Lymphocytic myocarditis at autopsy in patients with dengue fever

Potential role of transthoracic echocardiography for screening LV systolic dysfunction in patients with a history of dengue infection. A cross-sectional and cohort study and review of the literature

Background

Dengue virus can affect the cardiovascular system and men may be at higher risk of severe complications than women. We hypothesized that clinical dengue virus (DENV) infection could induce myocardial alterations of the left ventricle (LV) and that these changes could be detected by transthoracic echocardiography.

Methodology/Principal findings

We examined individuals from Acre in the Amazon Basin of Brazil in 2020 as part of the Malaria Heart Study. By questionnaires we collected information on self-reported prior dengue infection. All individuals underwent transthoracic echocardiography, analysis of left ventricular ejection fraction (LVEF) and global longitudinal strain (GLS). We included 521 persons (mean age 40±15 years, 39% men, 50% urban areas) of which 253 (49%) had a history of dengue infection. In multivariable models adjusted for clinical and sociodemographic data, a history of self-reported dengue was significantly associated with lower LVEF (β = -2.37, P < 0.01) and lower GLS (β = 1.08, P < 0.01) in men, whereas no significant associations were found in women (P > 0.05). In line with these findings, men with a history of dengue had higher rates of LV systolic dysfunction (LVEF < 50% = 20%; GLS < 16% = 17%) than those without a history of dengue (LVEF < 50% = 7%; GLS < 16% = 8%; P < 0.01 and 0.06, respectively).

Conclusions/Significance

The findings of this study suggest that a clinical infection by dengue virus could induce myocardial alterations, mainly in men and in the LV, which could be detected by conventional transthoracic echocardiography. Hence, these results highlight a potential role of echocardiography for screening LV dysfunction in participants with a history of dengue infection. Further larger studies are warranted to validate the findings of this study.

Dengue hemorrhagic fever and cardiac involvement

Dengue viral infection (DVI) is one of the world’s most significant viral infections spreading. Most of the patients have been asymptomatic, with relatively benign clinical manifestations and outcomes. However, a small number of patients have progressed to severe dengue diseases, including hemorrhage, multi-organ impairment, and increased vascular leakage causing hypovolemic shock, which can cause cardiovascular collapse and death. Numerous lines of evidence have demonstrated that DVI could also cause cardiac dysfunction, arrhythmias, and severe myocarditis. The treatment for dengue hemorrhagic fever (DHF) patients remains symptomatic and supportive, with close monitoring of hemodynamic status. The contributory role of cardiac dysfunction in DHF patients has potentially critical implications on the management. This review will address the current knowledge of cardiac involvement in DHF patients and the management strategy to reduce the fatality outcome.

Dengue: 30 years of cases in an endemic area

The present study aimed to review literature on studies of dengue cases conducted over 30 years in the state of Ceará.

Between November 2015 and January 2016, articles published in Portuguese and English in 7 databases were searched using keywords and a Boolean operator. A total of 191 articles were identified in the databases; 133 were excluded according to the exclusion criteria, and 58 were included in the study.

Of the 58 articles analyzed, 6 reported data from Brazil; including the Northeast region and the state of Ceará; 41 reported data for only the city of Fortaleza; 7 reported data for the state of Ceará; 4 reported data for cities in the interior of the state; and 3 included only children. The studies adopted different approaches and focused on different aspects of the disease. Study outcomes included the identification of serological, epidemiological, clinical, and laboratory characteristics; potential larvicides and biological predators of mosquitoes; potential antiviral agents; vector density characteristics; and educational dengue prevention and control strategies. Additionally, one vaccine trial was included.

Although studies on dengue in the state of Ceará are scarce, they are encompassing, including several lines of research, and the number of studies and reports on dengue in the state of Ceará continues to increase.

Heart and liver are infected in fatal cases of dengue: three PCR based case studies

Background

Dengue is a global problem mainly in the tropics. Meticulous clinical management of cases has reduced the death rate significantly, but large numbers of people still succumb to severe complications of the infection. Presence of myocarditis is often overlooked leading to a poor outcome. Clinical management guidelines of dengue do not stress the importance of myocarditis as a manifestation in dengue infection. Severe hepatic dysfunction also needs emphasis.

Case presentation

We present three patients who had come to hospital on the 3rd day of fever. Two of them (case 1 and 3) were in shock on admission and case 2, who was stable on the3^rd day, went into the critical phase and developed shock while in the hospital on the 4^thday. All three had tachycardia on admission that got worse with time. The clinical course was unstable with fluctuations in urine output and deterioration of organ function. Despite frequent monitoring and life support they survived only 2–3 days in hospital. All three patients had myocarditis during the critical phase. In the first case, myocarditis was confirmed by troponin estimation and echocardiogram. In the second and third cases, histopathology confirmed myocarditis. Haemorrhagic necrosis of the liver was found in case 2 and 3 with exponential rise of transaminases. In all three cases, viral RNA was detected in both heart and liver tissues by PCR amplification.

Conclusions

We stress that detection of myocarditis and liver involvement in any dengue patient is important from the onset of the illness where treatment should be tailored to prevent development of hypotension. Our findings are novel as PCR and histology are rarely done on tissues of deceased dengue patients in the world. Studies are needed to find therapeutic interventions to reverse cardiac and hepatic dysfunction in dengue infection.