[Hemolytic uremic syndrome: the experience of a pediatric center]. / Síndrome hemolítico urémico: experiencia de un centro pediátrico.

BACKGROUND: Hemolytic uremic syndrome (HUS) is one of the main causes of acute renal failure in the Chilean pediatric population. AIM: To report the features of patients with HUS, admitted to the pediatric ward of a clinical hospital. MATERIAL AND METHODS: Retrospective review of medical records of patients admitted with the diagnosis of HUS between 1995 and 2002. RESULTS: During the period, 58 patients were admitted with the diagnosis of HUS but only 43 (age range 1 month to 6 years, 22 females) had complete medical records for review. Ninety five percent presented with prodromic diarrhea, mainly dysenteric. Antibiotics were administered to 70%, in the previous days. Acute renal replacement, mainly peritoneal dialysis, was required in 40%. The clinical signs and laboratory parameters that correlated better with the indication for dialysis were anuria, hypertension, initial and permanently high serum creatinine and blood urea nitrogen. Four patients with blood urea nitrogen over 100 mg/dl but without anuria or hyperkalemia, were treated conservatively, and experienced an uneventful course (permissive azotemia). Hospital stay was almost 3 times greater in dialyzed than in non dialyzed children. No deaths related to HUS were reported in the study period. In an average follow up of 54 months, 11.6% of the patients developed chronic renal failure of diverse magnitude. CONCLUSIONS: Despite the fact that our study group behaved clinically similar to published HUS patients in other series, no mortality was observed in a retrospective analysis of patients with this disease.

Post-streptococcal acute glomerulonephritis in Chile--20 years of experience.

In order to characterize the epidemiological and clinical picture of post-streptococcal acute glomerulonephritis (PSAGN), a prospective study was designed to investigate all admissions to a general hospital of a local health service in Chile. The protocol included the investigation of previous streptococcal infections (SI), clinical symptoms and signs, socioeconomic situation (SES), throat and skin swabs for the isolation of group A beta-hemolytic streptococci, sequential determination of serum antistreptolysin O (ASO) titer, anti-DNAase B antibodies, and C3. During the 20 years studied, 926 cases were admitted (56% males). Incidence showed an endemic period (EP) 1980-1983, an epidemic outbreak (EO) 1984-1989, and a late period (LP) 1990-1999, with a rate per 100,000 inhabitants of 6.2, 13.2, and 1.7, respectively. The clinical picture was similar in the three periods. SES was homogeneous, with 80% of the population in low and middle-low categories. The average size of the family was 6.9 compared with 4.8 in the general population. Pyoderma was more frequent than pharyngeal infection, and more so during the EO. The isolation rate of group A beta-hemolytic streptococci from the pharynx was 20% compared with 60% from skin swabs. During EP, the most prevalent serotypes were T14-M0 and T1-M1 from the pharynx and TImp19-M0 from the skin. During EO, T14-M0 was more prevalent (30%). M or T classification was possible in EP and EO in 80%-85% of all strains isolated from the two locations. Significant titers for ASO and anti-DNAase B were found on admission: 55% and 75%, respectively. Both tests allowed identification of 100% of previous SI. In conclusion, the incidence of PSAGN had an uneven trend during the observed period. EO was mainly due to skin infection and a predominance of one serotype, T14-MO, was observed. After the EO, the yearly rate gradually decreased from 13.2 in 1988 to 0.0 in 1999, a rate similar to that of industrialized nations.

Captopril scintigraphy in the study of arterial hypertension in pediatrics.

Renovascular hypertension (RVH) is responsible for 10% of arterial hypertension in children. The early diagnosis of RVH permits specific treatment leading to the cure of hypertension and avoidance of parenchymal damage. Captopril renal scintigraphy (CRS) provides information on the renovascular cause of the arterial hypertension. To validate the usefulness of CRS in hypertensive children, clinical, scintigraphic, and radiological data from 20 patients (mean age 6.1+/-5.5 years) were reviewed. Two patients were newborns. All had renal ultrasound scans and 9 had aortograms. In 7 children, RVH was confirmed by angiography, and CRS was positive for RVH in 6 of these. CRS was negative for RVH in 12 of 13 children without RVH. CRS was non-diagnostic in 3 children with abnormal baseline renal scintigraphy and severely decreased relative renal function ( <35%), 1 of whom had RVH. No side effects of captopril renography were observed. Captopril renography provides a logical, non-invasive, safe, and cost-effective approach in the evaluation of children suspected of having RVH.

[Newborn hydronephrosis: dynamic renal scintigraphy with Tc99m MAG3 in the first month of life]. / Hidronefrosis del recién nacido: cintigrafía renal dinámica con Tc99m MAG3 durante el primer mes de vida.

BACKGROUND: The early and accurate diagnosis of obstructive uropathy in the newborn, prevents secondary complications and kidney damage. AIM: To study the usefulness of Tc99M MAG3 diuretic renogram in newborns with hydronephrosis. MATERIAL AND METHODS: Forty newborns, aged 1 to 30 days, with hydronephrosis, were studied. A Tc99M MAG3 diuretic renogram (DR) was done and its results were compared with clinical features and other imaging studies. Each kidney and its ureter, were considered a renal unit. RESULTS: Seventy six renal units were evaluated. Twenty six were normal on prenatal ultrasound examination and DR. In 11 of the 50 renal units with hydronephrosis, renal function was impaired. Thus, it was impossible to obtain an excretory curve. In 17 of the 39 remaining renal units, the absence of obstructive uropathy was demonstrated clinically. In 16 of these, the DR showed absence of obstruction. In 20 of 21 renal units with confirmed obstructive uropathy, DR showed an obstructive pattern. CONCLUSIONS: In newborns, there is an adequate Tc99M MAG3 uptake and diuretic response. Thus, DR becomes a good functional assessment method in newborns with hydronephrosis.

[Risk factors for permanent kidney damage in children with urinary tract infection]. / Factores de riesgo de daño renal permanente en niños con infección del tracto urinario.

BACKGROUND: In children, urinary tract infection (UTI) is a very common disease, and can cause permanent kidney damage. AIM: To determine risk factors for permanent kidney damage, in children with UTI. PATIENTS AND METHODS: In 337 children with UTI (237 female, mean age 4.2 years) a static renal scintigraphy was performed to assess the presence of permanent kidney damage. The history of vesicoureteral reflux and number of episodes of UTI was obtained. RESULTS: One hundred three children had a history of one episode of infection and the rest had recurrent infections. Permanent kidney damage was observed in 161 children (48%). This damage was observed in 39% of children of less than one year of age, in 43% of children aged 1 to 5 years of age and in 58% of children older than 5 years (p = 0.02). Sixty three percent of 122 children with vesicoureteral reflux had permanent kidney damage, compared with 27% of children without this condition (p < 0.001). Likewise, damage was observed in 36% of children with one episode of infection and 47% of children with recurrent infections (p < 0.01). No gender differences were observed. CONCLUSIONS: Vesicoureteral reflux, recurrence of UTI and age are associated with permanent renal damage in children with UTI.