Altered mental status in patients with cancer

To identify the causes of an altered mental status in a cancer population.

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.

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).

Patients with cancer usually have multiple causes of delirium, many of which are treatable, with rapid improvement in their cognitive status.