International Journal of Cardiology 172 (2014) e76–e78
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Letter to the Editor
Leptospiral myocarditis — a rare assault on myocardium Victor Voon ⁎, Lavanya Saiva, Brian Prendiville, David Brennan, Jonathan Dodd, Charles McCreery St. Vincent's University Hospital, Elm Park, Dublin 4, Ireland
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Article history: Received 23 September 2013 Accepted 21 December 2013 Available online 27 December 2013 Keywords: Myocarditis Leptospirosis Electrocardiogram Late gadolinium enhancement Cardiac magnetic resonance imaging
A 40 year old man presented to the emergency department with a 6day history of constitutional symptoms of fever, chills, rigors, fatigue, myalgia and anorexia. He had been previously well and reported no symptoms of dyspnoea, chest pain, or palpitations. However, further questioning revealed that he was self-employed in organising extreme fitness courses and approximately 2 weeks ago, he had a minor puncture injury during an adventure course in bog water. He was subsequently treated with tetanus prophylaxis and prescribed a course of oral antibiotics but was non-compliant in the regimen. At the time of admission, he appeared unwell, flushed and diaphoretic with cold, clammy peripheries. Vital signs and cardiovascular examination were unremarkable. He had an exanthem rash visible on his upper torso and his oral mucous membranes appeared dry. Twelve-lead electrocardiogram (ECG) showed normal sinus rhythm with T wave inversion in II, III, aVF and V3–V6 (Fig. 1A). No abnormality was detected on chest X-ray but urine dipstick was positive for bilirubin, blood and protein with trace glucose, and negative for nitrites and leucocytes. Blood tests demonstrated low platelet count (102 g/L) and high urea (17.5 mmol/L), creatinine (230 mmol/L), bilirubin (19 μmol/L), aspartate aminotransferase (AST) (332 IU/L), alanine aminotransferase (ALT) (336 IU/L), gamma GT (180 IU/L) and alkaline phosphatase (ALP) (125 μmol/L). He also had elevated C-reactive protein (CRP) (388.4 mg/L), creatinine kinase (CK) (3208 IU/L), CK–MB
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(N80 ng/mL) and myoglobin (N500 ng/mL) but a normal serial troponin I. The patient was immediately transferred to the high dependency unit for telemetry monitoring and was commenced on intravenous (IV) fluid replacement and IV benzylpenicillin for presumed rhabdomyolysis and a spirochaetal infection. Overnight, he developed transient symptoms of nausea and diaphoresis which was associated with intermittent complete atrioventricular dissociation on telemetry (Fig. 1B). Although haemodynamically stable, he was transferred to the coronary care unit for closer monitoring. A temporary pacing wire was not felt to be required. Calcium and magnesium levels were normal. As advised by the microbiologist, IV Cefotaxime was started to increase cover for Lyme disease as well as leptospirosis in view of the new onset cardiac conduction defects. Transthoracic echocardiogram showed normal ejection fraction with mild basal septal hypokinesis. Transoesophageal echocardiogram was performed and did not show evidence of vegetations or thrombus. Liver ultrasound showed no signs of chronic liver disease. Results of serological tests including hepatitis B, C, Novovirus RNA and lyme were negative. However, leptospira IgM result was found to be positive, confirming initial suspicion. Cardiac MRI performed a week after index admission, demonstrated myocardial late gadolinium enhancement (LGE) in the mid-basal anteroseptal segment, and several tiny focal areas in the mid-basal inferior segment. Left ventricular ejection fraction was normal with no regional wall motion abnormalities or thrombus (Fig. 2). Overall, these findings were consistent with leptospiral myocarditis. Fortunately, the patient gradually improved and was discharged on oral doxycycline for a week. His blood tests had normalised at discharge. 4 months later, 24-hour holter monitor demonstrated return to normal sinus rhythm. Leptospirosis (known as Weil's disease) is a zoonosis caused by the spirochete Leptospira interrogans, of which there are over 200 known serovars. Human infection results from exposure of mucous membrane, conjunctiva or skin wound to animal urine or contaminated water. Although the condition is endemic to the tropics, its incidence has increased in several temperate and developed regions worldwide [1]. In these regions, risk factors for infection are predominantly occupational, as occurred in our case; recreational (fishing, kayaking etc.); and travel to endemic areas. The presentation of leptospirosis is commonly non-specific and systemic, its clinical course highly variable and potentially fatal. In addition, myocardial disease, in particular myocarditis, is a rarely reported but increasingly recognised complication. Myocarditis is an immuno-inflammatory state of the myocardium that can be induced by a variety of infectious agents including leptospirosis. Several studies have demonstrated accompanying features of
V. Voon et al. / International Journal of Cardiology 172 (2014) e76–e78
extracellular matrix and perivascular fibroinflammation, and cellular necrosis in myocarditis [2–5]. Although these molecular changes may indeed contribute to resultant arrhythmias, progressive ventricular remodelling, heart failure and/or sudden death, establishing determinants of poor prognosis is an ongoing effort. Long-term prognosis has been shown to be discordant post-recovery beyond the acute phase of infection and initial inflammatory changes detected in myocardial tissue [5]. In addition, the majority of literature to date has focused on viral models in the diagnosis and risk stratification of myocarditis [6]. Therefore, although likely to be detrimental, the clinical evaluation and evolution of leptospiral myocarditis remains largely unknown. However, evidence indicates that several phenotypic markers are associated with worse outcome including presence of dilated cardiomyopathy (DCM), ECG abnormalities, and LGE positivity — the latter two risk factors were present in our case with eventual resolution of ECG changes. Establishing the diagnosis of myocarditis has been traditionally dependent on endomyocardial biopsy (EMB) as the gold standard.
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However, reasons limiting its routine use include sampling error in focal disease and increased risk of procedural complications [6]. ECG abnormalities are common early indicators but not accurate predictors of regional myocardial damage [7,8]. Cardiac MRI has shown good correlations with histological sampling by EMB in diagnosing myocarditis and in patients with biochemical evidence of myocyte damage [9]. However, in patients with normal troponin, as in our case, the prognostic significance of non-DCM LGE positivity has yet to be evaluated and may be the result of focal expansion of extracellular space, especially in the acute phase. Interestingly, similar LGE patterns have been noted in both DCM and myocarditis [3]. Therefore, such LGE positivity may be linked with the development of DCM in certain patients with acute myocarditis and this requires further evaluation. In summary, leptospiral myocarditis is rare but increasingly prevalent. Early identification and treatment are required to prevent potentially lethal consequences. Despite progress in diagnostic modalities, prognosis remains variable and uncertain.
Fig. 1. A. Twelve-lead electrocardiogram (ECG) demonstrating sinus rhythm and T wave inversion in II, III, aVF and V3–V6. B. Overnight telemetry showing intermittent atrioventricular dissociation (black arrows).
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References
Fig. 2. Cardiac magnetic resonance imaging showing late gadolinium enhancement in the basal anteroseptal segment and focal area of the mid-basal inferior segment in the short axis view (black arrows).
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