Lithogenic risk factors for renal stones in patients with Crohn's disease.

OBJECTIVES: Calcium oxalate kidney stones are more common in patients with Crohn's disease (CD). The aims of this study were to verify the prevalence of the main risk factors for calcium oxalate nephrolithiasis in patients with CD and to evaluate the degree of urinary relative supersaturation for calcium oxalate (CaOx), dihydrogen uric acid (DHUA) and monohydrogen calcium phosphate (MHCaP). SUBJECTS AND STUDY PROTOCOL: 42 patients with CD (22 male and 20 female, aged 15-72 years) and 18 controls (8 male and 10 female, aged 26-65) were studied. Nine patients were evaluated during an active episode and 33 in a quiescent phase. All patients had normal glomerular filtration rate. All subjects collected a 24-hr urine sample and fasting venous blood was drawn. Good compliance of urine collection was assessed by the Cockcroft and Gault formula. In urine pH and oxalate (Ox), calcium (Ca), phosphate (P), uric acid (UA), citrate (Cit), magnesium (Mg), sulphate (Sulph), sodium, potassium and chloride concentrations were measured and their excretions calculated. Urinary RS index was obtained using the software EQUIL93. RESULTS: A decreased urinary volume (61.9%) was the most frequent finding. A decreased excretion of Cit, Mg and Sulph (38.1%, 31.0% and 31.0%, respectively) and increased excretion of P, Ox, UA and Ca (33.3%, 23.8%, 16.7% and 14.3%, respectively) were found. Thirty four patients (81.0%) showed at least 2 lithogenic risk factors and only 2 patients showed none. Urine of patients had a higher urinary CaOx and DHUA relative super saturation. Patients studied in an active episode showed a higher urinary CaOx and MHCaP RS than those studied in the quiescent period. CONCLUSIONS: The majority of patients with CD have a multifactorial high risk for calcium oxalate and a single patient usually has several metabolic disturbances which are more evident in an active episode.

Relation of kidney size to kidney function in early insulin-dependent diabetes.

Renal function and renal size have been studied in ten early insulin-dependent diabetic patients and in ten matched control subjects. Glomerular filtration rate, renal plasma flow and radiological kidney size were determined in each subject. Glomerular filtration rate and renal plasma flow were increased in diabetics (mean +/- SD: 169.6 +/- 16.1 and 690.1 +/- 52.6 ml/min/1.73 m2, respectively) compared with controls (120.6 +/- 9.7 and 605.9 +/- 67.2 ml/min/1.73 m2; p less than 0.001 and p less than 0.01). Calculated kidney weight corrected to 1.73 m2 of body surface area was elevated in diabetics (385.2 +/- 29.0 g) with respect to controls (277.5 +/- 17.5 g; p less than 0.001). No significant differences were found between diabetics and control subjects when glomerular filtration rate was expressed per gram calculated kidney weight, while renal plasma flow was significantly lower in diabetics than control subjects when so expressed (p less than 0.01). A positive correlation was found between glomerular filtration rate, renal plasma flow and kidney size in both controls and diabetics (p less than 0.01 in all cases). These findings support the conclusion that in the early state of diabetes glomerular hyperfunction is related to enlargement of the kidneys and augmented renal plasma flow.

[Tubular function and renal acidifying in juvenile diabetes mellitus of short evolution]. / Estudio de la función tubular y capacidad renal de acidificación en la diabetes mellitus infanto-juvenil de corta evolución.

The fractional excretion of uric acid, calcium, phosphorus, magnesium and other ions, and the urinary acidifying capacity were studied in then patients with juvenile diabetes of short evolution and in a control group matched for age, sex, and body surface. The diabetic patients showed a hyperexcretion of uric acid, sodium, potassium, chloride and ammonium which was unrelated to the increment of glomerular filtration rate or to glucosuria, and could not be ascribed to diet. The pathophysiologic interpretation of these findings is discussed, concluding that they might be the result of an increase in the filtered load and the behaviour of the tubules in front of the glomerular hyperfunction or metabolic disturbance inherent to the diabetic condition.

[Study of the renal tubular function in alcoholic hepatic cirrhosis (author's transl)]. / Estudio de la función tubular renal en la cirrosis hepática alcohólica.

The renal plasma flow (RPF), glomerular filtrate (GF), renal concentration strength and urinary acidification capacity in eight patients with alcoholic cirrhosis and five control subjects was studied. The maximum urinary acidification capacity was tested by means or arginine monochloride. In two patients, renal tubular acidosis (RTA) was observed. One patient manifested a slight decrease in RPF, GF, hyposthenuria, hyperchloremic metabolic acidosis and bicarbonaturia. The test for maintained acidification and the overload of bicarbonate indicated a mixed RTA. The other patient manifested incomplete distal RTA, which was briefly corrected with the administration of furosemide. These tubular defects were not associated with the loss of proteins, phosphates, glucose, aminoacids or renal lithiasis. Neither were they related to the serum levels of copper, globulins, or predisposition to hepatic encephalopathy. The association between hepatic cirrhosis and distal tubular acidosis is known, but until the present work, the fact that this hepatopathy can simultaneously affect the proximal and distal tubules had not been described.