3.1 Congenital Anomalies

Congenital abnormalities of the gallbladder and biliary system result from embryonic maldevelopment and are most interesting for the surgeon attempting to identify biliary anatomy at cholecystectomy. Agenesis of the gallbladder is rare. Curiously, it is associated with common duct stones.

3.2.1 ACUTE ACALCULOUS CHOLECYSTITIS

Inflammation of the gallbladder can occur in the absence of gallstones. Though uncommon in adults, acute acalculous cholecystitis may appear associated with AIDS, pregnancy, trauma, burns, sepsis or following major surgery. In young children, acute cholecystitis frequently occurs without gallstones and follows a febrile illness, although no definite infectious agent is identified. Biliary stagnation sometimes accompanied by sludge appears to be a factor. Impaired blood flow to the gallbladder, coagulation factors and prostaglandin may also have roles. Cytomegalovirus or Cryptosporidia can cause gangrenous cholecystitis in AIDS.

Clinical presentation is identical to that of acute cholecystitis, with pain, fever and abdominal tenderness in the right upper quadrant. These features are often obscured by the patient's underlying critical condition. Diagnosis is then revealed at laparotomy, but sometimes can be determined preoperatively by nonvisualization of the gallbladder on cholescintigraphy (although nonvisualization is less sensitive here because of the prolonged fast many are on) or by ultrasonographic evidence of a thickened gallbladder wall. Perforation, gangrene and empyema are all too frequent complications. The best treatment is prompt cholecystectomy. Prevention is possible in some patients on complete TPN (no oral intake) following major surgery, trauma or burns. Daily injections of cholecystokinin (CCK) can prevent sludge formation and its complication, cholecystitis.

Recurrent biliary-type pain in the absence of gallstones has been associated with rather modest inflammation. The basis is presumed to be a motility disorder, impaired gallbladder evacuation; hence the alternative term "biliary dyskinesia." Relief can follow cholecystectomy. Difficulties arise in attempting to make this diagnosis: the symptoms are often not clear-cut (sometimes having features of the irritable bowel syndrome or nonulcer dyspepsia), and there are no gallstones to detect. Abnormal gallbladder evacuation in response to CCK may be evident on cholescintigraphy. Sensitivity and specificity of these tests remain unclear. CCK infusion alone can reproduce the biliary pain, but the value of this provocative test is uncertain. The entity remains poorly defined. In some, the origin of the problem is dysfunction of the sphincter of Oddi. In many, it may represent one facet of the irritable bowel syndrome.

Cholesterolosis consists of deposits of cholesterol esters and triglycerides within the gallbladder wall. These submucosal deposits produce a fine yellow reticular pattern on a red background of mildly inflamed mucosa, providing an appearance like a strawberry: hence the term "strawberry gallbladder." Some of the cholesterol deposits protrude like polyps and can be detected on ultrasound. There is no well-defined symptom complex linked to this entity. Although frequently an incidental finding at post mortem, it is sometimes associated with vague dyspeptic complaints, the irritable bowel syndrome or recurrent right upper quadrant abdominal pain. The importance of CCK provocative tests to reproduce the pain or demonstrate reduced gallbladder emptying on quantitative cholescintigraphy in response to CCK is unclear.

Adenomyosis is characterized by hyperplasia of the gallbladder mucosa and by deep clefts. The meaning of any biliary-type symptoms is moot.

Cholecystectomy relieves the symptoms of most, but definitely not all, patients with biliary calculi. The occasional patient will experience diarrhea following cholecystectomy, perhaps the result of unmasking a malabsorption of bile acids, which leads to a cholerrheic (bile acid-induced) diarrhea. Symptoms persist or recur in 5-50%, depending upon selection bias. Most often the original complaint was not true biliary pain, but rather reflux esophagitis, peptic ulcer disease or the irritable bowel syndrome. There may be recurrent biliary tract problems such as a biliary stricture, retained common duct stone or even pancreatic disease. In suspected cases, ERCP is indicated. Occasionally, narrowing (papillary stenosis) or increased tone in the sphincter of Oddi (sphincter dysfunction) will produce recurrent biliary-type pain, often with abnormal liver biochemistry tests or increased serum amylase. Nuclear medicine scanning (cholescintigraphy) and sphincter of Oddi pressure measurements (manometry) provide diagnostic clues. Endoscopic sphincterotomy relieves pain in selected patients.

Carcinoma of the gallbladder is fortunately uncommon, as its prognosis is extremely poor. Adenocarcinoma is generally cured only when incidentally discovered at cholecystectomy for cholelithiasis. Gallstones are present in most (75%) cases, probably as innocent bystanders rather than as causal agents (Figure 2). Any risk is too low to advocate prophylactic cholecystectomy in the many people with asymptomatic gallstones. A porcelain gallbladder with calcifications in the wall predisposes to adenocarcinoma and calls for cholecystectomy. Large gallstones (>3 cm) are also a risk factor for carcinoma.

The clinical features of gallbladder carcinoma consist of pain, a hard mass in the right epigastrium, jaundice, pruritus and weight loss. Ultrasound and CT scan help define the mass and metastases. Prognosis is grim, as it is common for the cancer to spread. The five-year survival is less than 5%. Therapy is palliative; most are not resectable unless removed incidentally at the time of cholecystectomy.

Benign tumors of the gallbladder are uncommon. Adenomas are asymptomatic, being detected on ultrasound or found incidentally at surgery. Small masses in the wall of the gallbladder, however, are relatively common findings on ultrasound; when multiple they usually represent cholesterol polyps or adherent gallstones. Polypoidal masses warrant a repeat ultrasound in six months. If these are larger than 1 cm, surgery is necessary to exclude a carcinoma.