E.J. Dorhout Mees

Lowered Tissue-Fluid Oncotic Pressure Protects the Blood Volume in the Nephrotic Syndrome

We have studied the role of adjustments of tissue-fluid colloid osmotic pressure (COP) in the maintenance of the blood volume in 10 patients with the nephrotic syndrome before and after diuretic treatment until dry weight. A mean weight reduction of 13.5 +/- 6.4 kg was attended by a fall in blood volume in 3 patients and no change in 6, but the final blood volume was within the normal range: 84.3 +/- 3.7 ml/kg (normal value: 87.6 +/- 8.8 ml/kg). Albumin content and COP of tissue-fluid, obtained with subcutaneous wicks, were low before edema removal and rose slightly after it, parallel to changes in the plasma. Thus, the transcapillary gradient in COP did not change: 6.5 +/- 1.5 mm Hg before and 6.2 +/- 1.7 mm Hg after diuretic treatment. Considering the low COP, 8.6 +/- 1.6 mm Hg in edematous and 11.7 +/- 3.7 mm Hg in dry conditions, this gradient was only slightly below the value of about 10 mm Hg normally found with this technique. We conclude that a lowered tissue-fluid COP is important for the preservation of blood volume in dry patients with the nephrotic syndrome. In addition, this adaptation can explain why the blood volume is often normal and not expanded despite the sometimes huge overhydration in these patients.

Variant of Bartter’s Syndrome with a Distal Tubular Rather than Loop of Henle Defect

A 19-year-old normotensive patient had all of the clinical features of Bartter’s syndrome: hypokalemia, elevated renin and aldosterone levels and increased excretion of prostaglandin E. In contrast to

Clinical Aspects of Uraemic Polyneuropathy

In order to establish the relationship between uraemic polyneuropathy and impairment of renal function, 83 patients with severe renal insufficiency not treated by maintenance dialysis were neurologica

Fractional Oxalate Clearance in Subjects with Normal and Impaired Renal Function

The 14C-oxalate clearance was determined in 13 healthy subjects and 22 patients with various diseases and varying degrees of renal function impairment, including 5 patients with primary hyperoxaluria (PH). The clearances of oxalate (Cox) and creatinine (Ccr) were correlated (r = 0.95). The regression line intersects the ordinate at the origin, while the regression coefficient is 2.0. This implies that the fractional Cox is constant, irrespective of the underlying disease and the degree of renal failure. Plasma oxalate (Pox), as calculated from the urinary oxalate excretion (Uox) and Cox, was elevated in patients with severely impaired kidney function and those with PH. Plasma creatinine (Pcr) and Pox were correlated as well (r = 0.83). Pox values of patients with PH were above the 95% confidence limits of the regression line. It is of practical importance that Pox can be estimated from Uox and Ccr when a 14C-oxalate clearance test cannot be performed. The reasons for the constancy of the Cox/Ccr ratio are discussed, and it is suggested that the effective renal plasma flow (ERPF) is the regulating factor for the tubular secretion of oxalate.

Observations on Plasma Renin Substrate in the Nephrotic Syndrome

Literature data on renin in the nephrotic syndrome are conflicting: renin values are reported to be elevated as the rule, but sometimes normal or low; data on renin substrate are scanty and pointing to low values. In the present study, plasma renin activity (PRA) and plasma renin substrates (PRS) were measured in 27 episodes of the nephrotic phase in 24 patients with nephrotic syndrome with various lesions. 10 patients were reinvestigated after remission; 1 patient could be followed during development of the edema phase as well as during prednisone-induced remission. During the nephrotic phase, PRS was suppressed in 8%, normal in 44 and elevated in 48%, while PRA was suppressed in 41%, normal in 48 and elevated in 11% of the patients. After remission, PRA increased in 70% and PRS decreased in 20 and increased in 50% of the cases. The purpose of this study was to investigate PRA and PRS in nephrotic patients; it is concluded that low PRS and high PRA are not as characteristic for the nephrotic syndrome as they are generally thought to be.

Dilated uremic cardiomyopathy in a dialysis patient cured by persistent ultrafiltration.

A patient is presented who after 2 years of hemodialysis showed all of the features of congestive cardiomyopathy to a very severe degree: dilation of all cardiac compartments, increased left ventricular mass, low ejection fraction, diastolic disturbances, third- to fourth-degree mitral and tricuspid regurgitation, ascites, and low blood pressure. All of these abnormalities gradually but completely disappeared during 5 months of persistent ultrafiltration during or between dialysis sessions. It was concluded that chronic fluid overload was a major factor in the cardiac disease of this patient. Unrecognized hidden fluid overload has long been known (but also neglected), and its prevention deserves top priority in chronic dialysis patients.

Spontaneous perirenal hematoma due to periarteritis nodosa.

Dr. Fehmi Akcicek, Mithatpasa Cad. 776/13, Kopru, TR-35280 Izmir (Turkey) Dear Sir, Spontaneous perirenal hematoma (SPH) of the kidney is a rare entity and SPH of both kidneys is even more unusual. In this letter we present a patient who underwent bilateral nephrectomy 1 month apart due to retroperi-toneal hemorrhage as a result of kidney rupture. A 50-year-old white female was referred to Ege University Hospital because of progressive renal insufficiency, and hypertension. Her previous history revealed intermittent skin eruptions of her upper extremities and trunk since 4 years. Physical examination showed a blood pressure of 150/110 mm Hg, and mild tenderness in right hypochondrium and loin. Hematocrit (Htc) 40%, blood urea nitrogen (BUN) 70 mmol/l (175 mg/dl), crea-tinine 222 μmol/l (2.52 mg/dl), ESR 26 mm/ h, urine protein (+ + +), and 10-15 RBCs in urine sediment. While these investigations were being completed, the patient suddenly developed agonizing right flank pain and went into shock. A rapidly growing mass in the right loin was palpated. Upper abdomen ultrasonogram (US) and computerised tomo-gram (CT) revealed a perirenal mass having liquid ecogenity. The patient was immediately operated. At operation, a large retroperi-toneal hematoma was found and continuous bleeding from lacerations on the kidney surface which could be controlled only by right nephrectomy. Light microscopy showed fi-brinoid necrosis of the small and medium-sized arteries with numerous neutrophils in and around the walls (fig. 1). Several aneurysms and hematomas were also present. The majority of the glomeruli had crescents. The overall picture suggested a necrotizing vasculitis, especially periarteritis nodosa (PAN). Postoperative laboratory analysis displayed: Htc 21%, BUN 71.6 mmol/l (179 mg/dl), creatinine 786.8 μmol/l (8.94 mg/dl), HBsAg (-), ANA (-), anti-DNA (-). Chest and sinus radiographies were normal. In skin biopsy specimen perivascular lymphocyte infiltration in addition to Clq accumulation in der-moepidermal junction was observed. Methyl-prednisolone 1 gi.v./day together with cyclo-phosphamide 500 mg i.v./week as pulse therapies were begun. Her clinical condition improved gradually.

Renal Hemodynamic and Tubular Response to Furosemide in Man during Normal and Restricted Sodium Intake

To investigate the factors determining the natriuretic response to furosemide (F) during Na restriction, we performed clearance studies in 7 healthy humans on a daily Na intake of 200 and 20 mmol. The maximum urine flow during water loading (Vmax) and simultaneous F administration was used as index of tubular fluid output from the proximal tubules. The F-induced natriuresis was only moderately reduced during Na restriction (Na excretion on low vs. normal Na intake: 4.28 +/- 0.25 vs. 4.94 +/- 0.25 mmol/min; p less than 0.05). The diminished natriuresis was mainly due to a significant fall in Na delivery to Henles loop of 0.51 +/- 0.10 mmol/min which was either caused by a decrease in filtered Na load or a rise in fractional proximal reabsorption. Fractional distal Na reabsorption was less suppressible by F during Na restriction, but this contributed relatively little (0.15 +/- 0.11 mmol/min) to the total reduction in Na excretion (0.66 +/- 0.10 mmol/min). The F-induced increases in uric acid, phosphate, and bicarbonate excretion suggest an additional proximal site of action of F. This was confirmed by a rise in lithium clearance (CLi), another alleged index of tubular fluid delivery from the proximal tubules. However, the magnitude of the rise in CLi to values markedly exceeding Vmax suggest that CLi overestimates tubular fluid delivery to Henles loop during F administration.

Effect of Captopril in Bartter's Syndrome

R.J. Hené, Department of Nephrology and Hypertension, University Hospital, Catharijnesingel 101, 3511 GV Utrecht (The Netherlands) Dear Sir, We read with great interest the article ‘Effect of Captopril on Blood pressure, Renal Function, the Electrolyte Balance and the Renin-Angiotensin System in Bartter’s Syndrome’ (Nephron 33: 274–278, 1983) by Aurell and Rudin. They concluded that ‘captopril had no effect on the mechanism leading to hypokalaemia in Bartter’ s syndrome’. This conclusion is only correct for short-term treatment. We treated 2 patients having this disease with captopril on a long-term base. Like in the patients of Aurell and Rudin, no effect on serum potassium excretion was noticed during the first days of treatment; the long-term results were different. In both patients serum potassium increased from values below 3.0 mmol/l to 3.5 mmol/l after 1 month, and this level has maintained for 18 and 6 months, respectively. The plasma aldosterone concentration was reduced in both patients to 25–50% of control levels. The findings in our 1st patient are published elsewhere [1], those of our 2nd patient are shown in table I. Thus, it is possible to increase serum potassium levels in patients with Bartter’s syndrome by long-term treatment with captopril, probably by a sustained decrease in plasma aldosterone concentration. Table I. Patient with Bartter’s syndrome treated by 25 mg captopril three times daily

Urinary Oxalate Excretion during Intravenous Infusion of Diuretics in Man

We present the oxalate excretion in two studies before and after intravenous infusion of diuretics in healthy subjects. One study was performed in 7 male subjects. An intravenous injection of 1 mg bumetanide was given, followed by intravenous infusion at a rate of 0.5 mg/h. A similar study was performed in 5 male subjects, who received an intravenous injection of 500 mg acetazolamide, followed by intravenous infusion at a rate of 250 mg/h. Urinary oxalate was measured by an enzymatic method