Multiple Tracheal Diverticula in a COVID-19 Positive Patient

Abstract

A tracheal diverticulum is a type of paratracheal air cyst and is usually an incidental finding after a computed tomography scan of the neck and thorax. With an incidence between 1% and 4% in adults, tracheal diverticula are rare entities that can be symptomatic in certain cases. We present a case of a COVID-19 positive patient who presented to our hospital and was diagnosed with multiple tracheal diverticula during his hospitalization.

Case Description

A 63-year-old male patient with a history of hypertension presented to our hospital’s emergency department complaining of weakness and fatigue for the past 2 days. He had received his first dose of COVID-19 vaccination one week before. Upon presentation, the patient appeared tachypnoic, afebrile, with normal vital signs, except for an oxygen saturation level of 87%. Physical examination did not reveal any abnormal signs, and thus a full blood workup and a chest radiogram (CXR) were ordered. Furthermore, otorhinolaryngological examination and upper airway tract endoscopy did not reveal any pathological findings. A nasopharyngeal swab for COVID-19 testing was obtained, which came out positive. The CXR showed ground-glass opacification and consolidation, and a chest computed tomography (CT) scan was performed, revealing multifocal, bilateral lesions with ground-glass pattern, bronchiectasis, and the presence of multiple tracheal diverticula (TD), the largest with a diameter of 33 mm (Figures 1 and 2). The patient was admitted for antibiotic and antiviral treatment, as well as oxygen therapy. After reevaluation and thoracic surgical consultation, close observation of the diverticulum with CT scanning was suggested, with surgical treatment being reserved in case of recurrent respiratory infections.

Figure 1.

Computed tomography in axial plane, showing the tracheal diverticulum (marked yellow “d”) next to the right side of the trachea (yellow “T”).

Figure 2.

Computed tomography in coronal plane, lung window, showing the tracheal diverticulum (yellow “d”) next to the right side of the trachea (yellow “T”). Also, multifocal, bilateral lesions with ground-glass pattern are recognized (yellow arrows), due to the COVID-19 infection.

Discussion

Tracheal diverticulas are a rare type of paratracheal air cysts with an incidence of 1% to 4%. ^{1 -9} They present as air-filled cystic formations in the paratracheal region, usually connected to the tracheal lumen. In 97% of the cases, they appear on the right posterolateral side of the trachea, due to lack of support from the esophagus and absence of cartilaginous tissue. ^1,6,8 They have a diameter of approximately 2 to 6 mm, and in 1.3% are multiple. ⁶ Our patient presented with multiple diverticula, the largest of which was 33 mm (Figure 3).

Figure 3.

Computed tomography with 3D reconstruction, showing (α) the larger tracheal diverticulum (yellow “D”) and (B) the smaller tracheal diverticula (yellow arrows).

Tracheal diverticulas are classified into 2 categories. Congenital TDs arise due to defects during the tracheal development and are associated with other congenital anomalies. They appear more frequently in male patients, having a small diameter and a narrow connection to the trachea. Their wall is similar to the trachea, consisting of cartilage, smooth muscle, and epithelium. Furthermore, 98% are located at the vertebral level T1 to T3, 4 to 5 cm below the vocal folds or above the carina. ^{2 -4,6,10}

Acquired TDs present due to increased intraluminal pressure, causing herniation of the epithelial membrane through a weak spot in the tracheal wall. In comparison with congenital TDs, they are larger, with wider openings to the tracheal lumen, and thinner walls consisting only of epithelium. Moreover, they present at any level and rarely are multiple in number. ^{2 -4,6,10} Their appearance can be associated with chronic cough, chronic obstructive pulmonary disease, intraoperative injury (tracheotomy ¹¹ and thyroidectomy ¹² ), and tracheomalacia. ⁶

In most cases, patients are asymptomatic. Tracheal diverticulas are usually an incidental finding during radiological examination but can sometimes cause local mass effect symptoms depending on their size and location, such as pain, dysphagia, hiccups, and vocal fold paralysis. The entrapment of mucus and secretions leads to recurrent respiratory infections, with fever, cough, hemoptysis, and stridor. ^1,7,8,13 In more serious cases, patients can present with a paratracheal abscess, dyspnea, and spontaneous pneumomediastinum due to rupture of a diverticulum. ⁸ Finally, intubation of a patient with TDs can be challenging and special care should be taken to position the tracheal tube properly. ^1,6,14

Differential diagnosis includes pharyngocele, laryngocele, Zenker’s diverticulum, pulmonary hernia, apical paraseptal bullae and blebs, mediastinal mass, and intrathyroid tumor. ^3,6,7

A chest CT with 1 mm slices, multiplanar and 3D reconstructed images can confirm the diagnosis. Tracheal diverticulas present as air and mucus-filled sacs in the paratracheal area. The number, location, content, size of the diverticula, the contour and thickness of their wall, and possibly a connection to the trachea can be described. Differentiation between congenital and acquired TDs can be made due to their different characteristics. ^4,6,10 In addition, bronchoscopy can be of assistance, although an opening to the tracheal lumen is not always present, or is too narrow to be detected. Finally, barium studies and fiberoptic esophagoscopy can help during the differential diagnosis. ^1,6

The treatment of TDs depends upon the patient’s age, clinical presentation, history, and comorbidities. ^1,6,7,10 On the one hand, asymptomatic and elderly patients are observed and treated conservatively with antibiotics, mucolytic agents, bronchodilators, and physiotherapy. The aim of treatment is preventing respiratory infections. ^3,6,10 On the other hand, young patients with a history of multiple infections, and often the presence of a single mucus-filled diverticulum in the CT, are in need of surgical intervention. ^6,10 Resection of the diverticulum is performed either via an open excision, or endoscopically with the use of laser, or electrocoagulation and fulguration.