Treatable dementias.

Dementia, a syndrome of acquired intellectual deterioration, is an etiologically nonspecific condition that can be permanent or reversible. When evaluating demented patients, a careful exposure history will determine the possible role of drugs, metals, or toxins. Physical examination may reveal focal deficits in cases of intracranial mass lesions and spasticity or ataxia of the lower limbs if hydrocephalus is present. Coexistence of dementia and a peripheral neuropathy usually indicates the existence of a toxic or metabolic disorder. Depressed mood, sleep disturbance, anorexia, impotence, constipation, and psychomotor retardation indicate the presence of a depressive syndrome. Asterixis, myoclonus, and postural tremor are common in toxic-metabolic dementias, whereas resting tremor, choreoathetosis, or rigidity occur in progressive extrapyramidal disorder. EEG is focally abnormal in cases of cerebral mass lesions and shows generalized slowing in toxic-metabolic encephalopathies. CT will aid in the identification of hydrocephalus, subdural hematomas, and intracranial mass lesions. A thorough laboratory evaluation including complete blood count, erythrocyte sedimentation rate, electrolytes, blood urea nitrogen and blood sugar, liver and thyroid function tests, serum calcium and phosphorus levels, B12 and folate levels, serum copper and ceruloplasmin, VDRL, chest X-ray, electrocardiogram, and lumbar puncture may demonstrate treatable disorders that are adversely affecting intellectual function. Elderly individuals are particularly susceptible to the effects of toxic or metabolic disorders, and a mild dementia may be exaggerated by relatively minor fluctuations in metabolic status. Treatable causes of dementia should be sought in all demented patients.