Cardiac Magnetic Resonance of Myocardial Involvement in Leptospirosis.

Leptospirosis is a zoonotic infection caused by the Leptospira interrogans. Although it is endemic in tropical countries, global incidence has increased in several temperate and developed regions. Here, we present a cardiac magnetic resonance (CMR) and multidetector computer tomography (MDCT) chest features of active systemic leptospiral infection in a 19-year-old male. The MDCT appearances of lungs and CMR appearances of myocardium in icteric leptospirosis are described. Early diagnosis and prompt treatment is important to manage the cardiothoracic complications.

INTRODUCTION

Leptospirosis is a widespread and prevalent zoonotic disease.[12] The incidence in the tropical countries like India is almost 10 times higher than in temperate regions.[13] The source of infection in humans is usually either direct or indirect contact with the urine of an infected animal. The disease is seasonal with epidemic outbreaks.

CASE PRESENTATION

A 19-year-old male presented to our hospital with a 4-day history of fever, yellowish discoloration of eyes, loss of appetite, and generalized weakness. On examination, vital parameters were stable with icterus and abdominal distension. Blood investigation showed deranged liver function test. Patient was admitted in hospital and treated for viral hepatitis. During the course of disease, patient developed dyspnea and was found to have increased jugular venous pressure, pedal edema, and bilateral crepitations. Echocardiography showed dilated heart chambers with left ventricle (LV) systolic dysfunction and global hypokinesia. Blood investigation revealed IgM antibody positive for leptospirosis.

Cardiac magnetic resonance (CMR) imaging was performed for further assessment. CMR showed biventricular dilatation with LV ejection fraction of 11% and global hypokinesia predominantly affecting anterior and septal wall [Video 1]. Myocardial edema was noted in the basal and mid-anterior segments on Short Tau Inversion Recovery (STIR) imaging [Figure 1a]. There was no evidence of infarction or infiltration on delayed enhancement imaging. Multidetector computed tomography (MDCT) of chest revealed moderate bilateral pleural effusions with ground-glass densities in bilateral lungs and multiple patchy consolidations in bilateral lower lobes. Most of these consolidations were nodular in nature with one showing central ground-glass change [Figure 1]. Subsegmental collapse of anterior segment of right upper lobe was also noted.

Figure 1

(a) Short axis Short Tau Inversion Recovery image at mid cavity level showing myocardial edema in anterior wall (arrows). (b and c) Multidetector computed tomography image of chest showing bilateral pleural effusions, patchy ground-glass densities (short arrows) with nodular peripheral consolidations (block arrows). Note the consolidation in left lower lobe with central ground-glass attenuation (arrowhead)

DISCUSSION

Leptospirosis is a zoonotic infection caused by Leptospira interrogans. Although it is endemic in tropical countries, global incidence has increased in several temperate and developed regions.[4] Icteric leptospirosis is a severe form of disease, in which the clinical course is rapidly progressive. It may involve various systems including lungs and heart. There is increased mortality in severe leptospirosis associated with pulmonary alveolar hemorrhage and myocarditis.[56]

CMR features of leptospiral myocarditis are myocardial hyperintensities on STIR sequence with or without delayed enhancement. MDCT features of pulmonary manifestation of leptospirosis are pleural effusions, ground glass opacities, nodules, and patchy consolidations which represent alveolar hemorrhages.[7] In the present case, the MDCT appearances of lungs and CMR appearances of myocardium in icteric leptospirosis are described.

A mild form of leptospirosis can be treated with doxycycline, ampicillin, or amoxicillin. A Severe form of leptospirosis requires hospital admission and intravenous administration of penicillin G or third-generation cephalosporins.[8] Severe leptospirosis can affect any organ system and results in multiorgan failure. Therefore, careful management of renal, hematological, and hepatic complications is of great importance. Continuous cardiac monitoring is essential in severe form as it can cause arrhythmias, ventricular tachycardia, atrial fibrillation, or flutter. Early treatment has been shown to offer the best clinical outcomes and early recovery of patients.[910]

Leptospirosis affects directly the myocardium causing its inflammation which may proceed to necrosis. Gold standard investigation to diagnose myocarditis is endomyocardial biopsy. However, the procedural complications and sampling errors limit the frequent use of biopsy.[11] ECG can show changes in myocarditis; however, these are very nonspecific.[1213] On the other hand, CMR shows promising results in detecting myocarditis due to its high spatial resolution and multiplanar imaging techniques.[14] STIR imaging along with newer sequences such as T2* mapping is very sensitive to detect myocardial inflammation.[151617] Early diagnosis of severe leptospiral myocarditis can administer the prompt treatment and early recovery of clinical condition.

CONCLUSION

Although leptospiral myocarditis is a rare presentation, its prevalence is increasing. Early diagnosis and treatment is important to prevent the lethal outcomes. CMR and MDCT are an excellent tool for early diagnosis of leptospiral myocarditis.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.