Dialysis dementia

Secondary metabolic encephalopathy. Diagnosis and treatment

Secondary metabolic encephalopathy is a diffuse disorder of the brain caused by an extracerebral process. Underlying causes include oxygen deprivation, systemic metabolic disease, and drug intoxication. Symptoms and signs usually suggest a generalized disturbance of brain function: alterations in the level of consciousness; diffuse and, occasionally, focal motor abnormalities; and seizures. Electroencephalography in most instances gives evidence of generalized neuronal disturbance. Early diagnosis is important because encephalopathy secondary to an extracerebral process is potentially reversible. Treatment is directed toward reversal or control of the underlying process, supportive care, and prevention of complications such as infection, electrolyte imbalance, and cerebral edema.

A fatal encephalopathy in chronic haemodialysis patients

A distinct neurological syndrome in twelve chronic haemodialysis patients is described. This syndrome is currently the leading cause of death in one Denver dialysis unit. The hallmarks of this syndrome are progressive speech difficulties, mental changes, and a markedly abnormal electroencephalogram which may be present months before the clinical signs appear. Additional clinical features including seizures, myoclonus, asterixis, apraxia, focal neurological signs, and psychiatric symptoms may also be observed. Neuropathological changes are slight and non-specific. The aetiology of this syndrome is unknown but the clinical and pathological features suggest a toxic/metabolic disorder. To date, this disorder has been refractory to several therapeutic measures.

The dialysis encephalopathy syndrome. Possible aluminum intoxication

The aluminum content of muscle, bone and brain was measured in control subjects and in uremic patients on dialysis who had been maintained on phosphate-binding aluminum gels. The mean muscle aluminum was 14.8 ppm, and the trabecular-bone aluminum 98.5 ppm in the patients on dialysis, as compared with 1.2 and 2.4 in control subjects (P less than 0.05). Brain gray-matter aluminum values in a group of uremic patients on dialysis who died of a neurologic syndrome of unknown cause were 25 ppm as compared with 6.5 ppm in a group of uremic patients on dialysis who died of other causes and 2.2 ppm in control subjects. The fact that brain gray-matter aluminum was higher in all patients with the dialysis-associated encephalopathy syndrome than any of the control subjects or other uremic patients on dialysis suggests that this syndrome may be due to aluminum in intoxication.

Pneumoencephalographic and clinical characteristics of diffuse cerebral atrophy

The clinical features in 268 patients with diffuse cerebral atrophy of initially unknown origin have been analysed. Pneumoencephalography showed supratentorial ventricular atrophy in 87 per cent (cortical in 71 per cent), and brain stem and/or cerebellar atrophy in 17 per cent of the patients. Epileptic seizures, dizziness and clumsiness were the most frequent initial symptoms. Vibration in work, psychic impairment, gait difficulties, co-ordinative dysfunction, excessive use of alcohol, and arterial hypertension dominated the clinical picture. Serum cholesterol and triglycerides, and beta-globulins in the cerebrospinal fluid protein electrophoresis were normal. Diffuse cerebral atrophy without defined cause appears to affect all parts of the brain, with particular predilection for the frontotemporal area and the left side, and to have diffuse and unspecific clinical characteristics.

Dialysis-associated dementia

Two patients from an Australian Dialysis Centre developed a progressive neurological disorder with features similar to those recently discribed as the snydrome of Dementia Dialytica. These two patients are reported here and this newly recognised syndrome reviewed.