Progressive dialysis encephalopathy

Movement Disorders and Dementia in a Woman With Chronic Aluminium Toxicity: Video-MRI Imaging

Background:

Aluminium encephalopathy results from exposure to aluminium from occupational, recreational, and environmental sources. Movement disorders, cerebellar ataxia, pyramidal tract signs, dementia, microcytic anemia and bone disease are typical manifestations.

Case Report:

A 55-year-old woman had clinical manifestations, persistent hyperaluminemia without magnetic resonance imaging (MRI) scan changes of toxic encephalopathy following a prolonged exposure to marine grade paints containing 30% aluminium. Chelation therapy with ethylenediaminetetraacetic acid (EDTA) demonstrated decreased levels of aluminemia and significant neurological improvement over time.

Discussion:

This diagnosis should be entertained in patients with movement disorders, cerebellar ataxia, pyramidal signs, and dementia of unknown etiology.

Highlights:

Aluminium encephalopathy (AE) is a neurological syndrome caused by aluminium neurotoxicity. Manifestations include cognitive impairment, motor dysfunction, microcytic anemia and bone disease. This case illustrates AE with hyperaluminemia associated with chronic exposure to industrial paints and clinical and biochemical reversibility after chelation therapy with ethylenediaminetetraacetic acid. Movement disorders are highlighted.

Accumulation Patterns of Sub-chronic Aluminum Toxicity Model After Gastrointestinal Administration in Rats

Although aluminum chronic neurotoxicity is well documented, there are no well-established experimental protocols of Al exposure. In the current study, toxic effects of sub-chronic Al exposure have been evaluated in outbreed male rats (gastrointestinal administration). Forty animals were used: 10 were administered with AlCl₃ water solution (2 mg/kg Al per day) for 1 month, 10 received the same concentration of AlCl₃ for 3 month, and 20 (10 per observation period) saline as control. After 30 and 90 days, the animals underwent behavioral tests: open field, passive avoidance, extrapolation escape task, and grip strength. At the end of the study, the blood, liver, kidney, and brain were excised for analytical and morphological studies. The Al content was measured by inductively coupled plasma mass-spectrometry. Essential trace elements-Co, Cr, Cu, Fe, Mg, Mn, Mo, Se, and Zn-were measured in whole blood samples. Although no morphological changes were observed in the brain, liver, or kidney for both exposure terms, dose-dependent Al accumulation and behavioral differences (increased locomotor activity after 30 days) between treatment and control groups were indicated. Moreover, for 30 days exposure, strong positive correlation between Al content in the brain and blood for individual animals was established, which surprisingly disappeared by the third month. This may indicate neural barrier adaptation to the Al exposure or the saturation of Al transport into the brain. Notably, we could not see a clear neurodegeneration process after rather prolonged sub-chronic Al exposure, so probably longer exposure periods are required.

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.

Toxin-Induced Movement Disorders

Toxins can be cited as a cause of several movement disorders, but this association is rare and the resultant syndromes usually include additional signs that are not typical for the idiopathic movement disorders. Most instances of confirmed toxin-induced movement disorders show lesions on CT and MRI scans of cortical or subcortical structures. A common underlying element in these toxin-induced syndromes is the development of lesions primarily in the pallidum and striatum. Because many toxins result in lesions affecting these structures, a selective vulnerability to hypoxic or metabolic insults has long been postulated. The susceptibility of these structures may relate to a number of factors, including the pattern of oxidative metabolism, heavy metal concentration, vascular perfusion, and neuronal innervation. Finally, in addition to causing disability, certain neurotoxins have led to a better understanding of human disease through the development of research models. As an example, the MPTP model has not only provided an animal model to study therapeutic strategies in PD but has also contributed important insights into the mechanism of neuronal degeneration.

Research trends in Alzheimer's disease

Alzheimer's disease (AD) is a tragic condition. The individual experiencing the loss of memory, difficulty with language, change in personality, and disturbance in behavior associated with AD is not alone; the number of people with AD is estimated at 4 million; by the year 2050, as many as 14 million Americans may be afflicted (National Institute of Aging, 1992). AD is the fourth leading cause of death for adults, taking more than 100,000 lives annually. The families of these patients also are victims, as they watch their loved ones slowly forget them and all that was once meaningful in their lives.

Precipitation of dialysis dementia by deferoxamine treatment of aluminum-related bone disease

Five patients with chronic renal failure, complicated by bone aluminum toxicity, were treated with deferoxamine (DFO). This treatment appeared to precipitate dialysis dementia, which was fatal in three patients. In two patients, continuous treatment with lower doses of DFO was possible. The development of dialysis dementia in chronic renal failure patients with very high serum aluminum levels may be a complication of DFO treatment.

Psychopathology of chronic haemodialysis: is it a behavioural cognitive continuum?

Neuropsychiatric complications of chronic renal haemodialysis cover a wide gamut of clinical syndromes. These pictures can be diagnostically classified as non-psychotic and psychotic-like syndromes. On the basis of a review of the literature, some nosological precisions are formulated, and a hypothesized cognitive-behavioural psychopathological continuum is presented. The hypothesis postulates that a central cognitive disturbance, due to multiple organic aetiopathogenic factors, results in a step-wise decline, initially disguised as an affective, neurotic or personality disorder, and further deteriorating into the well-known "dialysis dementia", with a variety of other clinical presentations in between. Additional research in the biological and psychosocial areas is needed to verify different aspects of these conditions, their validity in the context of the authors' hypothesis, and their relevance to the overall "quality of life" of chronic haemodialysis patients.

The regional cerebral blood flow in patients under chronic hemodialytic treatment

Regional cerebral blood flow (rCBF) was measured by the xenon-133 inhalation method in an unselected group of nine chronic hemodialysis patients before and after a single hemodialytic treatment. All patients underwent neurological, neuropsychological, and biochemical evaluations on the same occasions. Predialysis rCBF values did not differ from those obtained in age-matched normal controls. Following hemodialysis, there was a mild reduction in the rCBF by a mean of 7 +/- 2.6% (p = 0.02). The posthemodialysis rCBF reduction was not associated with any neurological or cognitive dysfunction. The causes of hemodialysis-induced rCBF decreases are unknown, but increased blood viscosity and biochemical changes, such as urea reduction and blood alkalinization, may play a role.

Dialysis encephalopathy: neuropathologic aspects

The clinical, epidemiologic, electroencephalographic, and toxicologic features of dialysis encephalopathy (DE) have been clarified, but the neuropathologic and clinicopathologic aspects of the disease have remained obscure. In three cases of DE associated with a dialysate of high aluminum content, spongy change restricted to the upper layers of the cerebral cortex was found. The spongy change was distributed through the cerebral cortex bilaterally and diffusely, but the left hemisphere was involved more severely and extensively than the right hemisphere, and the opercular portions of the frontal and temporal lobes were affected more than the remainder of those lobes. This topographic distribution correlated with the clinical defects in higher cortical functions, including aphasia. The spongy change consisted of vacuoles in the neuropil and inside nerve cell bodies. The vacuoles in the neuropil were located in dendrites, astrocytic processes, and, possibly, other structures. Thus, DE is a disease of neurons and astrocytes of the cerebral cortex. Although spongy change of the upper layers of the cerebral cortex is a nonspecific abnormality, when it occurs in the distribution described and in the absence of other diffuse cerebral diseases, it is characteristic of DE.

Alzheimer's disease in a patient on long-term hemodialysis: a case report

This case report describes a progressive dementia in a 49-year-old black male on long-term hemodialysis. The initial presentation simulated depression. The dementia persisted after an unsuccessful cadaver homograft transplant. The character of the dementia was nonspecific but typical features of dialysis dementia were lacking. Autopsy revealed a ruptured cerebral aneurysm, polycystic kidneys, moderately severe atherosclerosis, miliary tuberculosis, and neurofibrillary degeneration of the hippocampus. The significance of a possible relationship between end-stage renal disease (ESRD), hemodialysis, and Alzheimer's disease in this case is discussed.

Brain gamma-aminobutyric acid and benzodiazepine receptor binding in dialysis encephalopathy

We measured gamma-aminobutyric acid (GABA) and benzodiazepine binding in autopsied frontal cortex of 8 patients dying with dialysis encephalopathy (DE). No alteration in [3H] GABA binding was observed. However, a mild reduction (-23%, P less than 0.05) of [3H] flunitrazepam-binding density was found in DE cortex. The magnitude of this reduction was similar to that observed in frontal cortex of amygdala-kindled rats [10]. We suggest that a reduction in benzodiazepine receptor number, in combination with markedly reduced GABA concentration in DE cerebral cortex may contribute to some of the clinical features (especially seizures) characteristically observed in this syndrome.

Dialysis encephalopathy: a review

Dialysis encephalopathy (DE) is a distinct neuropsychiatric syndrome typically occurring in patients undergoing longterm hemodialysis. It is characterized by electroencephalographic abnormalities in association with disturbances of speech, cognition, movement, affect, or behavior. Previously thought to be relentlessly progressive, recent evidence linking the illness to aluminum overload has led to advances in prevention and treatment. Early diagnosis aids in the reversal or amelioration of the syndrome and can be of immense value to the patient, the family and involved health personnel. The general features of the syndrome, etiologic considerations, differential diagnosis and treatment are discussed. Three case studies are included to illustrate salient features of the syndrome.

Multiple sclerosis in association with dialysis encephalopathy syndrome

Images

Electroencephalograms in patients with progressive dialytic encephalopathy

We compared the electroencephalograms (EEGs) of 17 patients with progressive dialytic encephalopathy with 17 chronic renal failure patients who did not have dialytic encephalopathy and who had been matched for age, type and duration of dialysis. The EEGs were analyzed in a semiquantitative fashion by counting the number of paroxysms of frontal intermittent rhythmic delta activity and frontocentral spike-waves, and by grading the amount of diffuse theta and delta waves during waking EEG on a 4-point scale. The two most important EEG predictors of dialytic encephalopathy in the present study consisted of synchronous and symmetrical frontal intermittent rhythmic delta waves and frontocentral spike-waves, confirming our previous observations.

Progressive encephalopathy in children with chronic renal insufficiency in infancy

A retrospective analysis of children with renal failure during the first year of life revealed that 20 of 23 patients developed profound neurologic abnormalities. The encephalopathy was characterized by developmental delay, microcephaly, hypotonia, seizures, dyskinesia, and EEG abnormalities. No patient had been dialyzed, and four had not received aluminum salts prior to the development of neurologic symptoms. Inadequate statural growth and poor nutrition were present in all patients. It is probable that infants with chronic renal insufficiency are more susceptible to the development of this syndrome than are older children or adults because of the significant growth and maturation of the brain that occurs during the first years of life.

Intellectual functioning in renal failure and chronic dialysis

The research literature on intellectual functioning in uremia and maintenance hemodialysis for renal failure is critically reviewed. The most frequently assessed neuropsychological functions have been general intelligence, memory, and attentional processes. Studies have consistently found lowered performance IQ scores compared to verbal IQ scores in renal failure patients prior to dialysis onset, suggesting the presence of intellectual deficit due to cortical dysfunction. The role of intelligence in adjustment to dialysis has not been clearly explicated, due in part to methodological variations among studies. Several studies point to significant improvement in short-term memory both after onset of maintenance dialysis and from one day before to one day after an individual dialysis treatment session. Attentional functions appear to improve after onset of dialysis treatment as well, but small sample sizes limit the conclusiveness of the data on these cortical processes. Future research efforts should be aimed at correlating physiologic with neuropsychological data and at longitudinal study of intellectual functioning in dialysis patients.

Longitudinal study of neuropsychological functioning in patients on chronic hemodialysis: a preliminary report

This study is part of a five-year project to investigate the long term effect of chronic hemodialysis on patients with end-stage renal failure. Previous research has associated hemodialysis with progressive dialysis encephalopathy (PDE), which is characterized by speech disturbances, cognitive impairment, myoclonus and behavioral changes. Little is known about the cause or the course of this syndrome except that it begins 14-36 months after treatment onset and usually culminates in death. The purpose of this study was to investigate neuropsychological (cognitive and behavioral) functioning in dialysis patients over a period of years. To date, 34 patients have been studied for 22 months utilizing a cross-sectional method comparing patients at different stages of treatment combined with a longitudinal method of repeated evaluations over time. Current findings show improved cognitive functioning during at least the first year of treatment and no evidence of cognitive deterioration in patients on dialysis for more than one year (M = 4.3). These findings offer strong evidence that PDE is not necessarily a general phenomenon among patients on chronic hemodialysis.

Dialysis encephalopathy and osteomalacic bone disease: a case-controlled study

Nine patients on long-term hemodialysis with dialysis encephalopathy were studied, with sex matched control subjects for eight of the patients. Each patient with dialysis encephalopathy and control subject were contemporaries in a similar dialysis environment. Rib and other fractures were found in excess in the patients with dialysis encephalopathy (p less than 0.005 and p less than 0.01). These patients had less radiographic hyperparathyroid bone disease, and no more osteopenia as measured by metacarpal thickness than did their control counterparts. Severe osteomalacia was documented by bone biopsy in four of te patients. In a retrospective review of clinical, biochemical and pharmacologic differences, the patients with dialysis encephalopathy were significantly older at the start of dialysis (45.6 years versus 38.6 years, p less than 0.02) and had higher mean concentrations of blood urea nitrogen (BUN) and lower serum hemoglobin in the first year of dialysis than the control subjects. Blood pressure weight, creatinine, calcium, phosphate, alkaline phosphatase and a number of transfusions did not differ significantly. There was no difference in prescribed vitamin D and elemental aluminum in phosphate binders. This study demonstrates that patients with dialysis encephalopathy had more rib fractures without more parathyroid or osteopenic bone disease than did the control subjects and suggests that the etiology of dialysis encephalopathy and osteomalacia is multifactorial.

[Dialysis dementia. Electroencephalographic study of a case]

A case of a 65 years-old black man with chronic renal failure, treated with chronic haemodialysis, in which a dialysis dementia syndrome developed is reported. In the initial phase the electroencephalogram had the typical burst of sharp and slow waves, waning with haloperidol and diazepam treatment. The withdrawal of this medication induced reappearance of the symptoms and EEG. abnormalities. As soon as the patient came back to the diazepine (potassium clorazepate), the mental symptoms subsided, but few weeks later he died of a cerebral haemorrhage. The electroencephalographic features are described and a brief comment about this disease is made.

Oral aluminum and neuropsychological functioning. A study of dialysis patients receiving aluminum hydroxide gels

Nine dialysis patients with significantly increased serum-aluminum levels due to chronic ingestion of aluminum hydroxide gels and eleven dialysis patients with normal serum-aluminum levels were tested neuropsychologically for generalized functions (intelligence, reasoning, memory) and for more specific abilities (visual memory, verbal and reading fluency, manual dexterity). All tests did not reveal any significant difference in neurophyscholigical functioning between the two groups. This finding seems to indicate that oral aluminum is not neurotoxic for man, even under circumstances of renal failure. This contradicts the idea that oral aluminum plays a role in etiology of dialysis dementia. However, the possibility cannot be excluded that aluminum overload in the present sample was not sufficient to induce changes in CNS functioning. Thus, until the importance of oral aluminum has been decided, it seems wise to keep all sorces of aluminum overload as low as possible.