Acute cholecystitis refers to inflammation of the gallbladder most commonly occurring due to impacted gallstones.
After biliary colic, acute cholecystitis is the second most common complication of gallstones (cholelithiasis) affecting an estimated 0.3-0.4% of patients with asymptomatic gallstones each year. Relatively rarely acute cholecystitis occurs in the absence of gallstones (acalculous cholecystitis).
Management aims to treat the infection and symptoms (antibiotics, fluids, analgesia) and prevent recurrence (laparoscopic cholecystectomy - 'hot' or interval).
See our Cholelithiasis notes for more about the aetiology, types and risk factors.
Cholelithiasis (gallstones) are by far the most common cause of acute cholecystitis.
Gallstones affect up to 20% of the population. The prevalence of gallstones increases with advancing age before levelling off in the sixth - seventh decade of life. They are more common in women and tend to affect those of Caucasian, Native American and Hispanic backgrounds more.
Outside of haemolytic anaemias, gallstones are rarely seen in childhood. The vast majority of people with gallstones will remain asymptomatic (80%). There are a number of risk factors are associated with the development of cholelithiasis:
Inflammation and infection occur when a stone becomes impacted in the cystic duct (see Cholelithiasis notes to review the basic anatomy).
The exact pathogenesis is still not understood and it is thought the presence of additional mediators is required for cholecystitis to occur. An impacted stone leads to impaired drainage of gallbladder contents and the release of inflammatory mediators.
Though patients with acute cholecystitis are always treated with antibiotics some have posited that a significant proportion of patients have a sterile inflammation.
Acute acalculous cholecystitis refers to gallbladder inflammation in the absence of gallstones.
Acalculous cholecystitis is far less common than calculous cholecystitis and is normally seen in patients with significant systemic upset or following major surgery. Risk factors include:
Again the pathogenesis is not fully understood but is thought to relate to biliary stasis and/or gallbladder ischaemia. In a proportion of cases, infection is the primary cause but it is thought infection is normally secondary to established inflammation.
Acute cholecystitis presents with abdominal pain, tenderness and signs of infection.
Murphy's sign is indicative of cholecystitis. As the patient breathes out, place your hand below the right costal margin. As the patient breathes in the inflamed gallbladder moves inferiorly to the hand causing the patient to catch their breath. To be considered positive, it should be absent on the left side.
Acute cholecystitis is most commonly confirmed on USS or CT abdomen/pelvis.
Patients typically present with upper abdominal pain, tenderness and fever. Most patients are haemodynamically stable but the condition can present with significant sepsis. Blood tests reveal elevated inflammatory markers and mild derangement of the liver function tests is common.
Ultrasound: in acute cholecystitis gallstones and a 'radiological' Murphy's sign may be seen. Suggestive findings include a thickened gallbladder and pericholecystic fluid. It also allows for the assessment of the CBD.
Computed tomography: may be used to demonstrate cholecystitis and exclude alternative causes of symptoms. Again a thickened gallbladder and pericholecystic fluid may be seen. It has a poor sensitivity (around 60-70%) for picking up simple gallstones, only clearly demonstrating stones that are calcified.
MRCP: magnetic resonance cholangiopancreatography offers excellent visualisation of the biliary tree. Arranged if there is suspicion of stones in the biliary tree.
ERCP: Endoscopic retrograde cholangiopancreatography involves the endoscopic intubation of the ampulla of Vater. It offers excellent views of the biliary tree whilst allowing therapeutic intervention such as drainage. ERCP is now generally a therapeutic rather than diagnostic intervention (due to the advent of MRCP), in this setting used when stones are retained in the CBD.
Acute cholecystitis is managed with intravenous antibiotics, fluids and cholecystectomy.
Initial management should follow an ABC approach in those who are acutely unwell. The sepsis 6 protocol should be implemented when indicated. Key components of management include:
Some patients become very unwell with their cholecystitis, do not improve with medical management and may develop gallbladder empyemas. Often the patient is not suitable for a 'hot' laparoscopic cholecystectomy.
In these patients, a percutaneous cholecystostomy (drain into the gallbladder placed by interventional radiology) may be more appropriate. Once recovered, patients are often discharged with this drain in situ until definitive management can be arranged.
In patients with simple cholecystitis, the definitive management is with laparoscopic cholecystectomy. There are two main options:
Prior to cholecystectomy, it is key that CBD stones are excluded. All patients will have had a USS and set of LFTs as a minimum. If there is suspicion of CBD stones (e.g. dilated CBD or CBD stone on USS, raised bilirubin on LFTs) then there are two main options:
In patients with significant co-morbidities, a cholecystectomy may represent unacceptable risk and as such more conservative measures trialed.
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