Electroencephalograms in patients with progressive dialytic encephalopathy

Advances in dialysis encephalopathy research: a review

Dialysis encephalopathy (DE) is a progressive, fatal disease with a high mortality rate. Understanding the causes of this disease and the efforts to prevent and treat it would help improve the prognosis and quality of life of affected patients. This paper reviews the etiology, clinical features, methods of examining accessory features, diagnosis, treatment, and prevention of DE. We found that DE is likely to be related to aluminum poisoning. The clinical manifestations of DE include language disorders, mental and behavioral disorders, cognitive decline, and movement disorders. Electroencephalogram (EEG) findings mainly consist of an abundance of low waves, intermittent bilateral synchronous high-amplitude spikes, and ridge waves. Assessing the clinical features and obtaining an EEG are of great value in diagnosis, and DE is treated by both reducing aluminum intake and increasing aluminum excretion. Deferoxamine (DFO) is an effective treatment for DE.

Interictal EEG and the diagnosis of epilepsy

The interictal EEG provides information that aids in diagnosis and management of epilepsy. One must remember that the EEG is merely a tool, and its usefulness depends largely upon the skill of the individual who wields it. Like all diagnostic tests, it has significant limitations and cannot substitute for a careful history and exercise of good judgment. Nonetheless, in skilled hands, it provides unique and vital information in many patients, and enhances our understanding of their condition.

Clinical and radiologic correlates of frontal intermittent rhythmic delta activity

To assess the clinical and radiologic correlates of frontal intermittent rhythmic delta activity (FIRDA), the authors reviewed the hospital charts of patients whose EEGs depicted this EEG finding, and recorded their past medical and neurologic history, the reason for hospital admission, and their neurologic status both on admission and during EEG recordings. Laboratory results on admission and concomitant to the EEG recording, computed tomography, or MRI findings during hospital admission were also reviewed. Sixty-eight patients were assessed. The gender ratio was 1:1; mean age was 56 years. Chronic disease occurred in 78% of patients, including hypertension (34%), diabetes (32%), and renal failure (18%). On admission, renal failure (n = 34) and hyperglycemia (n = 22) were most prominent. The majority of patients had at least one abnormal laboratory result. Thirty-eight of 51 patients in whom the level of consciousness was stated during EEG were described as awake. More than half of 58 patients whose EEG background activity was stipulated demonstrated diffuse slowing, mostly in the theta range. MRI was abnormal in 15 of 17 patients. Intrahemispheric lesions, particularly ischemic and hemorrhagic, were most common (n = 10), followed by basal ganglia lacunae (n = 4). Computed tomography was abnormal in 29 of 44 patients. Hemispheric pathology, diffuse or localized, occurred in 22 patients. Frontal intermittent rhythmic delta activity is associated with mild to moderate encephalopathy and is detected principally in awake patients. Most patients in this series had chronic systemic illness. Old ischemic structural brain lesions may predispose some patients to develop FIRDA during acute metabolic derangement, such as uremia and hyperglycemia. Frontal intermittent rhythmic delta activity was not associated with EEG epileptiform activity. Deep midline lesions, posterior fossa tumors, and hydrocephalus were not detected in this series of patients with FIRDA.

Experimental aluminium encephalopathy: quantitative EEG analysis of aluminium bioavailability

Single oral doses of aluminium hydroxide (50 to 200 mg/kg) were found to induce in mice a dose-dependent diminution of the power of the 7.5 to 12 Hz frequency band, with a parallel dose-dependent increase of aluminium content in the brain, as early as 45 min after administration, and indicated that aluminium hydroxide is readily absorbed through an empty stomach or duodenum and is able to induce alterations of background EEG rhythms at doses equivalent to the ones used in human therapy. These data suggest that the EEG disturbances of the background type, (which are observed during the early stage of dialysis encephalopathy in man), may be partly due to a pharmacological and therefore reversible effect induced by an increase in aluminium level in the brain.