Differential Diagnosis for Elevated Alk Phos, Elevated Liver Function Tests, but Normal Electrolytes

• Single Most Likely Diagnosis
  • Cholestasis due to Intrahepatic or Extrahepatic Bile Duct Obstruction: This condition is characterized by elevated alkaline phosphatase (alk phos) and liver function tests (LFTs) due to the obstruction of bile flow, which can be caused by gallstones, tumors, or strictures. Normal electrolytes are consistent with this diagnosis as the primary issue is with bile flow rather than electrolyte imbalance.
• Other Likely Diagnoses
  • Primary Biliary Cholangitis (PBC): An autoimmune disease that leads to progressive destruction of the bile ducts within the liver, causing cholestasis. It presents with elevated alk phos and LFTs, and patients often have normal electrolyte levels.
  • Primary Sclerosing Cholangitis (PSC): A chronic liver disease characterized by inflammation and scarring of the bile ducts, leading to cholestasis. It can present with elevated alk phos and abnormal LFTs, with electrolytes typically being normal.
  • Drug-Induced Cholestasis: Certain medications can cause cholestasis, leading to elevated alk phos and LFTs. The effect on electrolytes is usually minimal.
• Do Not Miss Diagnoses
  • Hepatocellular Carcinoma with Bile Duct Invasion: Although less common, hepatocellular carcinoma can invade the bile ducts, causing obstructive jaundice and elevated LFTs, including alk phos. Missing this diagnosis could be fatal.
  • Pancreatic Cancer with Bile Duct Obstruction: Pancreatic cancer can obstruct the bile duct where it passes through or near the pancreas, leading to elevated alk phos and LFTs. Early detection is crucial for treatment.
• Rare Diagnoses
  • Vanishing Bile Duct Syndrome: A rare condition characterized by the progressive destruction and disappearance of the intrahepatic bile ducts, leading to cholestasis. It can be idiopathic or secondary to other conditions.
  • Alagille Syndrome: A genetic disorder that affects the liver, heart, and other parts of the body. It can cause bile duct paucity, leading to elevated alk phos and LFTs. It is rare and typically presents in childhood.