Iatrogenic muscle fibrosis. Arm levitation as an initial sign.

Three patients had iatrogenic muscle fibrosis, without weakness or sensory loss. Deltoid muscle fibrosis produced the unique clinical sign of gradual, involuntary, and irreducible arm levitation. The third patient had both levitated arms and levitated legs, a result of injections in the rectus femoris muscles. Repeated intramuscular injections apparently resulted in muscle fibrosis and intramuscular nerve-twig damage. Pentazocine (Talwin) is a particularly offending agent. One patient showed an unusual tissue reaction to foreign material, which may have played a role in her muscle fibrosis. Nevertheless, dramatic recovery of muscle function followed surgical sectioning of the fibrous deltoid bands.