What condition does the Psoas sign suggest?

The Psoas sign is a physical examination finding that indicates irritation of the iliopsoas muscle, which can occur due to inflammation or irritation from nearby structures, particularly the appendix. When a patient experiences pain in the right lower quadrant upon passive extension of the hip or active flexion of the hip against resistance, it suggests that the underlying cause may be appendicitis. This sign is particularly utilized in assessing acute abdominal pain and is relevant in distinguishing appendicitis from other conditions that could cause similar symptoms.

In contrast, pneumonia generally presents with respiratory symptoms, such as cough or dyspnea, rather than localized abdominal signs. Gallbladder inflammation typically would exhibit symptoms like right upper quadrant pain and may show signs such as Murphy's sign, rather than the Psoas sign. Spleen enlargement can cause discomfort, but it would not specifically elicit a Psoas sign response and is often examined through other signs and symptoms. Thus, the Psoas sign is primarily associated with appendicitis, as it indicates irritation of the psoas muscle due to inflammation in the area of the appendix.