1. What is cholecystitis?

• Cholecystitis is inflammation of the gallbladder. It can present in three primary forms:
  • Acute Calculous Cholecystitis: Caused by gallstones obstructing the cystic duct.
  • Acute Acalculous Cholecystitis: Inflammation without gallstones, often seen in critically ill patients.
  • Chronic Cholecystitis: Recurrent inflammation leading to fibrosis and thickening of the gallbladder wall.

2. Why does cholecystitis happen?

• Primary causes:
  • Obstruction of the cystic duct, typically by gallstones or sludge.
  • Stasis of bile leading to infection by gut bacteria.
  • Increased intraluminal pressure causing ischemia and inflammation.
• Predisposing factors:
  • Female gender, obesity, pregnancy, or rapid weight loss.
  • Chronic illnesses like diabetes.
  • Critical illness leading to biliary stasis (acalculous type).

3. What are the pathophysiological mechanisms?

• Obstruction leads to bile stasis and superimposed infection.
• Pressure buildup reduces gallbladder perfusion, causing mucosal ischemia.
• Chronic inflammation weakens the mucosa, increasing susceptibility to further injury.

4. How is cholecystitis diagnosed?

• History:
  • Symptoms include persistent right upper quadrant (RUQ) pain, nausea, vomiting, and anorexia.
• Physical Exam:
  • Fever, RUQ tenderness, and positive Murphy's Sign (arrest of inspiration upon RUQ palpation).
• Laboratory findings:
  • Elevated white blood cell (WBC) count and C-reactive protein (CRP).
  • Liver function tests (LFTs) may show mild elevations in bilirubin and alkaline phosphatase.
• Imaging:
  • Ultrasound: First-line tool, showing gallstones, gallbladder wall thickening (>3 mm), and pericholecystic fluid.
  • HIDA Scan: Used when ultrasound is inconclusive, assessing cystic duct obstruction.

5. What is Murphy’s Sign?

• Definition: Pain and cessation of deep inspiration when palpating the RUQ under the costal margin.
• Historical Context: Described by Dr. John Benjamin Murphy, a 19th-century American surgeon renowned for innovations in general surgery.

6. What laboratory tests are important in acute cholecystitis?

• Key labs:
  • Complete blood count (CBC): Elevated WBC.
  • CRP: Inflammatory marker often elevated.
  • LFTs: May show mild abnormalities if bile duct involvement is suspected.

7. What imaging studies are crucial?

• Ultrasound:
  • High sensitivity for gallstones.
  • Detects gallbladder wall thickening, pericholecystic fluid, and a sonographic Murphy’s sign.
• HIDA Scan:
  • Used to confirm cystic duct obstruction.
  • Sensitivity and specificity are higher when ultrasound is inconclusive.

8. What are the treatment options?

• Acute Cholecystitis:
  • Medical Management:
    • NPO (nothing by mouth), IV fluids, and antibiotics.
    • Pain control with NSAIDs or opioids as needed.
  • Surgical Management:
    • Cholecystectomy (laparoscopic preferred) within 72 hours for most cases.
• Acalculous Cholecystitis:
  • Percutaneous cholecystostomy in critically ill or unstable patients.
• Chronic Cholecystitis:
  • Elective cholecystectomy after symptom optimization.

What is the first-line imaging modality for acute cholecystitis?

• Ultrasound is the preferred initial imaging technique for diagnosing acute cholecystitis.
• Advantages:
  • Widely available.
  • Non-invasive and radiation-free.
  • Cost-effective.

What are the key ultrasound findings in acute cholecystitis?

• Gallbladder wall thickening > 3 mm.
• Wall edema: Seen as a double-layer or "railroad track" appearance.
• Gallbladder distension: Diameter > 4 cm.
• Positive sonographic Murphy's sign: Pain elicited when the probe is pressed on the RUQ over the gallbladder during inspiration.
• Pericholecystic fluid: Fluid collection around the gallbladder, also referred to as the "C-sign."

What are the limitations of ultrasound?

• Operator-dependent results, requiring proper imaging technique.
• May be limited in patients with obesity or excessive bowel gas.

What is the next imaging modality if ultrasound findings are inconclusive?

• HIDA Scan (Hepatobiliary Iminodiacetic Acid Scan):
  • Uses a radiotracer (technetium-99m) to assess biliary tree function.
  • High sensitivity and specificity for acute cholecystitis.
  • Diagnostic finding: Absence of gallbladder filling within 60 minutes, indicating cystic duct obstruction.

What are the advantages of a HIDA scan?

• Confirms acute cholecystitis when ultrasound findings are equivocal.
• Provides functional assessment of the biliary system.

What are the potential uses of HIDA with adjuncts like CCK?

• Evaluates gallbladder ejection fraction.
• Can diagnose biliary dyskinesia or functional gallbladder disorders.

What critical question must be answered after diagnosing acute cholecystitis?

• Assess for associated common bile duct stones:
  • This determines whether additional procedures, such as ERCP or laparoscopic bile duct exploration, are necessary.

Why is it important to assess for common bile duct stones in acute cholecystitis?

• Associated CBD stones can complicate acute cholecystitis by causing:
  • Obstruction of bile flow.
  • Potential cholangitis or pancreatitis.
• Identifying CBD stones is crucial for planning additional interventions like ERCP or intraoperative exploration.

Can liver function tests alone diagnose CBD stones?

• No, liver blood tests (LFTs) should not be used as the sole indicator of CBD obstruction.
• Transient obstruction may resolve spontaneously, leading to unnecessary interventions.

Which lab findings suggest a higher likelihood of CBD stones?

• Alkaline Phosphatase:

  • 2× the upper limit of normal has a 97% specificity for CBD stones.

• Total Bilirubin:

  • 1.7 mg/dL: ~60% specificity.

  • 4 mg/dL: ~75% specificity.

• Gamma-glutamyl transferase (GGT):
  • Also useful, but alkaline phosphatase and bilirubin are more predictive.

What are the ultrasound findings for CBD stones?

• Best finding: Direct visualization of a stone within the common bile duct.
• Dilation of the CBD (>6 mm) may suggest stones but is not definitive without direct visualization.

What is the best method to stratify risk for CBD stones?

• SAGES Criteria:
  • High Risk:
    • Stone seen on imaging.
  • Moderate Risk:
    • Total bilirubin >4 mg/dL or CBD dilation >6 mm with bilirubin 1.8–4 mg/dL.
  • Low Risk:
    • None of the above findings.

How should the risk stratification guide management?

• High Risk:
  • Preoperative ERCP, postoperative ERCP, or laparoscopic CBD exploration.
• Moderate Risk:
  • Additional imaging (e.g., MRCP, endoscopic ultrasound, intraoperative cholangiography, or intraoperative ultrasound).
• Low Risk:
  • No further preoperative evaluation needed.

What imaging modalities help confirm CBD stones?

• MRCP: High sensitivity and specificity for detecting CBD stones.
• Endoscopic Ultrasound: Useful for detailed imaging of the biliary tree.
• Intraoperative Cholangiography or Ultrasound: Identifies stones during surgery.

What are the next steps for confirmed CBD stones?

• Management options include:
  • ERCP for stone removal, either pre- or postoperatively.
  • Laparoscopic common bile duct exploration during cholecystectomy.

What is acalculous cholecystitis?

• Acalculous cholecystitis is inflammation of the gallbladder without gallstones.
• It commonly occurs in critically ill or septic patients and is associated with high morbidity.

What are the risk factors for acalculous cholecystitis?

• Critical Illness:
  • Severe trauma or burns.
  • Shock or septic shock.
• Prolonged Fasting or Total Parenteral Nutrition:
  • Leads to gallbladder stasis.
• Systemic Infections:
  • E.g., typhoid fever.
• Other Factors:
  • Major surgeries or long-term ICU stays.

What is the pathophysiology of acalculous cholecystitis?

• Gallbladder Stasis:
  • Decreased motility and bile drainage lead to bile stasis.
• Increased Intravesical Pressure:
  • Causes mucosal ischemia similar to appendicitis.
• Superimposed Infection:
  • Secondary bacterial infection exacerbates the condition.
• Progression:
  • Can lead to necrosis, perforation, and septic shock.

How is acalculous cholecystitis diagnosed?

• Clinical Context:
  • Critically ill patient with sepsis, unexplained fever, or RUQ pain.
• Imaging:
  • Ultrasound:
    • Markedly thickened gallbladder wall (>1 cm).
    • Absence of stones.
    • Pericholecystic fluid or positive sonographic Murphy’s sign.
  • HIDA Scan:
    • Confirms diagnosis by showing lack of gallbladder filling.
  • CT Scan:
    • Can show gallbladder wall thickening and surrounding inflammation if ultrasound is inconclusive.

What are the complications of untreated acalculous cholecystitis?

• Gallbladder necrosis and perforation.
• Sepsis or septic shock.
• Peritonitis and abscess formation.

How is acalculous cholecystitis managed?

• Initial Stabilization:
  • NPO status, IV fluids, and broad-spectrum antibiotics.
• Definitive Treatment:
  • Percutaneous cholecystostomy (preferred in unstable patients).
  • Cholecystectomy (definitive, if the patient is stable).