Many people occasionally experience difficult or impaired swallowing, but they often adapt their eating patterns to their symptoms and do not seek medical attention.¹ Among those who do seek care, the most common causes are generally benign and self-limited, and serious or life-threatening conditions are rare. However, many older adults with progressive neurologic disease have significant but unrecognized dysphagia, which increases their risk of aspiration pneumonia and malnourishment. In these patients, the diagnosis of dysphagia should prompt a discussion about goals of care. Understanding the basic pathophysiology of swallowing and the etiologies and clinical presentations of dysphagia allows family physicians to distinguish between oropharyngeal and esophageal pathology, make informed management decisions, and collaborate appropriately with specialists.

Pathophysiology

Swallowing (deglutition) is a complex process involving voluntary and involuntary neuromuscular contractions coordinated to permit breathing and swallowing through the same anatomic pathway (Figure 1).² Deglutition is commonly divided into oropharyngeal and esophageal stages. In the oropharyngeal stage, food is chewed and mixed with saliva to form a bolus of appropriate consistency in the mouth. With the initiation of the swallow, the bolus is propelled into the oropharynx by the tongue. Other structures simultaneously seal the nasopharynx and larynx to prevent regurgitation or aspiration, and the lower esophageal sphincter begins to relax. In the esophageal stage, the food bolus passes the upper esophageal sphincter and enters the esophageal body, where it is propelled by peristalsis through the midthoracic and distal esophagus and into the stomach through the now fully relaxed lower esophageal sphincter.^3,4

Oropharyngeal Pathology

Oropharyngeal dysphagia is most commonly related to chronic neurologic conditions, particularly Parkinson disease, stroke, and dementia; it is not part of normal aging.⁵ It may be the first symptom of a neuromuscular disorder, such as amyotrophic lateral sclerosis or myasthenia gravis.^6,7

Some chronic conditions, such as poor dentition, dentures, dry mouth (xerostomia), or medication adverse effects, may be poorly tolerated in patients who also have progressive oropharyngeal dysfunction. Tardive dyskinesia with choreiform tongue movements related to long-term antipsychotic use may cause decompensation in older adults; it also may cause dysphagia in younger patients.⁸ Chronic cough related to angiotensin-converting enzyme inhibitor use may interfere with swallowing or be mistaken for aspiration.

Structural abnormalities (e.g., Zenker diverticulum, cricopharyngeal bars or tumors, chronic infections with Candida or herpes virus) and extrinsic compression from cervical osteophytes or goiter can also interfere with normal swallowing (Table 1).^5–14

Esophageal Pathology

Gastroesophageal reflux disease (GERD), functional esophageal disorders, and eosinophilic esophagitis are the most common causes of esophageal dysphagia^5,15 (Table 2^1,5,13–15). Less common causes include medications, obstructive lesions, and esophageal motility disorders.

GASTROESOPHAGEAL REFLUX DISEASE

GERD and recurrent acid exposure result in changes ranging from submucosal inflammation and dysmotility to erosive esophagitis and stricture. Patients with GERD may experience dysphagia even in the absence of apparent mucosal damage.¹⁶

EOSINOPHILIC ESOPHAGITIS

Eosinophilic esophagitis is an increasingly common inflammatory condition triggered by food allergens.¹⁵ Chronic eosinophilic infiltration leads to progressive fibrosis, esophageal rings and furrows, and dysmotility.¹⁷