Dengue Myocarditis Without Plasma Leakage: A Rare, Potentially Fatal Entity

To the Editors: An 11-year-old girl presented with a history of fever and vomiting for 4 days. On admission, she was lethargic and had tachypnoea, tachycardia, poor peripheral pulses and hypotension. Rest of the systemic examination was unremarkable. The patient was resuscitated with fluids, and inotropic support (noradrenaline) was initiated. The initial laboratory tests showed a hemoglobin level of 9.5 g/dL, packed cell volume of 30.3, total leukocyte count of 16.9 × 103 (neutrophilic predominance) and a platelet count measuring 2.15 lac/cmm. Her liver function test and renal function test were normal. Her tropical infection workup was positive for Dengue NS1 ELISA. Gradual reduction of inotropic support was commenced after 24 hours as her vitals improved. However, she developed new-onset respiratory distress requiring noninvasive respiratory support with worsening of shock, 72 hours postadmission. Subsequent investigations showed hemoglobin 10.2 g/dL, packed cell volume (PCV) 30.6 and platelet count 0.77 × 103. Additionally, troponin T was positive, and the N-terminal pro-B-type natriuretic peptide value exceeded 13,000 pg/mL. Her 2D echocardiography was suggestive of left ventricular dysfunction (ejection fraction 25%) and she was diagnosed as a case of severe dengue shock with myocarditis, requiring 3 inotropic drugs (adrenaline, noradrenaline and milrinone). Throughout her entire illness, the patient exhibited no signs of plasma leakage, as presented in Table 1. Intravenous immunoglobulin (IVIG) (2 g/kg) with steroids (methylprednisolone) 2 mg/kg were started leading to improvement within 12 hours. Respiratory and inotropic support were gradually weaned over the next 72 hours. Follow-up 2D echocardiography was normal, and steroids were tapered over 6 weeks. TABLE 1. - Laboratory Investigations Parameters Admission 12 hours 24 hours 48 hours 60 hours 72 hours Hemoglobin (g/dL) 9.5 9.3 10.7 10.2 11.8 10.2 Platelet (lac/cmm) 2.15 1.42 1.57 1.76 1.39 0.77 TLC (× 10 3) (N%) 16.9 (50) 10.65 (62) 16.11 (85) 10.05 (79) 10.27 (75) 5.28 (67.5) PCV 30.3 30 31 30.6 36.8 30.6 AST/ALT (U/L) 16.7/33.6 294/540 434/685 226/407 127/270 NT Pro BNP (pg/mL) 13700 ALT indicates alanine aminotransferase; AST, aspartate aminotransferase; TLC, total leucocyte count; PCV, packed cell volume. Dengue is a prevalent zoonotic disease progressing through febrile, critical and recovery phases. The critical phase is characterized by vasculopathy and coagulopathy leading to plasma leakage, excessive hemoconcentration and bleeding, causing shock and organ dysfunction. Dengue myocarditis has a reported prevalence of 37.8% in India with children showing a higher rate of 46.2%.1 The condition is more common in severe dengue infections (72.7%).1 Documented cases of severe dengue without evidence of plasma leakage are scarce. Apart from our case, only 1 other case of fatal dengue myocarditis with cerebral edema and no evidence of plasma leakage has been documented in the literature.2 The World Health Organization does not endorse the use of corticosteroids for dengue management due to insufficient evidence. Research on the efficacy of IVIG and steroids in treating dengue myocarditis remains limited. However, a small number of randomized controlled trials in children and several observational studies suggest that the potential benefits of corticosteroids should not be disregarded in Dengue myocarditis.3 A few randomized controlled trials comparing IVIG to placebo have shown that IVIG can be effective in treating refractory dengue shock, owing to its ability to modulate and restore immune function.4 This atypical case of dengue myocarditis without plasma leakage highlights the need for increased awareness and regular monitoring for myocardial involvement. The myocardial involvement in dengue is an understudied topic with limited guidelines on management with steroids and IVIG. Our case reiterates the potential benefits of corticosteroids and IVIG in reducing hospital stay, fatal outcomes and enhanced patient recovery.