Asymptomatic aortic aneurysm causing right vocal cord palsy and hoarseness: A rare presentation.

Vocal cord palsy (VCP) presenting as hoarseness of voice can be the first symptom of very serious and sinister common pathologies. But vocal cord palsy resulting from aortic aneurysm is a rare entity and still rarer is the right cord palsy due to aortic aneurysm. We are reporting a rare case in which a 52-year old male smoking for last 30 years having asymptomatic aortic aneurysm presented to us with hoarseness of voice. On Panendoscopy, no local pathology was found and CECT from base of skull to T12 was advised. CECT showed a large aneurysm involving ascending aorta and extending upto abdominal aorta with compression of the bilateral bronchi. CTVS consultation was sought and they advised for regular follow-up only. We are reporting this case to warn both the anaesthetist and the surgeon about the catastrophic complications if they are not alert in handling such cases.

INTRODUCTION

Hoarseness of voice is a fairly common complaint for which patients often visit to the hospital. A number of well-known disorders, diseases, and surgical sequelae can cause vocal cord paralysis (VCP). However, causes remain idiopathic in approximately 12% of cases according to Laccourreye et al.,[1] and Jørgensen et al.[2] Ramadan et al.,[3] evaluated 98 patients with unilateral VCP. The cause was found to be neoplastic disease (32%), idiopathic (16%), postsurgery (30%), trauma (11%), central nervous system (CNS) disorder (8%, all eight cases were the result of stroke), or infection (3%).

The left vocal cord is more vulnerable to injury than the right, contrary to our case. The left recurrent laryngeal nerve is longer. In general, there is a 28% difference in length; it can vary from 5 to 15 cm.[4] In addition, there is pronounced variation in the way in which the two recurrent laryngeal nerves meet the larynx.[5]

Although laryngeal carcinoma and laryngeal trauma are the most common causes of paralyzed true vocal cord; a variety of extra-laryngeal diseases can affect the recurrent laryngeal nerve and result in VCP. Malignant neoplasms involving thyroid, esophagus, mediastinum, lung, or jugular foramen have been reported as the most common causes of extra-laryngeal VCP.[6] It is imperative that the treating physician, surgeon, and the anesthesiologist must rule out various causes before proceeding further in order to prevent any major catastrophe.

CASE REPORT

A 52-year-old male patient presented to ENT clinic with hoarseness of voice for 6 months. Patient had been chronic smoker, who recently stopped smoking after 30 years. His medical history revealed that he was both diabetic and hypertensive and was taking oral hypoglycemic agents and antihypertensive agents for that. He had been treated for pulmonary tuberculosis around 20 years back with a complete course of antitubercular treatment. On examination, indirect laryngoscopy revealed right vocal cord palsy, without palpable cervical lymph nodes. Laboratory workup was normal. Chest radiograph revealed mediastinal lymphadenopathy with right upper lobe and lower zone lesions. A working differential diagnosis of carcinoma larynx, carcinoma esophagus or carcinoma bronchus was reached in view of clinical profile.

Patient was scheduled for panendoscopy to determine the cause of hoarseness of voice. Preanesthetic checkup showed fair glycemic control and adequate control of blood pressure. Patient was premedicated with Ativan 2 mg the night before surgery and asked to continue antihypertensive medications. A general anesthetic technique was employed with midazolam 1 mg followed by fentanyl 2 mcg/kg intravenously after attaching monitors. General anesthesia was induced with propofol 2.5 mg/kg intravenously and relaxation was facilitated with vecuronium 0.1 mg/kg after preoxygenating the patient with 100% oxygen for 5 min. A 6.0 ID endotracheal tube was inserted after gentle laryngoscopy. Panendoscopy was done by the ENT surgeon, and intraoperative period was uneventful. At the end of the procedure, the patient was reversed and extubated successfully. Patient was sent to the postanesthesia care unit for recovery.

The panendoscopy revealed no local abnormality. In view of chest X-ray findings, computed tomography (CT) scan of the thorax was done to find out extra-laryngeal causes of vocal cord palsy. CT scan revealed a large aortic aneurysm extending from the arch of the aorta to the level of the descending aorta, causing compression of right bronchus and recurrent laryngeal nerve and thus right vocal cord palsy [Figures 1–3]. Cardio-thoracic vascular surgeon consultation was sought and he advised for regular follow-up.

Figure 1

Axial CT scan of thorax (lung window) at the level of Carina

Figure 3

Axial CT scan of thorax (mediastinal window) at the level of arch of aorta showing aneurismal dilatation

Axial CT scan of thorax (mediastinal window) at the level of Carina showing aneurismal dilatation

DISCUSSION

Hoarseness of voice is a fairly common phenomenon for which patients seek medical attention. The causes of hoarseness are numerous and are as follows:

Infectious: Vocal cord nodules, laryngitis, bacterial tracheitis;

Chronic irritation and inflammation: Vocal cord nodules, polyp, contact ulcer or granuloma, gastroesophageal reflex;

Neurologic:

VCP

Tumors (thyroid, CNS, neural, lung)

Stroke

Iatrogenic (thyroid or thoracic surgery)

Idiopathic

Left atrium enlargement, aneurysm of the aorti carch

Neuromuscular abnormalities like myasthenia gravis

Neurologic disorders such as pseudobulbar palsy, amylotrophic lateral sclerosis, etc.

Trauma: External trauma to laryngeal framework, intubation injury;

Laryngeal cysts: Ductal and saccular cysts, laryngocele;

Neoplasms: Benign, malignant or neuroendocrine;

Others: Hypothyroidism, autoimmune disorders, amyloidosis.

The left vocal cord is more vulnerable to injury than the right, contrary to our case. The left recurrent laryngeal nerve, with its longer course around the aortic arch is longer as compared to right recurrent laryngeal nerve, which passes around the subclavian artery. Typically, there is a 28% difference in length, which varies from 5 to 15 cm.[4] In addition, there is pronounced variation in the way in which the two recurrent laryngeal nerves meet the larynx.[5]

Although laryngeal carcinoma and laryngeal trauma are the most common causes of paralyzed true vocal cord; a variety of extra-laryngeal diseases can affect the recurrent laryngeal nerve and result in VCP. Malignant neoplasms involving thyroid, esophagus, mediastinum, lung, or jugular foramen have been reported as the most common causes of extra-laryngeal VCP.[6] The most common extra-laryngeal malignancy causing VCP is bronchogenic carcinoma. Most commonly, it involves left vocal cord, but it can also involve right recurrent laryngeal nerve if right-sided mediastinal lymphadenopathy extends cephalad to the right subclavian artery.

Cardiovocal syndrome was first described a century ago by Ortner.[7] He attributed a case of left vocal fold immobility to compression of the recurrent laryngeal nerve by a dilated left atrium in a patient with mitral valve stenosis. Since then, the term Ortner's syndrome has come to denote any nonmalignant, cardiac, intrathoracic process that results in embarrassment of either recurrent laryngeal nerve usually by stretching, pulling, or compression, and causes vocal fold paralysis.

Another rare cardiac cause for VCP is aortic aneurysm, which usually compresses left recurrent laryngeal nerve and causes left vocal cord palsy. Tracheal and esophageal compression is a well-recognized complication of aneurysms of the aortic arch. Right-sided aortic arch is a relatively rare congenital anomaly with incidence of 0.1%.[8] The right arch passes over the right main stem bronchus to the right of the trachea and esophagus.[9] In the adult population, a right-sided aortic arch is often asymptomatic unless aneurysmal disease develops. This usually occurs at the level of the take-off of an aberrant left subclavian artery and is known as a Kommerell's aneurysm. In spite of its rarity, this condition is clinically relevant because of the mortality associated with rupture, the morbidity caused by compression of mediastinal structures, and the complexity of the surgery.[9]

The anesthetic considerations in the aortic arch aneurysm surgery are compression of the airway and inability to ventilate, massive blood loss due to rupture and tracheomalacia after extubation. The induction of general anesthesia could be risky, because it may precipitate complete airway closure and make facemask ventilation and tracheal intubation impossible. Hence, loss of control of the airway can occur at any stage of anesthesia and consequences may be fatal. Its management poses special problems due to frequent involvement of the lower airways. Another concern is tracheomalacia in these patients, which can complicate both intubation and extubation.[10] Thus, cardiovocal hoarseness is an important entity and must be ruled out in any case of hoarseness or vocal cord palsy before undertaking the patient for any procedure.

The management of patients with VCP requires establishing the site and cause for paralysis. While clinical history and examination will diagnose cases with prior surgery, laryngeal neoplasms and laryngeal trauma; radiologic evaluation is often necessary to diagnose etiology of remaining cases. Radiologic evaluation of patients with extra-laryngeal causes includes chest radiograph, barium swallow, radionuclide thyroid imaging, and CT of the neck and thorax. CT demonstrates extend and location of disease more accurately as compared with physical examination or conventional radiography. A negative CT reassures clinician that the VCP is idiopathic in origin. Rarely, CT may help in diagnosing nonneoplastic cause of VCP as in aortic aneurysm.[11]

CONCLUSION

Thus, we conclude that anesthetists and ENT surgeons should evaluate first the cause for VCP with a thorough history, clinical examination, and investigations before taking the patient for any procedure as it can have grave consequences both for the patient and the treating surgeon. Evaluating the cause for cord paralysis beforehand can also avoid an unnecessary risk involved with anesthesia and surgical procedure.