Symptomatic hypercalcaemia in paediatric tuberculosis

Successful management with bisphosphonate treatment in a child with tuberculosis-associated hypercalcemia

Hypercalcemia is a common metabolic abnormality in children and generally occurs due to hyperparathyroidism, vitamin D toxicity, some genetic disorders and malignant diseases. Granulomatous diseases are a rare cause of hypercalcemia in children, which are usually mild and asymptomatic. Severe hypercalcemia in granulomatous diseases has also been reported in the literature. Here, we report a child presenting with severe hypercalcemia secondary to miliary tuberculosis with successful management with bisphosphonate treatment. Increased 1,25(OH)2D3 synthesis by activated macrophages in the granuloma tissue is the major mechanism of hypercalcemia in tuberculosis.

Acute Hypercalcaemia and Hypervitaminosis D in an Infant with Extra Pulmonary Tuberculosis

In patients with tuberculosis, abnormal extrarenal production of 1,25-dihydroxyvitamin D3 by activated macrophages in granulomatous tissues may result in hypercalcaemia. More commonly reported in adults with active pulmonary tuberculosis, this complication may rarely occur in extrapulmonary tuberculosis, and children. The hypercalcaemia may be precipitated by usually recommended vitamin D and calcium supplementation in patients with tuberculosis. We report here an infant with tubercular meningitis who developed hypercalcaemia 12 days after starting routine vitamin D and calcium supplementation. This communication highlights the importance of close monitoring of calcium levels in patients with tuberculosis, especially if started on vitamin D and calcium replacement before anti-tubercular therapy.

[Hypercalcemia complicating BCG lymphadenitis: case report]

One of the side effects of the BCG vaccine is a local infection that may spread to the regional lymph nodes causing lymphadenitis, which can resolve spontaneously without treatment. We report the case of an immunocompetent infant who developed lymphadenitis after administration of the BCG vaccine, complicated with persistent symptomatic hypercalcemia in spite of the usual treatment including corticotherapy. Antituberculous treatment was necessary to reduce this hypercalcemia.

A predictive signature gene set for discriminating active from latent tuberculosis in Warao Amerindian children

BACKGROUND

Tuberculosis (TB) continues to cause a high toll of disease and death among children worldwide. The diagnosis of childhood TB is challenged by the paucibacillary nature of the disease and the difficulties in obtaining specimens. Whereas scientific and clinical research efforts to develop novel diagnostic tools have focused on TB in adults, childhood TB has been relatively neglected. Blood transcriptional profiling has improved our understanding of disease pathogenesis of adult TB and may offer future leads for diagnosis and treatment. No studies applying gene expression profiling of children with TB have been published so far.

RESULTS

We identified a 116-gene signature set that showed an average prediction error of 11% for TB vs. latent TB infection (LTBI) and for TB vs. LTBI vs. healthy controls (HC) in our dataset. A minimal gene set of only 9 genes showed the same prediction error of 11% for TB vs. LTBI in our dataset. Furthermore, this minimal set showed a significant discriminatory value for TB vs. LTBI for all previously published adult studies using whole blood gene expression, with average prediction errors between 17% and 23%. In order to identify a robust representative gene set that would perform well in populations of different genetic backgrounds, we selected ten genes that were highly discriminative between TB, LTBI and HC in all literature datasets as well as in our dataset. Functional annotation of these genes highlights a possible role for genes involved in calcium signaling and calcium metabolism as biomarkers for active TB. These ten genes were validated by quantitative real-time polymerase chain reaction in an additional cohort of 54 Warao Amerindian children with LTBI, HC and non-TB pneumonia. Decision tree analysis indicated that five of the ten genes were sufficient to classify 78% of the TB cases correctly with no LTBI subjects wrongly classified as TB (100% specificity).

CONCLUSIONS

Our data justify the further exploration of our signature set as biomarkers for potential childhood TB diagnosis. We show that, as the identification of different biomarkers in ethnically distinct cohorts is apparent, it is important to cross-validate newly identified markers in all available cohorts.