Related Subjects:Acute Cholecystitis
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⚠️ Acalculous cholecystitis is inflammation of the gallbladder without gallstones or cystic duct obstruction, typically in critically ill patients (e.g., ICU with sepsis, trauma, burns, TPN, post-op). It accounts for 5–14% of acute cholecystitis cases and carries higher morbidity/mortality than calculous disease.
Ultrasound is the preferred first-line imaging; CT is valuable for complications or equivocal findings.
📖 About
- Occurs predominantly in critically ill/ICU patients (trauma, major surgery, sepsis, burns, multiorgan failure), elderly, or those with prolonged fasting/TPN.
- Presentation similar to calculous cholecystitis but no stones; often insidious in ventilated/sedated patients.
- Worse prognosis: mortality 15–75% (vs <1–3% in calculous), driven by comorbidities and delayed diagnosis.
- Pathophysiology: bile stasis → mucosal ischaemia → bacterial overgrowth/invasion (secondary infection common).
🧬 Aetiology & Pathophysiology
- Inflammation without mechanical cystic duct obstruction (unlike calculous).
- Key mechanisms: bile stasis (fasting/TPN/opiates), gallbladder ischaemia (hypotension/sepsis/vasopressors), direct mucosal injury, secondary bacterial infection (Gram-negatives, anaerobes, occasionally fungi in immunocompromised).
- Can progress rapidly to gangrene/perforation due to thin-walled ischaemic gallbladder.
🔗 Risk Factors & Associations
- Critical illness: sepsis/multiorgan failure, major trauma/burns (>30% TBSA), prolonged ICU stay.
- Post-operative: cardiac/vascular/abdominal surgery (especially after cardiopulmonary bypass).
- Prolonged fasting/TPN (>1–2 weeks), opiate use (reduced motility).
- Comorbidities: diabetes, vascular disease, HIV/AIDS, immunosuppression, vasculitis.
- Other: major burns, trauma, haemorrhagic shock, vasculitis (e.g., polyarteritis nodosa).
🩺 Clinical Features
- Often non-specific in critically ill: unexplained fever, leucocytosis, sepsis worsening despite treatment.
- RUQ pain/tenderness (may be masked by sedation/ventilation); positive Murphy’s sign (less reliable in intubated patients).
- Systemic: fever, tachycardia, hypotension, deranged LFTs (cholestatic pattern), jaundice rare.
- High index of suspicion in at-risk patients with persistent sepsis/RUQ signs.
🔍 Investigations
- Bloods: ↑WCC (often marked), ↑CRP, deranged LFTs (↑ALP, ↑bilirubin mild), possible coagulopathy/AKI.
- Ultrasound (USS): First-line (TG18/WSES preferred due to availability, no radiation, bedside). Findings: wall thickening (>3–5 mm), pericholecystic fluid, sludge/distension, no stones; sonographic Murphy’s sign (if feasible); may show intramural gas (emphysematous) or perforation.
- CT abdomen: Highly useful in ICU/equivocal USS; shows wall thickening (>4 mm), pericholecystic stranding/fluid, intramural gas, mucosal irregularity/sloughing, complications (abscess/perforation). Often preferred for overall assessment in critically ill.
- HIDA scintigraphy: High sensitivity (~100%) for non-filling of gallbladder (cystic duct "obstruction" functional); useful if USS equivocal but limited availability/ICU logistics.
- MRI/MRCP: Alternative if needed (e.g., complex anatomy); rarely first-line.
⚠️ Complications
- Gangrenous cholecystitis / necrosis.
- Perforation → localised peritonitis or free peritonitis/septic shock.
- Pericholecystic/abscess formation.
- Emphysematous cholecystitis (gas-forming organisms; higher risk in diabetes).
- Sepsis/multiorgan failure escalation, ARDS, disseminated intravascular coagulation.
🔎 Differential Diagnosis
- Calculous cholecystitis (exclude stones on imaging).
- Acute pancreatitis / peptic ulcer perforation.
- Right-sided pyelonephritis / hepatic abscess.
- Subphrenic abscess / pneumonia / mesenteric ischaemia.
- Other ICU sepsis sources (line infection, VAP).
💊 Management (TG18 / WSES-Aligned)
- Supportive / resuscitation: ABC approach, IV fluids, vasopressors if shock, analgesia, organ support in ICU/HDU.
- Antibiotics: Broad-spectrum IV (cover Gram-negatives + anaerobes); e.g., piperacillin-tazobactam, meropenem (if high-risk/resistant), or ceftriaxone + metronidazole. Duration: 4–7 days post-source control (shorter if improving).
- Source control (definitive):
- Percutaneous cholecystostomy (PC): Preferred in unstable/high-risk/critically ill patients (TG18/WSES recommend as bridge or definitive; lower mortality vs surgery in severe cases).
- Cholecystectomy: Laparoscopic (preferred) or open if patient stabilises; early if feasible (within days); often delayed in severe illness.
- ERCP/stenting: Rare adjunct if concurrent biliary obstruction suspected.
- Severity grading (TG18 applies to acalculous):
- Mild (Grade I): No organ dysfunction → consider early surgery/PC.
- Moderate (Grade II): Local complications (e.g., abscess) or prolonged symptoms → urgent drainage/surgery.
- Severe (Grade III): Organ dysfunction (e.g., shock, respiratory failure) → resuscitation + urgent PC (surgery high-risk).
- Prognosis: Poor in ICU/multimorbid patients (mortality 20–50%+); early diagnosis + source control improves outcomes; recurrence low after PC if no stones.
📚 References (Current as of March 2026)
