Which sign is associated with achalasia?

The bird beak sign is associated with achalasia, a condition characterized by the failure of the lower esophageal sphincter to relax properly during swallowing. This results in a characteristic narrowing of the distal esophagus, which can be visualized through imaging studies, such as a barium swallow. The "bird beak" appearance is named for the funnel-like shape it resembles at the point where the esophagus narrows, indicating that there is an obstruction in the passage of food.

This sign is significant in the diagnosis of achalasia because it reflects the underlying problem of esophageal motility and the inability for food to pass into the stomach, leading to symptoms such as dysphagia (difficulty swallowing) and regurgitation. The presence of this sign helps differentiate achalasia from other causes of esophageal obstruction, making it an important feature in pediatric and adult gastroenterology.

In contrast, the other signs listed are associated with different gastrointestinal conditions. The double bubble sign indicates duodenal atresia, the string sign is linked to conditions like Crohn's disease, and the target sign is associated with conditions like intussusception. Understanding these distinctions is crucial for clinical diagnosis and management in pediatric medicine.