Acute Cholecystitis

Question 1

Briefly describe the pathophysiology of acute cholecystitis

Answer 1

Bile is formed from cholesterol, phospholipids, and bile pigments (products of haemoglobin metabolism). It is stored in the gallbladder, before passing into the duodenum upon gallbladder stimulation.

Gallstones form as a result of supersaturation of the bile. There are three main types of gallstones: cholesterol, pigment and mixed.

Question 2

Briefly differentiate between the 3 types of gallstones

Note: cholesterol, pigment and mixed

Answer 2

Cholesterol stones

• Composed purely of cholesterol, from excess cholesterol production
• There is a well recognised link between poor diet, obesity, and cholesterol stones

Pigment stones

• Composed purely of bile pigments, from excess bile pigments production
• Commonly seen in those with known haemolytic anaemia

Mixed stones

• Comprised of both cholesterol and bile pigments

Question 3

Briefly describe the anatomy of the biliary tree

Answer 3

Question 4

What is acute cholecystitis?

Answer 4

Acute cholecystitis refers to inflammation of the gallbladder, which is caused by a blockage of the cystic duct preventing the gallbladder from draining.

Question 5

What are the risk factors for acute cholecystitis?

Answer 5

Classically the common risk factors for gallstone disease are colloquially described as the “5 F’s”:

• Fat
• Female
• Fertile
• Forty
• Family history

Other recognised risk factors include pregnancy and oral contraceptives*, haemolytic anaemia (specifically for pigment stones), and malabsorption (such as previous ileal resection or Crohn’s disease).

Question 6

Why does oral contraceptive use increase the risk of acute cholecystitis?

Answer 6

Oestrogen causes more cholesterol to be secreted into bile.

Question 7

What are the clinical features of acute cholecystitis?

Answer 7

Patients with acute cholecystitis will report a constant pain in the RUQ or epigastrium, associated with signs of inflammation, such as fever or lethargy.

Patients with acute cholecystitis will be tender in the RUQ and may demonstrate a positive Murphy’s sign. Ensure to check for any guarding (may suggest a gallbladder perforation) and for features of sepsis.

Question 8

Why does the consumption of fatty food lead to acute cholecystitis?

Answer 8

Fatty acids stimulate the duodenum endocrine cells to release cholecystokinin (CCK), which in turn stimulates contraction of the gallbladder.

Question 9

How common are clinical features of acute cholecystitis?

Answer 9

Studies have shown for those who are symptomatic, over 50% will present as biliary colic and 35% as an acute cholecystitis.

Question 10

What is Murphy’s sign?

Answer 10

Whilst applying pressure in the RUQ, ask the patient to inspire. Murphy’s sign is positive when there is a halt in inspiration due to pain, indicating an inflamed gallbladder. This can be achieved more accurately with an ultrasound, namely the sonographic Murphy sign.

Question 11

What investigations should be ordered for acute cholecystitis?

Note: laboratory investigations

Answer 11

Certain blood tests can help in the initial evaluation of suspected cases:

• FBC and CRP- assess for the presence of any inflammatory response, which will be raised in cholecystitis
• LFTs- biliary colic and acute cholecystitis are likely to show a raised ALP (indicating ductal occlusion), yet ALT and bilirubin should remain within normal limits (unless a Mirizzi syndrome, discussed below)
• Amylase (or lipase)- to check for any evidence of pancreatitis

A urinalysis, including a pregnancy test if relevant, should be performed to exclude any renal or tubo-ovarian pathology.

Question 12

What investigations should be ordered for acute cholecystitis?

Note: imaging

Answer 12

A trans-abdominal ultrasound is one of the most sensitive modalities for visualising gallstone disease and is typically used first line to investigate suspected gallstone pathology.

If results from US scans are inconclusive, further imaging options are available. The gold standard investigation for gallstones is Magnetic Resonance Cholangiopancreatography (MRCP), largely replacing ERCP for diagnostic purposes. MRCP can show potential defects in the biliary tree caused by gallstone disease, with a sensitivity approaching 100%.

Question 13

What are the 3 things observed on an ultrasound scan of acute cholecystitis?

Answer 13

Three specific areas are often visualised on US:

• The presence of gallstones or sludge (the start of gallstone formation)
• Gallbladder wall thickness (if thick walled, then inflammation is likely)
• Bile duct dilatation (indicates a possible stone in the distal bile ducts)

Question 14

Briefly describe labels A-D on MRCP

Answer 14

MRCP image showing stones in the distal common bile duct: A

• A: gallbladder with stones
• B: stone in bile duct
• C: pancreatic duct
• D: duodenum

Question 15

Briefly describe the conservative management of acute cholecystitis

Answer 15

Patients with acute cholecystitis should be started on appropriate intravenous antibiotics (such as co-amoxiclav +/- metronidazole). Concurrent analgesia and antiemetics should also be prescribed.

Question 16

Briefly describe the surgical management of acute cholecystitis

Answer 16

A laparoscopic cholecystectomy is indicated within 1 week of presentation, as per NICE guidance, however this ideally should be done within 72hrs of presentation for a likely simpler procedure.

For those not fit for surgery and not responding to antibiotics, a percutaneous cholecystostomy can be performed to drain the infection (although as the gallstones remain in-situ, the risk of recurring disease remains).

Question 17

Why may a patient post-cholecystectomy have RUQ pain?

Answer 17

Any patient readmitted with RUQ pain post-cholecystectomy, it is important to exclude a retained CBD stone post-operatively. US abdomen scan may be useful, yet if this is unremarkable, then further investigation via MRCP imaging is warranted.

Question 18

What differentials should be considered for RUQ pain?

Answer 18

There are a wide variety of pathologies that can present with RUQ pain. However, differentials to consider include gastro-oesophageal reflux disease, peptic ulcer disease, acute pancreatitis or inflammatory bowel disease.

Question 19

What is Mirizzi Syndrome?

Answer 19

A stone located in Hartmanns pouch (an out-pouching of the gallbladder wall at the junction with the cystic duct) or in the cystic duct itself can cause compression on the adjacent common hepatic duct.

This results in an obstructive jaundice, even without stones being present within the lumen of the common hepatic or common bile ducts. Diagnosis is confirmed by MRCP and management is usually with laparoscopic cholecystectomy.

Question 20

What is gallbladder empyema?

Answer 20

A gallbladder empyema is when the gallbladder becomes filled with pus. Patients will become unwell, often septic, presenting with a similar clinical picture to acute cholecystitis. They are associated with significant morbidity and mortality.

The condition is diagnosed by either US scan or CT scan. Treatment is via laparoscopic cholecystectomy (may require intra-operative drainage if tense gallbladder) or percutaneous cholecystostomy (if unsuitable for surgery).

Question 21

What is chronic cholecystitis?

Answer 21

Patients with chronic cholecystitis will typically have a history of recurrent or untreated cholecystitis, which has led to a persistent inflammation of the gallbladder wall. Patients present with ongoing RUQ or epigastric pain with associated nausea and vomiting.

It can be diagnosed typically by CT imaging (or often noted on histology post-cholecystectomy). Management in uncomplicated cases is via elective cholecystectomy. Its main complications are gallbladder carcinoma and biliary-enteric fistula.

Question 22

What is Bouveret’s Syndrome and gallstone ileus?

Answer 22

Inflammation of the gallbladder (typically if recurrent) can cause a fistula to form between the gallbladder wall and the small bowel, termed a cholecystoduodenal fistula, allowing gallstones to pass directly into the small bowel (typically at the duodenum)

As a consequence, bowel obstruction can occur:

• Bouveret’s Syndrome: a stone impacts in the proximal duodenum, causing a gastric outlet obstruction
• Gallstone ileus:a stone impacts at the terminal ileum (the narrowest part of the small bowel), causing a small bowel obstruction