A rare cause of hoarseness in a patient with a history of pulmonary tuberculosis

Hoarseness is a common clinical condition with underlying causes which can vary from reversible and benign to life-threatening and malignant. Cardiovocal syndrome may cause hoarseness secondary to left recurrent laryngeal nerve palsy when the recurrent laryngeal nerve is mechanically affected due to enlarged cardiovascular structures. We report a 28-year-old male who presented to the Government Medical College, Thiruvananthapuram, India, in 2013 with hoarseness. He had undergone irregular treatment for pulmonary tuberculosis (TB) two years previously. Fiber-optic laryngoscopy indicated left vocal cord palsy and a computed tomography scan of the chest revealed features of pulmonary hypertension with extensive enlargement of the pulmonary arteries. An echocardiogram confirmed severe pulmonary arterial hypertension with severe tricuspid regurgitation. He was diagnosed with left recurrent laryngeal palsy secondary to cardiovocal syndrome. Although reports exist of recurrent laryngeal palsy in TB, this case appears to be the first to report cardiovocal syndrome in a patient treated for pulmonary TB.

A mong patients with tuberculosis (tb), hoarseness can occur either due to the tuberculous inflammation of the vocal cord (i.e. tuberculous laryngitis) or recurrent laryngeal nerve palsy as a result of acute lymphadenopathy, caseating granulomatous inflammation or late complications of chronic fibrosis. 1,2 This report describes a 28-year-old male with cardiovocal syndrome who presented with hoarseness and a history of non-compliant treatment for pulmonary TB. To the best of the authors' knowledge, although there are previous reports of recurrent laryngeal palsy in patients with TB, cardiovocal syndrome has never been before reported with pulmonary TB. 3

Cardiovocal Syndrome
A rare cause of hoarseness in a patient with a history of pulmonary tuberculosis e482 | SQU Medical Journal, November 2017, Volume 17, Issue 4 The mitral valve apparatus was normal and there was no sign of aortic dilatation. A CT pulmonary angiogram ruled out a pulmonary embolism; however, arterial blood gas analysis showed hypoxaemia with hypercapnia.
A diagnosis of pulmonary hypertension group III was made according to the classifications of the World Health Organization. 4 As such, the patient was treated with oxygen administration, bronchodilators, a low-salt diet, diuretics (furosemide) and calcium channel blockers (diltiazem). While the symptoms of breathlessness gradually improved over the course of the following week, there was no improvement in the hoarseness. Supplemental oxygen therapy was considered; however, this was not pursued due to financial constraints. The patient was discharged after two weeks of admission and was unfortunately lost to further follow-up.

Discussion
Also known as Ortner's syndrome, cardiovocal syndrome was first described in 1897 among three patients with severe mitral stenosis, wherein it was postulated that left atrial dilatation can cause left recurrent laryngeal nerve palsy due to the compression of the nerve against the aorta. 5 During autopsies, Fetterolf et al. found that the normal distance between the aorta and pulmonary artery in the aortic window was 4 mm; as such, compression of the recurrent laryngeal nerve between these structures can cause palsy. 6 Other causes of hoarseness in cardiac disorders include lymphadenitis in the aortic window, pressure from the left bronchus, right ventricular hypertrophy, pulmonary artery atherosclerosis, the anatomical position of the ligamentum arteriosum, a dilated pulmonary artery, mitral regurgitation, atrial myxoma or a left ventricular aneurysm. 7 ethambutol. However, due to patient noncompliance, the treatment was discontinued after two months and was only resumed five months later. At this point, the patient completed the treatment regimen and was found to be sputum smear-negative for TB.
Upon examination, the patient was emaciated and had bilateral pitting pedal oedema, elevated jugular venous pressure, palpable second heart sounds with a loud pulmonary component, loud right ventricular third heart sounds and a pansystolic murmur with inspiratory increase in the tricuspid area. He also exhibited features of volume loss of the right lung, including drooping shoulders and narrowing of the intercostal spaces with rib crowding on the right side of his chest. Voluntary and reflex movements of the soft palate were present and a neurological examination was essentially normal. The results of repeat sputum acid-fast bacilli stains and culture tests were negative.
Fiber-optic laryngoscopy confirmed left vocal cord palsy. A chest X-ray showed extensive fibrosis of the right lung with a mediastinal shift to the right and increased aeration of the left lung due to compensating emphysema [ Figure 1]. A computed tomography (CT) scan of the chest showed signs of pulmonary arterial hypertension, including extensive dilatation of the central pulmonary artery at 32 mm, abrupt tapering of the peripheral pulmonary vessels, right ventricular hypertrophy and right atrial enlargement [ Figure 2]. There was no evidence of any other mediastinal pathology. The left recurrent laryngeal nerve palsy was caused by the compression of the nerve between the aorta and dilated pulmonary artery. An echocardiogram indicated severe pulmonary arterial hypertension with severe tricuspid regurgitation causing gross dilatation of the right atrium, right ventricle and pulmonary artery (tricuspid annular plane systolic excursion: 14 mm; right ventricular systolic pressure: 55 mmHg).

Rakul Nambiar, Dae Dalus and Anjali Srikumar
Case Report | e483 The left vagus nerve gives rise to the left recurrent laryngeal nerve at the level of the aortic arch. The recurrent laryngeal nerve then curves around the aorta on the outer side of the ligamentum arteriosum and ascends in the groove between the trachea and the oesophagus. This thoracic course makes the recurrent laryngeal nerve vulnerable to injury and it has been suggested that compression of the nerve between the dilated pulmonary artery and the aorta occurs among almost all patients with cardiovascular disease. 7 In the current case, the left recurrent laryngeal nerve palsy was due to the compression of the nerve between the dilated pulmonary artery and thoracic aorta, in which the dilated pulmonary artery was secondary to pulmonary hypertension. Initially, the suspected cause of the recurrent laryngeal nerve palsy was a mediastinal lymph node; however, this was ruled out by the chest CT scan.
Interestingly, pulmonary TB has not yet been included as a cause for the development of pulmonary hypertension in the existing Western literature. In contrast, it is not unusual to find patients in India who have been treated for pulmonary TB to present with features of right heart failure; according to a recent study, the prevalence of cor pulmonale among Indian patients with pulmonary TB was 11%. 8 Pulmonary hypertension in TB can be caused by the destruction of the vascular bed due to parenchymal abnormalities, endarteritis or vasculitis leading to the reduced crosssectional area of the pulmonary vasculature. 9 It has been suggested that recurrent secondary respiratory tract infections also play an important role in the pathogenesis of pulmonary hypertension in previously treated pulmonary TB patients. 10 Commonly, such patients present with dyspnoea to a degree disproportionate to that indicated radiologically or with desaturation present even upon mild exertion. In rare instances, the presentation can also include overt heart failure with pedal oedema, raised jugular venous pressure and tender hepatomegaly. 11 This is consistent with that seen in the current case, whereby the patient presented with features of right heart failure.
Among former TB patients presenting with worsening dyspnoea, the management and diagnosis can be challenging as such cases can be misdiagnosed as a TB relapse. The correct diagnosis and timely management of pulmonary TB can prevent future complications, such as those observed in the patient described in the present case report. Although the patient had previously received antitubercular therapy, his initial noncompliance with the treatment may have led to further lung damage and resulted in the subsequent development of pulmonary hypertension two years later.

Conclusion
Clinicians should be aware of cardiovocal syndrome as a cause of left recurrent laryngeal nerve palsy, particularly among patients with a history of TB who may also be at risk of developing pulmonary hypertension. Although reports exist of recurrent laryngeal palsy in TB cases, cardiovocal syndrome has never before been reported among patients with pulmonary TB.