**Question:** Thurston Holland sign is seen in:

A. Painless acute appendicitis
B. Acute diverticulitis
C. Acute cholecystitis
D. Acute pyelonephritis

**Core Concept:** Thurston Holland sign is a clinical sign used to differentiate between acute appendicitis, acute diverticulitis, and acute cholecystitis.

**Why the Correct Answer is Right:** Thurston Holland sign is positive when there is a palpable mass in the right iliac fossa (RIF) that is tender to the touch, moves with respiration, and increases in size during inspiration (i.e., the mass enlarges when the patient inhales). This sign is indicative of acute appendicitis, as it is a clinical manifestation of the verrucous process of appendicitis, where the appendix enlarges due to inflammation and edema.

**Why Each Wrong Option is Incorrect:**

A. Painless acute appendicitis: Thurston Holland sign is typically non-existent or negative in painless acute appendicitis, as the appendix is inflamed without significant pain.

B. Acute diverticulitis: Although acute diverticulitis can present with RIF tenderness, the sign of movement with respiration and enlargement during inspiration is not specific to this condition.

C. Acute cholecystitis: Thurston Holland sign is less likely to be present in acute cholecystitis compared to appendicitis, as the gallbladder is not a part of the respiratory system and does not undergo verrucous enlargement.

D. Acute pyelonephritis: This condition involves the kidneys and ureters, and Thurston Holland sign is not relevant or applicable to this condition since the respiratory system is not involved.

**Clinical Pearl:** The correct identification of Thurston Holland sign helps in narrowing down the differential diagnosis in cases of RIF pain and a palpable mass to differentiate between appendicitis, diverticulitis, and cholecystitis, which are all conditions presenting with RIF pain and mass. A positive sign can increase the likelihood of appendicitis and guide the clinician to consider surgery as a potential treatment option.