Hemolytic uremic syndrome caused by Shiga toxin-producing Escherichia coli in children: incidence, risk factors, and clinical outcome.

BACKGROUND: Hemolytic uremic syndrome (HUS) is a multisystemic disease. In a nationwide study, we characterized the incidence, clinical course, and prognosis of HUS caused by Shiga toxin (Stx)-producing Escherichia coli (STEC) strains with emphasis on risk factors, disease severity, and long-term outcome. METHODS: The data on pediatric HUS patients from 2000 to 2016 were collected from the medical records. STEC isolates from fecal cultures of HUS and non-HUS patients were collected from the same time period and characterized by whole genome sequencing analysis. RESULTS: Fifty-eight out of 262 culture-positive cases developed verified (n = 58, 22%) STEC-HUS. Another 29 cases had probable STEC-HUS, the annual incidence of STEC-HUS being 0.5 per 100,000 children. Eleven different serogroups were detected, O157 being the most common (n = 37, 66%). Age under 3 years (OR 2.4), stx2 (OR 9.7), and stx2a (OR 16.6) were found to be risk factors for HUS. Fifty-five patients (63%) needed dialysis. Twenty-nine patients (33%) developed major neurological symptoms. Complete renal recovery was observed in 57 patients after a median 4.0 years of follow-up. Age under 3 years, leukocyte count over 20 × 109/L, and need for dialysis were predictive factors for poor renal outcome. CONCLUSIONS: Age under 3 years, stx2, and stx2a were risk factors for HUS in STEC-positive children. However, serogroup or stx types did not predict the renal outcome or major CNS symptoms.

Relation of bronchial and alveolar nitric oxide to exercise-induced bronchoconstriction in atopic children and adolescents.

BACKGROUND AND OBJECTIVE: Exercise challenge test is widely used in diagnostics and follow-up of childhood asthma, but the method is complex, time consuming, and expensive. In this study, we aimed to find out whether flow-independent nitric oxide (NO) parameters (bronchial NO flux [J'aw(NO)] and alveolar NO concentration [CA(NO)]) predict exercise-induced bronchoconstriction (EIB) in atopic children and adolescents with asthma-like symptoms. Also, the respective NO parameters corrected for axial backward diffusion (J'aw(NO) [TMAD] and CA(NO) [TMAD]) were calculated and included in the analysis. METHODS: Thirty patients (6-19 yr old) with confirmed atopy (positive skin prick tests or allergen-specific IgE) and asthma-like respiratory symptoms were included in the study. Before the current investigations, none of the patients had been diagnosed to have asthma and none were on inhaled corticosteroids. Exhaled NO was measured at multiple exhalation flow rates, and exercise challenge test was carried out. Bronchial NO flux and alveolar NO concentration were calculated according to the linear method with and without correction for axial backward diffusion. Sixty-six healthy school children served as controls. RESULTS: The patients were divided into two groups according to EIB. Patients with EIB (EIB+ group, n = 18) had enhanced bronchial NO output as compared to patients without EIB (EIB- group, n = 12); but the EIB- group did not differ from healthy controls. EIB+ group had also higher alveolar NO concentration than EIB- group and healthy controls, but EIB- group did not differ from healthy controls. When bronchial NO flux and alveolar NO concentration were corrected for axial diffusion, J'aw(NO) (TMAD) had equal difference as J'aw(NO) between the groups as expected. However, only EIB+ had higher CA(NO) (TMAD) than healthy controls, and the patient groups did not differ from each other. In patients, bronchial NO output correlated with the magnitude of exercise-induced change in PEF (r(s) = -0.388, p = 0.034), FEV(1) (r(s) = -0.395, p = 0.031), and FEF(50%) (r(s) = -0.431, p = 0.020), i.e., the higher the bronchial NO output, the larger the decrease in PEF/FEV(1) /FEF(50%) . Alveolar NO concentrations correlated with the change in FEV(1) (r(s) = -0.439, p = 0.015), FEF(50%) (r(s) = -0.454, p = 0.013), FEF(75%) (r(s) = -0.447, p = 0.017), and FVC (r(s) = -0.375, p = 0.045). For J'aw(NO) (TMAD), the correlations and p-values were equal to those of J'aw(NO) , but, interestingly, CA(NO) (TMAD) had no significant correlations with any of the exercise-induced changes in lung function. CONCLUSION: The results showed that in atopic children and adolescents, increased bronchial NO output as well as J'aw(NO) (TMAD) were associated with EIB, while alveolar NO concentration (but not CA(NO) [TMAD]) correlated with the degree of obstruction in smaller airways induced by exercise challenge.

Increased bronchial NO output in severe atopic eczema in children and adolescents.

Atopic children have an increased risk for asthma, which is preceded by bronchial inflammation. Exhaled nitric oxide (NO) measured at multiple exhalation flow rates can be used to assess alveolar NO concentration and bronchial NO flux, which reflect inflammation in lung periphery and central airways, respectively. Exhaled breath condensate is another non-invasive method to measure lung inflammation. The purpose of the present study was to find out if the severity of atopic eczema is associated with lung inflammation that can be observed with these non-invasive tests. We studied 81 patients (7-22 yr old) with atopic eczema and increased wheat-specific IgE (>or=0.4 kUA/l) and no diagnosis of asthma. Exhaled NO was measured at multiple exhalation flow rates, and bronchial NO flux and alveolar NO concentration were calculated. Cysteinyl-leukotriene concentrations were measured in exhaled breath condensate. The patients were divided into two groups according to the severity of atopic eczema. Patients with severe atopic eczema had enhanced bronchial NO output as compared with patients with mild eczema (2.1 +/- 0.5 vs. 0.9 +/- 0.1, p = 0.003). No statistically significant differences in alveolar NO concentrations were found between the groups. In the whole group of patients, the bronchial NO output correlated positively with serum eosinophil protein X (r(s) = 0.450, p < 0.001), serum eosinophil cationic protein (r(s) = 0.393, p < 0.001), serum total IgE (r(s) = 0.268, p = 0.016) and with urine eosinophil protein X (r(s) = 0.279, p = 0.012), but not with lung function. Alveolar NO concentration correlated positively with serum eosinophil protein X (r(s) = 0.444, p < 0.001) and with serum eosinophil cationic protein (r(s) = 0.362, p = 0.001). Measurable cysteinyl-leukotriene concentrations in exhaled breath condensate were found only in one-third of the patients, and there were no differences between the two groups. The results show that increased bronchial NO output is associated with eosinophilic inflammation and severe atopic eczema in patients without established asthma.

Long-term pulmonary function in children with recessive polycystic kidney disease.

BACKGROUND: Neonatal autosomal-recessive polycystic kidney disease (ARPKD) is associated with pulmonary hypoplasia and severe respiratory distress. There is no published information on long-term lung function in ARPKD survivors. METHODS: Pulmonary function tests, including spirometry and diffusion capacity, were performed in a nationwide cohort of Finnish paediatric patients with ARPKD. The annual incidence of respiratory infections and the need for permanent asthma medication were also evaluated in this population. RESULTS: Pulmonary function in 11 children surviving the neonatal period was good when measured after a median follow-up time of 10.4 years (range 5.4-16.1 years). None of the patients required oxygen supplementation, and only one patient had asthma. Patients who had received ventilator therapy during infancy had significantly lower maximal instantaneous forced expiratory flow (MEF%) (66%; 43-93% vs 105%; 63-110%; p=0.048) and forced expiratory volume/forced vital capacity (0.76; 0.7-0.81 vs 0.89; 0.77-0.91; p=0.03) than patients without a history of mechanical ventilation, suggesting tendency for airway obstruction in the former group of patients. The frequency of respiratory infections did not differ from Finnish paediatric population in general. CONCLUSIONS: The results of pulmonary function tests were within reference values for most patients with ARPKD, which suggested good long-term lung prognosis. Lung function tests should be considered for patients with ARPKD with a history of mechanical ventilation during infancy.