[Treatable dementia syndromes]

Dementia--a syndrome of acquired intellectual deterioration--is an etiologically non-specific condition which is permanent, progressive, or reversible. In the evaluation of demented patients, a careful exposure history will determine the possible role of drugs, metals, or toxins. The physical examination may reveal focal deficits in cases of intracranial mass lesions and spasticity or ataxia of the lower limbs if hydrocephalus is present. Coexistance of dementia and peripheral neuropathy usually indicates a toxic or metabolic disorder. Asterixis, myoclonus, and postural tremor are common in toxic-metabolic dementias, while resting tremor, choreoathetosis, and rigidity occur in progressive extrapyramidal disorders. EEG is focally abnormal in cases of cerebral mass lesions and exhibits 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 tests, 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 might be exaggerated by relatively minor fluctuations in metabolic status. Treatable causes of dementia should be considered in all demented patients.