Dysphagia is investigated according to the level its cause is likely to lie at: oropharyngeal dysphagia is examined with tests of swallowing function, while esophageal dysphagia is examined for a structural or mucosal lesion first and for a motility disorder second. The history usually decides which route to take, so it is the first step in both.
Oropharyngeal dysphagia
The pharyngeal phase lasts less than a second, so it cannot be assessed by examination alone. Videofluoroscopy, also called the modified barium swallow, records the swallow in real time and is the gold standard for oropharyngeal function; it shows the mechanics of the swallow and can help predict the risk of aspiration pneumonia. Where that service is unavailable, fiberoptic endoscopic evaluation of swallowing (FEES) uses a transnasal endoscope to watch the pharynx while the patient swallows. Nasoendoscopy — an upper gastrointestinal endoscope passed through the nose, a different test from FEES — shows structure and pooled secretions well, but it is not a sensitive way to detect abnormal swallowing function: followed up with videofluoroscopy, it misses 20–40% of the aspiration that the fluoroscopic study shows. A bedside water-swallow test is a cheap screening step — the patient drinks a measured volume as quickly as possible while the examiner records the time taken and the number of swallows — but a formal bedside protocol is more reliable, and stroke units screen before allowing oral intake for that reason.
Esophageal dysphagia
Persistent esophageal dysphagia is investigated with endoscopy first, because endoscopy can see inflammatory and structural lesions and can take biopsies, which a barium study cannot. Biopsy matters because eosinophilic esophagitis can look normal to the eye; several biopsies are taken from the proximal and distal esophagus so that the diagnosis is not missed. Barium esophagram keeps a role when endoscopy is not available or is judged risky, and it can complement endoscopy in particular situations such as a suspected achalasia or a Zenker’s diverticulum. When endoscopy and biopsies are normal, esophageal manometry — preferably high-resolution — is used to assess motility disorders such as achalasia. In achalasia, a timed barium swallow can measure how well the esophagus empties before and after treatment.
A trial of acid suppression
In a patient under 50 with reflux symptoms, no alarm features and no other red flags, a four-week trial of a twice-daily proton-pump inhibitor is reasonable, with further testing only if the dysphagia does not resolve completely. The trial is deliberately short: a longer one would delay the diagnosis of a cancer, so in older patients or those with alarm features, endoscopy is not deferred.