Acute Cholecystitis

Gastroenterology (12%) Core Clinical Conditions

1B The Physician Associate is able to identify the condition as a possible diagnosis: may not have the knowledge/resources to confirm the diagnosis or to manage the condition safely, but can take measures to avoid immediate deterioration and refer appropriately.

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Definition Aetiology Pathophysiology Sign and Symptoms Investigations Management

Acute cholecystitis is a medical condition characterised by the inflammation and swelling of the gallbladder. The gallbladder is a small, pear-shaped organ located on the right side of the abdomen, below the liver. It plays an essential role in the digestion process by storing and concentrating bile until it is needed to break down fats.

Gallstone-related Acute Cholecystitis:

The most common cause of acute cholecystitis is the presence of gallstones within the gallbladder. Gallstones can block the cystic duct, which connects the gallbladder to the common bile duct. This obstruction can prevent the flow of bile, causing it to accumulate and subsequently trigger inflammation of the gallbladder walls. If the blockage remains for an extended period, it can lead to infection and even necrosis of the gallbladder tissue.

Biliary Sludge and Stasis:

In some cases, acute cholecystitis may develop due to the build-up of biliary sludge within the gallbladder. Biliary sludge is a mixture of bile components that solidify, creating a thickened substance that can obstruct the cystic duct. Sludge formation is often associated with conditions such as pregnancy, rapid weight loss, fasting, or prolonged use of total parenteral nutrition.

Stasis of bile, which refers to the slowing or insufficient drainage of bile from the gallbladder, can also contribute to the development of acute cholecystitis. Stasis can occur due to conditions like cystic duct strictures or functional disorders of the gallbladder, impairing the normal movement of bile and leading to inflammation.

Ischemic Acute Cholecystitis:

Ischemic acute cholecystitis is a less common form of the condition and occurs when there is a reduction in blood supply to the gallbladder. This can result from systemic illnesses such as sepsis, congestive heart failure, or extensive surgery. Ischemia deprives the gallbladder of oxygen and nutrients, leading to tissue damage and inflammation.

Infectious Causes:

Acute cholecystitis can also be caused by infectious agents. Bacterial infections, such as Escherichia coli or Klebsiella pneumoniae, can ascend from the bile duct or enter the gallbladder through the bloodstream. Viral infections, such as cytomegalovirus, have also been associated with acute cholecystitis, albeit less frequently.

Other Factors:

Various other factors can contribute to the development of acute cholecystitis. These include trauma to the abdomen, tumours compressing or obstructing the cystic duct, autoimmune conditions, and certain medications.

1. Gallstone Formation: The majority of acute cholecystitis cases are attributed to the presence of gallstones within the gallbladder. These stones can originate from the precipitation of cholesterol or bilirubin, or a combination of both. Conditions such as obesity, a sedentary lifestyle, and a high-fat diet increase the risk of gallstone formation. When gallstones block the cystic duct, they obstruct the normal flow of bile, leading to gallbladder distention.

2. Impaired Gallbladder Emptying: The gallbladder is responsible for storing bile and releasing it into the duodenum when required for fat digestion. Hormones such as cholecystokinin (CCK) trigger gallbladder contraction, leading to bile release. However, if the gallbladder is unable to empty efficiently due to factors like gallstones or scarring, bile stagnates within the gallbladder. Consequently, distention of the gallbladder occurs, increasing the pressure inside.

3. Ischemia and Perfusion Impairment: The obstruction of the cystic duct by gallstones leads to compromised blood supply to the gallbladder wall. Reduced blood flow leads to ischemia, depriving the tissues of oxygen and nutrients. The stagnant bile within the gallbladder creates a favourable environment for the proliferation of bacteria, leading to infection. The inflamed and distended gallbladder walls undergo necrosis, further contributing to the inflammatory response.

4. Inflammatory Response: The obstruction, ischemia, and bacterial infection trigger an immune response in the gallbladder. The immune cells, predominantly neutrophils, infiltrate the gallbladder wall to combat the infection, leading to inflammation. The release of inflammatory mediators such as interleukins and tumour necrosis factor-alpha further contributes to the local inflammatory response, causing pain, swelling, and tenderness in the right upper quadrant of the abdomen.

1. Abdominal Pain: The most common symptom of acute cholecystitis is severe pain in the upper right quadrant of the abdomen. This pain can be continuous or episodic and may radiate to the back or right shoulder. It typically worsens after eating fatty or greasy foods and can last for several hours.

2. Fever and Chills: Inflammation within the gallbladder can lead to an infection, causing the body to respond with a fever. High body temperature, accompanied by chills and sweating, may indicate the presence of acute cholecystitis.

3. Nausea and Vomiting: Many individuals with acute cholecystitis experience feelings of nausea and may have episodes of vomiting. These symptoms are often triggered by the pain and discomfort in the abdomen.

4. Tenderness and Swelling: Upon examination, tenderness and increased sensitivity can be observed over the gallbladder area. The region may also exhibit swelling and inflammation due to the ongoing inflammatory process.

5. Jaundice: In some cases, acute cholecystitis can lead to a blockage of the common bile duct, causing bile to accumulate in the bloodstream. This can result in jaundice, which is characterised by a yellowing of the skin and eyes.

6. Abdominal Distension: The inflammation and swelling of the gallbladder can lead to an enlargement of the abdominal region. This can cause a sensation of fullness, discomfort, and distension.

7. Changes in Bowel Movements: Some individuals may experience alterations in their bowel habits, such as diarrhoea or clay-coloured stools. These changes can occur due to the interruption of the normal bile flow caused by the obstruction.

Clinical Assessment:

A skilled PA will begin by gathering the patient's medical history, focusing on symptoms such as acute pain in the right upper quadrant of the abdomen, accompanied by nausea, vomiting, and fever. The presence of risk factors like obesity, female gender, and a history of gallstones aids in the diagnosis.

Lab Investigations:

1. Full Blood Count (FBC): This helps identify the presence of infection or inflammation by evaluating the white blood cell count, including the differential count.

2. Liver Function Tests (LFTs): These tests assess the level of liver enzymes, such as alanine transaminase (ALT), aspartate transaminase (AST), alkaline phosphatase (ALP), and bilirubin. Elevated levels may indicate gallbladder inflammation or the presence of common bile duct stones.

3. C-reactive Protein (CRP): An elevated CRP level suggests an ongoing inflammatory response, present in acute cholecystitis.

Imaging Studies:

1. Ultrasound (US): Ultrasonography is the primary imaging modality used in the diagnosis of acute cholecystitis. It helps visualise gallstones, thickening of the gallbladder wall (>3 mm), pericholecystic fluid collection, and sonographic Murphy's sign (pain elicited when the gallbladder is pressed during the examination).

2. Magnetic Resonance Cholangiopancreatography (MRCP): MRCP is a non-invasive imaging technique that provides excellent visualisation of the biliary system, assisting in detecting common bile duct stones, strictures, or other causes of bile duct obstruction.

3. Hepatobiliary Iminodiacetic Acid (HIDA) Scan: This nuclear medicine test evaluates the gallbladder's function, particularly its ability to fill and empty. A HIDA scan can confirm acute cholecystitis when the gallbladder fails to fill or empty properly.

4. CT Scan: In complex or atypical cases, a computed tomography (CT) scan may be ordered. CT is useful in detecting complications such as perforation, abscess formation, or peritonitis.

Medical Therapy

1. Pain Control: Acute cholecystitis can cause severe abdominal pain, which requires adequate pain management. Non-steroidal anti-inflammatory drugs (NSAIDs) or opioids can be used to provide relief. However, caution should be exercised with opioids due to their potential side effects and risk of addiction.
2. Antibiotics: Broad-spectrum antibiotics are usually prescribed to combat infection caused by the inflammation. Antibiotic choice should be based on local guidelines and should cover the common organisms associated with biliary tract infections, including gram-negative and anaerobic bacteria.

Surgical Intervention

Laparoscopic Cholecystectomy: The gold-standard treatment for acute cholecystitis is a laparoscopic cholecystectomy. It is minimally invasive, resulting in shorter hospital stays and faster recovery compared to open cholecystectomy. However, conversion to an open procedure may be required if there are technical difficulties or complications encountered during laparoscopy.

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