Cardiovascular Journal of Africa: Vol 32 No 5 (SEPTEMBER/OCTOBER 2021)

CARDIOVASCULAR JOURNAL OF AFRICA • Volume 32, No 5, September/October 2021 280 AFRICA Dengue cases follow a common course: a febrile phase, critical phase and recovery (convalescent) phase. In the first phase (febrile) the patient exhibits a biphasic fever (> 40°C/104°F), associated with generalised, retro-orbital pain and headache lasting two to seven days. Skin manifestations, such as rashes or petechiae, can be present in 50 to 80% of the patients. 6,14 Light rash is likely observed early in the course of infection (day one to two) and it progresses to a measles-like rash at day four to seven. Petechiae and bleeding from the mucous membranes of the mouth and nose also appear at this point. After resolution of the high fever, a small proportion of patients progress to a critical phase, which typically lasts for 24 to 48 hours. This phase is characterised by plasma leakage with or without bleeding. There may be significant accumulation of fluids in the thoracic and abdominal cavities, leading to hypovolaemic shock that can result in organ dysfunction, metabolic acidosis, disseminated intravascular coagulation and severe bleeding, typically from the gastrointestinal tract. The last phase is the recovery, which lasts for two to three days. 6,14 CV manifestations of dengue can be present in any of the different phases. 2,6,14 Clinical manifestations of CV involvement can vary widely, from silent disease to severe myocardial dysfunction and arrhythmias, resulting in death. 15 Symptoms suggesting CV involvement include chest pain, palpitations, pleurisy, irregularities of the pulse, hypotension, pulmonary oedema and features of shock. 14 Although the cardiac complications of dengue are rare, asymptomatic myocardial involvement has been documented. Acute myocarditis is the most common cardiac pathology described in cases of severe dengue. 16 The earliest CV manifestation typically seen is tachycardia. Other abnormalities such as bradycardia, hypotension, myocarditis, pericarditis, myocardial depression with symptoms of heart failure, and shock have been reported within the spectrum of associated CV manifestations. 15 (Fig. 4). The presence of tachycardia and progression to shock early in the disease should increase clinical suspicion of myocarditis. 15,17,18 Additionally, there have been cases of reported Takotsubo cardiomyopathy and myopericarditis mimicking acute myocardial infarction associated with dengue. 19,20 Finally, pericarditis (without myocarditis) has been reported both at the onset of dengue and in the following days. 21 Asymptomatic ECG changes and arrhythmias are the predominant CV manifestations associated with dengue, and sinus tachycardia is reported most frequently. The majority of the cardiac rhythm abnormalities secondary to dengue have been reported in children. 8,22 Bradyarrhythmia, such as sinus bradycardia, first-degree heart block, Mobitz type I second- degree atrioventricular block, bundle branch blocks, complete atrioventricular dissociation and ventricular asystole have been reported. 8,23-26 Additionally, there is a case report of junctional rhythm of 50 beats per minute following a patient’s recovery from dengue. 27 Ventricular arrhythmia, atrial fibrillation and atrioventricular block have been primarily observed during the acute stage of severe dengue. 28-30 In the convalescent stage of dengue, most of the cardiac rhythm abnormalities reported are bradyarrhythmia or premature atrial and/or ventricular beats. 22 Other manifestations Symptoms suggesting cardiac involvement: chest pain, palpitations, pleurisy, hypotension, pulmonay oedema, and features of shock Fig. 4. Cardiovascular manifestations of dengue.