions with variable prognosis. It is
important to recognize that hypotonia is not equivalent to weakness. Infants
with central causes, such as Down syndrome, may have severe hypotonia with
normal muscle strength. Peripheral hypotonia is frequently associated with
weakness, which can be predominantly distal in neuropathies or predominantly
proximal in myopathies. In general, central hypotonia is much more commonly
encountered; however, the prognosis is worst for hypotonia secondary to
neuromuscular pathology. The distinction between central and peripheral
hypotonia is therefore critical for proper evaluation and management. Stepwise
and accurate assessment is very important to reach the correct diagnosis
promptly. In this review, I present a concise clinical approach for evaluating
the hypotonic infant. Some practical tips and skills are discussed to improve
the likelihood of obtaining an accurate diagnosis. Reaching a specific
diagnosis is needed for providing appropriate therapy, prognosis, and
counseling.
