Introduction
A pharyngeal pouch (also known as a Zenker's diverticulum) is an outpouching of the pharyngeal mucosa through an area of muscular weakness at the posterior pharyngeal wall called Killian's dehiscence. It is a type of oesophageal diverticulum, which is an umbrella term also including midthoracic diverticula and epiphrenic diverticula.
Pharyngeal pouches occur in 1 in 200,000 people in the UK and typically affect older males. They are an important cause of dysphagia and are often associated with regurgitation, cough and halitosis.
Pharyngeal pouches occur in 1 in 200,000 people in the UK and typically affect older males. They are an important cause of dysphagia and are often associated with regurgitation, cough and halitosis.
Epidemiology
- Incidence: 2.00 cases per 100,000 person-years
- Peak incidence: 70+ years
- Sex ratio: more common in males 5:1
| Condition | Relative incidence |
|---|---|
| Gastro-oesophageal reflux disease | 2500.00 |
| Oesophageal cancer | 5.00 |
| Pharyngeal pouch | 1 |
| <1 | 1-5 | 6+ | 16+ | 30+ | 40+ | 50+ | 60+ | 70+ | 80+ |
Aetiology
- It is not known why some people develop pharyngeal pouches whilst others do not, however, some proposed mechanisms include:
- Uncoordinated swallowing
- Impaired relaxation of the cricopharyngeus muscle leading to increased pressure in the distal pharynx
- Anatomical predisposition to larger Killian's dehiscence
- Common risk factors include:
- Older age: pharyngeal pouches are uncommon under the age of 40, and most commonly occur in the seventh decade of life or later
- Male sex: pharyngeal pouches are 5 times more common in men
- Positive family history: this may be related to having an anatomically larger Killian's dehiscence
Pathophysiology
- A pharyngeal pouch is formed when pharyngeal mucosa herniates through a weak area of the posterior pharyngeal wall
- This area is known as the Killian's dehiscence and is located between the cricopharyngeus and thyropharyngeus muscles (the muscles which form the upper oesophageal sphincter)
- Over time, excessive pressure within the lower pharynx, caused by swallowing, can result in ballooning of the pharyngeal mucosa through Killian's dissidence, forming a pharyngeal pouch
- Uncoordinated swallowing may contribute to this excessive pressure
- A pharyngeal pouch may be several centimetres in diameter and grow over time
- The pouch is known as a pseudodiverticulum as it does not involve all layers of the oesophageal wall
Clinical features
- A pharyngeal pouch may be asymptomatic, however, patients typically present with:
- Physical examination findings may include:
- A neck swelling which gurgles on palpation (Boyce's sign)
- Signs of weight loss and/or malnutrition
- Symptoms may develop over weeks or years and tend to worsen as the pharyngeal pouch grows larger
- Sudden worsening of dysphagia and/or presence of haemoptysis may suggest malignancy within the pouch and should be investigated using a 2-week wait referral
Investigations
- Patients presenting with dysphagia are referred for an oesophagoduodenoscopy (OGD) as an initial investigation
- An OGD may be able to identify and assess the extent of a pharyngeal pouch if it is present
- A barium swallow test is the gold standard investigation to confirm the presence of a pharyngeal pouch
- A barium swallow test is also known as oesophagram and is often performed after an OGD if a pharyngeal pouch is suspected
- The patient swallows liquid barium sulphate whilst X-ray images are taken
- The barium will pool in the pharyngeal pouch and not move between films, as a food bolus would
- This confirms the presence of a pharyngeal pouch
Differential diagnosis
The symptoms of a pharyngeal pouch can also be caused by many other pharyngeal and oesophageal conditions.
Possible differential diagnoses:
Possible differential diagnoses:
- Gastro-oesophageal reflux (GORD)
- Similarities: both may cause dysphagia, regurgitation and cough
- Differences: GORD is more common and does not cause neck swelling or a gurgling sound
- Diffuse oesophageal spasm
- Similarities: both may cause dysphagia and regurgitation
- Differences: the main presenting symptom of oesophageal spasm is often chest pain; neck swelling is not a feature
- Oropharyngeal carcinoma
- Similarities: both may cause dysphagia, regurgitation and weight loss; increasing age and male sex are risk factors for both
- Differences: haemoptysis and local pain are alarm symptoms for oropharyngeal carcinoma, and there is typically a history of smoking and/or excessive alcohol consumption
- Oesophageal achalasia
- Similarities: both may cause dysphagia
- Differences: achalasia typically causes retrosternal pain
Management
All patients with symptoms of a pharyngeal pouch should be referred to Ear, Nose and Throat (ENT) for assessment and management.
The mainstay management of a pharyngeal pouch is surgery, however, in patients with mild symptoms or those unable to have surgery, a 'watch-and-wait' approach may be more appropriate.
The mainstay management of a pharyngeal pouch is surgery, however, in patients with mild symptoms or those unable to have surgery, a 'watch-and-wait' approach may be more appropriate.
- In 2015 NICE published guidelines on the surgical techniques approved for the management of pharyngeal pouch
- Traditionally, open surgery is performed and the pouch is completely removed (called a diverticulectomy)
- Endoscopic techniques using rigid endoscopes are now preferred to open surgery as they are quicker, less invasive, more cost-effective and tend to have a shorter recovery time
- During endoscopic surgery, the pharyngeal pouch may be treated using a diathermy laser or stapling technique
- Current guidelines recommend that open surgery should only be performed after 2 failed endoscopic surgeries, or if patients have any contraindications to endoscopic surgery, such as poor mobility of the cervical spine due to osteoarthritis
Complications
- Malnutrition
- Clinical malnutrition may be identified in up to 31% of patients with a pharyngeal pouch and is likely a result of dysphagia
- Aspiration pneumonia
- Up to 12% of patients with a pharyngeal pouch may develop an aspiration pneumonia
- Small increased risk of squamous cell carcinoma within the pouch
- This is a rare but important complication (reported incidence of up to 1.1%)
- It is thought to be due to chronic inflammation of the mucosa within the pouch over time