MYOFASCIAL TRIGGER POINTS IN INTERCOSTAL MUSCLES SECONDARY TO HERPES-ZOSTER INFECTION OF THE INTERCOSTAL NERVE

Chronic pain in the chest wall is a major complication after herpes te ster infection of intercostal nerves. It is usually difficult to contr ol pain of such origin. Two cases are reported of postherpetic neuralg ia after herpes tester infection involving the intercostal nerves. Bot h patients had shooting, burning, aching, and localized pain in the mu scle supplied by the involved intercostal nerves 1 to 3 months after o nset. Compression palpation of a tender spot in one of these muscles i nduced a referred pain that followed the corresponding interspace, usu ally in the distal anterior direction. Local twitch responses could be elicited during injection of 0.5% or 1% Lidocaine into one of these t ender spots the pain in the interspace was consistently eliminated imm ediately after injection. One patient had complete pain relief after t hree series of injections. The effect of pain relief for the other pat ient lasted for 1 to 2 weeks after the initial injection and lasted pr ogressively longer (up to 2 months) after repeated injections. It appe ars that many of the tender spots formed in intercostal muscles after herpes tester are myofascial trigger points that respond to injection with referred pain, local twitch responses, and immediate pain relief. (C) 1998 by the American Congress of Rehabilitation Medicine and the American Academy of Physical Medicine and Rehabilitation.