[Acute renal insufficiency]. / Insuficiencia renal aguda.

The incidence of acute renal failure in children is higher due to the prevalence of diarrheal dehydration, use of nephrotoxic substances and sepsis. The occurrence in the newborn has increased, probably due to the large number of seriously sick infants maintained in neonatal intensive care units. Various laboratory examinations have been proposed as diagnostic indices of acute renal failure in children. Among these are the urine-to-plasma concentrations of urea and creatinine and the urine-to-plasma osmolality ratio. The fractional excretion of sodium and the so-called renal failure index are the most reliable of the diagnostic tests. The functional abnormalities and complications of acute renal failure include reduced glomerular filtration rate, retention of nitrogenous wastes, hyponatremia, hyperkalemia, metabolic acidosis, hypocalcemia, hyperphosphatemia and hypermagnesemia. The principles of management and treatment of complications are discussed.

[IgA nephropathy (Berger's disease) in children]. / Nefropatía IgA (enfermedad de Berger) en niños.

IgA nephropathy, also called Berger's disease, is characterized by recurrent gross hematuria or persistent microscopic hematuria, together with mesangial glomerular deposits of IgA found in the renal biopsy. Seven children with IgA nephropathy were studied. Most of them presented initially with recurrent macroscopic hematuria and low or moderate-grade proteinuria, without hypertension or renal function impairment. Only one patient presented with a rapidly progressive glomerulonephritis. Four patients did not receive any treatment; one of them is in remission, one has improved and two remain with moderate proteinuria and hematuria. One patient with significant proteinuria improved after prednisone and azathioprine treatment. The patient with rapidly progressive glomerulonephritis improved his renal function after oral prednisone and intravenous boluses of methylprednisolone and cyclophosphamide.

[Nephrotic syndrome associated with AIDS in children]. / Síndrome nefrótico asociado al síndrome de inmunodeficiencia adquirida en niños.

Several renal and renal-related disturbances have been described in patients with AIDS (acquired immune deficiency syndrome), in adults and children as well. These are mainly electrolyte and acid-base imbalance, acute renal failure and nephrotic syndrome. The latter is usually steroid non-responder. The renal histopathological lesions described more commonly are minimal change, mesangial hyperplasia and focal segmental glomerulosclerosis. Herein, we describe a 5 year-old with AIDS, that developed nephrotic syndrome, characterized by edema, ascites, hypoalbuminemia and massive proteinuria. A percutaneous renal biopsy showed mesangial proliferation. She did not respond to a 6 week treatment with prednisone. She died with sepsis after several viral and bacterial infections.

[Acute kidney failure due to stings by Africanized bees]. / Insuficiencia renal aguda por picadura de abejas africanizadas.

Africanized bees are unique in their aggressive behavior, characterized by massive attacks during which the victims are injected an important amount of venom. For this reason, Africanized bees are extremely dangerous. Their venom contains biological toxic substances, mainly mellitin, phospholipases, histamine, hyaluronidase and apamin. Non-sensitized persons that survive a massive attack may develop acute renal failure, as a consequence of the severe hemolysis, rhabdomyolysis and shock. These complications may lead to acute renal tubular necrosis. Also, the clinical pattern and treatment of the acute renal failure secondary to bee stings are discussed.

Obstructive aortic and renal thrombosis in the newborn--spontaneous recovery.

A 13-day-old infant presented with acute renal failure secondary to a large thrombus formation involving the umbilical aorta and both renal arteries. The initial clinical manifestations were hematuria, followed by anuria, severe dehydration, grunting respirations, and cyanosis of her feet. She was treated with intravenous fluids and peritoneal dialysis. At the onset, there was no blood flow into the abdominal aorta or into the kidneys. Heparinization and fibrinolytic therapies were unsuccessful in dissolving the clot. However, the aortic clot recanalized spontaneously a few weeks later, but the renal arteries remained permanently occluded. Despite this, her kidneys showed blood flow bilaterally and she recovered her renal function, probably by reperfusing her kidneys through collateral circulation. Malignant hypertension ensued after improvement of renal function, but it could be controlled by appropriate antihypertensive therapy.

Unusual complication in a patient with renal transplantation: cerebral cysticercosis.

A patient with cadaveric renal transplantation was diagnosed by brain-computed tomography and ELISA as having neurocysticercosis in the CSF. Complete cure was achieved after praziquantel therapy. Function of the allograft was not affected.

Adequacy of chronic peritoneal dialysis in low socioeconomic class uremic children.

The ability to provide successful rehabilitation in 57 uremic children from a low socioeconomic background was prospectively evaluated by means of assessment of growth and development, incidence of complications, compliance, mortality rate and final outcome. Forty-three patients were on intermittent peritoneal dialysis (PD) and 14 on continuous ambulatory peritoneal dialysis (CAPD). The overall incidence of peritonitis was 5.6 episodes per patient-year; 41 patients are alive; 12 continue on intermittent dialysis; 16 received a renal allograft and 13 shifted to hemodialysis. Hypervolemia, sepsis due to peritonitis and abandonment of treatment were the main causes of death in 16 children. Malnutrition and non-compliance were the main factors leading to unsatisfactory rehabilitation.

Prednisone versus placebo in membranoproliferative glomerulonephritis: long-term clinicopathological correlations.

Eighteen children with primary MPGN were included in a double blind controlled study. Experimental group received prednisone and control group received lactose. Studies of renal biopsy on admission, at 3 yr (17 pt) and 5 yr (8 pt) were performed. Mean time of observation in both groups was similar (6.5 yr). Four patients of the control group developed ESRD and none of the experimental group. Two patients of the control and one of the experimental group remitted. Serial immunopathological studies showed decreasing mesangial cellularity, thickening of the capillary walls and deposits in both groups. Increase tubulointerstitial alterations and percentage of global sclerotic glomeruli was generally observed except in cases in whom proteinuria disappeared. Our results suggest that prednisone therapy may retard the development of ESRD in children with MPGN. However, longer periods of observation and greater number of cases are necessary to confirm if this treatment in useful.

[Arteriovenous fistula and thrombosis of the renal vein: complication of a surgical renal biopsy]. / Fístula arteriovenosa y trombosis de vena renal: complicación de una biopsia renal quirúrgica.

Hematuria is the most common complication of renal biopsy. Other complications are less frequent, but some of them may be life threatening. Herein, we present a case or recurrent hematuria. Within one year, two renal biopsies were surgically performed in this patient. The histological diagnosis reported minimal change glomerular lesions. Complications arose after the second biopsy, with development of an abdominal mass in the left side with severe pain. IVP showed absence of dye excretion from the left kidney. Renal arteriogram showed an arteriovenous fistula in the lower pole and absence of venous circulation in the same side. This data was consistent with renal vein thrombosis. The fistula was a complication of the renal biopsy, and most likely, the renal vein thrombosis developed from the fistula. Both complications disappeared spontaneously, the patient is asymptomatic and the IVP is normal. We conclude that the renal biopsy is not a harmless surgical procedure and it is necessary to carry out a through evaluation in order to justify the necessity to perform it.

Hematuria in children.

Hematuria is the most common sign of renal lesions in childhood. Most common renal causes are glomerulonephritis, Alport's syndrome and IgA mesangiopathy. Urological and systemic causes are less frequently seen. Diagnostic approach focuses on the clinical presentation of hematuria: gross or microscopic, and accompanying signs or symptoms. Monosymptomatic hematuria causes are variable in each age group. Prognosis of cases with hematuria depends upon the cause.

Renal emergencies in children.

Acute renal failure, severe hypertension, and some complications of the nephrotic syndrome and chronic renal failure are the renal emergencies most frequently seen in the pediatric age group. Diagnosis of acute renal failure is based mainly upon U/P ratios of osmolality and urea as well as a negative mannitol test. Conservative medical management is useful in uncomplicated cases, whereas dialytic procedures are more effective in severe or complicated cases. The most frequent reversible complications in chronic renal failure are infections, extracellular volume changes, electrolyte imbalance and cardiovascular alterations. Intercurrent infection and vein thromboses are the most frequent complication in minimal change nephrotic syndrome and they may be a cause of death. Early diagnosis and adequate treatment are mandatory in these complications.