Twenty-seven patients with acute neurosurgical injuries were compared with 23 patients with neurosurgical and multisystem injuries and 10 patients with multisystem injuries without neurosurgical injuries. Patients with isolated acute neurosurgical injuries did not demonstrate a hypermetabolic state with increased loss of nitrogen and decreased circulating levels of albumin, prealbumin, and retinol-binding protein when compared to multisystem-injured patients. Patients with demonstrated hypermetabolism on day 1 were supported with parenteral nutrition which decreased their protein losses and stabilized other metabolic variables such as calcium and phosphorus. It is concluded that patients with neurosurgical and other multisystem injuries require close metabolic monitoring. Early institution of metabolic support in hypercatabolic patients may prevent clinically significant depletion states.