ICD-10 Codes for Cholecystitis
The ICD-10 code for acute calculous cholecystitis is K80.0, while acute acalculous cholecystitis is coded as K81.0. 1
Primary ICD-10 Codes
Calculous Cholecystitis (Gallstone-Related)
- K80.0: Calculus of gallbladder with acute cholecystitis - used for the 90-95% of acute cholecystitis cases caused by gallstone obstruction of the cystic duct 1, 2
- This code applies when gallstones are present and causing acute inflammation 1
Acalculous Cholecystitis (Non-Gallstone)
- K81.0: Acute cholecystitis without cholelithiasis - used for the 5-10% of cases occurring without gallstones, typically in critically ill patients 2
- This represents acute gallbladder inflammation in the absence of stones 2
Clinical Context for Code Selection
The distinction between calculous and acalculous cholecystitis is critical for proper coding, as it reflects fundamentally different pathophysiology and patient populations 2:
Calculous cholecystitis (K80.0) occurs when cystic duct obstruction by gallstones triggers inflammation, progressing through edematous (2-4 days), necrotizing (3-5 days), and suppurative phases (7-10 days) 3
Acalculous cholecystitis (K81.0) develops in severely ill patients without gallstones, often in ICU settings with critical illness 2
Diagnostic Confirmation Required for Coding
Proper ICD-10 code assignment requires imaging confirmation, not just clinical suspicion 1:
- Abdominal ultrasound should document presence or absence of gallstones, gallbladder wall thickening >3mm, pericholecystic fluid, and sonographic Murphy sign 4
- Ultrasound has 81% sensitivity and 83% specificity for acute cholecystitis diagnosis 2
- When ultrasound is inconclusive, hepatobiliary scintigraphy serves as the gold standard diagnostic test 2
Common Coding Pitfalls
Do not assign cholecystitis codes based solely on right upper quadrant pain and fever - imaging confirmation of gallbladder inflammation is required 1. The combination of clinical symptoms (right upper quadrant pain, fever, nausea), laboratory findings (leukocytosis in 41-59% of cases), and imaging findings must be present 1.
Verify the presence or absence of gallstones on imaging before selecting between K80.0 and K81.0, as ultrasound has 96% accuracy for detecting gallstones but can miss small stones or those in the gallbladder neck 4.