Reviewed by Dr. Eddie Hackler III
Nunes, MC, et al. Heart 2017 May:103(9):651-58
Parasitic infections due to protozoa and helminths are extending outside endemic areas and becoming more common worldwide. These parasitic infections present in a variety of ways, including injury of the myocardium and pericardium. It is essential that healthcare workers globally are aware of these clinical manifestations.
Chagas disease or American Trypanosomiasis, caused by Trypanosoma cruzi, is most prevalent in Latin America. Transmitted by infected triatomine bugs, the infection has an acute and chronic phase, with the latter continuing for the duration of the host’s life. Chagas disease is characterized by involvement of the esophagus, colon, nervous system and heart with Chagas cardiomyopathy being the most serious form of disease. The heart disease is considered an “arrhythmogenic cardiomyopathy,” characterized by atrial and ventricular arrhythmias and conduction system defects that manifest as right bundle branch block on ECG. Fibrosis classically involving the posterior and apical regions of the left ventricle differentiates Chagas from other forms of cardiomyopathy. Apical aneurysm associated with mural thrombi and embolic events is a hallmark finding as well. Treatments include nifurtimox or benznidazole.
Sleeping sickness or African Trypanosomiasis, caused by Trypanosoma brucei gambeinse and brucei rhodesiense are transmitted by tsetse flies and occur mostly in sub-saharan Africa. There are two stages with stage 1 (hemolymphatic) being a systemic febrile illness and stage 2 (meningoencephalitic) being a variety of neurologic symptoms. Cardiac manifestations such as myocarditis, pancarditis, arrhythmias and heart failure occur mostly during the hemolymphatic stage. ECG findings may show low voltage, PR depression, nonspecific ST-T wave changes and prolonged QT. Treatments include Suramin, pentamidine, eflornithine and organic arsenicals.
Leishmaniasis is mostly transmitted by the phlebotomine sand fly, which is found in the tropics, subtropics and southern Europe. There are some case reports of myocarditis and pericarditis but most commonly, the cardiac complications are caused by treatment side effects. Pentavalent antimonials (SbV) are associated with t-wave inversions, prolonged QT, AVCs, PVCs, torsades de pointes and SCD at higher doses. Amphotericin B can cause a reversible cardiomyopathy.
Schistosomiasis is caused by Schistosoma mansoni, S. haematobium and S. japonicum, affects people in over 70 countries, and requires direct contact with snail-infested water. In humans, the worms migrate in the blood to the liver to mature and spread to the intestines, bladder or other sites. The disease is characterized by acute and chronic phases, both of which can be asymptomatic or include symptoms such as portal hypertension, urinary reflux and obstruction, and pulmonary arterial hypertension leading to right heart failure. Diagnosis is made by finding schistosome eggs in stool, urine or rectal snips. Treatment is recommended regardless of symptoms with Praziquantel.
Tropical Endomyocardial Fibrosis, thought to be the most common form of restrictive cardiomyopathy worldwide, is found mostly in the tropics of Africa, Asia and South America. Etiology and pathogenesis are not understood well but chronic hypereosinophilia from parasitic infections is thought to be a probable principal cause. Separated by active and chronic phases, EMF typically presents initially as a febrile illness associated with pancarditis and hypereosinophilia. The chronic phase is characterized by ventricular thrombosis leading to endocardial fibrosis, eventually involving both ventricles. Patients often present with heart failure (with right ventricular restriction predominating) and ascites. Diagnosis is made with echocardiography exhibiting restrictive filling with apical fibrosis, reduction of ventricular volume, and atrial enlargement and dysfunction. EMF has a poor prognosis with a high occurrence of sudden death from fatal arrhythmias or thromboembolism. Medical management of heart failure, arrhythmias and thromboembolism is standard but surgical intervention improves survival.
Protozoa and helminths can affect the heart, mostly the myocardium and pericardium. As the number of travelers and those with immunocompromise increases, these illnesses which were previously contained in specific endemic areas are beginning to be seen around the world, including our very own Parkland Hospital! It is essential that clinicians know the risk factors and presentations of these parasitic infections and keep them in their differential.