Differential Diagnosis for RUQ Pain with Fever and Leukocytosis
Single most likely diagnosis:
- Acute cholecystitis: This is the most likely diagnosis given the presentation of RUQ pain, fever, leukocytosis, and a tender RUQ mass, along with ultrasound findings of a distended, thin-walled gallbladder (GB) with a stone. These symptoms and findings are classic for acute cholecystitis, which is inflammation of the gallbladder, often caused by gallstones blocking the cystic duct.
Other Likely diagnoses:
- GB mucocele: Although less common, a GB mucocele could present similarly, especially if the gallbladder is distended and there's a concern for possible obstruction. However, the presence of a stone and the specific symptoms point more towards an inflammatory process like acute cholecystitis.
- Pancreatitis: While pancreatitis can cause RUQ pain and elevated white blood cell count, the specific findings of a distended gallbladder with a stone and a tender RUQ mass are more suggestive of gallbladder pathology. Pancreatitis would typically have additional symptoms or lab findings such as elevated pancreatic enzymes.
Do Not Miss (ddxs that may not be likely, but would be deadly if missed.):
- Acute cholangitis: Although the common bile duct (CBD) is reported as normal, and there's no jaundice, acute cholangitis is a condition that requires prompt recognition and treatment due to its potential for severe morbidity and mortality. It typically presents with jaundice, fever, and abdominal pain (Charcot's triad), but the absence of jaundice does not rule it out entirely, especially if there's a concern for a stone in the CBD that was missed.
Rare diagnoses:
- Other rare conditions such as a gallbladder tumor or Mirizzi's syndrome (where a gallstone becomes impacted in the cystic duct and causes obstruction of the common bile duct) could present with similar symptoms but are less likely given the information provided. These would be considered if initial treatments for more common conditions fail or if additional diagnostic findings suggest these alternatives.