Fever Without Infection in the Neurological Intensive Care Unit

Many fevers in the neurological intensive care unit (NICU) occur directly from brain injury (termed central fever), rather than from an underlying infection. However, NICU patients also face a high risk for infection because of numerous factors such as immobility, impaired airway reflexes, and indwelling urinary catheters and central venous catheters. Identifying the cause of fever in this population can be difficult but is important, because overuse of antibiotics breeds resistant organisms, whereas delay in antibiotic administration can lead to overwhelming sepsis.

To identify characteristics that can help distinguish central from infectious fever, investigators at an academic tertiary-care hospital retrospectively reviewed the records of all adult patients admitted to the NICU for >48 hours who had a temperature >38.3°C on at least two consecutive days; only the first eligible fever episode was analyzed for each patient. Fevers were classified as infectious if cultures were positive or a full course of antibiotics was administered for a clinical diagnosis of infection. Patients with noninfectious and noncentral fever were excluded.

Among the 526 patients included, nearly half of fevers (46.8%) were noninfectious. Central fevers occurred earlier in the NICU course and were associated with younger age, subarachnoid or intraventricular hemorrhage, brain tumor, blood transfusion, and a clear chest x-ray. Using various combinations of these risk factors allowed identification of patients whose likelihood of infection was as low as 10%.