Choledocholithiasis and Cholangitis
Choledocholithiasis is the formation or presence of stones in the bile ducts. It can cause biliary colic,biliary obstruction ,gallstone pancreatitis, or bile duct infection (cholangitis)
Diagnosis usually requires visualization by magnetic resonance cholangiopancreatography or ERP.
Early endoscopic or surgical decompression is indicated.
Primary stones (usually pigment stones) form in the bile ducts. Secondary stones (usually cholesterol) form in the gallbladder but migrate to the bile ducts.
Residual stones are those missed at the time of cholecystectomy .
Recurrent stones develop in the ducts > 3 years after surgery .In the developed countries, over 85 % of common duct stones are secondary, affected patients also have stones still located in the gallbladder.
Conversely up to 10% of patients with symptomatic gallstone have associated common duct stones.
After cholecystectomy,brown pigment stones may occur from stasis (e.g postioperative stricture) and infection.
The proportional ductal stones that are pigmented increase with time after cholecystectomy.
Bile duct stones may pass into the duodenum asymptomatically .
Biliary colic occurs if they become partially obstructed . More complete obstruction cause duct dilatation, jaundice and eventually bacterial infection (cholangitis).
Stones that obstruct the ampulla of vater can include gallstone pancreatitis. Some patients (usually the elderly) present with with biliary obstruction due to stones that have caused no symptoms previously.
In acute cholangitis – Bile duct obstruction permits bacteria to ascend from the duodenum.
Although most (85%) cases results from common duct stones,bile duct obstruction may results from tumor or other conditions.
Common infecting organisms include gram negatives (e.g Escherichia coli,Klebsiella,Enterobacter), less common are gram positive (e.g Entrococcus sp) and mixed anaerobes (e.g Bacteroides,Clostridia)
Symptoms include abdominal pain, jaundice, and fever or chills (Charcot’s triad).
The abdomen is tender and often the liver is tender and enlarged (often containing abscesses).
Confusion and hypotension predict about a 50% mortality rate and high morbidity.
Diagnosis
Common duct stones should be suspected in patients with jaundice and biliary colic. Liver function test and an imaging study should be obtained.
Elevated levels of bilirubin,alkaline phosphatase,ALT,and gamma-glutarly-transferase, consistent with extrahepatic obstruction ,are suggestive,particulary in patients with symptoms of acute cholecystitis.
Utrasound may reveal stones in the gallbladder and occasionally in the common duct. The common duct is dilated ( > 6mm in diameter if the gallbladder is intact >10mm after cholecystectomy ).
If the ducts are not dilated early in the presentation (e.g first day), then stones have probably passed.
If doubts exists,magnetic resonance cholangiopancreatography (MRCP) is highly accurate for retained stones. ERCP is performed if MRCPM is equivocal,it can be therapeutic as well as diagnostic . CT scan is less accurate that ultrasound.
For suspected acute cholangititis, CBC and blood cultures should also be obtained.
Leukocytosis is common, and aminotransferases may reach 1000IU/L,suggesting acute hepatic necrosis, often due to micro abscesses. Blood cultures guide antibacterial therapy.
Treatment
For suspected biiary obstruction, ERCP and sphincterotomy are necessary to remove the stone. Laparoscopic cholecystectomy,which is not as well suited for operative cholangiography or common duct exploration,can be undertaken electively after the ERCP and sphincterotomy. Open cholecystectomy with common duct exploration has a higher mortality and morbidity.
In patient at high risk for cholecystectomy,such as the elderly, sphinterotomy alone is an altenative.
Acute cholangititis is an emergency requiring aggressive supportive care and urgent removal of the stones endoscopically or surgically. Antibiotics are given,similar to those used for acute cholecystitis.
Altenatives in order of preference,are iipenem and ciprofloxacin,metronidazole is given to very ill patients to cover anaerobes.
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