Acute Cholecystitis: Definition and Causes
Acute cholecystitis is an acute inflammation of the gallbladder that represents the most frequent and potentially life-threatening complication of gallstone disease, requiring timely diagnosis and treatment. 1
What It Is
Acute cholecystitis is a progressive inflammatory process of the gallbladder that evolves through distinct pathological phases 2:
- Edematous phase (days 0-4): Congestion and edema predominate 2
- Necrotizing phase (days 3-5): Characterized by hemorrhage and necrosis of the gallbladder wall 2
- Suppurative phase (days 7-10): Purulent inflammation develops 2
- Chronic progression: If untreated, the condition transitions to subacute and eventually chronic cholecystitis 2
The disease typically presents with right upper quadrant pain, fever, nausea, vomiting, and anorexia 1. Physical examination reveals right upper quadrant tenderness, and Murphy's sign (focal tenderness over the gallbladder) may be elicited 3, 4.
Primary Causes
Calculous Cholecystitis (90-95% of Cases)
Gallstone obstruction of the cystic duct is responsible for 90-95% of acute cholecystitis cases. 5
- Gallstones are identified in approximately 95% of acute cholecystitis cases 6
- The obstruction leads to increased intraluminal pressure, compromised blood flow, and subsequent inflammation 7
- Acute cholecystitis develops in only 1-3% of patients with symptomatic gallstones 3
Acalculous Cholecystitis (5-10% of Cases)
Acalculous cholecystitis occurs without gallstones and typically affects critically ill patients. 5
This form is associated with 7:
- Recent major surgery or trauma
- Severe burns
- Multisystem organ failure
- Prolonged parenteral nutrition
- Critical illness requiring intensive care
- Ischemia and compromised gallbladder perfusion
Other Causes
Less common etiologies include 7:
- Ischemic injury: Compromised blood supply to the gallbladder
- Chemical irritation: Substances entering biliary secretions
- Motility disorders: Drug-induced gallbladder dysfunction
- Infections: Microorganisms, protozoa, and parasites
- Collagen vascular diseases
- Allergic reactions
Special Populations
Immunocompromised Patients
In transplant recipients, acute cholecystitis presents with atypical features 8:
- Acalculous cholecystitis accounts for up to 40% of cases (versus 5-10% in general population) 8
- Clinical signs may be masked by immunosuppression 8
- Incidence reaches 72.2% after heart transplant and 30% after kidney transplant 8
- Mortality rates are significantly elevated, with urgent biliary operations carrying up to 29% mortality 8
Clinical Pitfall
Laboratory findings alone are insufficient for diagnosis—no single clinical or laboratory feature has adequate diagnostic power to establish or exclude acute cholecystitis. 4 The diagnosis requires a combination of clinical presentation (right upper quadrant pain, fever, Murphy's sign), laboratory abnormalities (elevated C-reactive protein, leukocytosis), and imaging confirmation 4. However, note that leukocytosis may be absent in immunocompromised patients despite active infection 8.