Fatal Rupture of Occult Posttraumatic Left Ventricular Aneurysm in a Child.

Left ventricular aneurysm is a potentially serious but rare condition in children. This case describes delayed but fatal rupture of an occult posttraumatic left ventricular aneurysm in an 11-year-old boy with a history of blunt chest trauma from a high-impact automobile collision 7 months earlier. (Level of Difficulty: Intermediate.).

Human leukocyte antigen association with familial steroid-sensitive nephrotic syndrome.

Steroid-sensitive nephrotic syndrome (SSNS) is the most common form of nephrotic syndrome in childhood. Cases with the familial occurrence of SSNS suggest that genetics may play a role in the disease. Human leucocyte antigen (HLA) alleles have been associated with SSNS. We present genetic findings in nine families (44 participants), each with at least two affected siblings. A total of 19 patients were affected with familial SSNS. Six of nine families showed linkage to markers on chromosome 6p (27.29-33.97 Mbp) (Hg19), especially to markers D6S1629 and D6S1560 on HLA dense region in this location. Interestingly, we also found linkage of disease phenotype of familial SSNS on chromosome 15 (91.7-96.9 Mbp) (Hg19) with a logarithm of odds (LOD) score Z = 3.02.Conclusion: Our findings confirm the linkage of HLA markers on chromosome 6, which strengthens the association of HLA alleles in SSNS. What is Known: • Human leukocyte antigen (HLA) alleles have been associated with idiopathic steroid-sensitive nephrotic syndrome (SSNS). Only few studies have investigated the association between HLA alleles and familial SSNS. What is New: • We present evidence of linkage of familial SSNS to chromosome 6p (27.29-33.97 Mbp) (Hg19), especially to markers D6S1629 and D6S1560 on HLA dense region in this location. We also found linkage of the disease phenotype of familial SSNS on chromosome 15 (91.7-96.9 Mbp) (Hg19) with a logarithm of odds (LOD) score of Z = 3.02 following autosomal recessive inheritance pattern.

Infants with prenatally diagnosed kidney anomalies have an increased risk of urinary tract infections.

AIM: This study estimated the urinary tract infection (UTI) risk in a nationwide cohort of infants prenatally diagnosed with parenchymal kidney anomalies compared with a comparison cohort. METHODS: A Danish population-based nationwide cohort of foetuses diagnosed with parenchymal kidney anomalies between 2007 and 2012 had previously been identified. These were compared with foetuses without kidney anomalies who were prenatally scanned the same year. Live born infants were followed from birth until the diagnosis of UTI, emigration, death or two years of age. Cumulative incidences of UTIs were computed. Mortality was estimated using the Kaplan-Meier method. RESULTS: We identified 412 foetuses with parenchymal kidney anomalies out of 362 069 who underwent ultrasound scans and 277 were born alive. The overall risk of a UTI before the age of two years was 19%, and it was 14% among infants without prenatally diagnosed co-occurring urinary tract malformations. The corresponding risk in the 4074 controls was 1%. After two years, mortality was 2.2% in infants with prenatally diagnosed parenchymal kidney anomalies and 0.2% in the controls. CONCLUSION: Infants prenatally diagnosed with parenchymal kidney anomalies had a substantially increased risk of UTI. Awareness of this increased risk may facilitate earlier diagnosis of UTIs in this population.

Aberrant glomerular filtration of urokinase-type plasminogen activator in nephrotic syndrome leads to amiloride-sensitive plasminogen activation in urine.

In nephrotic syndrome, aberrant glomerular filtration of plasminogen and conversion to active plasmin in preurine are thought to activate proteolytically epithelial sodium channel (ENaC) and contribute to sodium retention and edema. The ENaC blocker amiloride is an off-target inhibitor of urokinase-type plasminogen activator (uPA) in vitro. It was hypothesized that uPA is abnormally filtered to preurine and is inhibited in urine by amiloride in nephrotic syndrome. This was tested by determination of Na(+) balance, uPA protein and activity, and amiloride concentration in urine from rats with puromycin aminonucleoside (PAN)-induced nephrotic syndrome. Urine samples from 6 adult and 18 pediatric patients with nephrotic syndrome were analyzed for uPA activity and protein. PAN treatment induced significant proteinuria in rats which coincided with increased urine uPA protein and activity, increased urine protease activity, and total plasminogen/plasmin concentration and Na(+) retention. Amiloride (2 mg·kg(-1)·24 h(-1)) concentration in urine was in the range 10-20 µmol/l and reduced significantly urine uPA activity, plasminogen activation, protease activity, and sodium retention in PAN rats, while proteinuria was not altered. In paired urine samples, uPA protein was significantly elevated in urine from children with active nephrotic syndrome compared with remission phase. In six adult nephrotic patients, urine uPA protein and activity correlated positively with 24 h urine protein excretion. In conclusion, nephrotic syndrome is associated with aberrant filtration of uPA across the injured glomerular barrier. Amiloride inhibits urine uPA activity which attenuates plasminogen activation and urine protease activity in vivo. Urine uPA is a relevant target for amiloride in vivo.

Remission of nephrotic syndrome diminishes urinary plasmin content and abolishes activation of ENaC.

BACKGROUND: Urinary plasmin activates the epithelial Na(+) channel (ENaC) in vitro and may possibly be a mechanism of sodium retention in nephrotic syndrome (NS). This study used a paired design to test the hypothesis that remission of NS is associated with a decreased content of urinary plasmin and reduced ability of patients' urine to activate ENaC. METHODS: Samples were collected during active NS and at stable remission from 20 patients with idiopathic NS, aged 9.1 ± 3.2 years. Plasminogen-plasmin concentration was measured with an enzyme-linked immunosorbent assay. Western immunoblotting for plasminogen-plasmin was performed in paired urine samples. The patch clamp technique was used to test the ability of urine to evoke an inward current on collecting duct cells and human lymphocytes. RESULTS: The urinary plasminogen-plasmin/creatinine ratio was 226 [95 % confidence interval (CI) 130-503] µg/mmol in nephrotic urine versus 9.5 (95 % CI 8-12) µg/mmol at remission (p < 0.001). Western immunoblotting confirmed the presence of active plasmin in urine collected during active NS, while samples collected at remission were negative. Nephrotic urine generated an inward amiloride- and α2-anti-plasmin- sensitive current, whereas the observed increase in current in urine collected at remission was significantly lower (201 ± 31 vs. 29 ± 10 %; p = 0.005). CONCLUSIONS: These findings support the hypothesis that aberrantly filtered plasminogen-plasmin may contribute to ENaC activation and mediate primary renal sodium retention during active childhood NS.

High plasma aldosterone is associated with a risk of reversible decreased eGFR in childhood idiopathic nephrotic syndrome.

BACKGROUND: Oedema formation in nephrotic syndrome (NS) may be associated with volume overload or volume contraction. The present study investigates if plasma aldosterone was related to a clinical course symptomatic of either volume expansion or hypovolaemia. METHODS: Twenty patients with NS were included. Blood and urine samples were collected before treatment of NS and at stable remission. Aldosterone and other vasoactive hormones were measured in plasma and the patients were classified based on the aldosterone concentrations. RESULTS: Five patients were classified with stimulated aldosterone, mean 611 pg/mL [95% confidence interval (CI): 365-993], 12 with suppressed aldosterone, mean 13 pg/mL (95% CI: 6-26), and 3 with unchanged aldosterone, mean 117 pg/mL (95% CI: 101-135). Patients with high aldosterone were characterized by lower estimated glomerular filtration rate (eGFR) (87 ± 30 versus 142 ± 30, P < 0.01), and increased albuminuria (14 ± 11 versus 6 ± 4 g/L, P = 0.03) compared with the remaining patients. eGFR was normalized rapidly by volume expansion in four of these five patients. CONCLUSIONS: Elevated plasma aldosterone during NS may be associated with a risk of temporary reduced eGFR. The normalization of eGFR by volume expansion supports the hypothesis of functional hypovolaemia in some patients. Our data suggest that acute measurement of aldosterone may have implications for the management of oedema.