Hypotonia

Excerpt

The tone of the muscle is defined as a residual tension in a muscle at rest. It is a continuous and passive partial contraction of the muscles, which maintains posture. It is determined by resistance encountered with the passive stretching of a muscle or the passive movement of a limb at a joint. Hypotonia is a poor muscle tone resulting in floppiness. It is abnormally decreased resistance encountered with passive movement of the joint. It must be differentiated from weakness, which refers to a decrease in the maximum power a muscle can generate.

Hypotonia may or may not be associated with muscle weakness. Although easily recognizable, it may be challenging for a clinician to determine the underlying cause of hypotonia. There is an extensive list of causes, but approaching the case systematically and obtaining a detailed history and physical examination can help reach a diagnosis. Determining the etiology is crucial for the management and prognostication. Specific treatments are available for some diseases, but treatment generally comprises supportive care with rehabilitation services and nutritional and respiratory support.