Haemophagocytic lymphohistiocytosis after rubella-measles vaccination in a 9-month-old toddler

Haemophagocytic lymphohistiocytosis (HLH) is a life-threatening disease resulting from dysregulated activation and proliferation of lymphocytes. Its occurrence after vaccination is possible but exceptional in children. All cases reported in the literature are secondary to measles vaccination. We report the case of a nine-month-old toddler, not consanguineous, with no particular medical history. Having received his first dose of the measles-rubella vaccine. Who presented 7 days after an alteration of the general condition, a generalized papular rash, and an extensive petechial and ecchymotic purpura. A fever of 39.5°c, complicated by a state of convulsive illness, acute diarrhea, and an acute edema of the lungs were noted. The patient admitted to pediatric intensive care unit was intubated-ventilated-sedated and placed on broad spectrum antibiotic therapy. The brain scan followed by lumbar puncture was normal. CRP was slightly increased to 32 mg / l. The remainder of the biological assessment showed bicytopenia (hypochromic microcytic anemia, thrombocytopenia), and predominantly neutrophilic leukocytosis. Acute renal failure, significant hepatic cytolysis (transaminases greater than 10 times normal), and persistent hyponatremia at 129 mmol / l were noted. Feritinemia and LDH were very high. The serologies of hepatitis A, B, C, HIV, and CMV were negative. A realized myelogram showed a histological appearance of a macrophage activation syndrome. The evolution was marked by hemodynamic instability refractory to adapted resuscitation measures. The patient had a multi-visceral failure and died 48 hours after admission. HLH after vaccination against measles remains a rare but formidable complication. Favoring factors, clinical and biological characteristics, as well as the possibility of a genetic predisposition must be specified.