Acalculous Cholecystitis - Causes, Symptoms, and Diagnosis

Introduction:

The gallbladder is a small pear-shaped digestive organ located beneath the liver on the right side. It is otherwise known as cholecyst. Its function is to store bile (also known as gall) produced by the liver. Bile, the greenish-yellow fluid produced by the liver and stored in the gallbladder, is needed for the digestion of fats in our diet. This bile gets expelled from the gallbladder to the duodenum (the first part of the small intestine) whenever we consume fatty foods. The digestion of fats from the partly digested foods occurs at the duodenum, where bile gets drained.

What Does Acalculous Cholecystitis Mean?

Acalculous cholecystitis means inflammation of the gallbladder due to an infection. During gallbladder inflammation, the gallbladder outlet (also known as cystic duct), through which bile exits the gallbladder to drain into the duodenum, gets blocked. Usually, a gallstone blocks the cystic duct and prevents gallbladder emptying. But in the case of acalculous cholecystitis, there are no gallstones or mechanical blockage of the duct, but an infection causes gallbladder inflammation, thereby causing gallbladder dysfunction and impaired emptying.

Acalculous cholecystitis was first described by James Duncan, a surgeon, in 1844. This is a life-threatening condition, and failing to receive immediate medical intervention can be fatal.

There are two types of acalculous cholecystitis,

• Acute acalculous cholecystitis.

• Chronic acalculous cholecystitis.

Though acalculous cholecystitis usually presents as an acute form of the disease necessitating immediate medical assistance, it can exhibit some chronic symptoms over a period. In the acute form of the disease, symptoms are present for nearly a month before they become serious, and in the chronic form, symptoms extend beyond three months before their condition worsens. Most commonly, they experience severe upper right abdominal pain and fever.

What Factors Cause Acalculous Cholecystitis?

The following factors increase the risk of development of acalculous cholecystitis,

• Sepsis.

• Patients on long-term total parenteral nutrition (TPN).

• Patients in intensive care units (ICU).

• Gallbladder dysmotility (impaired function of the gallbladder muscles).

• Diabetes.

• Aortic dissection.

• Hepatitis A.

• HIV (human immunodeficiency virus) infection.

• People with suppressed immune responses.

• Burns patients.

• Fasting patients.

• Patients with multiple system trauma.

• End-stage renal disease.

• Shock.

• Infectious diseases.

How Does Acalculous Cholecystitis Develop?

Stasis (slowing down of flow) of bile is the chief cause of the development of acalculous cholecystitis. People who are critically ill, along with fever, dehydration, and not taking foods orally, experience increased bile viscosity and diminished gallbladder contraction. This can also cause bile stasis apart from the risk factors mentioned above. Since there is no gallstones obstruction in the case of acalculous cholecystitis, the mechanical obstruction can be the result of cysts due to Echinococcus (parasitic tapeworm) eggs, roundworm infection, hemophilia, or narrowing bile duct.

Due to bile stasis, bacteria can get colonized and trigger inflammation. Also, there is a rise in intraluminal pressure (pressure within the gallbladder) which can cause gallbladder wall ischemia (a decrease in blood flow and oxygen supply) and inflammation. Without emergency management, persistent ischemia can progress and cause gangrene (death of the tissue due to lack of blood flow or infection), necrosis, perforation, sepsis, and shock. Such life-threatening conditions occur in the acute form of the disease. In the chronic form, the symptoms are not so severe and do not develop abruptly as in the case of acute acalculous cholecystitis.

What Signs and Symptoms Does Acalculous Cholecystitis Cause?

Acalculous cholecystitis does not necessarily cause signs and symptoms. It can also be asymptomatic. When symptomatic, the following signs and symptoms are present,

Symptoms:

• Fever.

• Jaundice.

• Vomiting.

• Abdominal pain.

• Severe pain on the upper right side of the abdomen (biliary colic).

• Fatigue.

• Bloating.

• Belching.

• Intolerance to food.

Signs:

• Leukocytosis (increased white blood cell count).

• Gallbladder abscess (accumulation of pus within the gallbladder).

• Gallbladder distension (stretching and swelling of the gallbladder due to inflammation).

• Murphy’s sign (the patient is asked to hold the breath after inhalation, and the physician will then palpate right below the right rib cage region) - It is positive in acalculous cholecystitis if the patient experiences sharp pain with palpation.

• Decreased intestinal motility (decreased intestinal contractions).

How Common Is Acalculous Cholecystitis?

Acalculous cholecystitis is known to affect nearly 0.12 % of the population. It is less common. It has a slight male predilection and especially in males aged 50 years and above. This disease accounts for 10 % of acute cholecystitis and 5 % to 10 % of cholecystitis.

How Serious Is Acalculous Cholecystitis?

Acalculous cholecystitis is a life-threatening condition with a high morbidity rate and up to 50 % mortality rate due. This is because it develops in people who already have devastating health conditions such as burns, sepsis, shock, etc. Also, diagnosis is not easy due to the absence of reliable diagnostic methods.

How Can Acalculous Cholecystitis Be Confirmed?

Diagnosis of acalculous cholecystitis is really challenging due to the vague symptoms or sometimes lack of symptoms and the level of accuracy needed for diagnosis. Clinical features are always correlated with the diagnostic findings to confirm the condition.

• HIDA Scan - The hepatobiliary iminodiacetic acid (HIDA) scan involves the usage of HIDA, a radioactively labeled compound. This is administered intravenously, and the movement of bile can be traced using a specialized camera. With this, the bile production, movement, and blockage within the gallbladder can be detected.

• Cholangiography.

• Computed tomography (CT scan).

• Magnetic resonance imaging (MRI).

• Ultrasound scan of the upper right quadrant.

• Complete blood count.

• Liver function test.

What Diagnostic Findings Indicate Acalculous Cholecystitis?

• In the HIDA scan, the radionuclide material secreted into the bile does not fill the gallbladder within an hour of administration.

• Ultrasound and CT scans reveal gallbladder wall thickness greater than 3 mm (3.5 mm to be specific). The gallbladder wall shows pericholecystic fluid (fluid around the gallbladder), edema, and gas.

• The gallbladder is distended with thickened walls.

• White blood cell (WBC) count is raised.

How Can Acalculous Cholecystitis Be Managed?

• Emergency cholecystectomy is performed (using the open or laparoscopic method).

• But as acalculous cholecystitis most commonly occurs in critically ill and hospitalized patients, if in case cholecystectomy cannot be performed considering their inability to undergo surgery, ultrasound or CT-guided placement of cholecystostomy tube (percutaneously) until the patient recovers from their underlying condition and become stable to undergo a surgery.

• Routine administration of broad-spectrum antibiotics is also done.

• Recovery post-surgery usually takes place over a long period.

Conclusion:

As there is a need for high levels of suspicion and accuracy for diagnosing the condition and its management, an interprofessional team including a gastroenterologist, radiologist, general surgeon, nurse, dietician, and physiotherapist are needed to manage the condition successfully. With recent advancements, the mortality rates have been decreasing. Prolonged recovery post-surgery and the development of serious events such as multiorgan failure and sepsis indicate poor treatment outcomes.