Plasmapheresis in a very young infant with atypical hemolytic uremic syndrome.

Atypical hemolytic uremic syndrome (HUS) is a heterogeneous group of disorders, the pathogenesis of which is unclear. Plasma transfusions and plasmapheresis are widely used modes of therapy for adults with this life-threatening syndrome. There is very limited experience in using plasmapheresis therapy in children and infants with atypical HUS. Plasmapheresis, which is considered a relatively safe procedure in adults and older children, may be hazardous in neonates and very young infants and can result in severe complications. We report a 2-month-old infant with idiopathic atypical HUS, who was successfully treated with a 1-month course of plasmapheresis during the acute phase of the disease. Appropriate preparations as well as several adjustments were made in order to meet the special needs of this very young infant who, to the best of our knowledge, is the youngest reported patient with atypical HUS to undergo plasmapheresis. Plasmapheresis therapy of the infant was not associated with any complications of the procedure and resulted in marked clinical improvement. We conclude that plasmapheresis in neonates and in very small infants is technically feasible, can be performed without major complications, and may be of benefit in individual cases.

Genetic polymorphisms of the renin-angiotensin system and the outcome of focal segmental glomerulosclerosis in children.

BACKGROUND: The clinical course of primary focal segmental glomerulosclerosis (FSGS) in children is variable, with some patients having a much more rapidly progressing course than others. The purpose of our study was to compare the frequency of three polymorphisms of the renin-angiotensin system (RAS) in children with FSGS with that in healthy controls of matching ethnic groups, and to determine whether the clinical outcome of FSGS was associated with different RAS genotypes. METHODS: Three RAS genotypes were examined in 47 Jewish and Arab children with biopsy-proven primary FSGS and in a large control group: the ACE insertion/deletion polymorphism in intron 16, the M235T mutation in the angiotensinogen gene, and the A1166C in the angiotensin II type 1 receptor gene (AT1R). RESULTS: Arab patients showed a greater tendency towards progressive renal disease than their Jewish counterparts (12 of 21 vs. 9 of 26, P = 0.05) and were less likely to achieve remission (3 of 21 vs. 11 of 26, P < 0.04), despite similar clinical presentation, medical management and follow-up. The RAS allele prevalence was similar among patients and controls of matching ethnic backgrounds, and no difference in allele frequency was found between Arabs and Jews. Homozygotes for the ACE insertion genotype (II) were significantly less likely to have progressive renal disease than patients with the other genotypes (ID and DD; 0 of 6 vs. 21 of 41; P < 0.022). The other RAS polymorphisms were not associated with variations in the clinical course of childhood FSGS. CONCLUSIONS: Homozygosity for the ACE insertion allele may have a protective effect in children with FSGS and can serve as a positive prognostic indicator at diagnosis. The D allele may exert a detrimental dominant effect on outcome. Neither the ACE gene polymorphism nor the other RAS polymorphisms studied are associated with disease prevalence. The AT1R and angiotensinogen gene polymorphisms are not associated with progression of renal disease in FSGS. Ethnic differences in the clinical course of the disease are not linked to these polymorphisms.

Isoniazid-induced crescentic glomerulonephritis in a child with a positive tuberculin skin test.

Acute nonoliguric renal failure developed in a 13-year-old girl, 1 month after the institution of isoniazid therapy because of a positive tuberculin test at school screening. A renal biopsy demonstrated severe crescentic glomerulonephritis with focal interstitial changes. Discontinuation of isoniazid and a short course of steroids and cyclophosphamide therapy were followed by complete recovery. Whereas isoniazid has been shown to induce a lupus-like syndrome and antihistone antinuclear antibodies, our patient displayed none of the clinical or immunological features that are characteristic of drug-induced lupus. Furthermore, none of the identifiable causes for crescentic glomerulonephritis was evident in this girl. To the best of our knowledge this is the first report suggesting a possible association of crescentic glomerulonephritis to isoniazid treatment.