A laryngocele is an air-filled herniation of the saccule of the laryngeal ventricle which is in communication with the lumen of the larynx. The laryngeal ventricle is a fusiform fossa
delimited by the true and the false vocal cord and extending from the thyroid notch to the arytenoid cartilage. The anterior part of the roof of the ventricle leads up into a blind pouch of the mucous membrane called the saccule or appendix. Embryologically, the saccule and ventricle of the larynx develop as a secondary outpouching from the laryngeal lumen towards the end of the second intrauterine month 3
Several hundred laryngoceles have been reported in the English literature. A total of 39 cases of laryngopyocele have been reported in the world literature 1
. Only in 4 of these cases had a laryngopyocele caused acute airway obstruction and only one case of internal laryngopyocele causing acute airway obstruction has been reported until now 9
. The case described here is the first case reported in the English literature of a female patient in a septic condition, with an internal laryngopyocele causing acute airway obstruction ().
Laryngopyoceles as a cause of airway obstruction.
In the case presented here, the patient was in a septic condition, at the time of admission, based on her clinical picture and the laboratory results. Indirect flexible laryngoscopy demonstrated a large smooth mass which originated in the right false vocal cord and caused an almost total obstruction of the airway. The differential diagnosis of acute upper airway obstruction includes several entities, except laryngopyocele (). Diagnosis of an internal laryngopyocele was made by correlating the history, the clinical picture and the laryngoscopic and the radiographic findings (Table II).
Causes of acute upper airway obstruction in adults.
Laryngoceles are rare entities, occurring in only one per 2.5 million population per year in the UK 5
. The sex incidence is 5:1 in favour of male sex and the maximum age of incidence is in the sixth decade 5
. Based on location, three types of laryngoceles have been described, the external, the internal and the combined type. The external laryngocele presents clinically as a swelling in the neck, at the level of hyoid bone, anterior to the sternocleidomastoid muscle. During Valsava's manoeuvre, the swelling is increased and it becomes smaller on palpation. The internal and combined type, appear on laryngoscopy as a smooth swelling mass of the supraglottis.
The precise aetiology of laryngocele is unknown. Many authors have hypothesized that congenital or acquired factors may be responsible 2
. It is believed that laryngoceles occur in subjects with congenitally dilated saccules. A less important role is played by the narrowness of the periventricular connective tissue and the weakening of the thyroaryepiglottic muscles 10
. A congenital weakness or defect predisposes to the formation of laryngoceles under the influence of acquired factors 16
. Factors that increase intra-glottic pressure such as professional trumpet playing, glass blowing, singing, straining at passing of stools, weight lifting and carcinoma of the larynx are considered to promote the development of laryngoceles 5
The glandular serum-mucus secretion is evacuated through the ventricular opening. Some situations, such as chronic inflammations, laryngeal trauma or laryngeal carcinoma, lead to incomplete mechanical stenosis of the neck of the appendix 4
. When the neck of the laryngocele is obstructed, the laryngocele becomes filled with mucus. If the mucus-filled laryngocele is infected, it is called a laryngopyocele 2
. A review of the English literature showed that the most common type is the mixed laryngocele (44%), 30% were internal and 26% were external. Bilateral laryngoceles were found in 23% 12
. Laryngopyocele occurs even more rarely. Approximately 8% of laryngoceles become infected and present as laryngopyoceles and most of these are of the combined variety 5
. The most common bacteria isolated from laryngopyocele are Escherichia coli, haemolytic Streptococcus B, Staphylococcus Aureus and Pseudomonas Aeruginosa 4
Laryngoceles are usually asymptomatic. The most frequent presenting symptom is hoarseness. Variable degrees of dyspnoea, dysphagia, cough and stridor may be present, depending on the dimension of the laryngocele. Laryngopyoceles may present with signs of rapidly progressive respiratory obstruction and/or an infected painful neck mass which may rapidly increase in size. The symptoms of laryngopyocele include hoarseness, dyspnoea, stridor, dysphagia, odynophagia, pain, sensation of a foreign body and fever 7
. In the internal and combined forms, flexible nasolaryngoscopy can reveal a smooth mass of the vestibular fold, aryepiglottic fold and pyriform sinus which may displace the larynx to one side.
In the case presented here, after the emergency tracheotomy, computed tomography of the neck was performed which revealed a cystic 29 mm hypodense mass extending from the right false vocal cord to the level of the epiglottis, narrowing the laryngeal cavity and causing an almost 100% airway obstruction (-). The lesion was confined within the larynx and it was diagnosed as an internal laryngopyocele. The cystic cavity was full of fluid and no air-fluid level was observed ().
Radiological evaluation includes neck ultrasound which may determine swelling dimensions and content and a CT scan that permits diagnosis. CT scan shows the characteristic intra-laryngeal and extra-laryngeal expansion and defines laryngopyocele content, the relationship with the laryngeal ventricle and thyroid membrane and the presence of a carcinoma 8
. A contrast-enhanced CT scan can demonstrate signs of inflammation such as thickening of the walls or perimeter enhancement of the laryngocele and assist the differential diagnosis 12
. In the differential diagnosis of laryngopyocele, it is necessary to take into consideration the saccular cyst, fluid filled laryngocele, branchial cysts, paraganglioma, schwannoma, and thyroglossal duct cysts which exist in the supraglottic area 7
Laryngopyocele complications consist particularly in inhalation of the purulent material after cyst rupture, leading to acute respiratory damage. Therefore, the recommended treatment of laryngopyocele is immediate endoscopic drainage 9
. The infection is treated with broad spectrum intravenous antibiotics and steroids. Additional surgery can be performed immediately after endoscopic drainage or at a later date. For the treatment of internal laryngopyocele, an endoscopic decompression with marsupialization is recommended. For external and combined laryngopyoceles, additional definitive surgery should be performed, via an external approach 9
. This approach could be performed through a horizontal lateral cervicotomy, at the level of the thyroid membrane 4