Title : Dengue myocarditis and outcomes in paediatric patients– An observational study from a tertiary care centre in India
Abstract:
Dengue fever is considered one of the most common viral illnesses, widely distributed throughout the tropical and subtropical regions of the world. The exact pathogenesis of myocardial injury due to DENV has not been clearly understood but direct invasion of virus and cytokine-mediated immune response may be responsible. Our study aimed to describe the characteristics of paediatric patients with dengue-induced myocarditis.
The study population included children aged 12 years and below admitted to Paediatric Intensive Care Unit (PICU) with features of severe dengue infection, positive dengue serology and a biochemical picture of myocarditis. Our study showed elevated Troponin I and CK-MB in 87.5% and 85.9% patients respectively. NT-proBNP was elevated in all patients (100%). Other studies show contrasting findings. A reduced ejection fraction (50% or less) was seen in 29.7% of patients in our study. Echocardiographic findings in dengue myocarditis patients vary between different studies. Khongphatthanayothin et al. reported similar findings of EF <50% in 13.8%, and 36% of patients with DHF and DSS during the toxic stage of myocarditis while Datta et al. in their study on 120 dengue patients reported reduced ejection fraction in only 3.3% of their patients. ECG abnormalities were seen in only 5 of our patients, with 11 (17.2%) had echocardiographic evidence of diastolic dysfunction. ECG changes reported from various studies include ST-T wave changes, tachyarrhythmias, ectopic beats and intraventricular conduction delays.16 of our patients (25%) had fluid-responsive shock and 43 (67.2%) required inotropic support for shock. 68.7% of the children required upto 3 inotropes for shock and 28.1% required inotropes for more than 24 hours. It has been shown that during dengue illness, underlying reduced end-diastolic volume results in low cardiac index and low ejection fraction in toxic stage which returns to normal during convalescence. These patients have significantly more hepatomegaly and larger pleural effusions. In our study, 15.6% had pericardial effusion, 87.5% had hepatomegaly, 42.2% had features of fluid overload at the time of admission with ultrasonographic evidence of polyserositis in 95.3% children. Studies show that among children with dengue myocarditis, clinical features of fluid overload are common, requiring careful fluid resuscitation.
8 (12.5%) patients had AKI (as per KDIGO definition) of which 4 (6.3%) underwent peritoneal dialysis as renal replacement therapy. 57 (89.1%) had deranged LFT in the form of transaminitis. 7 of our patients had ARDS and pulmonary haemorrhage which would reflect the state of fluid overload in these mechanically ventilated children. 48.4% of our patients had encephalopathy and 14.1% had seizures. 11 (17.1%) patients had confirmed co-infections with dengue. These included enteric fever, hepatitis A, leptospirosis, and scrub typhus.
We would like to highlight that atypical manifestations of severe dengue such as myocarditis are no longer unusual although largely underreported. Proper training for early detection of warning signs and subtle clinical signs can go a long way in reducing the brunt of these complications.
