Regional hypothermia in response to minor injury

Minor injuries are sometimes followed by a potentially disabling syndrome of hyperalgesia, hyperesthesia, allodynia, and sudomotor disturbance as well as, eventually, weakness, muscle atrophy, trophic skin changes, and bone and joint abnormalities. Vasomotor changes frequently present as hypothermia or hyperthermia. Most of the literature refers to this syndrome as reflex sympathetic dystrophy (RSD). To observe possible early RSD changes, we studied 1000 military recruits before and during basic training. Evaluations consisted of lower limb clinical examinations and pain assessment. Infrared images were taken of anterior, posterior, medial, lateral legs, and plantar surface of the feet. If the clinical examination suggested a possible stress fracture, a bone scan was performed. Recruits were studied before training and again each time musculoskeletal complaints arose. The controls were recruits tested before the onset of training who had no musculoskeletal complaints. Two-hundred seven soldiers were injured. Regional hypothermia was noted in 8.6% of all thermograms, with 75% on the left and 25% on the right. The most common injuries causing this phenomenon were ankle pain/sprain and minor foot stress fractures, especially the left metatarsals. Hypothermia occurred within 24 to 48 h, usually beginning in the periphery and ascending proximally, lasting a few days to 6 wk (end of study). None of the recruits developed the full syndrome of RSD during the study period. Whether the continued training, even though modified, helped to prevent this complication or the observed post-traumatic hypothermia has no relationship to RSD needs to be determined.