Mannose-binding lectin (MBL) and the risk for febrile neutropenia and infection in pediatric oncology patients with chemotherapy.

BACKGROUND: We determined whether mannose-binding lectin (MBL) deficiency is associated with an increased risk of febrile neutropenia (FN) and/or infection in pediatric oncology patients. PROCEDURE: We systematically searched and reviewed all the literature on MBL and infections in children with cancer, identified from a literature search of Medline, Embase, and Central (1966-April 2010). We extracted information on the type of study, patient characteristics, definition of MBL deficiency, definition of infection and method of detection, follow-up period and the results of the outcome in different groups. The validity of each study was assessed. RESULTS: Six cohort studies were retrieved, consisting of 581 children with leukemia (n = 2) or varying types of cancer (n = 4). Many different outcome definitions were used. In only one out of three genotype studies, variant MBL2 genotypes, as well as MBL levels < 1,000 µg/L, were associated with an increased duration of FN. In one additional MBL level study the number of FN episodes, bacteremia and severe bacterial infection were increased in patients with MBL levels < 100 µg/L as compared to those with MBL levels of 100-999 µg/L. Sepsis, pneumonia, viral infection, and fungal infection were not associated with either MBL levels or genotypes in any of the studies. CONCLUSIONS: MBL deficiency could not be identified as an independent risk factor for FN or infection in pediatric oncology patients. A multicenter study of children with comparable chemotherapy regimens, relevant and equal outcome definitions and measuring both MBL levels and genotypes, will be required to avoid clinical and methodological inconsistencies.

Poorly Controlled Congenital Hypothyroidism due to an Underlying Allgrove Syndrome.

BACKGROUND: Congenital hypothyroidism of thyroidal origin (CHT) is a common disorder in pediatric endocrinology practices, which can be difficult to manage. Elevated thyrotropin (TSH) concentrations are in the great majority of cases explained by poor compliance to levothyroxine therapy. METHODS: Case description. RESULTS: We present a boy with CHT, with 2 heterozygous mutations in the TSH receptor gene, who showed persistently elevated TSH concentrations and psychomotor retardation, initially misinterpreted as malcompliance. At the age of 4 years, he was diagnosed with adrenal insufficiency, wherefore a broad diagnostic search was initiated. After the start of glucocorticoid replacement therapy, his TSH normalized and the levothyroxine could be lowered. At the age of 6 years, his TSH increased again, this time caused by malabsorption of levothyroxine due to esophageal achalasia. In retrospect, alacrima was also present and the diagnosis of Allgrove syndrome was genetically confirmed. The CHT was considered a separate disease entity. CONCLUSIONS: In case of persistently elevated TSH levels in children with CHT, causes other than noncompliance must be considered. Second, in establishing the cause of adrenal insufficiency, specific symptoms, such as alacrima, are easily overlooked. Third, Allgrove syndrome is a rare disorder, in which diagnostic delay can lead to potentially life-threatening complications.

Mannose-binding lectin and infection risk in newborns: a systematic review.

The authors systematically reviewed the literature on mannose-binding lectin (MBL) and infections in newborns to determine whether infection risk is increased in MBL-deficient newborns. All original reports on MBL and infections in newborns were retrieved from Embase, Medline and CENTRAL from 1966 to December 2009. Information extracted from each article included study design, definitions of MBL deficiency and neonatal infection, follow-up period and risk factor analysis. The validity of each study was assessed. Eight prospective cohort studies, including 3166 (range 47-1832) premature or term neonates, were assessed. MBL levels were measured in five studies and MBL2 genotype in six studies. Definitions of MBL deficiency and infection varied. In three out of five phenotypic studies low MBL levels were statistically significantly associated with increased culture-confirmed sepsis rates, also after correction for gestational age or birth weight. In the first study, the median MBL level was decreased in newborns with confirmed sepsis (170 µg/l) compared with newborns without sepsis (1450 µg/l). In two other studies, culture-confirmed sepsis was associated with MBL levels ≤700 µg/l (OR 15.0, 95% CI 1.5 to 151.3) and ≤400 µg/l (OR 3.1), respectively. The remaining two studies investigated various non-culture-confirmed infections. Only one study included the timepoint of clinical suspicion of infection in multivariate analysis. Contradicting results were reported in six MBL2 genotypic studies. Newborns with low MBL levels appear to have culture-confirmed sepsis more frequently than MBL-sufficient newborns. However, the influence of confounding factors was analysed insufficiently. Variant MBL2 genotypes appear to have less influence.

Sleep breathing abnormalities in kyphoscoliosis.

Five patients with severe kyphoscoliosis were studied during sleep. A spectrum of breathing abnormalities was found ranging from no abnormalities to severe episodes of prolonged central apnea. Rapid-eye-movement (REM) sleep was the period of greatest physiologic disturbance in all the patients, being the time of greatest oxygen desaturation. Within this small group, those with the most clinical evidence of chronic hypoxemia, polycythemia, and cor pulmonale, had the most severe derangements during sleep. Derangements in breathing pattern and arterial oxygen saturation (SaO2) had no apparent relation to the degree of thoracic deformity, the results of pulmonary function tests, arterial PCO2, or the chemical drives to breathe.