[Dengue. Apropos of 2 cases].

BACKGROUND. Dengue is an acute febrile illness caused by several arthropod-born viruses and characterized by biphasic fever, myalgia or arthralgia, rash, leukopenia and lymphadenopathy. Its diagnosis is based on knowledge of the geographic distribution of dengue viruses. CASE REPORTS Case no 1: A 11 year-old boy suffered from sudden onset of fever accompanied by retro-orbital headache, arthralgia and diffuse myalgia. There was no rash. Hemogram showed: hemoglobin: 11.6 g%; leukocytes: 3,400/mm3 (PMN: 76%); platelets: 190,000/mm3. A diagnosis of viral infection was considered, but, as the boy had recently been to the French West-Indies, a serologic study was performed. This was negative 2 days after the onset of disease and positive (specific IgM for the 4 dengue types), 13 days later. Case no 2: A 7 year-old boy suffered from sudden onset of fever. Severe calf muscle pain 4 days later led to his admission. Creatine phosphokinase activity was very high: 83,100 units (N: 30-120). Hemogram showed: hemoglobin: 11.4 g%; leukocytes: 2,500/mm3 (PMN: 60%); platelets: 124,000/mm3. A diagnosis of acute myositis was considered, but as the patient had recently visited Venezuela, a serologic study was performed. This was negative 8 days after the onset of disease and positive (specific IgM for the 4 dengue types) 16 days later. CONCLUSION. The first case is characteristic of the classical form of dengue fever. The second patient presented with very localized myalgia. The diagnosis in both cases was facilitated by the knowledge that the patient had recently stayed in an endemic area.