Biliary Colic

Etiology

Gallstones are formed within the gallbladder and may be composed of either cholesterol or bilirubin. These stones may stay in the gallbladder and remain asymptomatic or may enter the cystic duct or common bile duct where they may become lodged and cause pain when the gallbladder contracts. The pain typically arises after fatty meals, when the gallbladder contracts to release bile into the duodenum to aid in digestion by emulsifying fats. Stones commonly exist within the gallbladder without symptoms, referred to as asymptomatic cholelithiasis. Asymptomatic cholelithiasis typically requires no medical or surgical treatment and may be managed expectantly and does not require further follow up. However, if pain, nausea, or vomiting do present, most commonly as right upper quadrant (RUQ) abdominal pain, the patient may be diagnosed with symptomatic cholelithiasis and will require surgical evaluation.[3][4] If the pain resolves on its own, typically by the stone either passing through the common bile duct and into the duodenum or by falling back into the gallbladder after obstructing the cystic duct, then it is termed biliary colic.

Epidemiology

It is estimated that somewhere between 10% to 20% of adults have gallstones, of which 1% to 3% of patients are symptomatic. In the United States, approximately 500,000 people require cholecystectomy due to all types of biliary disease. Biliary colic has a female predominance due to the influence of estrogen on the formation of gallstones. Obesity and elevated cholesterol are also strongly correlated to biliary colic and gallbladder disease because in the United States most gallstones are cholesterol-based.[5][6] In the developing world, the so-called pigmented stones derived from bilirubin are more common and are associated with hematologic disorders as well as biliary tree infections. Any type of stone may cause biliary colic, potentially progressing to cholecystitis or cholangitis, if it obstructs the cystic duct or the common bile duct.

Pathophysiology

Gallstones are formed in the gallbladder and can be composed of cholesterol or bilirubin. Fatty meals cause the release of cholecystokinin (CCK) from the duodenum, which subsequently causes contraction of the gallbladder. This contraction can expel stones from the gallbladder into the cystic duct or common bile duct. Less commonly, stones may also be formed within the common bile duct (CBD) and are referred to as primary CBD stones. These stones irritate the lining of the ducts, causing pain, which notably is present during times of gallbladder and duct contraction.[7][8] The stones may also become impacted in the cystic duct or common bile duct, with pain resulting when the gallbladder contracts against the obstruction.

History and Physical

Patients typically present with postprandial pain that "comes and goes," hence the term colic. The pain is usually in the RUQ of the abdomen and may have radiation into the back. With uncomplicated biliary colic, patients will likely present only with pain. However, some may also report nausea and/or vomiting. These symptoms are accentuated after meals.

Biliary colic patients are afebrile and will commonly have no abnormal vitals in contrast to acute cholecystitis or cholangitis, which may present with fevers, tachycardia, or even hypotension if they progress to septic shock.

Patients with biliary colic will generally only have right upper quadrant (RUQ) or epigastric tenderness on physical exam. Abdominal distension and rebound tenderness are less common. Jaundice is not seen with blockage of the cystic duct; however, it is common with blockage of the common bile duct due to an elevation of direct bilirubin. This finding would suggest a more serious obstruction of the biliary tree and should raise suspicion for potential cholangitis rather than biliary colic.

Risk factors to ascertain for biliary colic:

• Elderly patient
• Pregnancy
• North European descent
• Recent weight loss
• Obesity
• Liver transplant

Evaluation

Laboratory tests to be ordered include a complete blood count (CBC) and a metabolic panel with liver function tests. It is important to have these tests to rule out more serious gallbladder pathology such as acute cholecystitis or cholangitis. With an elevated white blood cell (WBC) count, the suspicion of acute cholecystitis or cholangitis rises. Elevated liver enzymes such as direct bilirubin, AST, ALT, ALP, and GGT suggest a stone or blockage in the common bile duct. Stones within the gallbladder or cystic duct typically do not produce any laboratory abnormalities unless it has progressed from biliary colic to cholecystitis in which case leukocytosis may be seen.[2][9]

RUQ abdominal ultrasound is the first radiologic test to evaluate suspected biliary pathology. HIDA scans are useful in evaluating acute or chronic cholecystitis and biliary dyskinesia. Abdominal CT is less sensitive than ultrasound at evaluating stones within the gallbladder. However, CT scans are a common modality used by emergency room physicians for nonspecific severe abdominal pain, which may find gallstones present. MRCP may be used for better visualization of the biliary tree, especially when evaluating for choledocholithiasis. Endoscopic retrograde cholangiopancreatography (ERCP) can be used to evaluate for common bile duct stones if all other imaging is equivocal. ERCP is also a therapeutic intervention for choledocholithiasis.

Classic findings on RUQ ultrasound for biliary colic include stones (size may vary) or stone shadow. Findings of pericholecystic fluid, thickened wall (greater than 0.4 cm), and distended gallbladder are more indicative of acute cholecystitis.

Treatment / Management

Management of biliary colic is primarily surgical. Medical management of biliary colic involves strict maintenance of a low-fat diet and supportive management with antiemetics and pain control, however since patients typically have multiple stones the risk for recurrence of their biliary colic is high. There is no role for antibiotics in biliary colic as there is no infectious etiology, such as in acute cholecystitis or cholangitis. Oral ursodeoxycholic acid has also been used to help dissolve gallstones. Surgical intervention with laparoscopic cholecystectomy remains the gold standard. In patients who are poor surgical candidates, extracorporeal shockwave lithotripsy may be considered, but there is a considerable chance of stone recurrence. Open cholecystectomy is a less common approach, used in patients who are not candidates for laparoscopic surgery.[10][11](B2)

Endoscopic retrograde cholangiopancreatography (ERCP) is both diagnostic and therapeutic for common bile duct stones. Sphincterotomy of the ampulla of Vater can assist in removing stones after ERCP and prevent future stones from becoming lodged in the common bile duct.

Patients with biliary colic do not necessarily require hospital admission. They may be treated symptomatically with a low-fat diet, pain control, and anti-emetics, and follow up for a laparoscopic cholecystectomy as an outpatient within a reasonable time-frame. However, if the patient has severe or intractable abdominal pain, hospital admission, and more urgent surgical management are warranted for symptomatic relief. Other considerations for possible admission include large gallstones. Stones greater than 1 cm in size have a greater propensity to obstruct the cystic duct and may predispose to acute cholecystitis, so they should be treated with surgical management more urgently. If the patient is unable to tolerate anything by mouth (even liquid), admission should be considered.

Differential Diagnosis

• Hepatitis
• Cholangitis
• Mesenteric ischemia
• Pancreatitis
• Renal calculi
• Viral or bacterial gastroenteritis
• Biliary dyskinesia

Complications

• Pancreatitis
• Cholangitis
• Gallbladder perforation