USMLE Guide: Cholecystitis

Introduction

Cholecystitis refers to the inflammation of the gallbladder, usually caused by the presence of gallstones obstructing the cystic duct. This condition is commonly encountered in clinical practice and understanding its pathophysiology, clinical presentation, diagnostic approach, and management is essential for medical professionals. In this guide, we will cover the key points related to cholecystitis for the United States Medical Licensing Examination (USMLE).

Pathophysiology

• Cholecystitis is primarily caused by gallstones, obstructing the cystic duct and leading to bile stasis within the gallbladder.
• Bile stasis triggers an inflammatory response, resulting in local tissue damage and subsequent inflammation.
• Inflammation can progress to infection, gangrene, or rupture if left untreated.

Clinical Presentation

• Right upper quadrant (RUQ) abdominal pain is the hallmark symptom of cholecystitis, often radiating to the right shoulder or scapula.
• Patients may experience nausea, vomiting, and low-grade fever.
• Murphy's sign, tenderness in the RUQ on inspiration, is a classic physical examination finding.

Diagnostic Approach

• Initial evaluation includes a thorough history and physical examination to assess for typical symptoms and signs.
• Laboratory tests often reveal elevated liver function tests (LFTs), such as increased alkaline phosphatase (ALP) and alanine transaminase (ALT).
• Abdominal ultrasound is the initial imaging modality of choice, demonstrating gallstones and thickening of the gallbladder wall.
• If ultrasound findings are inconclusive, a hepatobiliary iminodiacetic acid (HIDA) scan can be performed to assess gallbladder function.

Management

• conservative management includes bowel rest, intravenous fluids, pain control, and antibiotics (if infection is suspected).
• The definitive treatment for symptomatic cholecystitis is cholecystectomy, preferably performed within 72 hours of diagnosis.
• In patients with contraindications to surgery or high surgical risk, percutaneous cholecystostomy can be considered as a bridge to definitive treatment.

Complications

• If left untreated, cholecystitis can progress to serious complications, such as empyema (pus-filled gallbladder), gangrene, or perforation.
• Complications can lead to peritonitis, sepsis, and abscess formation.
• Choledocholithiasis, the presence of gallstones in the common bile duct, may result in obstructive jaundice or acute pancreatitis.

Prognosis

• With prompt diagnosis and appropriate management, the prognosis of cholecystitis is generally favorable.
• Delayed or inadequate treatment can result in severe complications and increased morbidity and mortality.

Remember to review additional resources and consult relevant guidelines for a comprehensive understanding of cholecystitis.