[Vitamin D supplementation: not too much, not too little!]. / Supplémentation en vitamine D : ni trop, ni trop peu !

Vitamin D deficiency is common in the general population and even more frequent in patients with chronic diseases. The prevention of rickets with native vitamin D supplementation is one of the oldest and most effective prophylactic measures ever reported in medicine, leading to an almost complete eradication of vitamin D-deficient rickets in developed countries. We report on two children with vitamin D abnormalities: the first, 10-year-old child developed rickets without any vitamin D supplementation despite different risk factors (autism, ethnicity, nutritional problems, chronic antiepileptic therapies). In contrast, the second, 8-month-old child received double doses of native vitamin D from birth for several months and was referred for acute and symptomatic hypercalcemia. As such, vitamin D supplementation must follow specific rules: neither too much nor too little! We also discuss the emergence of "new" genetic diseases such as mutations in the 24-hydroxylase (CYP24A1) gene inducing neonatal hypercalcemia and nephrocalcinosis: we believe that before prescribing conventional vitamin D supplementation as recommended by the national guidelines, pediatricians should quickly rule out a potential genetic abnormality in phosphate/calcium metabolism (namely a history of lithiasis or hypercalcemia) that would lead to further biological investigations.

[Neurological symptoms due to Mycoplasma pneumoniae infection in nine children]. / Formes neurologiques des infections à Mycoplasma pneumoniae : à propos de neuf cas pédiatriques.

Mycoplasma pneumoniae infection is common in children. Extrapulmonary symptoms usually reveal as neurological symptoms, mainly as encephalitis with significant morbidity and mortality. Various other neurological presentations have also been reported. We describe a cohort of nine children with neurological manifestations due to M. pneumoniae infection, including five cases of encephalitis, one of polyradiculoneuritis, one of ophthalmoplegia, one of optic neuritis, and one of myositis. Progression was variable from ad integrum recovery to severe brain damage. Diagnosis is usually confirmed by PCR and/or serological follow-up, but the latter is still insufficiently used in practice to systematically affirm the diagnosis. Therapeutic management is not clearly defined and long-term progression can be uncertain despite early antibiotic and/or anti-inflammatory treatments.