Laparoscopic Cholecystectomy in Pregnancy: A Video Case

Saad Shebrain, MD, MBBch; Elizabeth A. Steensma, MD; Dwight Slater, MD

Disclosures

April 21, 2011

Testing for Gallbladder Disease During Pregnancy

Ultrasonography remains the preferred initial imaging study in the evaluation of the pregnant woman presenting with acute abdomen, because it does not expose the fetus to ionizing radiation. Ultrasound is a safe, noninvasive, rapid, relatively inexpensive, and versatile tool that is readily available.[16] However, it is operator dependent.

The presence of cholelithiasis with a positive sonographic Murphy sign has a positive predictive value of 92% for the diagnosis of acute cholecystitis.[17] Ultrasonography has 90%-95% sensitivity and 78%-80% specificity for cholecystitis. It is approximately 95% sensitive in the detection of gallstones larger than 2 mm. Other findings include gallbladder distension (> 5-cm diameter), gallbladder wall thickening (> 3 mm), pericholecystic fluid, and sludge in the gallbladder.[17]

Because gallstones are best visualized in a distended, bile-filled gallbladder, ultrasonography should be performed following a fast of at least 6-8 hours.

Hepatobiliary Scintigraphy: HIDA Scan

The HIDA scan is a principal test, in addition to ultrasound, for diagnosing acute cholecystitis. This nuclear study evaluates the physiologic function of the gallbladder by assessing the ability of the gallbladder to fill and empty, thereby identifying obstruction of the biliary system. Overall, the HIDA scan has a 95% accuracy rate in diagnosing acute cholecystitis when nonfilling is identified. The reported sensitivities and specificities of HIDA scan study are in the range of 90%-100% and 85%-95%, respectively.

Normally, in a healthy person, the gallbladder, common bile duct, and small bowel fill with radiotracer within 30-45 minutes of initiating the exam. In the case of acute cholecystitis, the gallbladder will not be visualized because functional obstruction of the cystic duct prevents filling. The addition of morphine can reduce the number of false-positive results by increasing tone and resistance to bile flow through the sphincter of Oddi, resulting in filling of the gallbladder if the cystic duct is patent. In the pregnant patient, doses of the required injected radionucleotide are generally within the range of acceptable fetal exposure. However, consultation with the nuclear radiologist should be undertaken to assure correct dosing and minimal exposure.

CT and MRI Scan

Although infrequently studied in pregnant women, CT is a sensitive diagnostic modality when evaluating an acute abdomen during pregnancy. Some studies have shown that limited helical scanning reduces radiation exposure to approximately 300 milliradian (mrad) absorbed dose, which is well below the safe level of fetal exposure (5 rad).[18] The sensitivity and specificity of CT and MRI scan for predicting acute cholecystitis have been reported to be greater than 95%.[19] Findings suggestive of cholecystitis include wall thickening (> 4 mm), pericholecystic fluid, subserosal edema (in the absence of ascites), intramural gas, and sloughed mucosa. CT and MRI scan are also useful in excluding other intra-abdominal pathologies if the diagnosis is uncertain.

ERCP

Generally, ERCP has the dual advantage of being both a diagnostic and a therapeutic maneuver. It allows the practitioner to visualize the anatomy of the biliary system, remove stones from the common bile duct, and perform a sphincterotomy. In a study of a nonpregnant population, Sahai and colleagues found that ERCP was preferred over endoscopic ultrasound and intraoperative cholangiography for patients who were undergoing laparoscopic cholecystectomy and who were at high risk for common duct stones.[20] However, ERCP has some disadvantages, which include being an invasive procedure that requires a skilled operator, having a high cost of operation, and carrying a risk for complications. The reported rates of complications from endoscopic biliary interventions range from 7%-16%. The complications consist mainly of post-ERCP pancreatitis, preterm labor, and post-sphincterotomy bleeding.[21,22,23,24,25] For this reason, ERCP should be used cautiously when the potential benefits are determined to outweigh associated risks.

Possible indications for ERCP include abnormal liver function tests indicating an obstructive process such as choledocholithiasis, or the patient with picture of cholangitis. Magnetic resonance cholangiopancreatography may be a viable alternative to aid in the diagnosis of choledocholithiasis; however, it has not been studied in the pregnant population.

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