Acute and chronic hypothermia in a man with spinal cord injury: environmental and pharmacologic causes

It is well known that people with spinal cord injuries can develop hypothermia when exposed to an unusually cold environment. Hypothermia can also develop during inpatient rehabilitation, particularly as a side effect of certain medications. We present a patient with C4 incomplete spinal cord injury whose core body temperature was chronically subnormal, and who developed acute hypothermia on several occasions during inpatient rehabilitation. The results of tests of his autonomic function were abnormal. Acute hypothermia (core temperature approximately 34C) was induced when he was challenged with nifedipine. The serum level of phenytoin became elevated to toxic levels during two episodes of acute hypothermia, but the serum level of carbamazepine did not change appreciably. This case demonstrates that people with spinal cord injuries are at risk for hypothermia, that hypothermia can be induced by nifedipine, and that significant thermal challenges can occur during routine inpatient rehabilitation. In addition, hypothermia appears to affect the metabolism of phenytoin.