What causes pharyngeal dysphagia?

Causes of Pharyngeal Dysphagia

Pharyngeal dysphagia is primarily caused by neurological disorders affecting the central swallowing network or peripheral nerves, muscles, and structures involved in the swallowing process. 1

Neurological Causes

Neurological disorders are the most common etiology of pharyngeal dysphagia:

• Stroke: Affects at least 50% of patients with ischemic or hemorrhagic stroke, leading to a three-fold increased risk of aspiration pneumonia 1

• Neurodegenerative diseases:

  • Parkinson's disease: A major risk factor for pneumonia (the most frequent cause of death in this population) 1
  • Amyotrophic Lateral Sclerosis (ALS): Up to 30% present with swallowing impairment at diagnosis, and virtually all develop dysphagia as disease progresses 1
  • Multiple Sclerosis: Occurs in more than one-third of patients 1
  • Dementia: Progressive cognitive decline affects swallowing coordination 1

• Neuromuscular disorders:

  • Myasthenia gravis: Initial presentation in 15% of cases; over 50% develop dysphagia as disease progresses 1
  • Inflammatory myopathies: Dermatomyositis (20%), polymyositis (30-60%), inclusion body myositis (65-86%) 1

Structural Causes

• Pharyngeal or cricopharyngeal strictures 1
• Oropharyngeal tumors 1
• Posterior pharyngeal diverticulum 1
• Cervical webs 1
• Thyroid nodules: Can cause dysphagia when they compress surrounding structures 2
• Cricopharyngeal bars 1
• Cervical osteophytes or skeletal hyperostosis 1

Functional Causes

• Upper esophageal sphincter dysfunction: Hyperfunction can lead to hypopharyngeal retention of swallowed material and subsequent aspiration 1
• Presbyphagia: Age-related multifactorial changes in swallowing physiology 1
• Pharyngeal muscle atrophy: Decreased pharyngeal wall thickness and increased pharyngeal width at rest are associated with dysphagia, particularly in Parkinson's disease 3

Diagnostic Approach

When evaluating pharyngeal dysphagia, consider:

1. Clinical presentation: Patients typically complain of food sticking in the throat, globus sensation, coughing/choking during swallowing, nasal-quality voice, nasal regurgitation, food dribbling, and difficulty initiating swallow 1

2. Imaging studies:

   • Modified barium swallow: Evaluates oral and pharyngeal phases of swallowing 1
   • Videofluoroscopy: Assesses bolus manipulation, tongue motion, hyoid and laryngeal elevation, and cricopharyngeal function 1
   • Biphasic esophagram: Important to evaluate the entire esophagus, as distal esophageal or gastric cardia lesions can cause referred dysphagia to the pharynx 1

3. Measurement parameters: Pharyngeal wall thickness <4.05 mm and pharyngeal width at rest >16.05 mm are predictive of aspiration risk in patients with Parkinson's disease 3

Clinical Pearls and Pitfalls

• Important pitfall: Abnormalities of the mid or distal esophagus or gastric cardia may cause referred dysphagia to the upper chest or pharynx, whereas pharyngeal abnormalities rarely cause referred dysphagia 1

• Key consideration: In patients with unexplained oropharyngeal dysphagia, a complete examination of the esophagus should be performed, as 68% of patients with complaints of dysphagia for solids have abnormal esophageal transit, and in one-third of these cases, the esophageal abnormality is the only finding 1

• Warning sign: Reflexive cough during eating or drinking has a sensitivity of 74% and specificity of 74% for aspiration in neurologically impaired patients 1

By understanding the diverse causes of pharyngeal dysphagia, clinicians can better target their diagnostic approach and develop appropriate management strategies to reduce morbidity and mortality associated with this condition.