Cholelithiasis and Cholecystitis

Key Points

1
Gallstones are common and generally asymptomatic.
2
Gallstones can result in various clinical sequelae, including biliary pain and acute cholecystitis.
3
Cholecystectomy is the first-line treatment for symptomatic gallstones and acute cholecystitis.
4
In patients who are poor surgical candidates, alternative therapeutic options include percutaneous gallbladder drainage, transpapillary gallbladder drainage, or endoscopic ultrasound (EUS)–guided gallbladder drainage.

Cholelithiasis (Gallstones)

1.
Gallstone disease is common and affects 20 to 25 million persons in the United States. About 20% of women and 10% of men have gallstones by 60 years of age.
2.
Gallstone disease is costly, with an estimated annual direct cost of $15 billion. Approximately 750,000 cholecystectomies are performed annually.
3.
Gallstones are asymptomatic in 80% of persons who have them; however, the stones can cause significant abdominal pain in up to 20% and carry a mortality rate of up to 0.6%.
4.
Gallstones can be broadly divided into cholesterol, black pigment, and brown pigment.
5.
Cholecystectomy, the first-line therapy for symptomatic gallstones, is the most commonly performed nonemergent gastrointestinal surgical procedure in the United States.

Types of Gallstones

1.
Cholesterol stones
- a.
  In the American population, 70% to 80% of gallstones are cholesterol stones.
- b.
  Cholesterol stones are composed of 50% to 100% cholesterol, in combination with mucin and calcium salts. The stones are generally yellow-brown in color.
- c.
  Cholesterol stones form primarily in the gallbladder as a result of increased secretion of cholesterol by the liver, supersaturation of bile with cholesterol, and an increase in gallbladder mucin and calcium. A stone nidus is formed by aggregation of calcium salts and mucin, following precipitation of cholesterol monohydrate crystals.
- d.
  Risk factors for cholesterol stone formation
  - ▪
    Older age: Prevalence rises with increasing age in men and women.
  - ▪
    Female gender: Risk of gallstone formation in women is twice that of men.
  - ▪
    Diet: Cholesterol gallstone formation is associated with a diet high in saturated fat and low in fiber. Cholesterol stones are more frequent in North America and Europe compared with Asia and Africa.
  - ▪
    Obesity
  - ▪
    Rapid weight loss
  - ▪
    Pregnancy
  - ▪
    Genetics
  - ▪
    Ethnicity: High prevalence among North American Indians, Mapuche Indians
  - ▪
    Medications: Estrogens
2.
Pigment stones
- a.
  Black pigment stones account for about 20% to 30% of gallstones in Americans.
  - ▪
    They form primarily in the gallbladder.
  - ▪
    Main composition: Calcium bilirubinate, calcium phosphate, and calcium carbonate
  - ▪
    They are black, hard, and radiopaque.
  - ▪
    Risk factors for formation
    - –
      Chronic hemolysis
    - –
      Cirrhosis
    - –
      Cystic fibrosis
    - –
      Crohn disease
- b.
  Brown pigment stones form primarily in the bile duct.
  - ▪
    They are composed of calcium bilirubinate, calcium palmitate, calcium stearate, cholesterol, and mucin.
  - ▪
    Risk factors for formation
    - –
      Stagnation of bile in combination with bacterial and parasite infection of the bile duct, including Escherichia coli , Bacteroides spp, Clostridium spp, Opisthorchis viverrini , and Ascaris lumbricoides.

Diagnosis

1.
Ultrasonography (US) is the primary modality for the diagnosis of cholelithiasis; it is both noninvasive and sensitive for the detection of cholelithiasis, with a sensitivity of 95% for gallstones >2 mm in size.
2.
The sensitivity of computed tomography (CT) for the detection of cholelithiasis is 79%—lower than that of US—because of insufficient calcium content in some stones.
3.
Magnetic resonance imaging (MRI) is also not recommended as a first-line imaging modality for detection of cholelithiasis; however, MRI has a role in the diagnosis of bile duct stones, with a sensitivity of 93%.
4.
EUS is at least as sensitive as abdominal US for the detection of cholelithiasis, including very small stones <2 mm in size and sludge ( Fig. 34.1 ); however, use of EUS is limited by the invasive nature of this technique.
5.
Although CT, MRI, and EUS can be used for diagnosing cholelithiasis, these imaging modalities should be reserved for detecting complications that can arise from gallstones, such as acute cholecystitis, acute pancreatitis, or choledocholithiasis, rather than as the primary modality for uncomplicated cholelithiasis.

Occasionally, other diseases of the gallbladder, such as cholesterolosis (“strawberry gallbladder”) and adenomyomatosis, are identified on imaging studies, including oral cholecystography ( Table 34.1 ).

TABLE 34.1

Diseases of the Gallbladder

	Clinical Features	Laboratory Features	Initial Diagnostic Test(s)	Treatment
Asymptomatic gallstones	Asymptomatic	Normal	Ultrasonography	None
Symptomatic gallstones	Biliary pain	Normal	Ultrasonography	Laparoscopic cholecystectomy
Acute cholecystitis	Epigastric or right upper quadrant pain, nausea, vomiting, fever, Murphy sign	Leukocytosis	Ultrasonography, HIDA scan	Antibiotics, laparoscopic cholecystectomy
Chronic cholecystitis	Biliary pain, constant epigastric or right upper quadrant pain, nausea	Normal	Ultrasonography (stones), oral cholecystography (nonfunctioning gallbladder)	Laparoscopic cholecystectomy
Cholesterolosis	Usually asymptomatic	Normal	Oral cholecystography	None
Adenomyomatosis	May cause biliary pain	Normal	Oral cholecystography	Laparoscopic cholecystectomy if symptomatic
Porcelain gallbladder	Usually asymptomatic, high risk of gallbladder cancer	Normal	Radiograph or CT	Laparoscopic cholecystectomy

CT, Computed tomography; HIDA, hepatic iminodiacetic acid.

Common Consequences (see also Chapter 35 )

1.
Asymptomatic gallstones
- a.
  Gallstones are discovered incidentally in 80% of affected persons; they are therefore asymptomatic and remain so for several decades in the majority of cases.
- b.
  Biliary pain develops in 2% to 3% in persons with gallstones each year, and in 10% by 5 years.
- c.
  Complications from gallstones are observed in only 1% to 2% persons with gallstones each year.
- d.
  Persons with asymptomatic gallstones do not require prophylactic cholecystectomy, which should only be considered in the following special circumstances:
  - ▪
    Persons with an increased risk of gallbladder cancer, including those with porcelain gallbladder (calcification of the gallbladder wall), anomalous pancreaticobiliary duct junction, and large gallstones >3 cm
  - ▪
    Persons who undergo solid organ transplantation, due to high morbidity associated with complications arising from gallstones in these patients
  - ▪
    Persons who undergo abdominal surgery for other indications, especially bariatric surgery; these patients are predisposed to gallstone formation because of rapid weight loss
2.
Biliary pain
- a.
  Biliary pain (“colic”) is characterized by intermittent right upper quadrant abdominal pain, typically with radiation to the right shoulder, lasting 30 minutes to 4 hours and occurring with variable frequency.
- b.
  The pain commonly follows a large or fatty meal because of contraction of the gallbladder in the presence of an obstructed cystic duct.
- c.
  The diagnosis is confirmed by visualization of gallstones on US, with exclusion of other etiologies of abdominal pain, such as acute pancreatitis, choledocholithiasis, peptic ulcer disease, and nephrolithiasis.

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