The diagnosis of an organic mental disorder should be considered in any medically ill person demonstrating an acute onset of agitation or uncooperative behavior, personality change, impaired cognitive function, altered attention span, fluctuating level of consciousness, or intense, uncharacteristic anxiety or depression. Early symptoms of delirium or other organic mental syndromes are often misdiagnosed as anxiety, anger, depression, or psychosis. Several delirium diagnostic and rating scales are now available to aid clinicians in assessment and management of delirious patients. Dementia, however, typically appears in relatively alert individuals with little or no clouding of consciousness. Occasionally, delirium is superimposed on an underlying dementia, particularly in elderly people or people with cancer, AIDS or a paraneoplastic syndrome.
Measures designed to aid in the diagnosis and assessment of the severity of delirium are available.
Given the large numbers of medications required by someone with cancer and the person's potentially fragile physiologic state, even routinely ordered hypnotics may cause delirium. Opioid analgesics such as meperidine, morphine sulfate, hydromorphone, and levorphanol may cause confusional states, particularly in elderly and terminally ill people with cancer. Chemotherapeutic agents known to cause delirium include methotrexate, ifosfamide, fluorouracil, vincristine, vinblastine, bleomycin, carmustine, cisplatin, asparaginase, procarbazine, and the glucorticosteroids. Although these disturbances are most common with high doses and usually develop within the first 2 weeks of steroid use, they can occur at any time on any dose, even during the tapering phase. These effects generally reverse after the drugs are withdrawn, although they can persist for 2 weeks.