Fever of unknown origin following traumatic brain injury

Incidence of fever in the rehabilitation phase following brain injury

There appears to be a high incidence of fever after brain injury. The most common cause for fever is infection. The incidence of fever occurring as a result of hypothalamic thermoregulatory dysfunction after brain injury is less clear. This study retrospectively reviewed the charts of 286 subjects with brain injuries. Subject subpopulations were divided into traumatic brain injuries, anoxic brain injuries, and brain injuries resulting from aneurysmal subarachnoid hemorrhage. Fever events were described as any core temperature greater than 99.9 degrees F. Most subjects suffered a severe brain injury and had an average acute hospital length of stay ranging from 35.4 to 60 days. The average rehabilitation length of stay ranged from 38.4 to 45.1 days. Twenty-four percent of subjects experienced fevers, with each of the populations having similar occurrence rates. Unexplained fever events were found in the traumatic brain injury (7%) and aneurysmal subarachnoid hemorrhage (8%) subpopulations only. No unexplained fever event was associated with a temperature greater than 100.8 degrees F.

Post-traumatic hyperthermia in acute brain injury rehabilitation

Fever frequently presents during recovery from traumatic brain injury (TBI). Elevated body temperature may result from ensuing infection, thrombophlebitis, drug reaction, or a defect in the central thermoregulatory system such as seen in post-traumatic hyperthermia (PTH). Typically, the diagnosis of PTH follows only after thorough investigation. Literature supports the theory that the febrile TBI patient, lacking a documented source, has central hyperthermia. The purpose of this study was to determine the incidence of PTH in the acute rehabilitation setting. We reviewed a consecutive series of 84 TBI patients participating in a rehabilitation programme. Four per cent of the patients in this study met our criteria for PTH. We describe a fever protocol that should aid the physician in diagnosis and treatment of the febrile TBI patient. Proposed mechanisms involved in thermoregulation are discussed.