Cholecystitis
From Medical-Wiki
Technically, cholecystitis is any inflammation of the gallbladder. Practically, it is a term used synonymously with obstruction of the cystic duct from cholelithiasis. 90% of cases involve obstruction secondary to stones. The other 10% are cases of acalculous cholecystitis.
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Etiology
When the outflow of bile from the gallbladder is obstructed, it becomes distended. This distension causes a compromise of blood flow and lymphatic drainage. This eventually leads to mucosal ischemia and finally necrosis. In 2000, the ability of endotoxin to cause necrosis, hemorrhage, areas of fibrin deposition, and extensive mucosal loss was demonstrated. Later, endotoxin was shown to have the capacity to abolish the gallbladder’s ability to contract in response to cholecystokinin (CCK), worsening gallbladder stasis and accelerating the process of infection. (Bile cultures are often positive for bacteria, but bacterial proliferation may be a more appropriate description of the overall process.)
Risk factors
Circumstances associated with biliary stasis such as debilitation, major surgery, severe trauma, sepsis, long-term total parenteral nutrition (TPN), and prolonged fasting, in addition to cardiac events, sickle cell disease, Salmonella infections, diabetes mellitus, and cytomegalovirus, cryptosporidiosis, or microsporidiosis infections in patients with AIDS are associated with acalculous cholecystitis.
It is postulated that acalculous cholecystitis may be the result of injury caused by the retention of concentrated bile, a very toxic substance. In the case of fasting, the gall bladder does not receive a cholecystokinin stimulus to empty.
Morbidity & mortality
Statistically, most episodes of acute cholecystitis resolve within a few days. However, roughly a third require surgery or progress to a complication. In 10% to 15% of cases, there is perforation of the gall bladder. [1]
Clinical presentation
A classic episode of biliary colic lasts from 1 to 5 hours. It is accompanied by moderate to severe pain, most commonly in the epigastrium or right upper quadrant. The pain is constant and rarely colicky. It may sometimes radiate posteriorly. It may be associated with nausea, vomiting, and fever. There may also be an element of pleuritic pain associated with the abdominal pain.
The pain may often follow a meal unusually rich in fat. While classic, this is by no means a constant. Some patients may have biliary colic precipitated by a variety of unexpected and non-fatty foods.
The pain quite often awakens patients from sleep. There is, in fact, an old rule that states that any woman of childbearing age awakened from sleep with abdominal pain has gallbladder disease until proven otherwise.
Biliary obstruction will prolong the pain. It may be decreased in intensity as the patient does some accommodation, but it is constant.
Many of the age old symptoms associated with gallstones, i.e. indigestion, belching, bloating, and fatty food intolerance, are no more common in patients with identifiable stones than in the general population. (The symptoms typically do not resolve after removal of the gallbladder.) Most gallstones are asymptomatic. Smaller stones, because of their ability to migrate into the common duct, are the most likely stones to cause acute problems.
Diagnosis
Physical findings
Physical findings correspond closely to whether a patient has simple biliary colic, cholecystitis, cholangitis, or sepsis. Biliary colic may occur in patients who are not even febrile. A patient with cholecystitis will appear far more toxic and far less tolerant of pain. Palpation or jarring of the RUQ will create an instant, and profoundly negative, reaction. Peritoneal signs are a foreboding physical finding. Typically, uncomplicated cholecystitis will not have peritoneal signs, so their presence must raise concerns about perforation or gangrene. Likewise, jaundice is an unusual sign in the early stages of cholecystitis. It too is a red flag that must be assessed. [2]
Laboratory findings
When assessing lab values for cholecystitis, it should be noted that they may be completely normal.
When they are abnormal, AST, ALT, and alkaline phosphate levels may be elevated; their elevation suggests the likelihood of a common bile duct stone, cholangitis, choledocholithiasis, or obstruction of the common bile duct by an impacted stone in the distal cystic duct. Amylase may be elevated up to 3 times normal—particularly in the face of gangrene.
Attention should be paid to calcium levels because of their relationship to pancreatitis.
Elevation in bilirubin may not come until days after obstruction begins and certainly not with an acute attack.
Even WBC counts are not reliably elevated with all attacks of biliary colic or early cholecystitis. In one study, only 61% of patients with cholecystitis had a WBC greater than 11,000. (A WBC greater than 15,000 may indicate perforation or gangrene.)
The usual rules regarding blood cultures apply to cholecystitis—at least 2 and not more than 4 should be seeded. Other tests that are standard for abdominal pain should always be part of a workup. These include UAs and pregnancy tests in women of childbearing capacity. Comorbid pathology can never be ignored. [3]
Radiological findings
The importance of imaging in the diagnosis of gallbladder pathology was demonstrated by a thorough, retrospective review of 195 studies that failed to define a “... single clinical finding or combination of findings or laboratory tests can reliably identify or exclude patients with acute cholecystitis without further testing (such as by ultrasonography).” [4]
National Guidelines still define ultrasound as the imaging technique of choice in the identification of cholecystitis. They go on to say, “Radionuclide scanning is not a useful test for the diagnosis of gallstones.” [5]
Treatment
Treatment guidelines call for patients to see a surgeon “within a few weeks if the acute episode has resolved or symptoms are mild.” However, “Patients with significant right upper quadrant tenderness, fever, or elevated white blood cell count should be seen the same day.”
Laparoscopic surgery is indicated unless there is a presence of complicating anatomy such as adhesions. Common duct stones may be removed either through ERCPT or surgically. The former is associated with a dramatically reduced level of morbidity and shortened hospital stay. [6]
