Cholecystitis: A Comprehensive Review
Introduction
Cholecystitis is an inflammatory condition of the gallbladder that is most commonly associated with gallstone obstruction, although it may also occur in the absence of stones. The gallbladder is a small, pear-shaped organ located beneath the liver, responsible for storing and concentrating bile produced by the liver. This bile plays a crucial role in the digestion of dietary fats. When the outflow of bile from the gallbladder becomes obstructed, it can lead to distension, irritation, and eventual inflammation of the gallbladder wall. Cholecystitis is a common clinical condition globally and constitutes one of the leading causes of acute abdominal pain requiring hospital admission.
The condition may be classified as acute or chronic, and further differentiated into calculous (stone-related) and acalculous (without stones) forms. While acute cholecystitis often develops abruptly and demands prompt medical attention, chronic cholecystitis develops gradually due to ongoing irritation of the gallbladder wall, typically caused by recurrent episodes of partial or transient obstruction by gallstones.
Understanding cholecystitis requires knowledge of gallbladder physiology, biliary anatomy, risk factors, clinical presentation, and diagnostic approaches. Early recognition and management are essential to prevent complications such as gangrene, perforation, and sepsis. This article provides a detailed exploration of the etiopathogenesis, clinical features, diagnostic modalities, treatment options, and prevention strategies associated with cholecystitis.
Anatomy and Physiology of the Gallbladder
The gallbladder is located in a fossa on the inferior surface of the liver. It is divided into four main parts: the fundus, body, infundibulum, and neck. The cystic duct connects the neck of the gallbladder to the common bile duct, which then joins the pancreatic duct before emptying into the duodenum through the ampulla of Vater.
Functions of the Gallbladder
- Storage of Bile: The liver continuously produces bile, and the gallbladder stores this bile between meals.
- Concentration of Bile: Through active absorption of water and electrolytes, the gallbladder concentrates bile up to five times.
- Release of Bile: In response to ingestion of fatty foods, cholecystokinin (CCK) stimulates gallbladder contraction and the relaxation of the sphincter of Oddi, allowing bile to enter the duodenum.
When normal bile flow is disrupted, the retained bile can irritate the gallbladder mucosa and contribute to inflammation, which is the hallmark of cholecystitis.
Types of Cholecystitis
1. Acute Calculous Cholecystitis
This is the most common form, accounting for approximately 90–95% of cases. It occurs when a gallstone lodges in the cystic duct, leading to obstruction, gallbladder distension, and inflammation.
2. Acute Acalculous Cholecystitis
This form occurs without gallstones and is frequently seen in critically ill patients, such as those with sepsis, burns, major trauma, or prolonged fasting. It often has a rapid and severe course with increased risk of complications.
3. Chronic Cholecystitis
Chronic cholecystitis results from recurrent episodes of inflammation, usually secondary to repeated gallstone obstruction. The gallbladder eventually becomes fibrotic, stiffened, and dysfunctional.
Etiology and Risk Factors
Gallstones
The primary cause of cholecystitis is gallstone-induced obstruction. Gallstones are classified as:
- Cholesterol stones (most common)
- Pigment stones
- Mixed stones
Risk Factors for Gallstone Formation
- Female gender (especially during reproductive age due to estrogen effects)
- Age > 40 years
- Obesity and high-fat diet
- Rapid weight loss or fasting
- Pregnancy
- Genetic predisposition
- Diabetes mellitus
- Hemolytic disorders (for pigment stones)
- Sedentary lifestyle
Risk Factors for Acalculous Cholecystitis
- Prolonged fasting or total parenteral nutrition
- Severe trauma, burns, or shock
- Mechanical ventilation
- Stroke or prolonged immobilization
- Sepsis
- Immunosuppression
Pathophysiology
The pathogenesis of cholecystitis begins with obstruction of the cystic duct. In calculous cholecystitis, this obstruction is typically caused by gallstones. The trapped bile causes gallbladder distension and increased intraluminal pressure, impairing venous and lymphatic drainage. The reduced perfusion causes ischemia and inflammatory changes in the gallbladder wall.
Additional Pathogenic Mechanisms
- Chemical irritation from concentrated bile salts
- Bacterial infection, most commonly by E. coli, Klebsiella, Enterococcus, and Streptococcus faecalis
- Inflammatory mediator release, such as prostaglandins, worsening edema and pain
In acute acalculous cholecystitis, gallbladder stasis and ischemia are the key triggers rather than gallstones.
Clinical Presentation
Symptoms
- Right Upper Quadrant (RUQ) Pain
- Steady, severe pain lasting more than 6 hours
- Often radiates to the right shoulder or back
- Fever
- Nausea and vomiting
- Loss of appetite
- History of fatty meal ingestion before pain onset
Signs
- Murphy’s Sign
- Localized tenderness in the RUQ with inspiratory arrest when palpated.
- Guarding and rigidity in severe cases
- Jaundice (if associated with choledocholithiasis or biliary obstruction)
Complications
If untreated, cholecystitis can progress to:
| Complication | Description |
|---|---|
| Empyema | Accumulation of pus within the gallbladder |
| Gangrene | Necrosis due to prolonged ischemia |
| Gallbladder Perforation | May lead to bile peritonitis |
| Cholecystoenteric Fistula | Abnormal communication with GI tract |
| Gallstone Ileus | Obstruction of intestine due to large stone |
| Sepsis | Systemic infection |
Diagnosis
Laboratory Investigations
- CBC: Elevated WBC count with left shift
- Liver function tests: May show mild elevation
- Serum amylase/lipase: To exclude pancreatitis
- CRP and ESR: Elevated in inflammation
Imaging
- Ultrasound (US)
- First-line investigation
- Shows gallstones, gallbladder wall thickening, pericholecystic fluid
- HIDA Scan
- Highly specific for obstructed cystic duct
- CT Scan
- Useful in complications such as perforation or gangrene
- MRCP
- Non-invasive assessment of biliary tree
Management
Initial Management
- Fasting (NPO)
- IV fluids
- Pain control (NSAIDs or opioids)
- Antibiotics (broad-spectrum covering gram-negative organisms)
Definitive Management
- Cholecystectomy (gallbladder removal) is the treatment of choice.
- Laparoscopic cholecystectomy is preferred over open surgery.
Acalculous Cholecystitis Management
- Requires urgent intervention due to severity.
- Percutaneous cholecystostomy may be performed in unstable patients.
Chronic Cholecystitis Management
Chronic cholecystitis is usually managed with elective cholecystectomy, especially when symptoms are recurrent. Dietary modification (low-fat meals) may help reduce episodes temporarily but is not curative.
Prevention
- Maintaining a healthy weight
- Avoid rapid weight loss diets
- Regular physical activity
- Balanced diet with fiber and low saturated fats
- Managing underlying metabolic disorders like diabetes
Prognosis
Most patients with acute cholecystitis recover fully following timely surgical treatment. However, delays in treatment significantly increase the risk of complications.
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Conclusion
Cholecystitis is a common but potentially serious condition, primarily resulting from gallstone obstruction. Recognizing the clinical features allows for timely diagnosis and treatment. Early cholecystectomy remains the standard of care, with excellent outcomes in most patients. Preventive strategies, including dietary modification and weight control, play a key role in reducing the risk of gallstone formation and subsequent cholecystitis.
