Comments on ‘Acute myocarditis in vivax malaria: an extremely rare complication’

The following are my comments on a recent publication of a case report of acute myocarditis in vivax malaria.

Mixed infections of enteroviruses (EVs) with malaria have been reported ¹ but, as rightly stated by Ahmed et al., ² plasmodium vivax is a very rare cause of myocarditis. The more common and reported cases of myocarditis are seen in patients with EV infections. Thus, in the case reported by Ahmed et al., it would have been prudent to search for common causes of myocarditis such as EV infections which are responsible for 25%–30% cases of myocarditis.^3,4 Moreover, there is a possibility that the patient did not have myocarditis and simply had decreased cardiac function due to a systemic inflammatory response.

The clinical presentation of viral myocarditis varies from nonspecific electrocardiographic abnormalities and mild viral illness to acute haemodynamic compromise or sudden cardiac death. The condition of some patients with acute focal myocarditis mimics a diagnosis of myocardial infarction with acute onset of chest pain, tachyarrhythmia or sudden death. ⁵

Laboratory diagnosis of EV71 is established primarily through virus isolation or molecular detection of the virus nucleic acid in appropriate clinical specimens. One potential limitation of EV-polymerase chain reaction (PCR) of upper respiratory tract specimens is the occasional cross-reaction with rhinoviruses. Samples for laboratory investigation should be selected according to the disease manifestations. Possibilities include: throat; rectal and ulcer swabs; samples of serum, urine and cerebrospinal fluid (CSF); and fluid from vesicles. In particular, virus detection in samples from sterile sites, such as vesicular fluid, CSF, serum, urine, or those gathered at autopsy, is more reliable than that in samples from non-sterile sites, such as the throat or rectum, where the presence of the virus might merely indicate coincidental carriage. ⁶ Histopathological examination is the gold standard for a definitive diagnosis of myocarditis. Myocarditis can also be diagnosed with the help of newer radiologic techniques, such as contrast enhanced magnetic resonance imaging, and immunodiagnostic tools, such as induction of major histocompatibility and intercellular adhesion molecules on cardiac myocytes, in addition to direct evidence of viral infection, such as PCR, antibody titres and cell cultures.

Treatment for viral myocarditis is supportive and a few reports have shown an increase in survival and recovery of ventricular function when the patient were given intravenous immunoglobulins. ⁴