Differential Diagnosis for Fever, Sore Throat, Low WBC, Raised CRP, and Gallbladder Edema with CBD Dilatation

• Single Most Likely Diagnosis

  • Acute cholecystitis or cholangitis: The presence of gallbladder edema and common bile duct (CBD) dilatation without calculus, along with systemic signs of infection (fever, raised CRP), points towards an infectious or inflammatory process involving the biliary system. The low WBC count could be seen in severe infection or sepsis, where the body's response may be overwhelmed.

• Other Likely Diagnoses

  • Viral hepatitis: Although hepatitis typically presents with elevated liver enzymes and jaundice, some forms can cause fever, sore throat (if associated with a viral prodrome), and elevated CRP. The gallbladder findings could be secondary to the hepatitis.
  • Sepsis of another origin with secondary biliary involvement: The low WBC count and raised CRP suggest a severe infection. If the primary source of infection is elsewhere (e.g., pneumonia, urinary tract infection), it could lead to secondary biliary system involvement due to the systemic inflammatory response.
  • Pyogenic liver abscess: This condition can present with fever, elevated CRP, and signs of biliary obstruction or inflammation, including gallbladder edema and CBD dilatation.

• Do Not Miss Diagnoses

  • Ascending cholangitis: This is a serious infection of the biliary system that can present with fever, jaundice, and abdominal pain (Charcot's triad). The absence of calculus does not rule out this diagnosis, as it can occur without stones. It's critical to consider this diagnosis due to its high mortality if untreated.
  • Sepsis due to any cause: Given the low WBC count and elevated CRP, sepsis from any source (not just biliary) must be considered and promptly addressed to prevent high mortality.
  • Biliary obstruction due to a non-calculus cause (e.g., tumor, stricture): While less common, obstruction of the biliary system can lead to infection and the clinical presentation seen. It's crucial to investigate for these causes, especially if initial treatments for infection do not improve the patient's condition.

• Rare Diagnoses

  • Acalculous cholecystitis: Although it can occur in critically ill patients, the presence of this condition without an obvious risk factor (e.g., severe illness, total parenteral nutrition) makes it less likely but still a consideration.
  • Mirizzi syndrome without a stone: This rare condition involves obstruction of the common bile duct due to a gallstone impacted in the cystic duct, causing compression of the common hepatic duct. However, it could theoretically occur without a visible stone if the stone has passed or is not visualized.
  • Biliary tuberculosis: This is a rare condition in many parts of the world but can mimic other biliary diseases, including cholecystitis and cholangitis, and should be considered in endemic areas or in patients with risk factors for tuberculosis.