13/02/2022
Cholelithiasis:
Cholelithiasis or gallstones are hardened deposits of digestive fluid that can form in your gallbladder. The gallbladder is a small organ located just beneath the liver. The gallbladder holds a digestive fluid known as bile that is released into your small intestine. 6% of men and 9% of women have gallstones, most of which are asymptomatic. In patients with asymptomatic gallstones discovered incidentally, the likelihood of developing symptoms or complications is 1% to 2% per year. Asymptomatic gallbladder stones found in a normal gallbladder and normal biliary tree do not need treatment unless they develop symptoms. However, approximately 20% of these asymptomatic gallstones will develop symptoms over 15 years of follow-up. These gallstones may go on further to develop complications such as cholecystitis, cholangitis, choledocholithiasis, gallstone pancreatitis, and rarely cholangiocarcinoma.
Causes:
There are three main pathways in the formation of gallstones:
1. Cholesterol super saturation
2. Excess bilirubin production
3. Gallbladder hypo motility or impaired contractility
Ninety percent of gallstones are cholesterol gallstones.
Symptoms & Complications:
Symptoms and complications of cholelithiasis result when stones obstruct the cystic duct, bile ducts or both. Temporary obstruction of the cystic duct (as when a stone lodges in cystic duct before the duct dilates and the stone returns to gallbladder) results in biliary pain but is usually short-lived. This is known as cholelithiasis. More persistent obstruction of cystic duct (as when a large stone gets permanently lodged in the neck of the gallbladder) can lead to acute cholecystitis. Sometimes a gallstone may get pass through the cystic duct and get lodged and impacted the common bile duct, and causes obstruction and jaundice. This complication is known as choledocholithiasis. If gallstones pass through the cystic duct, common bile duct and get dislodged at the ampulla of the distal portion of the bile duct, acute gallstone pancreatitis may result from backing up of fluid and increase pressure in pancreatic ducts and in situ activation of pancreatic enzymes. Occasionally, large gallstones do perforate the gallbladder wall and create a fistula between the gallbladder and small or large bowel, producing bowel obstruction or ileus. Patients with gallstone disease typically present with symptoms of biliary colic (intermittent episodes of constant, sharp, right upper quadrant (RUQ) abdominal pain often associated with nausea and vomiting), normal physical examination findings, and normal laboratory test results. It may be accompanied by diaphoresis, nausea, and vomiting. Biliary colic is usually caused by the gallbladder contracting in response to some form of stimulation, forcing a stone through the gallbladder into the cystic duct opening, leading to increased gallbladder wall tension and pressure which often result in pain known as biliary colic. As the gallbladder relaxes, the stones often fall back into the gallbladder, and the pain subsides within 30 to 90 minutes. Fatty meals are a common trigger for gallbladder contraction. The pain usually starts within an hour after a fatty meal and is often described as intense and dull, and may last from 1 to 5 hours. However, an association with meals is not universal, and in a significant proportion of patients, the pain is nocturnal. The frequency of recurrent episodes is variable, though most patients do not have symptoms on a daily basis. When fever, persistent tachycardia, hypotension, or jaundice are present, it requires a search for complications of cholelithiasis, including cholecystitis, cholangitis, pancreatitis, or other systemic causes. Choledocholithiasis is a complication of gallstones when stones obstruct the common bile duct it impedes the flow of bile from the liver to the intestine. Pressure rises resulting in elevation of liver enzymes and jaundice. Cholangitis is triggered by the colonization of bacteria and overgrowth in static bile above an obstructing common duct stone. This produces purulent inflammation of the liver and biliary tree. Charcot’s triad consists of severe RUQ tenderness with fever and jaundice and is classic for cholangitis. Surgical removal of the stone obstruction with intravenous antibiotics is required to treat this condition.
Evaluation & Diagnosis:
Initial labs to evaluate gallstones often include CBC, CMP, PT/PTT, lipase, amylase, Alkaline Phosphate, total bilirubin, urine a**lysis.
Ultrasound remains the first line and best imaging modality to diagnose gallstones. A systematic review estimated that the sensitivity was 84% and specificity was 99%, better than other modalities.
CT imaging of the abdomen does not add to increased sensitivity or specificity for diagnosing gallstones or cholecystitis. It can be helpful in determining if CBD dilatation is present, and can detect pancreatic inflammation or complications (masses, pseudo-cysts, necrotizing features).
Additionally, tests such as endoscopic or magnetic retrograde cholangiopancreatography (ERCP/MRCP) are sometimes useful when working up patients with jaundice and dilated CBD or suspected cholangitis, but are usually obtained after an ultrasound. ERCP is an invasive test, requiring the use of contrast dye but also has the advantage of allowing intervention if pathology is found (e.g., stenting, stone extraction, and biopsy). MRCP, on the other hand, is non-invasive and does not require contrast dye.
Treatment / Management:
Asymptomatic gallstones require the patient to be counselled regarding symptoms of biliary colic and when to seek medical attention.
Patients with symptoms and workup consistent with acute cholecystitis will require admission to hospital, surgical consult and intravenous antibiotics. Patients with choledocholithiasis or gallstone pancreatitis will also require admission to hospital, gastrointestinal (GI) consultation and ERCP or MRCP. Patients with acute ascending cholangitis are usually ill-appearing and septic. They often also require aggressive resuscitation and ICU-level care in addition to surgical intervention to drain an infection in the biliary tract. For those who are symptomatic, referral to a surgeon is recommended. Today, the standard of care is laparoscopic cholecystectomy which is performed as a day care procedure. Some patients with gallstones may develop bile duct stones or cholangitis and need admission additional treatment.
Courtesy NCBI
