What is the acalculous cholecystitis?

ACUTE ACALCULOUS CHOLECYSTITIS (AAC) 

acalculous cholecystitis

Acalculous cholecystitis is gallbladder inflammation without gallstones. It's less common, but usually more serious, than calculous cholecystitis. The exact cause of acalculous cholecystitis is not known, but it's usually a complication of a serious illness, infection or injury that damages the gallbladder.

What are the risk factors for acalculous cholecystitis?

- sepsis, ICU, TPN, immunosuppression.

- major trauma

- burns

- diabetes

- infections

- mechanical ventilation

- opiates

- CHD & CABG (chronic heart disease , coronary artery bypass graft).

- prolonged fasting

- childbirth

- nonbiliary surgery

- Losing or gaining weight rapidly.

- rarely seen in systemic vasculitides due to ischemic injury to gall bladder.

- Insidious presentation in already critically ill pts.

- Elderly

- Being female

- Hormone therapy 

- Obesity

 What are the signs & symptoms of acalculous cholecystitis?

¤ Clinical presentation variable, depending on predisposing conditions:

¤ RUQ pain absent in 75% of cases

¤ Fever or hyperamylasemia may be only clue.

¤ Unexplained sepsis w/- few early localizing signs.

¤ Half of patients already have experienced complication: gangrene,
perforation, abscess.

¤ RUQ pain, fever, & positive Murphy sign seen in minority.

Diagnostic Tests:

A- Laboratory:

¤ Leukocytosis w/ left shift in 70–85%

¤ Hyperamylasemia common

¤ Abnormal aminotransferases

¤ hyperbilirubinemia

¤ mild increase in serum alkaline phosphatase more common in acalculous than calculous cholecystitis.

B- Imaging

¤ Plain x-ray: exclusion of a perforated viscus, bowel ischemia, or renal stones

¤ US: absence of gallstones, thickened gallbladder wall

° (>5 mm) w/ pericholecystic fluid, failure to visualize

° gallbladder, perforation w/ abscess, emphysematous cholecystitis; sensitivity of 36–96%; high false-negative rate.

¤ CT: thickened gallbladder wall (>4 mm) in absence of ascites or hypoalbuminemia, pericholecystic fluid, intramural gas, or sloughed mucosa; superior to US w/ sensitivity of 50–100%.

¤ Radionuclide cholescintigraphy (HIDA) scan: failure to opacify gallbladder; sensitivity almost 100%; false-positive rate of up to 40% in which gallbladder not visualized in spite of nonobstructed cystic
duct seen in severe liver disease, prolonged fasting, biliary sphincterotomy, hyperbilirubinemia; important not to allow test to delay treatment in very ill pts.

The test of choice for chronic acalculous cholecystitis is a cholescintigraphy nuclear scan (HIDA) with the administration of cholecystokinin (CCK). This study examines the function of the gallbladder. After the radionuclide is administered, CCK is given to stimulate the gallbladder to empty.

What is the differential diagnosis of acalculous cholecystitis?

¤ Calculous (gallstones) cholecystitis

¤ peptic ulceration

¤ acute pancreatitis

¤ right-sided pyelonephritis

¤ hepatic or subphrenic abscess.

Management:

What is the common treatment for acalculous cholecystitis?

¤ CT: best test to exclude other pathology

¤ If suspect biliary sepsis, radionuclide study first; otherwise, CT first

General Measures:

¤ Blood cultures, IV broad-spectrum antibiotics

¤ Early recognition & intervention required due to rapid progression to gangrene & perforation.

¤ the definitive treatment of acalculous cholecystitis is cholecystectomy for patients who are able to tolerate surgery. 

¤ In selected patients with acute acalculous cholecystitis (AAC), nonsurgical treatment (such as antibiotics or percutaneous cholecystostomy) may be an effective alternative to surgery.

Specific therapy:

¤ Cholecystectomy; both open & laparoscopic

¤ If evidence of perforation, then open cholecystectomy urgently; inflammatory mass may preclude successful laparoscopy.

¤ US-guided percutaneous cholecystostomy may be first choice in critically ill pts; success rate 90%; no surgery necessary if postdrainage
cholangiogram normal; catheter usually removed 6–8 wk.

¤ Transpapillary endoscopic drainage of gallbladder may be done when pt too sick for surgery & unsuitable for percutaneous drainage(massive ascites or coagulopathy).

Which antibiotic is best for cholecystitis?

Because intestinal organisms producing β-lactamase, which are resistant to penicillins, and cefazoline, are likely to be detected, the use of penicillin/β-lactamase inhibitors, such as piperacillin/tazobactam or ampicillin/sulbactam is recommended.

complications and prognosis:

¤ <10% mortality

community-acquired cases.

¤ Up to 90% in critically ill pts.