What diseases is the "bird beak sign" seen in?

The "bird's beak sign" is commonly seen in conditions such as hiatal hernia, achalasia cardia, and sigmoid volvulus.

1. Hiatal Hernia

Hiatal hernia mainly occurs when any tissue outside the esophagus passes through an enlarged diaphragmatic esophageal hiatus into the thoracic cavity, causing enlargement of the hernia. Part of the abdominal organs may enter the chest cavity through this defect, forming the bird's beak sign. Patients may also experience symptoms such as heartburn and acid reflux.

2. Achalasia Cardia

Achalasia cardia is primarily related to neurological factors, possibly due to excessive relaxation of the lower esophageal sphincter and loss of active motility in the distal esophagus, preventing normal passage of food. This leads to dysphagia and heartburn. The upper portion of the esophagus may dilate, resulting in the appearance of the bird's beak sign.

3. Sigmoid Volvulus

This condition may result from a long sigmoid colon, short mesentery, or local inflammation. When the sigmoid colon twists, it causes intestinal obstruction. The proximal segment becomes narrow while the distal segment dilates, producing the characteristic bird's beak sign.

In addition, the bird's beak sign may also be caused by congenital hypertrophic pyloric stenosis. Patients should promptly seek medical evaluation at a hospital and undergo relevant examinations such as gastroscopy or colonoscopy to confirm the diagnosis.