What is Cholecystitis?
Cholecystitis is the medical term for inflammation of the gallbladder, the small sac that lies under the liver and stores bile. It may be acute or chronic. The most common cause of cholecystitis is due to gallstones obstructing the neck of the gallbladder or cystic duct. This is known as calculous cholecystitis. Other causes of cholecystitis that are not due to gallstones is known as acalculous cholecystitis but this accounts for a minority of cases.
How does cholecystitis occur?
Pathophysiology of Cholecystitis
The pathogenesis of cholecystitis is not clearly understood but it appears that gallstone obstruction (calculous cholecystitis) leads to distension of the gallbladder. This disrupts the blood flow and lymphatic drainage resulting in inflammation, which leads to ischemia (tissue injury) and eventually necrosis (tissue death) if left untreated.
Another possible mechanism is that damage of the gallbladder mucosa releases phospholipase which then interacts with the lecithin in the bile, converting it to lysolecithin. This compound is a known toxin which may cause inflammation of the gallbladder (chemically induced).
It is likely that both these mechanisms occur in acute calculous cholecystitis.
Chronic cholecystitis is often a result of repeated bouts of acute cholecystitis although it may arise with no previous episodes of acute cholecystitis.
Other Terms Relating to Cholecystitis
- Empyema of the gallbladder refers to a mainly pus exudate within the lumen of the gallbladder.
- Gangrenous cholecystitis is the green-black appearance of the gallbladder as result of necrosis (tissue death).
- Gallbladder perforation is a tear or “holes” in the gallbladder that arises from a number of pathologies including chronic cholecystitis or severe acute cholecystitis.
- Rokitansky-Aschoff sinuses are where there are outpouchings of the mucosal wall of the gallbladder.
- Porcelain gallbladder is a rare phenomenon where there is extensive calcification of the gallbladder wall.
- Xanthogranulomatous cholecystitis is a rare condition where there is focal or diffuse inflammation of the gallbladder wall with areas of necrosis and hemorrhage and accumulation of lipid laden macrophages, fibrous tissue and other inflammatory cells.
- Hydrops of the gallbladder is a distended gallbladder containing mucoid or clear and watery secretions often as a result of obstruction of the gallbladder outlet.
Symptoms of an Inflamed Gallbladder
Gallstones may not always be symptomatic or even result in cholecystitis. Most stones pass out of the gallbladder unhindered but if it obstructs the outlet of the gallbladder or even the bile ducts, cholecystitis may ensue. The two most prominent features of cholecystitis includes pain and fever.
As most cases are due to obstruction by gallstones, it is important to take note of the symptoms of gallstones. Attacks of gallstone pain (biliary colic) tends to come on suddenly and persist for up to 2 hours. However, when cholecystitis is present, this pain may continue for longer, sometimes up to 6 hours.
Typically the pain is in the right upper quadrant (RUQ) or epigastrium of the abdomen and even the epigastrium. The pain may radiate to the right shoulder, just as is seen with gallstone pain.
Milder recurrent pain may be seen in chronic cholecystitis, sometimes without any other signs and symptoms characteristic of chronic cholecystitis.
A fever is one of the cardinal features of an inflamed gallbladder. This may be absent in older patients, especially in cases of acalculous cholecystitis. Rigors is almost never seen with a cholecystitis fever.
Nausea is a common symptom in acute cholecystitis and may be accompanied by vomiting.
Patients also report a lack of appetite and stomach bloating (sensation of fullness).
Abdominal distension may also be present.
Other Clinical Features
- Tenderness in the right hypochondrium.
- Rigidity upon inspiration (Murphy’s sign).
- Gallbladder mass upon palpation.
- Jaundice – usually seen with bile duct stones (choledocolithiasis)
- Blood tests
- White blood cell (WBC) – elevated (leukocytosis)
- ALP (alkaline phosphatase) – elevated
- Bilirubin – elevated
Causes of an Inflamed Gallbladder
The most common cause is a gallstone lodged in the neck of the gallbladder or cystic duct.
Other causes of obstruction leading to cholecystitis may be seen with :
- Parasitic worms
- Impacted mucus
- Post-operatively in stent insertion
- Intensive care/critically ill patients often associated with parenteral nutrition – elderly, burn victims, septicemia, myocardial infarction (heart attack)
- Prolonged fasting, strict dieting or starvation
- Sickle cell disease
- Diabetes mellitus (sugar diabetes)
- Systemic vasculitis
- Infections (some bacterial species may not cause cholecystitis but complicate an existing case)
- Pseudomonas spp
- Cytomegalovirus, cryptosporidiosis, or microsporidiosis – usually seen in AIDS patients
Diagnosing an inflamed gallbladder (cholecystitis) may be conducted by a clinical evaluation involving a thorough case history, assessment of signs and reported symptoms and a complete blood count (elevated white blood cell count – leukocytosis). This exact cause should be confirmed by one or more imaging techniques and specific blood tests.
Investigations like an X-ray may be useful for identifying gallstones in calculcous cholecystitis. This however will only show radio-opaque stones and a CT scan should be done even if no gallstones are found upon an X-ray. A CT scan will also help identify complications like an empyema or gallbladder perforation that may require immediate surgical intervention.
Ultrasound examination may only identify gallstones larger than 2 millimeters but is also helpful in indicating thickening of the gallbladder wall and distension of the gallbladder.
A hepatobiliary iminodiacetic acid (HIDA) scan is extremely effective in diagnosing acute cholecystitis but this is matched by a CT scan or MRI. If the facilities are available and calculous cholecystitis is suspected based on initial finding, an endoscopic retrograde cholangiopancreatography (ERCP) may be considered for better visualization of the area and removal of stones as discussed under Gallstones Removal.
The tests are discussed further under Gallbladder Tests.
- Complete blood count (CBC) – leukocytosis (elevated white blood cell count)
- Liver function test (LFT) – elevated ALP (alkaline phosphatase), alanine aminotransferase (ALT), aspartate aminotransferase (AST). May also be elevated in hepatitis.
- Amylase – moderately elevated, high levels may be indicative of acute pancreatitis.
- Bilirubin – elevated in cases of bile duct obstruction
Treatment is based on the cause of cholecystitis as well as the presenting signs and symptoms.
- Analgesics (painkillers) – moderate pain : NSAIDs like acetaminophen, severe pain : opioids like pethidine.
- Antibiotics – a cephalosporin plus metronidazole in severely ill patients.
- Antiemetics – for nausea and vomiting.
- Aspiration (nasogastric) – for persistent vomiting.
- IV Hydration – to prevent dehydration in persistent vomiting and avoid oral intake of fluids
* A simple way to remember this is the five A’s – analgesics, antibiotics, antimetics, aspiration (nasogastric) and “aqua” (IV hydration).
Laparoscopic cholecystectomy (gallbladder removal surgery) is routinely conducted as cholecystitis tends to recur. The surgery is usually performed within 72 hours of hospital admission or within 5 days from the onset of symptoms. If percutaneous gallbladder drainage is deemed necessary, a cholecystectomy may be delayed for 4 to 6 weeks.