Altered Mental Status in Neurosurgical Critical Care

Abstract

Altered level of consciousness is a nonspecific symptom of many complications in neurosurgical patients and may be caused by conditions such as rebleeding of cerebral aneurysms, decompensating brain edema, postoperative hematoma, or seizures. Consciousness can be divided into wakefulness and awareness. The former includes arousal, alertness, and vigilance; and the latter is the sum of cognitive and emotional functions. The anatomical structures, upon which wakefulness and awareness depend, and the signs of dysfunction are shown in Table 75.1. Disorders of wakefulness are always accompanied by impaired awareness. Although the distinction between wakefulness and awareness is important for the understanding of the pathophysiology of altered consciousness, in our experience, the distinction between the two is of limited clinical importance as far as timing and manner of the clinical evaluation of patients with altered levels of consciousness are concerned. However, treatment may differ considerably.