Perimyocarditis in Dengue Shock Syndrome: A Primary Infection Challenging Traditional Paradigms — A Case Report

Dengue virus infection is a leading cause of febrile illness in travellers returning from endemic regions. While most primary infections are mild and self-limiting, a small proportion progresses to severe disease, such as dengue shock syndrome (DSS). With the global rise in dengue incidence, clinicians should remain alert to rare but serious complications—including cardiac involvement—even in primary infections. We report a rare case of DSS complicated by perimyocarditis in a previously healthy traveller returning from Indonesia, highlighting the importance of early recognition of atypical presentations. A 55-year-old woman presented with malaise, rash, and weakness two weeks after returning from Bali, Indonesia. Serological testing confirmed dengue virus infection (IgM +, IgG −, NS1 +). Electrocardiogram (ECG), transthoracic echocardiography (TTE), and elevated troponin levels led to the diagnosis of perimyocarditis. Due to the suspicion of obstructive shock, given persistent hypotension, rising lactate, and a pulsus paradoxus, a pericardiocentesis was performed, but without hemodynamic improvement. The shock was ultimately attributed to distributive shock due to capillary leak in the context of DSS, supported by hypoalbuminaemia, peripheral oedema, and pleural effusion. The patient improved with supportive care and recovered fully. This case challenges the traditional dogma that severe dengue occurs primarily in secondary infections, demonstrating that life-threatening complications, including perimyocarditis, can arise even in primary infections.