Total atrioventricular block as a cardiac manifestation in Weil’s disease: a case report

Abstract

Background

Weil’s disease is an infection caused by Leptospira bacteria. Leptospirosis may cause arrhythmias, such as atrial fibrillation and ST-T segment changes. We report a rare case of total atrioventricular block induced by leptospirosis. Early diagnosis and prompt management present particular challenges.

Case report

A 43-year-old Asian woman was referred from internal medicine to cardiology owing to an electrocardiogram abnormality. She complained of worsening chest discomfort 3 days earlier, accompanied by fever, nausea, and intermittent headaches. The patient appeared lethargic and jaundiced; blood pressure was 81/43 mmHg, heart rate was 41 bpm, respiratory rate was 20 times/minute, and temperature was 38.2 °C. The electrocardiogram showed a total atrioventricular block with a junctional escape rhythm of 45 bpm. Laboratory tests revealed increased renal and liver function, thrombocytopenia (98,000/µL), and positive immunoglobulin G and M anti-Leptospira. The patient was diagnosed with Weil’s disease (Faine’s score 32) and total atrioventricular block. The initial management involved fitting the patient with a transcutaneous pacemaker and giving dopamine 5 mcg/kgBW/minute, titrated to a target systolic blood pressure of > 90 mmHg. The patient was also scheduled to undergo temporary transvenous pacing. However, the patient died of suspected cardiogenic shock due to a deterioration in clinical condition.

Conclusion

Leptospirosis can cause rare but fatal arrhythmias, as seen in this case of fulminant leptospirosis with total atrioventricular block. Clinicians should be vigilant and consider this potential complication in similar cases.

Background

Leptospirosis is a zoonotic infection caused by the spirochete bacterium Leptospira [1]. Leptospirosis infection can manifest as a self-limiting influenza-like illness or progress to a severe form, known as Weil’s syndrome, characterized by multiorgan failure and mortality [2]. Leptospira enters the body through abraded skin or mucous membranes, following direct contact with infected vectors or indirect contact with a contaminated environment, such as urine-polluted soil or water [1, 3]. Leptospirosis manifests in two distinct forms: a self-limited anicteric syndrome, and a severe icteric form known as Weil’s disease. The anicteric presentation, representing 90% of cases, resembles a flu-like illness with sudden onset and constitutional symptoms. On the other hand, Weil’s disease presents with a much more severe course of symptoms, such as fever, kidney failure, jaundice, bleeding, respiratory distress, and potential cardiac involvement [1, 3, 4]. If left untreated, this form carries significant morbidity and mortality that exceeds 70%.

Leptospirosis exhibits tropism for various target organs, commonly affecting the spleen, liver, kidney, and skeletal muscles. However, the pathophysiology of cardiac involvement in leptospirosis remains largely unknown [5]. Cardiac complications in leptospirosis typically arise during the immune phase, involving pathogenic mechanisms such as Na/K-ATPase inhibition, myocardial inflammation, and vasculitis [6]. These processes disrupt ion homeostasis and contribute to conduction system dysfunction, leading to severe arrhythmias such as atrioventricular block [6]. This complex interplay between electrophysiological disturbances and inflammation underscores the challenges in managing cardiac involvement in leptospirosis. Cardiac electrical abnormalities in leptospirosis often manifest as electrocardiogram (ECG) changes, including sinus tachycardia, atrial fibrillation, and first-degree atrioventricular block [7, 8]. The wide variability in ECG changes presents a significant challenge in managing patients with leptospirosis with cardiac involvement. We report a rare case of total atrioventricular block (TAVB) manifesting as fatal bradyarrhythmia occurring in a patient with leptospirosis.

Case report

A 43-year-old Asian woman reported worsening chest pain that began 3 days prior and had intensified significantly over the past day. She reported experiencing lethargy, anorexia, nausea, fever, and intermittent headaches. Paracetamol had been administered before admission, which reduced her fever. She had no history of underlying diseases or comorbidities. Notably, her residential area was identified as a risk factor for leptospirosis and dengue fever.

Upon admission, the patient was alert and conscious but appeared weak, with blood pressure of 81/43 mmHg, heart rate of 41 bpm, respiratory rate of 20 times/minute, and temperature of 38.2 °C. Physical examination revealed anemic conjunctiva, icteric sclera, and jaundice. Lung auscultation detected crackles, and abdominal examination showed hepatosplenomegaly and tenderness, particularly in the right upper quadrant.

The patient’s symptomatic bradycardia prompted an electrocardiogram, which revealed TAVB with a junctional escape rhythm of 45 bpm and no signs of myocardial infarction or other pathological conditions (Fig. 1a). To rule out other possible diagnoses, we performed a chest X-ray, which revealed cardiomegaly (cardiothoracic ratio 0.52) with increased bronchovascular markings (Fig. 1b). Leukocytosis, anemia, thrombocytopenia, abnormal liver and renal function, increased C-reactive protein, and elevated troponin I were all found in admission laboratory tests (Table 1). These findings, combined with confirmatory tests, led to a diagnosis of leptospirosis. A dengue serology test was carried out owing to the endemic nature of the area, which returned a negative result. The patient was diagnosed with Weil’s disease, complicated by total atrioventricular block (TAVB) and unstable hemodynamics. The hemodynamic instability was likely related to either cardiogenic shock or septic shock as differential diagnoses. Faine’s score [9] was calculated to assess the severity of Weil’s disease, with the patient’s score being 32, indicating a severe case (Table 2).

Fig. 1

A 12-lead electrocardiogram recording showing total atrioventricular block with a junctional escape rhythm of 45 bpm (red indicates P waves, and blue indicates QRS). B Chest X-ray revealed cardiomegaly (cardiothoracic ratio 0.52) with increased bronchovascular markings

Table 1 Laboratory results during admission

Table 2 Faine’s score

The patient received 2 g of ceftriaxone and doxycycline 100 mg twice daily. Initial treatment also included an infusion of 0.9% NaCl, 40 mg of esomeprazole once daily, 8 mg of ondansetron twice daily, and 1 g of paracetamol three times daily. Owing to the ECG findings, transcutaneous pacing was initiated at 40 mA with a rhythm maintenance rate of 70 bpm. A dopamine infusion was also administered, starting at 5 mcg/kgBW/minute and later titrated to 10 mcg/kgBW/minute until the systolic blood pressure exceeded 90 mmHg or the mean arterial pressure reached more than 65 mmHg. The patient was then transferred to the intensive cardiac care unit and scheduled for temporary transvenous pacing. Transthoracic echocardiography was also performed and revealed a reduced left ventricular ejection fraction (LVEF) of 44% and global hypokinesia (Supplementary Material 1). Unfortunately, the patient experienced cardiac arrest, and despite ten cycles of cardiopulmonary resuscitation (CPR), a return of spontaneous circulation was not achieved. The patient passed away within 48 hours after admission, with cardiogenic shock suspected as the cause of death owing to the deterioration in clinical condition.

Discussion

Leptospirosis is a zoonotic infection caused by an obligate aerobic bacterium from the Spirochete phylum. The severe form of this infection, known as Weil’s disease, can be fatal. Severe leptospirosis cases can lead to intrinsic cardiac conduction dysfunction, potentially resulting in cardiogenic shock [10]. Table 3 outlines the ECG changes that may occur in patients with leptospirosis. Although the occurrence of TAVB is rare and atypical in leptospirosis, research on the mechanisms underlying these ECG changes remains limited. As a result, managing the cardiac manifestations of leptospirosis, particularly TAVB, presents significant challenges that require early and appropriate intervention. Moreover, cardiac involvement in leptospirosis is associated with a 42% mortality rate [11]. The presence of arrhythmia in patients with leptospirosis indicates a serious prognosis [2]. Therefore, timely investigation of ECG changes in leptospirosis is crucial for improving clinical outcomes.

Table 3 ECG changes in leptospirosis from several studies

Leptospirosis-induced arrhythmia is believed to result from a cytotoxic glycoprotein (GLP) found on the surface of certain serovars, such as Leptospira interrogans. GLP inhibits Na/K-ATPase, suggesting that alterations in Na/K-ATPase activity may play a key role in the arrhythmia pathophysiology of leptospirosis [6, 12]. However, while these mechanisms are considered fundamental to the development of leptospirosis-induced arrhythmia, the exact pathophysiology remains incompletely understood. Inhibition of the Na/K-ATPase has been observed to induce electrophysiological changes in the ventricles, leading to the emergence of late ventricular potentials in vitro [12]. These late potentials are indicative of ventricular arrhythmogenicity, particularly following myocardial infarction [1]. However, this inhibition is also associated with the occurrence of atrioventricular (AV) block, though the underlying mechanism remains unclear. Increased inhibition of the Na/K-ATPase pump causes an accumulation of Na ⁺  and K⁺, which in turn disinhibits the Na⁺/Ca ²⁺ pump, leading to increased Ca ²⁺ influx and decreased Ca ²⁺ efflux (Fig. 2) [12]. This cascade activates nuclear factor-kappa B (NF-κB), resulting in signal transduction defects, membrane lesions, and ultimately tissue apoptosis [12]. Furthermore, studies show that blocking Na/K-ATPase raises the effects of inotropic substances while lowering the effects of chronotropic substances [13]. This might help explain how AV block happens. High levels of Na⁺and Ca ²⁺ inside cells can cause arrhythmias and slow down the conduction between the atria and ventricles. [14]

Fig. 2

Cytotoxic glycoprotein mechanism against Na/K-ATPase in leptospirosis. GLP, cytotoxic glycoprotein; Na/K-ATPase, sodium–potassium adenosine triphosphatase; NF-κB, nuclear factor-kappa B; K ⁺ , potassium ion; Na ⁺ , sodium ion; Ca ²⁺, calcium ion

Another theory suggests that myocardial inflammation and vasculitis may lead to dysfunction of the heart’s intrinsic conduction system. A study found that myocarditis can cause AV conduction block in less than 20% of cases [15]. In our patient, the CRP level showed a moderate increase to 9 mg/dL, indicating an inflammatory process. Myocarditis causes diffuse inflammation in the right and left atrioventricular fasciculus, resulting in AV block [16]. Other studies have established criteria for cardiac involvement in leptospirosis, including transient echocardiographic abnormalities, elevated troponin levels followed by a decrease during recovery, and transient ECG changes [4].

In our case, the troponin level increased, which is a common finding in myocarditis. Elevated troponin indicates myocardial injury, as this biomarker is released into the bloodstream when heart muscle cells are damaged. In leptospirosis, myocarditis is a recognized complication, often manifesting as inflammation of the heart muscle, leading to the release of troponin [4, 17]. This elevation, along with clinical findings, can help differentiate leptospiral myocarditis from other potential causes of myocardial damage, such as ischemia [17]. Troponin levels tend to rise during the acute phase of infection and decrease as the patient recovers. The prognosis for cardiac manifestations in leptospirosis is generally poor, and no specific therapy exists to treat or prevent TAVB, a potentially fatal condition in leptospirosis.

Conclusion

We present a case of fulminant leptospirosis complicated by TAVB. This report highlights the rare occurrence of TAVB in the context of severe leptospirosis. Medical professionals must be aware of this serious complication. Further research into the causal relationship between arrhythmias and leptospirosis is strongly recommended to improve patients’ clinical outcomes.