Dementia Due to Other General Medical Conditions

Dementia Due to Other General Medical Conditions

Normal-pressure Hydrocephalus

Normal-pressure hydrocephalus is generally considered the fifth leading cause of dementia after Alzheimer’s, vascular, al-cohol-related, and AIDS dementias. Long considered reversible but often merely arrestable, normal-pressure hydrocephalus is a syndrome consisting of dementia, urinary incontinence and gait apraxia. It results from subarachnoid hemorrhage, meningitis, or trauma that impedes CSF absorption. Unlike other dementias, the dementia caused by normal-pressure hydrocephalus has physical effects that often overshadow the mental effects. Psychomotor retardation, marked gait disturbances and, in severe cases, com-plete incontinence of urine occur. A cisternogram is often helpful in the diagnosis, and CT and MRI show ventricular dilatation without cerebral atrophy. CSF analysis reveals a normal opening pressure, and glucose and protein determinations are within the normal range.

The hydrocephalus can be relieved by insertion of a shunt into the lateral ventricle to drain CSF into the chest or abdominal cavity, where it is absorbed. Clinical improvement with shunting approaches 50% with a neurosurgical complication rate of 13 to 25%. Infection remains the most common complication.

Wilson’s Disease

Hepatolenticular degeneration (Wilson’s disease) is an inherited autosomal recessive condition associated with dementia, he-patic dysfunction and a movement disorder. Localized to chro-mosome 13, this disorder features copper deposits in the liver, brain and cornea. Symptoms begin in adolescence to the early twenties and cases are often seen in younger children. Wilson’s disease should be considered along with Huntington’s disease, AIDS dementia, substance abuse dementia, head trauma and su-bacute sclerosing panencephalitis in the differential diagnosis of dementia that presents in adolescence and early adulthood. Personality, mood and thought disorders are common, and physical findings include a wing-beating tremor, rigidity, aki-nesia, dystonia and the pathognomonic Kayser–Fleischer ring around the cornea. Wilson’s disease can mimic other conditions including Huntington’s disease, Parkinson’s disease, atypical psychosis and neuroleptic-induced dystonia. Slit-lamp ocular examination, abnormal liver function tests and markedly de-creased serum ceruloplasmin levels are diagnostic. Chelating agents such as penicillamine, if administered early, can reverse central nervous system and nonneurological findings in about 50% of cases.

Other Medical Conditions

In addition to the conditions mentioned previously, other medi-cal illnesses can be associated with dementia. These include endocrine disorders (hypothyroidism, hypoparathyroidism), chronic metabolic conditions (hypocalcemia, hypoglycemia), nutritional deficiencies (thiamine, niacin, vitamin B₁₂), struc-tural lesions (brain tumors, subdural hematomas) and multiple sclerosis.

Treatment of Dementia

Most of the treatment strategies for dementia have been dis-cussed previously (see treatment of dementia of the Alzheimer type). In summary, the management of dementia involves 1) identification and, if possible, correction of the underlying cause; 2) environmental manipulation to reorient the patient; 3) intervention with the family by means of education, peer support, providing access to community organizations, dis-cussing powers of attorney, living wills, and institutionaliza-tion if appropriate, and arranging therapy if indicated; and 4) pharmacological management of psychiatric symptoms and behavior. Low dose antipsychotics with minimal anticholin-ergic potential and occasionally short-acting benzodiazepines (e.g., lorazepam) are the drugs of choice. Because depression occasionally accompanies dementia, pharmacotherapy with antidepressants of low anticholingeric and hypotensive poten-tial is often indicated. For patients with dementia, secondary to drug or alcohol abuse, appropriate referral for rehabilitation is essential.