An 11-year-old boy was referred in January 2019 to our Department of Pediatrics because of a prolonged fever lasting 10 days associated with gastrointestinal signs resistant to antibiotics. There were no known allergies and personal or family history of prolonged fever or any systemic disease. The patient was febrile with deterioration in his general condition. Notably, acute abdominal pain associated with vomiting and diarrhea was reported one week before his admission. Therefore, the diagnosis of typhoid fever was considered, and antibiotic therapy including intravenous ceftriaxone 100 mg/kg/day was started without any favorable improvement. In addition, arthralgia, hives, cough, and chest pain were also described. On physical examination, the child was asthenic with tachypnea and tachycardia. Abdominal palpation revealed a periumbilical tenderness. Furthermore, a skin rash on the chest area which had disappeared 2 days after appearing was noted. Bilateral ocular redness without any suppuration was also noticed. Moreover, cracked lips, a coated tongue, and pharyngitis (Figure 1), associated to nonpitting edema of the right foot and ankles were identified. Remarkably, periungual desquamation appeared few days after his admission (see timeline in Figure 2).
Biologically, a hypochromic microcytic anemia with hemoglobin at 9 g/dl, lymphopenia at 810/mm3, a high level of C-reactive protein (CRP) at 200 mg/L, a high erythrocyte sedimentation rate (ESR) at 64 mm/h, a normal platelet count at 245 g/l, and hypoalbuminemia at 26 g/l were found. The blood culture and procalcitonin level were normal; additionally, the serologies for hepatitis A, B, C, cytomegalovirus (CMV), Epstein-Barr Virus (EBV), human immunodeficiency virus (HIV), typhoid fever, Mycoplasma pneumoniae, leptospirosis, brucellosis, rickettsia, tuberculosis, and the hemophagocytic syndrome tests were without abnormalities. Moderate proteinuria at 412 mg/d (10.3 mg/kg/day) with sterile pyuria was the main renal finding. AST and ALT were <30UI/L, and complement 3 (C3), complement 4 (C4), and antinuclear antibodies were also within the normal range. However, the immunoglobulin E (IgE) level was abnormally so high at 1186 UI/ml. The radiological investigations were performed with a cerebral, thoracic, and abdominopelvic computed tomography (CTAP CT) scan; the results showed inflammation of the small bowel, air-fluid levels, reactional mesenteric lymphadenopathy, and a right-sided pleurisy with bilateral pulmonary consolidation (Figure 3).
His cardiac evaluation using transthoracic echocardiogram revealed a myocarditis, pericardial effusion, mitral regurgitation, 4 mm coronary dilatation (Z score +4), and a low left ventricular ejection fraction at 43% (Figure 4).
Sinus tachycardia and left ventricular hypertrophy at the electrocardiography were seen. Besides, cardiac troponin was high at 397.5 ng/ml with an increased brain natriuretic peptide (BNP) at 633 pg/ml. A therapeutic protocol based on intravenous immunoglobulin (IVIg) at a dose of 2 g/kg associated with acetylsalicylic acid 100 mg/kg/day during the acute phase was started 17 days after the onset of the symptoms, then after 5 days acetylsalicylic acid 5 mg/kg/day (antiaggregating dose) per os during 3 months.
During his follow-up, the proteinuria disappeared after few days, and there were no pulmonary lesions on the CT scan control. The coronary dilation has changed from 4 mm to 2.5 mm. The CT scan and the echocardiography were both performed 3 months after onset of treatment.