[Urinary acidification by furosemide test]. / Estudio de la acidificación urinaria mediante la prueba de furosemida.

The aim of this study was to investigate the effect of furosemide on urinary acidification in 7 healthy children (aged 7 to 9 years) 5 patients with normokalemic distal renal tubular acidosis (RTA) (aged 4 to 13 years) and in 1 patient with proximal RTA (aged 20 months). Furosemide was given (2 mg/kg orally) as a tool to stimulate H+ and K+ secretion by enhancing Na delivery and transport in distal tubular segments. Patients with distal RTA were diagnosed by means of the ammonium chloride test and the alkaline overload and the one with proximal RTA by the ammonium chloride test only. Urinary acidification was evaluated 1 hour before and until 4 hours after furosemide administration. Healthy children (Fig. 1) showed a significant fall in urinary pH, 5.8 +/- 0.27 to 4.88 +/- 0.18 (p less than 0.02) and increase of NH3 excretion from 38.58 +/- 10.33 to 79.09 +/- 10.38 microEq/min/1.73 m2 (p less than 0.05). There was a direct correlation between urinary pH and urinary flow: r = 0.62 p less than 0.01 (Fig. 3). In patients with distal RTA (Fig. 5) furosemide failed to lower urine pH below 6 and net acid excretion persisted low: 47.9 +/- 6.1 microEq/min/1.73 m2. In the patient with proximal RTA (Fig. 4) furosemide produced the same effect as in healthy children with a fall in urine pH to 4.4 and an increase in net acid excretion to 118 microEq/min/1.73 m2. Furosemide proved to be effective to differentiate the type of RTA.(ABSTRACT TRUNCATED AT 250 WORDS)

Verocytotoxin-producing Escherichia coli infection in family members of children with hemolytic uremic syndrome.

Thirty-four hemolytic uremic syndrome (HUS) patients and ninety-five family members were studied to determine the frequency of infection with verocytotoxin-producing Escherichia coli (VTEC) in household contacts using three diagnostic criteria: VTEC strains isolation and characterization, detection of free fecal VT (FVT) and VT-neutralizing antibodies (VT-NAbs). Gastrointestinal tract symptoms occurred in one to six family members in 8 (23.5%) of the index cases, the week before admission to hospital or simultaneously. The control group consisted of 34 children with acute gastroenteritis who did not develop HUS. Cumulative evidence of VTEC infection was found in 13 (38.2%) of 34 HUS patients, in 30 (31.6%) of 95 family members and in 10 (29.4%) of 34 control children. The serotypes of VTEC isolated were O157: H7 and O25: H2. The prevalent VT type was VT2 in VTEC and FVT; and VT1 in VT-NAbs. Both parents had the same infection rate by fecal toxin or serological data (11.1% FVT, 32% VT-NAbs). These were higher than those detected in siblings (6.2% FVT, 23.5% VT-NAbs) and grandparents (0% FVT, 18% VT-NAbs). Of 16 patients without evidence of infection, 3 had household contacts with FVT and 13 with VT-NAbs. Our results show the wide dissemination of VTEC in the population of Argentina and that family members of HUS patients are usually infected. Therefore, person-to-person transmission may play an important role in the high incidence of HUS in our country.

Fetal renal maldevelopment with oligohydramnios following maternal use of piroxicam.

A female neonate, born by cesarean section at 37 weeks of gestation, presented with respiratory distress syndrome, right pneumothorax and anuria. A sonogram showed increased echogenicity, with neither hydronephrosis nor macroscopic cysts. Peritoneal dialysis was started on the 14th day because of renal insufficiency, but the newborn died on the 33rd day. Family history was unremarkable, except that the mother received piroxicam at about the 26th week of gestation. A sonogram at the 28th week showed oligohydramnios. Histopathological study of the kidneys revealed crowded glomeruli and only few differentiated proximal convoluted tubules in the inner cortex, abnormally differentiated microcystic tubules and microcystic glomeruli in the outer cortex. Periodic acid-Schiff staining showed only traces of brush border in the dilated tubules of the outer cortex. Immunoperoxidase staining for epithelial membrane antigen was positive in the luminal border of all tubules. Electron microscopy confirmed the presence of brush border remnants and other proximal tubular characteristics in some segments. The renal abnormality bears some similarities to that found in familiar renal tubular dysgenesis, but it fits better with those described after maternal use of angiotensin converting enzyme inhibitors and nonsteroidal anti-inflammatory drugs. The lesion in this case appears to have resulted from fetal exposure to piroxicam. Recently, a second pregnancy ended in a completely normal female newborn.

Hemolytic uremic syndrome in families-an Argentinian experience.

Six hundred and thirty-one patients with hemolytic uremic syndrome (HUS) were treated from 1960 to 1992; 19 (3%) were familial cases, of which 9 were classified as concomitant (including twins), 6 as non-concomitant, and 4 as recurrent. In the recurrent group there were 15 HUS episodes, 10 being concomitant in 2 patients. Prodromal diarrhea was present only in concomitant and non-concomitant cases. Patients with recurrences were sisters from a single family. Concomitant and non-concomitant cases had clinical features, course, and age similar to typical endemoepidemic forms of HUS, in which an association with verocytotoxin-producing Escherichia coli has been reported. There may be a genetic determinant in concomitant cases; these occurred outside the season during which endemoepidemic forms are typically detected. In patients with recurrent disease a genetic factor which may lead to the development of the disease when triggered by viral infections is likely.

Haemolytic uraemic syndrome associated with faecal cytotoxin and verotoxin neutralizing antibodies.

Forty-nine patients with a diagnosis of idiopathic haemolytic uraemic syndrome (HUS) were investigated to determine evidence of infection by verotoxin-producing Escherichia coli (VTEC). Free faecal cytotoxin active on Vero cells (VT) was detected in 15 out of 49 patients (31%). Seroconversion or high titres of VT-neutralizing antibodies were detected in 11 out of 18 patients (61%). The results of the present study suggest an association between HUS and infection by VTEC.

[Fast intravenous rehydration with 90 mmol/L of sodium in dehydrated children with diarrhea]. / Rehidratación endovenosa rápida con 90 mmol/L de sodio en niños deshidratados por diarrea.

Twenty-two infants with moderate dehydration due to diarrhea in whom oral rehydration therapy (ORT) was contraindicated or who failed to respond to this method of therapy were treated with rapid intravenous rehydration (RIR). Clinical signs of dehydration without shock allowed us to estimate 5% to 10% of weight loss. Patients were 11 days to 19 months old, and 9 of them were undernourished. A standard solution containing 90 mmol/L sodium, 80 mmol/L chloride, 30 mmol/L bicarbonate, 20 mmol/L potassium and 111 mmol/L glucose was used for all patients. The IV infusion was maintained until the rehydration was completed at a rate of 15 to 20 mL/kg/hour. Complete rehydration was successfully achieved in all patients. A total of 89.5 +/- 25.0 mL/kg (mean +/- SD) was needed and the duration of the IV infusion was 5.1 +/- 1.6 hours. Weight gain achieved was 6.5 +/- 1.6%. None of the patients developed hypernatremia following treatment. The initial base deficit, -9.5 +/- 6.6, was reduced to -3.5 +/- 2.9. All of the patients tolerated refeeding immediately after completion of the IV infusion. Our study suggests that this modality of rehydration is well tolerated, safe and effective and enhances the possibility of an early hospital discharge.

Persistent glomerulonephritis following the haemolytic-uremic syndrome. Immunopathological and morphological studies.

Immunopathological and ultrastructural studies were carried out on kidney biopsies of eight children with a persistent nephropathy (PN) following the haemolytic-uremic syndrome (HUS). Significant amounts of in vivo-bound immunoglobulins and C3 were demonstrated by immunofluorescence methods in the glomeruli of all the cases, with a nodular pattern along the capillary walls. In four cases studied, C1q and C4 were also demonstrated, with an identical distribution. Transmission electron-microscope studies revealed a marked thickening of the glomerular basement membrane, and the existence of an electron-dense material with an intramembranous and subepithelial localization. With the exception of one case, serum complement studies did not present major modifications. Coagulation studies reveal that alterations observed in acute HUS were not present in the PN. Results of the present study suggest that an immune mechanism of glomerular damage operates in the pathogenesis of the PN observed after HUS, leading to a normocomplementemic, chronic glomerulonephritis. Although a hypothetical antigen (or perhaps several antigens) remains to be demonstrated, immunofluorescence and electron-microscope studies suggest the deposition of immune complexes in the renal lesions.

Dysfunction of the monocyte-macrophage system in the idiopathic minimal change nephrotic syndrome.

We studied the function of phagocytes and the distribution of lymphocyte subpopulations in 23 patients with Idiopathic Minimal Change Nephrotic Syndrome. All the patients were in relapse at the time of the study. The latter was performed before specific therapy was started. Our control group consisted of 26 normal children who were studied while undergoing routine analysis prior to plastic surgery. Polymorphonuclear leukocytes from the patients showed no alterations in their ability to ingest and to kill candidas. On the contrary, peripheral blood monocytes had a normal phagocytic function with a decreased candidacidal activity when compared to normal controls (p less than 0.001). No correlation was found between serum immunoglobulin levels and the monocyte lytic function. The absolute number of B lymphocytes was significantly increased (p less than 0.05), whereas the absolute number of total lymphocytes, T lymphocytes and T4+ and T8+ cell subsets did not differ from those of the age-matched normal controls. Natural killer cells were functionally normal.

Valoracion de factores involucrados en el fracaso de un plan de rehidratacion oral. / Valuation of factors involved in the failure of an oral rehydration plan

Los autores trataron de determinar la posible relacion entre el fracaso de un plan de rehidratacion oral y la edad, estado nutricional, grado de deshidratacion al ingreso, dias de enfermedad previos al ingreso, persistencia de la diarrea durante la rehidratacion, acidosis, recuento leucocitario, presencia de otros focos infecciosos, la natremia al comienzo del tratamiento y su variacion al completarse la hidratacion. El estudio se realizo sobre 43 ninos que ingresaron deshidratados por diarrea con o sin vomitos. Fueron rehidratados con la solucion glucoelectrolitica propuesta por la OMS. Se los clasifico en "EXITOS" y "FRACASOS", siendo "EXITOS" aquellos que solo recibieron rehidratacion oral y "FRACASOS" aquellos en que fue necesario recurrir posteriormente a hidratacion parenteral. Se hallo una diferencia estadisticamente significativa entre los "FRACASOS" y los dias de enfermedad previos al ingreso. Se sugiere continuar la investigacion de otros factores (estado de nutricion y recuento leucocitario) que mostraron tambien diferencias, aunque estadisticamente no fueron significativas

Estudio de la acidificación urinaria mediante la prueba de furosemida / Urinary acidification by furosemide test

Se estudiaron 7 niños sanos de 5 a 9 años de edad, 5 con acidose túbulo renal (ATR) distal no hiperkalémica de 4 a 13 años y 1 con ATR proximal de 20 meses para ver le efecto de la furosemida sobre la acidificación urinaria comparándola con las pruebas de sobrecarga ácida y alcalina. Una hora antes y hasta 4 horas después del suministro de furosemida 2 mg/kg por vía oral se medió pH, pCO2, AT, NH3, creatinina y electrolitos en orina cada 60 minutos y creatinina, pH, PCO2 y electrolitos en sangre al comienzo y al final de la prueba. En los ninos sanos y en el paciente con ATR proximal se comprobó significativa caída del pHu y aumento de la excreción ácida neta. Hubo correlación directa entre pH y flujo urinario. En los niños con ATR distal normokalémica la furosemida no hizo descender el pHu a menos de 6 y la excreción ácida neta permaneció baja. El estímulo sobre la secreción distal de hidrógeno que provocó la furosemida en niños sanos y con ATR proximal podría explicarse por un aumento de la oferta y transporte de sodio en el túbulo colector cortical. En los niños con ATR distal normokalémica, estaría implicada una falla en la secreción ...