CHOLECYSTITIS IN PREGNANCY lase, lipase, and alkaline phosphatase may be of some assistance in identifying pancreatic involve- ment. 17 RADIOGRAPHIC EVALUATION Ultrasound has revolutionized the accuracy and safety of diagnosing biliary tract disease. It has all but replaced oral cholecystography and intravenous cholangiography as the standard for diagnosis of gallbladder disease. Ultrasonography, as a rule though, provides no direct evidence of acute cho- lecystitis. Conversely, intravenous cholecystogra- phy gives a more functional diagnostic view of cho- lecystitis by directly revealing blockage of the cys- tic duct and biliary stasis. Additional sonographic findings may aid in dif- ferentiating cholelithiasis from acute eholecystitis. These include gallbladder wall thickening, gall- bladder distention, and tenderness upon deforma- tion of the gallbladder with the ultrasound trans- ducer (sonographic Murphy’s sign). However, none of these findings is an absolute indicator of acute cholecystitis. In fact, when reviewing the literature, several studies both support and refute the use of gallbladder wall thickening and sonographic Mur- phy’s sign to differentiate biliary colic from acute calculous or acalculos cholecystitis, s’lg,z In other words, ultrasound is imperfect in dem- onstrating biliary stones impacted in the cystic duct and this, unfortunately, is the cardinal sign of acute cholecystitis, e Nevertheless, ultrasound has no known medical contraindications or adverse side effects and should be used as the first line of diag- nostic study. One study reported a 96% sensitivity and 88% specificity for ultrasound in the diagnosis of cholecystitis when combined with all of the clinical criteria previously described, e The overall accuracy of ultrasound in diagnosing acute chole- cystitis is 93%. The same study cited above re- ported an overall accuracy of intravenous cholecys- tography as 88%; however, this was felt to be due to impaired hepatic excretion of contrast medium. Finally, the use of intravenous contrast media always runs the risk of hypersensitivity reactions. It is, therefore, reasonable to conclude that ultra- sound is accurate, safe, and the most practical method for diagnosing acute cholecystitis in preg- nancy. 306 INFECTIOUS DISEASES IN OBSTETRICS AND GYNECOLOGY CASEY AND COX TREATMENT Medical Management The primary issue in the management of acute cholecystitis is when to intervene surgically. Initial medical therapy is appropriate in all patients with biliary tract disease, however, clinicians should not procrastinate when surgery is indicated. Medical therapy includes eliminating oral intake, nasogas- tric suction, correction of electrolyte abnormalities, and analgesia. Morphine analgesia and its deriva- tives should be avoided, as they may cause spasm of the sphincter of Oddi. This spasm may exacer- bate an already painful condition. Finally, intrave- nous antibiotic therapy is usually indicated in pa- tients with suspected acute cholccystitis, even though superinfection of the bile/gallbladder may not occur until the latter stages of disease. The combination of a penicillin and an aminoglycoside has long been recommended as the initial treatment of choice for patients with infec- tions of the biliary tract. This initial antibiotic therapy is empirically based on the bacterial flora likely to bc encountered in the biliary tract. Aminoglycosides are used to treat gram-negative facultativc biliary pathogens including pseudomo- nas. Penicillins offer adequate gram-positive cov- erage. Specifically, ampicillin will cover most an- aerobes and enterococcus species. Therefore, their combination would empirically provide good anti- biotic coverage in patients with evidence of acute cholecystitis. Concern about aminoglycosidc-induced nephro- toxicity in patients with jaundice and sepsis coupled with the development of newer, more ef- fective cephalosporins has challenged penicillin plus aminoglycoside use as the preferred treatment in acute cholccystitis. Specifically, improved cov- erage against Bacteroides sp. by some second and third generation cephalosporins has led to their in- creased use in both prophylaxis and treatment re- gimes. In one study, cefepime, a third generation cephalosporin, was compared to mezlocillin and gentamicin therapy in patients with acute chole- cystitis undergoing cholecystectomy. The results indicated that single drug therapy with cefepimc was as effective as combination therapy with mcz- locillin and gentamicin, el Cefepime, like many later generation cephalosporins, requires 12 h dos- ing and can achieve high bile, blood, and gallblad-