Dialysis.

Willem Kolff designed his "kunstmatige nier" in the early 1940s using spare parts obtained from the Wehrmacht; with it, he treated 14 patients with acute renal failure. Although there has been a tremendous improvement in the design and construction of dialysis machines, the basic concepts are unchanged. In this review we show that dialysis dose and adequacy can now be predicted using simple clinical methodology. The second part of the article discusses the accumulation or excess removal of important biologically active substances which can result in hitherto unseen clinical syndromes and even pose a threat to life.

Importance of volume factors in dialysis related hypertension.

OBJECTIVE: To evaluate the relation between total body water and dialysis related hypertension. PATIENTS AND METHODS: Thirty stable chronic hemodialysis patients were studied. Twenty-four-hour ambulatory blood pressure on the day before dialysis, blood pressure before and after dialysis, weight gain, ultrafiltration and total body water were determined. Total body water was measured by body impedance analysis and expressed as percentage of dry weight (TBW %). Ambulatory blood pressure recordings were defined as hypertensive when the blood pressure load (% of readings above 140/90 mmHg) was more than 40%. RESULTS AND CONCLUSION: Patients, classified as normotensive (n = 11) or hypertensive (n = 19), based on 24-hour blood pressure measurements, had significantly different TBW % (54.7 +/- 5.3 vs. 58.9 +/- 4.6%, p = 0.046). Ambulatory blood pressure and postdialysis blood pressure, but not predialysis blood pressure, were significantly correlated with TBW %. Acute volume changes, as reflected by interdialytic weight gain and ultrafiltration did not correlate with TBW %. These changes correlated weakly with predialysis blood pressure. Multivariate analysis showed that only TBW % and antihypertensive medication had an independent influence on 24-hour blood pressure measurements. We conclude that 24-hour blood pressure and blood pressure after dialysis are better related to total body water than blood pressure before dialysis, which was however weakly related to the acute volume overload, induced by interdialytic weight gain. We hypothesize that this could be the result of a more important chronic volume overload leading to an increase in systemic vascular resistance. On the contrary the acute but less important changes in extracellular volume between dialyses cause no hypertension after dialysis and no sustained hypertension over 24 hours, but only in some cases a temporary increase in the blood pressure just before dialysis. This volume overload can be easily determined by measurement of total body water by bioelectrical impedance analysis.

Wegener granulomatosis is associated to exposure to silicon compounds: a case-control study.

Wegener granulomatosis is a rare disease of unknown aetiology. In the majority of these patients the kidney is involved in the disease process. We performed a case-control study to evaluate the role of occupational exposure in the development of Wegener granulomatosis with renal involvement. The occupational histories of 16 cases with clearly established diagnosis of Wegener granulomatosis with renal involvement were compared with those of 32 age- and sex-matched controls. It was observed that inhalation of silicon-containing compounds such as silica and grain dust gave a nearly sevenfold risk for Wegener granulomatosis. Further epidemiological and experimental work needs to be performed in order to corroborate these findings.

Does lead play a role in the development of chronic renal disease?

For many decades lead has been considered to be one of the causes of chronic renal failure. A critical analysis of the available epidemiological studies, however, indicates that the relationship between lead exposure and the development of chronic renal failure is largely circumstantial. Indeed, several aspects remain obscure: relative and absolute risk, risk factors, duration of exposure, pathology and diagnostic criteria. Moreover, methodological problems related to cohort selection (i.e. the 'Healthy worker effect'), study design and definition of renal dysfunction may limit the value of the epidemiological results. Although the available literature suggests that lead may play a direct or contributory role in the development of chronic renal failure it is concluded that additional detailed epidemiological studies are required.

Diuretics in the treatment of hypertension.

With 30 years of experience, it is possible to claim that diuretics are well tolerated antihypertensive drugs producing a significant decrease in systolic and diastolic blood pressure as good as obtained with beta-blockers, converting enzyme inhibitors, calcium antagonists and centrally acting drugs. Recently diuretics have been criticised because of a substantial number of important side-effects, and are disregarded by some authors as first-line agents for the treatment of mild hypertension. Diuretics seem however safe in the majority of hypertensive patients who do not present special problems. Using low doses, which are equally effective, most toxic properties can probably be avoided. Combination therapy, especially with ACE inhibitors, has not only additional effects, but lowers also the potential adverse effects, caused by diuretics. We are convinced that diuretics are still important as first-line agents for the treatment of arterial hypertension in the general population.

Mesenteric infarction: a fatal complication of renal transluminal angioplasty.

In a 47-year-old patient with renovascular hypertension due to a totally obstructed left and a severe constricted right renal artery, a successful transluminal renal angioplasty was performed with normalisation of blood pressure. Thirteen days later the patient died of a mesenteric infarction, possibly caused by normalisation of the blood pressure in the presence of a severe mesenterical stenosis. The benefit of preventive screening of other vital organs in highly atheromatous patients is discussed.

Propylene glycol-induced side effects during intravenous nitroglycerin therapy.

Propylene glycol, an alcohol frequently used as a solvent in medical preparations, is considered non-toxic. We found that this solvent, used in a commercially available IV nitroglycerin solution, may cause hyperosmolality, hemolysis and lactic acidosis. The influence of kidney function as the main determinant in causing accumulation of this solvent and consequently hyperosmolality is emphasized. A review of the literature dealing with propylene glycol is given. The possible mechanisms of neurological disturbances occurring during IV nitroglycerin therapy are discussed.

Functional acute renal failure in a patient with carcinoid syndrome.

Acute renal failure occurred in a patient with a carcinoid syndrome whenever he developed a flushing episode. Renal biopsy performed during one of these oliguric episodes did not reveal any lesions which could explain this reversible form of renal insufficiency. Urinary indices were not conclusive. Alteration of intrarenal hemodynamics by vasoactive compounds is proposed to be the causative mechanism of this relapsing acute oliguric renal failure.