AIMTo determine the true prevalence of thrombocytosis in children less than 2 years of age with bronchiolitis, its association with risk factors, disease severity and thromboembolic complications.METHODSA retrospective observational medical chart review of 305 infants aged two years or less hospitalized for bronchiolitis. Clinical outcomes included disease severity, duration of hospital stay, admission to pediatric intensive care unit, or death. They also included complications of thrombocytosis, including thromboembolic complications such as cerebrovascular accident, acute coronary syndrome, deep venous thrombosis, pulmonary embolus, mesenteric thrombosis and arterial thrombosis and also hemorrhagic complications such as bleeding (spontaneous hemorrhage in the skin, mucous membranes, gastrointestinal, respiratory, or genitourinary tracts).RESULTSThe median age was 4.7 mo and 179 were males (59%). Respiratory syncytial virus was isolated in 268 (84%), adenovirus in 23 (7%) and influenza virus A or B in 13 (4%). Thrombocytosis (platelet count > 500 × 109/L) occurred in 88 (29%; 95%CI: 24%-34%), more commonly in younger infants with the platelet count declining with age. There was no significant association with the duration of illness, temperature on admission, white blood cell count, serum C-reactive protein concentration, length of hospital stay or admission to the intensive care unit. No death, thrombotic or hemorrhagic events occurred.CONCLUSIONThrombocytosis is common in children under two years of age admitted with bronchiolitis. It is not associated with disease severity or thromboembolic complications.

Background. The Bacillus Calmette–Guérin (BCG) and rotavirus vaccines are live-attenuated preparations. In the United Arab Emirates, these products are universally administered to the young infants. This unguided practice does not account for the children with immunodeficiency, which frequently manifests after the administration of these vaccines. We present here a young infant with immunodeficiency that developed disseminated tuberculosis infection and severe diarrhea due to these improper immunizations. Case Presentation. This young infant was diagnosed at six months of age with “immunodeficiency type 19” (MIM#615617) due to homozygous nonsense variant, NM_000732.4 (CD3D):c.128G > A, p.Trp43∗ (variation ClinVar#VCV000643120.1; pathogenic). This variant creates premature stop-gain in CD3D (CD3 antigen, delta subunit, autosomal recessive; MIM#186790), resulting in loss-of-function. He also had “X-linked agammaglobulinemia” (MIM#300755) due to hemizygous missense variant, NM_001287344.1 (BTK):c.80G > A, p.Gly27Asp (novel). He had a sibling who passed away in infancy of unknown disease and family members with autoimmune disorders. Despite these clear clues, he was immunized with BCG at birth and rotavirus at 2 and 4 months. He was well in the first four months. He then developed high-fever, lymphadenopathy, and refractory diarrhea. Stool was positive for rotavirus, and lymph node biopsy showed acid-fast bacilli, consistent with tuberculosis lymphadenitis. These infections were serious and markedly complicated his clinical course, which included bone marrow transplantation from a matched sibling. Conclusions. These unfortunate events could have been avoided by compiling the available clinical information. This patient underscores the importance of implementing proper policies for BCG and rotavirus vaccinations. International registries of adverse events of universally administered vaccines are crucial.

Prolonged cholestasis is a rare complication of hepatitis A infection, characterized by a protracted, indolent course with persistent symptoms of pruritus and malabsorption lasting for several months. A 14-year-old girl, previously treated for acute hepatitis A, presented with yellowing of the eyes. An evaluation of her liver function revealed conjugated hyperbilirubinemia, and a liver biopsy confirmed hepatitis with cholestasis. Fortunately, she responded well to conservative treatment and recovered successfully.