[Hemolytic and uremic syndrome and maternal-fetal Escherichia coli K1 infection]. / Syndrome hémolytique et urémique au décours d'une infection materno-fœtale àEscherichia coli K1.

Hemolytic uremic syndrome (HUS) is primarily a disease of infancy and early childhood. In its classic form, it is preceded by a prodrome of Escherichia coli-mediated bloody mucoid diarrhea. Typical HUS is commonly related to an infection by shiga-toxin producing E. coli. Stool cultures may detect this bacteria or its toxin, and PCRs can detect the shiga-toxin virulence genes. Atypical cases of HUS are mainly related to abnormalities of the alternative complement pathway and mutations of H, I, or B factors. Some atypical cases of HUS may also be related to von Willebrand factor or vitamin B12 metabolism abnormalities. A number of HUS cases related to invasive pneumococcal infections (pneumonia or meningitis) have been reported. We report a case of HUS associated with a bacterial E. coli K1 infection in a newborn baby, with a good clinical outcome: there was no need for dialysis and normal renal function was quickly regained. The workup did not favor a toxinic origin or an abnormality on the alternative complement pathway.

[Virus and sensitization]. / Virus et sensibilisation.

Respiratory viruses are able to replicate in both the upper and lower respiratory epithelium, thus inducing wheezing. Most clinical studies suggest that wheezing illnesses due to respiratory viruses in early childhood are linked to a risk for asthma. Viruses may induce asthma exacerbations through direct effects on their main target, the respiratory epithelium, as well as via a systemic immune-inflammatory reaction. On other hand, studies have also yielded conflicting results in regard to the ability of viral infection to enhance subsequent allergic responses. Do early viral illnesses cause allergic asthma or viral wheezing episodes serve to reveal children who are already predisposed to this disease on basis of an abnormal lung physiology and/or immune response?

[Varicella, acute postinfectious arteriopathy and cerebral arterial thrombosis in childhood: a unique clinical and etiologic framework to be fully acknowledged]. / Varicelle, artériopathie aiguë post-infectieuse et infarctus cérébral artériel de l'enfant: un cadre clinique et étiologique à ne pas méconnaître.

Acute arteriopathies are the etiological factor of 25% of all the cerebral arterial thrombosis cases in childhood; they give way to ischemic strokes which have specific clinical and radiological features; varicella is the etiologic factor in 60% of the cases; favorable outcome is the rule; physiopathology and treatment remain under discussion.