Esophageal achalasia is defined as an esophageal motility disorder of unknown etiology characterized by failure of lower esophageal sphincter (LES) relaxation and impaired peristalsis of the lower esophageal body [2]. Diagnosis is difficult because achalasia is a rare disease (incidence, 1 in 100,000 people) with nonspecific subjective symptoms [3]. The most frequent symptoms of achalasia include dysphagia of solids and liquids (> 90%), regurgitation of undigested food (76–91%), respiratory complications such as nocturnal cough (30%) and aspiration (8%), chest pains (25–64%), heartburn (18–52%), and weight loss (35–91%) [4]. Oral reflux in patients with achalasia does not originate from the stomach and thus does not contain acidic contents. Furthermore, if the volume of the oral reflux is mild, the patient may be unaware of the reflux.
We assume two reasons for the aspiration during the first scheduled orthopedic surgery in this case. First, the patient was not aware of her rare disease. She had unusual habits such as washing food into her stomach with large amounts of water and purging watery vomit every night before bed. Nonetheless, she did not consider it unusual because her gastroenterologist told her that nothing was wrong. The diagnostic features of esophageal achalasia on upper gastrointestinal endoscopy include (1) dilatation of the esophageal lumen, (2) abnormal retention of food and fluid in the esophagus, (3) whitening and thickening of the esophageal mucosal surface, (4) functional narrowing of the esophagogastric junction, and (5) abnormal contraction waves of the esophagus [2]. In this case, preoperative endoscopy before Heller and Dor surgery showed fluid retention in the esophagus and functional narrowing of the esophagogastric junction, but the dilation of the esophageal lumen was mild. As a result, the gastroenterologist at the time was unable to detect achalasia, leading to her misconception that it was not a disease.
Second, we could not obtain information regarding dysphagia and food regurgitation in the preoperative examination. Our routine preoperative examination for orthopedic patients without gastrointestinal complications includes a detailed medical history, allergies, and asthma, but not dysphagia or food regurgitation. In patients with esophageal achalasia, 37% have solid residue, and 14.8% retain water, even after fasting for 24 h before surgery [5]. Fortunately, because this patient had a habit of vomiting every night before bed, and the vomit did not contain any solids, she did not develop severe pneumonia.
Achalasia is a rare disease, and only a few cases have been detected by aspiration during the induction of anesthesia [1, 6, 7]. Since achalasia is a chronic benign disease, patients may recognize it as a constitutional problem, as in this case. A detailed history of dysphagia and regurgitation should be taken from all patients during preoperative examinations to avoid aspiration risk, even if achalasia is not suspected. Pillow stains with drool while sleeping suggests the existence of achalasia. Although chest X-rays appear normal in the early phase of achalasia, the dilated esophagus creates new interfaces with the lung as the disease progresses, which makes achalasia-specific findings, including convex opacity overlapping the right mediastinum, air-fluid levels in the thorax esophagus, and small or absent gastric bubbles [8]. In this case, the esophageal dilatation was so mild that no suspicious contour was seen on the chest X-ray (Fig. 3). However, it should be worthwhile for physicians to get into the habit of looking for achalasia-specific findings on routine X-ray readings to detect undiagnosed achalasia. Furthermore, we would like to emphasize that achalasia should not be ruled out even if there are no findings specific to achalasia, especially in patients with symptoms such as dysphagia or regurgitation. If a chest CT is taken for the preoperative evaluation, physicians should also note the dilated image of the esophagus.
