Achalasia is a primary esophageal motility disorder involving the body of the esophagus and lower esophageal sphincter affecting equally both genders and all ages [1
]. Although endoscopy is considered to have a poor sensitivity and specificity in the diagnosis of achalasia, it has an important role in ruling out secondary causes of achalasia (i.e. pseudoachalasia). A chest X-ray can give important information. It may show the absence of a gastric air bubble. Barium swallow will show dilated esophagus, "bird beak" appearance of the distal esophagus and an esophageal air fluid level. In up to 20% of achalasia patients, however, these classic X-ray findings are not present. Manometry is the gold standard for diagnosing achalasia cardia [1
]. In patients with typical radiographic findings of achalasia, the barium study can be used to guide treatment without a need for manometry. If radiographic findings are equivocal, however, manometry may be required for a more certain diagnosis [2
]. But manometry is not available in all medical centers. In centers where manometry is not available, clinical history, endoscopy, chest X-ray and barium swallow are all taken together to diagnose achalasia cardia. With respect to treatment, Heller's myotomy and pneumatic balloon dilatations of the lower esophageal sphincter are considered definitive treatments for achalasia [3
Since achalasia cardia is associated with failure of the lower esophageal sphincter to relax, not enough air passes across into the stomach. This is manifested as an absent gastric bubble in the abdominal X-rays. Though this is not a sensitive method, absence of a gastric air bubble in the chest X-ray is one of the significant findings for diagnosing achalasia [4
]. After successful dilatation of the lower esophageal sphincter, the gastric air bubble reappears in the chest X-ray.
Sometimes achalasia presents with atypical presentations and atypical findings. There are case reports of achalasia presenting as acute airway obstruction and recurrent pneumonitis [5
]. In patients with atypical presentation and findings, the diagnosis is often delayed. In our patient, there was an atypical finding in the form of the presence of an air bubble below the left hemi-diaphragm in the gastric region in the chest X-ray film.
Based on the clinical history, examination, upper gastrointestinal endoscopy and barium swallow X-ray findings, a provisional diagnosis of achalasia cardia was made. Pneumatic balloon dilatation was done to relieve the symptoms. The chest X-ray taken after the successful procedure showed the appearance a second air bubble in the gastric region adjacent to the previous one. This phenomenon is an anticipated one. Careful examination of the first air bubble, which was seen even before the dilatation was done, showed haustral markings. Haustral markings are seen in the colon. This led us to the conclusion that the air bubble which was present before dilatation was indeed a colonic air bubble in the splenic flexure. Therefore, the second air bubble, which appeared after successful dilatation of the lower esophageal sphincter, was the gastric air bubble.
So in our patient, at the end of the dilatation, there were two air bubbles – a double bubble. A thorough Medline search was performed. To our knowledge, this finding has not been reported in the literature thus far. The appearance of a double bubble in patients with achalasia cardia is an interesting finding following a successful dilatation of the lower esophageal sphincter. This double bubble sign may pose a diagnostic challenge in the patients in whom it is present. Knowledge of this unusual sign may be helpful in these circumstances.