Acute cholecystitis is a clinical syndrome that is associated with gallbladder wall inflammation and characterized by right-upper-quadrant (RUQ) abdominal pain, fever, and leukocytosis. There are 2 main types of acute cholecystitis: calculous and acalculous.
Acute calculous cholecystitis:
Constitutes 90%-95% of all cases. Stones can be of the following types:
- Cholesterol stones – Approximately 75% of all gallstones in the United States.
- Pigment stones – 25% are pigment stones and are made of calcium bilirubinate and calcified bilirubin. This type of gallstone can be either black or brown. Black stones comprise 20% of all gallstones and are found in patients with chronic hemolytic anemia, Gilbert's syndrome, liver cirrhosis, or cystic fibrosis. Brown stones are more common in the Asian population, and they develop in the setting of chronic biliary tract infection such as parasite infection.
- Mixed stones – Mixture of cholesterol and pigment stones.
Constitutes 5%-10% of cholecystitis. Associated with critical illnesses such as trauma, burns, severe sepsis and diabetes, immunosuppression, HIV infection, recent non-biliary surgery, parenteral nutrition, or childbirth. There is a 25%-40% mortality rate, higher than for calculous cholecystitis.
Pathophysiology of acute cholecystitis:
About 10% of the population has gallstones, most of which are asymptomatic. Biliary colic develops in 1%-4% of patients annually, and acute cholecystitis eventually develops in about 20% of symptomatic patients if left untreated. Thus the presence of gallstones does not mean that a patient will develop symptoms.
The initial event in acute calculous cholecystitis is the obstruction to gallbladder drainage. This, by itself, causes biliary colic if it is brief; over many hours, it can cause inflammation, resulting in wall-thickening and subsequent development of pericholecystic fluid. Inflammation is sterile in early cases, but secondary infection develops in most patients. Common organisms are Enterobacteriaceae (Escherichia coli, Klebsiella spp., Enterobacter spp.), Enterococcus spp., and anaerobes (Bacteroides spp., Clostridium spp., Fusobacterium spp.).
Demographics and risk factors of acute cholecystitis:
Sex – Women are more likely to develop gallstones because of higher estrogen levels. For the same reason, pregnancy and hormone replacement therapy increase the risk of gallstones. Approximately 25% of women older than 60 have gallstones. Cholecystitis develops in women more frequently from the relative prevalence of gallstones.
Age – Gallstones are unusual in children. In cases when they occur, they are commonly pigment stones. The following conditions put children at a higher risk of having gallstones:
- Spinal injury
- History of abdominal surgery
- Sickle cell disease
- Impaired immunity
- Intravenous nutrition
Obesity and weight changes – In obesity, the liver overproduces cholesterol, which increases the risk of gallstone formation. Rapid weight loss is also a risk factor for the development of cholesterol gallstones.
Pregnancy – Increase in cholesterol saturation of bile and impaired gallbladder contraction during pregnancy predispose to formation of cholesterol stones or biliary sludge.
Genetics – Having a family member with gallstones increases one's risk. Mutation of gene ABCG8 increases the risk of gallstone formation.
AIDS – Biliary disease occurs via 2 mechanisms in patients with AIDS:
- Acute acalculous cholecystitis
- AIDS cholangiopathy (commonly due to Cryptosporidium or cytomegalovirus)
Ascariasis – This is a geographical risk factor in regions such as China and Southeast Asia. It can cause cholecystitis, cholangitis or hepatic abscess, or even pancreatitis.
Clinical manifestations of cholecystitis:
Symptoms include fever and RUQ pain.
- Biliary colic is the main symptom of uncomplicated cholelithiasis – Episodic, severe, and located in the epigastrium or RUQ.
- Following fatty food ingestion.
- Often at night.
- Radiates to the back or right shoulder.
- Prolonged or recurrent biliary colic can result in acute calculous cholecystitis. It presents with pain that is steady and severe, as opposed to episodic pain of biliary colic. This pain is often accompanied by nausea and vomiting.
- Arrest in inspiration while palpating the gallbladder during a deep breath.
- Sensitivity of 50%-60% and a high specificity of up to 79%-96%.
K81.9 – Cholecystitis, unspecified
76581006 – Cholecystitis