Abnormal thermoregulatory responses in patients with reflex sympathetic dystrophy syndrome

To look for asymptomatic thermoregulatory abnormalities in the noninvolved limbs in patients with well established reflex sympathetic dystrophy syndrome (RSDS). The study was prompted by the observation of development of severe upper limb Raynaud's phenomenon in a young woman with a history of RSDS affecting both lower limbs.

Eleven patients and 11 age and sex matched control subjects underwent a standard thermal stress test: cold water immersion of a hand unaffected by RSDS in water at 15 degrees C for one min. All controls had had injuries uncomplicated by RSDS.

Lag time (the lag phase between the end of the cold challenge and the onset of rewarming) was significantly increased (p < 0.01) in the patient group (median 5.67 min, range 0.50 to > 15) compared to the control group (median 0.50 min, range 0.50 to 12.92). The median maximum temperature recovery was lower in the patient group (81.6%, range 0 to 170.4) than in the control group (119.3%, range 49.1 to 153.1).

Our findings support an association between RSDS and a generalized abnormal response to cold challenge. Further studies are required to examine the temporal relationship underlying this. Early screening for thermoregulatory dysfunction of patients after fractures might allow identification of patients at risk of developing RSDS.