Case 2
A 5-month-old girl developed five days before admission high fever, pallor, irritability, nausea, vomiting, diarrhea and a perianal dermatosis. Clinically she was lethargic, dehydrated, with generalized pallor, tachypnea and bilateral rales, cervical, axillar and inguinal lymphadenopathies, hepatosplenomegaly and week peripheral pulses. Laboratory tests showed WBC 14,930/mm3 (PMN 5%, lymphocytes 55%, monocytes 40%), Hb 3.7g/dL, platelet count 8,000/mm3, albumin 2.3 g/dL, total bilirubin 1.1 mg/dL, CRP 37.1mg/dL, procalcitonin 11 ng/mL, ferritin 2,290 ng/mL and fibrinogen 398 mg/dL. Treatment was initiated with cefotaxime and vancomycin, a chest CT was performed with findings suggestive of COVID-19 infection, with interstitial infiltrates, ground-glass opacities bronchoalveolar thickening and left subsegmental atelectasis (Fig 1B). Laboratory tests showed a D-dimer 6.52 µg/mL, NT-proBNP 207 pg/mL, Troponin I <10 pg/ with positive immunoglobulin IgG serology and negative RT-PCR for SARS-CoV-2; the echocardiogram reported LVEF 48%. The diagnosis of MIS-C was made and received treatment with IVIG (2g/kg), three boluses of methylprednisolone (30 mg/kg/dose) and enoxaparin (1 mg/kg/dose).
She had persistent fever, bicytopenia with anemia and thrombocytopenia, albumin 2.9g/dL, total bilirubin 0.67 mg/dL, CRP 1.6 mg/dL, procalcitonin 0.53 ng/mL, D-dimer 6.14 mcg/mL, ferritin 1000 ng/mL, NT-proBNP 428 pg/mL triglycerides 531 mg/dL, fibrinogen 159 mg/dL, IL-6 levels in 4.52 pg/mL (<9.7); she developed multi-organ failure despite treatment and had significant hepatosplenomegaly. A bone marrow aspiration was performed with hemophagocytosis (Figure 3); HScore was 224. A second dose of IVIG was administrated and had induction treatment according to HLH 2004 Protocol with low dose etoposide and dexamethasone. Blood cultures grew Serratia marcescens was treated with meropenem. Clinical improvement was seen after 72 hours and the patient had a favorable response after six weeks of chemotherapy with normalization of CBC; follow-up, all medications were stopped and a new bone marrow biopsy showed normal findings (Figure 3C). Primary Hemophagocytic lymphohistiocytosis (HLH) was ruled out with next-generation sequencing.