Altered mental status in patients with cancer.

OBJECTIVE: To identify the causes of an altered mental status in a cancer population.
METHODS: We studied 140 confused patients with cancer (100 prospectively and 40 retrospectively) between January 1, 1991, and June 30, 1992, to determine clinical findings, causes, and outcome.
RESULTS: All patients had non-central nervous system cancers. The most common primary cancer types were lung (20%), gastrointestinal tract (18%), leukemia and lymphoma (17%), and breast (11%). Median patient age was 73 years, and 49% were men. Disseminated systemic metastases were present in 50% of patients; 34% were confused at hospital admission and 66% developed confusion during hospitalization. Symptoms included lethargy or coma in 61% of patients, agitation in 44%, disorientation in 83%, lateralizing signs in 41%, delusions or hallucinations in 28%, and seizures in 9%. A single cause of the altered mental status was found in 33% of patients, whereas 67% had multiple causes. Drugs, especially opioids, were associated with altered mental status in 64% of patients, metabolic abnormalities in 53%, infection in 46%, and recent surgery in 32%. A structural brain lesion was the sole cause of encephalopathy in 15% of patients. Although delirium improved in 67% of patients, it was a poor prognostic factor for overall outcome. Thirty-day mortality was 25%, and 44% of patients died within 6 months, usually from progression of the underlying cancer. Prolonged delirium suggested infection or coagulopathy. Younger patients and those with hypoxemia or kidney or liver dysfunction were more likely to die (P<.05).
CONCLUSION: Patients with cancer usually have multiple causes of delirium, many of which are treatable, with rapid improvement in their cognitive status.