Diseases of the Gallbladder and Bile Ducts¶
Chapter 357 | Part 10: Disorders of the Gastrointestinal System
KEY CLINICAL POINTS¶
- Gallstone disease is the most common biliary disorder, with cholesterol stones accounting for >90% of cases.
- Cholesterol gallstone formation is driven by bile supersaturation, nucleation, and gallbladder hypomotility.
- Acute cholecystitis is a common complication of gallstones, often requiring surgical intervention.
- Diagnostic imaging (ultrasound, MRCP, ERCP) and biochemical markers (elevated bilirubin, alkaline phosphatase) are critical for evaluation.
- Laparoscopic cholecystectomy is the gold standard for symptomatic gallstone disease.
1. DEFINITION & OVERVIEW¶
Gallbladder and bile duct diseases encompass disorders of bile production, storage, and excretion. The gallbladder concentrates bile, while bile ducts transport it to the duodenum. Pathophysiology involves disruptions in bile composition, flow, or motility, leading to conditions like gallstones, cholecystitis, and cholangitis.
Table 357-1: Predisposing Factors for Cholesterol and Pigment Gallstone Formation¶
| Factor | Cholesterol Stones | Pigment Stones |
|---|---|---|
| Demographic/Genetic | North American Indians, Chilean Indians, Northern Europe | Asia, rural settings (parasitic infections) |
| Obesity/Metabolic Syndrome | Increased biliary cholesterol secretion | - |
| Rapid Weight Loss | Mobilization of tissue cholesterol | - |
| Female Hormones | Estrogens increase cholesterol secretion | - |
| Pregnancy | Impaired gallbladder emptying | - |
| Age | Increased cholesterol secretion, decreased bile acid pool | - |
| Gallbladder Hypomotility | Stasis and sludge formation | - |
| Clofibrate Therapy | Increased cholesterol secretion | - |
| Genetic Defects | CYP7A1 (bile acid synthesis), MDR3 (phospholipid export) | CYP7A1, MDR3 |
1.1 Bile Physiology¶
Bile is synthesized by hepatocytes, containing bile acids, phospholipids, and cholesterol. The enterohepatic circulation recycles bile acids, with the gallbladder concentrating bile through water reabsorption. Disruption of this balance leads to supersaturation and stone formation.
1.2 Gallbladder Function¶
The gallbladder stores and concentrates bile, releasing it in response to cholecystokinin (CCK). Dysfunction in gallbladder motility contributes to biliary sludge and stone formation.
2. EPIDEMIOLOGY¶
Gallstone prevalence peaks in Western countries, with Native Americans and Hispanics having the highest rates. Risk factors include obesity, diabetes, female sex hormones, and genetic predisposition. Pigment stones are more common in Asia and associated with parasitic infections.
2.1 Incidence/Prevalence¶
Gallstones are prevalent in ~10–15% of adults in Western countries. Cholesterol stones dominate, while pigment stones are more common in Asia and associated with chronic hemolysis or parasitic infections.
2.2 Risk Factors¶
Obesity, metabolic syndrome, rapid weight loss, female hormones, age >50, and genetic factors (e.g., ABCG5/G8 mutations) increase risk. Ileal disease and cystic fibrosis predispose to pigment stones.
3. ETIOLOGY & PATHOPHYSIOLOGY¶
Cholesterol stones form from bile supersaturation, nucleation, and gallbladder stasis. Pigment stones arise from bilirubin metabolism abnormalities. Genetic defects in ABC transporters (e.g., MDR3, ABCG5/G8) disrupt bile composition and excretion.
Table 357-2: Diagnostic Evaluation of the Gallbladder¶
| Test | Advantages | Limitations | Comments |
|---|---|---|---|
| Ultrasound | Rapid, detects >95% stones | Bowel gas, massive obesity | Procedure of choice |
| Plain Abdominal X-Ray | Low cost | Low yield, calcified stones only | Useful for calcified gallstones |
| Cholescintigraphy | Detects cystic duct obstruction | Contraindicated in pregnancy | Useful for acalculous cholecystitis |
| Serum Bilirubin | Elevated in obstructive jaundice | Not specific | Indicates common duct stones |
| ERCP | Best visualization of distal biliary tract | Acute pancreatitis risk | Preferred for stone extraction |
3.1 Bile Composition¶
Bile contains 80% bile acids, 16% phospholipids, and 4% cholesterol. Supersaturation of cholesterol relative to bile acids and phospholipids promotes crystal formation.
3.2 Gallstone Formation¶
Cholesterol stones form via nucleation, growth, and retention. Pigment stones result from bilirubin metabolism disorders, such as hemolysis or infection.
4. CLINICAL FEATURES¶
Symptoms include biliary colic, right upper quadrant pain, jaundice, and pruritus. Complications like acute cholecystitis, cholangitis, and pancreatitis may occur. Physical exam findings include Murphy’s sign and gallbladder tenderness.
4.1 Biliary Colic¶
Sudden, severe RUQ pain radiating to the back or shoulder, lasting 30 min–5 h. Often triggered by fatty meals. May resolve spontaneously.
4.2 Acute Cholecystitis¶
Progressive RUQ pain, fever, leukocytosis, and peritoneal signs. Murphy’s sign is positive. May progress to perforation or gangrene.
5. DIFFERENTIAL DIAGNOSIS¶
Conditions mimicking gallbladder disease include peptic ulcer disease, pancreatitis, hepatitis, and biliary tract infections. Acalculous cholecystitis and Mirizzi’s syndrome must be considered in patients without stones.
5.1 Non-Gallbladder Causes¶
Peptic ulcer disease, pancreatitis, hepatitis, and mesenteric ischemia can present with similar symptoms. Imaging and lab tests help differentiate.
5.2 Acalculous Cholecystitis¶
Occurs in patients without stones, often due to prolonged fasting, trauma, or sepsis. Diagnosed via imaging and exclusion of stones.
6. INVESTIGATIONS & DIAGNOSIS¶
Imaging (ultrasound, MRCP, ERCP) and lab tests (bilirubin, alkaline phosphatase) are essential. Cholescintigraphy assesses gallbladder function. Endoscopic retrograde cholangiopancreatography (ERCP) is used for stone extraction and diagnosis.
6.1 Imaging Modalities¶
Ultrasound is first-line for detecting stones. MRCP and ERCP provide detailed biliary tree visualization. CT is used for complications like abscesses.
6.2 Laboratory Tests¶
Elevated bilirubin, alkaline phosphatase, and amylase/lipase suggest obstruction or pancreatitis. Liver function tests guide management.
7. MANAGEMENT & TREATMENT¶
Asymptomatic gallstones may be observed. Symptomatic cases require cholecystectomy (laparoscopic preferred). Medical therapies like UDCA may dissolve small stones. Complications like cholangitis or pancreatitis require urgent intervention.
Table 357-3: Diagnostic Evaluation of the Bile Ducts¶
| Test | Advantages | Limitations | Comments |
|---|---|---|---|
| Ultrasound | Rapid, detects dilated ducts | Bowel gas, ascites | Initial procedure of choice |
| CT | Detects masses, abscesses | Radiation exposure | Useful for complications |
| MRCP | Noninvasive, excellent sensitivity | Claustrophobia | First choice for choledocholithiasis |
| ERCP | Best visualization, therapeutic | Acute pancreatitis risk | Preferred for stone extraction |
| PTC | Drains obstructed ducts | Bleeding risk | Used when ERCP fails |
7.1 Surgical Options¶
Laparoscopic cholecystectomy is the gold standard. Open surgery is reserved for complex cases. ERCP is used for stone removal and biliary drainage.
7.2 Medical Therapy¶
UDCA may dissolve small cholesterol stones. Antispasmodics and antacids manage symptoms. Antibiotics treat cholangitis or sepsis.
8. PROGNOSIS & COMPLICATIONS¶
Most patients with gallstones have a favorable prognosis after cholecystectomy. Complications include cholangitis, pancreatitis, and secondary biliary cirrhosis. Mortality from acute cholecystitis is ~1–3% in centers with timely intervention.
8.1 Complications¶
Acute cholangitis, pancreatitis, and gallstone ileus are serious complications. Secondary biliary cirrhosis may develop from prolonged obstruction.
8.2 Long-Term Outcomes¶
Postcholecystectomy syndrome may occur in 5–10% of patients, with symptoms like diarrhea or dyspepsia. Regular follow-up is needed for patients with underlying conditions.
9. SPECIAL CONSIDERATIONS¶
Pregnancy increases gallstone risk due to hormonal changes. Elderly patients may have atypical presentations. Inflammatory bowel disease (IBD) is strongly associated with primary sclerosing cholangitis (PSC).
9.1 Pregnancy¶
Gallstone risk increases due to estrogen effects. Asymptomatic stones are often managed conservatively. Cholecystectomy is delayed until postpartum.
9.2 IBD and PSC¶
PSC is strongly linked to ulcerative colitis. Patients require regular monitoring for cholangiocarcinoma. ERCP and MRCP are used for diagnosis.
10. KEY POINTS & CLINICAL PEARLS¶
- Cholesterol stones are the most common, driven by bile supersaturation and gallbladder hypomotility. - Ultrasound is the first-line diagnostic tool for gallstones. - Laparoscopic cholecystectomy is the treatment of choice for symptomatic gallstones. - Acute cholecystitis requires prompt surgical intervention to prevent complications. - PSC is associated with IBD and requires long-term monitoring for malignancy.