Gallbladder Infection (Cholecystitis)

What is cholecystitis? 

Cholecystitis refers to infection and inflammation of the gallbladder, a small, pear-shaped organ beneath the liver that stores and releases bile to help digest fats. This condition usually occurs when the flow of bile is blocked, most often by gallstones. The blockage causes bile to build up, leading to irritation, pressure, and potential infection of the gallbladder wall. If untreated, cholecystitis can result in serious complications, such as gallbladder rupture, abscess formation, or infection spreading to other parts of the body.

Cholecystitis is a common gastrointestinal emergency, and while it can affect anyone, it is more frequently seen in women, older adults, and people with obesity or rapid weight loss. 

Types of Cholecystitis 

Gallbladder inflammation doesn’t always look the same; its severity, underlying cause, and pattern of recurrence help define the specific type of cholecystitis a patient may experience.

• Acute cholecystitis — this is the sudden onset of gallbladder inflammation, typically triggered by a gallstone obstructing the cystic duct. It presents with sharp pain in the upper right abdomen, fever, nausea, and tenderness. It is the most common and urgent form and often requires hospitalisation.

• Chronic cholecystitis — this form develops over time due to repeated episodes of acute cholecystitis or persistent gallstone irritation. The gallbladder wall becomes thickened and scarred, leading to dull, recurrent pain and digestive disturbances. Chronic cholecystitis often results in reduced gallbladder function and may lead to complications like gallbladder shrinkage or infection.

• Calculous cholecystitis — this is the most frequent type, caused by gallstones (cholelithiasis) blocking the cystic duct. It can be either acute or chronic and is responsible for over 90% of all cholecystitis cases.

• Acalculous cholecystitis — unlike calculous cholecystitis, this type occurs without gallstones. It is more common in critically ill patients or those with severe trauma, sepsis, or prolonged fasting. Acalculous cholecystitis is often more difficult to diagnose and carries a higher risk of complications due to delayed recognition.

Each type of cholecystitis requires prompt and appropriate medical attention. Timely diagnosis not only helps relieve symptoms but also prevents serious complications such as infection spread, gallbladder damage, or the need for emergency surgery.

What causes cholecystitis? 

Cholecystitis most often occurs when bile cannot flow out of the gallbladder, leading to irritation, swelling, and sometimes infection. The most common cause is gallstones blocking the cystic duct, the narrow channel that connects the gallbladder to the bile duct. When bile becomes trapped, it builds up and inflames the gallbladder wall.

However, cholecystitis can also occur without gallstones. This less common form, known as acalculous cholecystitis, is typically seen in people who are critically ill or recovering from major surgery, trauma, sepsis, or burns. Reduced blood flow to the gallbladder or stagnant bile can trigger inflammation in these cases.

What are the other possible causes of gallbladder infection? 

While gallstones remain the leading cause of gallbladder infection (cholecystitis), several other factors can also trigger inflammation or infection of the gallbladder:

• Severe illness or trauma — critically ill patients, especially those recovering from major surgery, burns, or severe injury, may develop acalculous cholecystitis due to poor blood flow or bile stasis.

• Infections — bacterial infections (such as E. coli, Klebsiella, or Enterococcus) can reach the gallbladder through the bile ducts, blood, or lymphatic system. In rare cases, viral infections like hepatitis or parasitic infections can also contribute.

• Tumours — cancers of the gallbladder, pancreas, or bile ducts may compress or block bile flow, setting the stage for inflammation and infection.

• Bile duct abnormalities — congenital or acquired narrowing (strictures) of the bile ducts can interfere with drainage, increasing the risk of cholecystitis.

• Sludge or thickened bile — in people with long-term fasting, rapid weight loss, or total parenteral nutrition (TPN), bile can become overly concentrated, forming sludge that blocks the cystic duct.

• Vascular compromise — reduced blood supply to the gallbladder, often due to atherosclerosis or shock, can cause tissue damage and inflammation.

Recognising these alternative causes is important for diagnosing cholecystitis in patients without gallstones and for tailoring the appropriate treatment strategy.

What are the symptoms of cholecystitis?

Cholecystitis typically causes sudden and sharp pain in the upper right side of the abdomen, but the symptoms can vary depending on whether the condition is acute or chronic. The pain may spread to the right shoulder or back and often worsens after eating, especially fatty meals.

Common symptoms include:

• Upper right abdominal pain — often severe and persistent, lasting more than a few hours.

• Fever and chills — indicate inflammation or possible infection.

• Nausea and vomiting — common due to digestive upset and inflammation.

• Tenderness over the gallbladder area — pain increases when pressure is applied to the right upper abdomen.

• Loss of appetite — often due to discomfort after eating.

• Bloating or abdominal fullness — especially after meals.

• Jaundice (in some cases) — yellowing of the skin or eyes if a bile duct is blocked.

In chronic cholecystitis, symptoms may be milder but recurring, including intermittent pain, indigestion, and bloating. Any suspected symptoms should be promptly evaluated, as delayed treatment can lead to serious complications like gallbladder rupture or widespread infection.

Who is at risk of cholecystitis in Singapore? 

Certain individuals have a higher risk of developing cholecystitis due to lifestyle, medical conditions, or physiological changes that promote gallstone formation or impair bile flow. Key risk factors include:

• Gallstones — the primary cause of cholecystitis; people with gallstones are at significantly higher risk.

• Female sex — women, especially those who are pregnant or using hormone therapy, are more prone to gallstones.

• Age over 40 — risk increases with age, particularly in adults over 40.

• Obesity or rapid weight loss — both conditions affect bile composition and increase gallstone formation.

• Pregnancy — hormonal changes can slow bile flow and raise cholesterol levels in bile.

• High-fat or low-fibre diet — poor dietary habits contribute to gallstone development.

• Diabetes or insulin resistance — these conditions can alter bile composition and gallbladder function.

• Fasting or long-term intravenous feeding (TPN) — reduced gallbladder activity increases bile stagnation and stone risk.

• Critical illness or recent surgery — increases the risk of acalculous cholecystitis due to poor gallbladder perfusion or bile flow.

What are the complications of cholecystitis? 

If not promptly diagnosed and treated, cholecystitis can lead to serious and potentially life-threatening complications. These arise when inflammation worsens or spreads beyond the gallbladder. Key complications include:

• Gallbladder gangrene — prolonged inflammation can cut off blood supply to the gallbladder, causing tissue death (gangrene). This is more common in older adults, people with diabetes, or those with delayed treatment. It will quickly lead to rupture of the gallbladder and patients can be very ill.

• Gallbladder perforation (rupture) — a severely inflamed or necrotic gallbladder may tear, allowing bile and infection to leak into the abdominal cavity, potentially leading to peritonitis (a life-threatening infection of the abdominal lining).

• Pericholecystic abscess — pus may collect around the gallbladder, forming an abscess that can cause severe pain and systemic infection if it bursts.

• Bile duct injury or obstruction — chronic inflammation or surgical complications can lead to bile duct narrowing, blockage, or fistulation, which may result in jaundice or cholangitis (infection of the bile ducts).

• Sepsis — in cases where infection spreads to the bloodstream, it can trigger a severe systemic response requiring emergency care.

• Fistula formation — an abnormal connection may form between the gallbladder and nearby organs, such as the intestines and bile duct due to persistent inflammation or infection.

• Gallstone ileus — a rare complication where a large gallstone passes into the intestine through a fistula and causes a bowel obstruction.

Recognising cholecystitis early and initiating treatment, usually with antibiotics, hospital observation, and potentially surgery, greatly reduces the risk of these complications.

How is cholecystitis diagnosed? 

Diagnosis of cholecystitis begins with a careful assessment of symptoms, followed by a physical examination and supportive tests to confirm inflammation and rule out other conditions. Key steps include:

• Medical history and physical exam — a doctor will assess symptoms like upper abdominal pain, fever, and tenderness. A common sign is a positive Murphy’s sign, where pain increases when the upper right abdomen is pressed during inhalation.

• Blood tests — these help detect signs of inflammation or infection, including elevated white blood cell count (WBC), liver enzymes, and markers of biliary obstruction.

• Ultrasound — this is the most commonly used imaging test for diagnosing cholecystitis. It can reveal gallstones, gallbladder wall thickening, fluid around the gallbladder, and signs of bile duct obstruction.

• CT scan — may be used if ultrasound results are unclear or to detect complications like gallbladder perforation or abscess.

• HIDA scan (hepatobiliary iminodiacetic acid scan) — a nuclear medicine test that shows how well bile is flowing from the liver into the gallbladder and intestines. Failure of the gallbladder to fill with the tracer suggests cholecystitis.

• MRCP (Magnetic Resonance Cholangiopancreatography) — an advanced imaging technique that provides detailed views of the bile ducts and is useful in cases where bile duct obstruction is suspected.

Early and accurate diagnosis is essential to prevent complications and guide appropriate treatment, which may include antibiotics, pain management, or gallbladder removal.

What are the treatment options for cholecystitis in Singapore? 

Treatment for cholecystitis depends on the severity of the condition, the presence of complications, and whether the inflammation is caused by gallstones. The main goals are to control the infection, relieve symptoms, and prevent further episodes.

Hospital care and supportive treatment

Most people with acute cholecystitis require hospitalisation for close monitoring and symptom management. Initial treatment typically includes:

• Fasting (NPO) — to rest the digestive system and reduce gallbladder stimulation.

• Intravenous fluids — to maintain hydration and electrolyte balance.

• Pain relief — usually with non-steroidal anti-inflammatory drugs (NSAIDs) or opioids.

• Antibiotics — to treat or prevent infection, especially if fever or raised white cell count is present.

Surgery (Cholecystectomy)

Surgery to remove the gallbladder, known as a cholecystectomy, is the definitive treatment for most cases of cholecystitis, especially when gallstones are the cause.

• Laparoscopic cholecystectomy — the most common and preferred treatment, this minimally invasive procedure involves removing the gallbladder through small incisions. Early laparoscopic cholecystectomy within 24 to 72 hours of onset of symptoms is the most optimal treatment approach. It is safe in trained expert hands and allows quick resolution of the infection while avoiding recurrence of attacks.

• Open cholecystectomy — may be necessary if there are complications such as gangrene, perforation, or widespread infection.

In high-risk or critically ill patients, surgery may be delayed or replaced by temporary drainage.

Gallbladder drainage (cholecystostomy)

For patients who are not fit for surgery due to age, illness, or sepsis, a catheter may be placed through the skin into the gallbladder to drain infected bile. This is often a temporary measure until the patient stabilises for surgery.

Treatment of underlying causes

In acalculous cholecystitis or secondary cases due to bile duct obstruction, trauma, or infection, treatment may include:

• Managing the primary illness (e.g. sepsis, trauma)

• Bile duct procedures to remove blockages (e.g. ERCP if stones are in the common bile duct) before cholecystectomy

• Nutritional support and adjustment of medications

Long-term management

After recovery, patients are advised to adopt lifestyle changes to reduce the risk of recurrence:

• Eating a balanced, low-fat diet

• Maintaining a healthy weight

• Managing diabetes or metabolic disorders effectively

Timely diagnosis and intervention are essential to prevent complications and improve outcomes. For most patients, gallbladder removal offers a permanent cure with minimal long-term impact on digestion.

Summary 

Cholecystitis is a condition where the gallbladder becomes inflamed, most commonly due to gallstones blocking the flow of bile. It can occur suddenly (acute) or develop gradually over time (chronic), and may be associated with gallstones (calculous) or occur without them (acalculous), particularly in critically ill patients. Symptoms typically include sharp upper right abdominal pain, fever, nausea, and tenderness. 

If not promptly treated, cholecystitis can lead to serious complications such as gallbladder rupture, abscesses, or sepsis. Diagnosis involves physical examination, blood tests, and imaging such as ultrasound or HIDA scans. Treatment usually begins with hospital care, antibiotics, and pain management, but gallbladder removal through cholecystectomy is often necessary to prevent recurrence. 

If you are experiencing persistent abdominal pain or suspect a gallbladder issue, schedule a consultation with Tan Siong San Surgery for timely evaluation and expert care.

Frequently Asked Questions (FAQs)