Initial Investigation of Suspected Achalasia
A 20-year-old woman reports two years of difficulty swallowing that is worse for liquids than for solids, with occasional regurgitation of undigested food and nocturnal cough. Her weight is stable and physical examination is normal. Chest radiograph shows no mediastinal mass. Which of the following is the most appropriate initial investigation?
- A.Barium swallowCorrect
- B.Chest ultrasound
- C.Upper gastrointestinal endoscopy
- D.Contrast enhanced chest CT
Explanation
Dysphagia that is worse for liquids than for solids is paradoxical dysphagia and signals an esophageal motility disorder rather than a mechanical obstruction. Mechanical narrowing from a stricture or tumour obstructs solids first and liquids only late, so the reversed pattern is the key discriminator. In a young patient with regurgitation of undigested food and nocturnal cough from aspiration, achalasia is the leading diagnosis. A barium swallow is the appropriate first test because it is a dynamic, real time study that shows both anatomy and the coordination of the swallow. In achalasia it demonstrates a dilated, sometimes sigmoid esophagus, retained food and a smooth tapering bird beak narrowing at the gastroesophageal junction, together with absent primary peristalsis. It is inexpensive, widely available and non-invasive, which makes it an excellent screening study. Upper endoscopy is essential in the workup, mainly to exclude pseudoachalasia from a tumour at the cardia, but it does not assess motility and typically follows the barium study. High resolution manometry remains the confirmatory gold standard once the barium study raises the suspicion. Ultrasound cannot image the esophagus behind the air filled trachea, and CT is used to look for extrinsic compression rather than to assess swallowing function.
Why each option
- A.
- Correct. A barium swallow is the best initial test for suspected motility disorder, showing esophageal dilatation, absent peristalsis and the classic bird beak taper.
- B.
- Ultrasound cannot visualise the esophagus through the air containing airway and mediastinum and has no role in evaluating swallowing.
- C.
- Endoscopy is needed later to exclude a tumour at the cardia causing pseudoachalasia, but it does not evaluate esophageal motor function.
- D.
- CT of the chest looks for extrinsic compression or malignancy and does not assess the functional coordination of swallowing.
Reference: ACG Clinical Guidelines: Diagnosis and Management of Achalasia, Am J Gastroenterol 2020
This is one of 3,306 questions in the MedBoardSA SMLE bank, with timed test mode, tutor mode, and progress tracking by topic.
Practise the full bank