Gallbladder Pain Causes
The pain of gallbladder disease almost always has one of two causes - gallstones or cholecystitis. Gallstones are stones that form in the gallbladder (often misspelled "gall bladder"). They vary in size from a millimeter or two to several centimeters and are made up of cholesterol or bile pigments. Cholecystitis means inflammation of the gallbladder. Although, cholecystitis is most commonly caused by gallstones, there are other less common causes as well.
What is the mechanism of gallbladder pain?
Gallstones have a tendency to become lodged in the bile ducts leading from the gallbladder or liver into the intestines. When gallstones lodge in the ducts, they give rise to a specific type of pain called biliary colic. The characteristics of biliary colic are very consistent, and it is important to recognize its characteristics because they direct the physician to the most appropriate test to diagnose gallstones, primarily abdominal ultrasonography. In approximately 5% of cases, ultrasonography will fail to show gallstones. In such situations, if the characteristics of biliary colic are typical, physicians will go on to other more advanced tests for diagnosing gallstones, specifically endoscopic ultrasound. Finally, most gallstones do not cause pain, and are frequently found incidentally during abdominal ultrasonography. If the symptoms for which the ultrasonography is being done are not typical of biliary colic, it is unlikely that the symptoms are caused by gallstones. The gallstones can be truly silent. This is important to recognize because surgery to remove the gallstones is unlikely to relieve the symptoms.
When gallstones lodge suddenly in the duct leading from the gallbladder (cystic duct), the duct leading from the liver to the cystic duct (common hepatic duct), or the duct leading from the cystic duct to the intestine (common bile duct), the normal flow of bile from the liver is interrupted. With obstruction of the common hepatic or common bile duct, the backup of bile causes the ducts (and the gallbladder in the latter case) to distend. This distention (stretching) is the cause of the biliary colic. When obstruction of the cystic duct occurs, fluid is secreted into the gallbladder causing it to distend. Again, the distention causes biliary colic. Biliary colic stops when the gallstone unlodges from the duct.
Gallbladder Pain Characteristics
The term, biliary colic, is a misnomer, that is, it is misnamed. A colicky type of pain is a pain that comes and goes. Biliary colic does not come and go. It may fluctuate over time in intensity, but it does not disappear. It is constant. It comes on rather suddenly, either starting as an intense pain or building up in intensity quickly to reach a peak. It remains constant (though possibly fluctuating in intensity) and then disappears, usually gradually. The duration of the pain is 15 minutes to several hours. If the pain is shorter than 15 minutes, it is unlikely to be caused by gallstones. If the pain lasts longer than several hours it is either not biliary colic, or the gallstone causing the biliary colic has led to a complication, for example, cholecystitis.
The pain of biliary colic usually is severe.
- Individuals with biliary colic tend to move around trying unsuccessfully to find a position of comfort.
- Movement does not make the pain worse, since movement has no effect on the distended ducts or gallbladder.
- It is most commonly maximal in the mid-upper abdomen (epigastrium).
- The next most common location is the right upper abdomen which is actually where the gallbladder is located. (The probable explanation for this is that the gallbladder forms embryologically as a midline organ, and its supply of nerves, including pain fibers, comes from the midline of the body. The nervous system "misidentifies" the problem causing the biliary colic as coming from the midline of the body.)
- Other less common areas of maximal intensity include the left upper abdomen, and rarely the lower abdomen.
- For unclear reasons, the pain may radiate (spread) to other areas, for example, the right shoulder or the tip of the right scapula; rarely these may be the areas of maximal pain.
It is widely but incorrectly believed that biliary colic occurs mostly after meals. In fact, biliary colic is more likely to occur in the evening or at night, often awakening individuals from sleep. It appears that the ingestion of food does not cause biliary colic, even though the theory has been proposed that food, particularly fatty food, causes the gallbladder to contract and push stones into the ducts.
Biliary colic is a recurring problem, but there is a tendency for episodes to occur infrequently, i.e, less than monthly.
Gallbladder Pain Symptoms
Other non-specific symptoms, more likely caused as a response to pain rather than the obstruction, are:
- sweating (diaphoresis),
- light-headedness, and
- shortness of breath.
Symptoms that suggest other causes for pain are pain that is maximal in the lower abdomen, abdominal bloating or belching, and abnormal bowel patterns.
Other Causes of Biliary Pain
The sudden obstruction of the bile ducts causes biliary colic. Other processes that suddenly obstruct the ducts also can cause biliary colic, for example, bleeding into the ducts or the entry of parasites into the ducts, but these causes are rare. The occurrence of slowly progressive obstruction does not cause biliary colic unless sudden obstruction is superimposed upon the progressive obstruction. For this reason, it is uncommon for slowly growing cancers of the bile ducts, gallbladder, or pancreas (through which the common bile duct passes) to cause biliary colic.
Diagnosis of gallstones as cause of biliary pain In addition to ultrasonography, it may be useful to obtain blood tests to assess the liver function (aminotransferases) and pancreas (amylase). If the tests are abnormal they support the diagnosis of a process involving the liver, bile ducts and gallbladder, or pancreas. They do not indicate specifically what the problem is, but an early rise and rapid fall in their levels suggests obstruction of the biliary ducts. Endoscopic ultrasonography is the best test for diagnosing gallstones, but it is expensive and carries the risk of complications.
Other Diseases that Mimic Gallbladder Pain
Whenever biliary colic is suspected, the possibility of heart pain (angina or heart attack, due to ischemia [reduced blood flow of the heart]) should also be considered and vice-versa. Heart pain and biliary pain, although caused by two very different processes, share some common characteristics. They may be confused with one another because sometimes heart pain can be felt in the mid-upper abdomen, and sometimes biliary colic can be felt in the chest. Heart pain also may be associated with nausea and vomiting. Therefore, any patient with pain typical of biliary colic should have an electrocardiogram (ECG, EKG) done, preferably during the pain and/or blood tests to exclude the possibility of heart ischemia.
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Cholecystitis may occur as a complication of prolonged obstruction of the ducts. It occurs when inflammation develops, usually as a result of bacterial infection. If it results as a complication of sudden obstruction of the ducts, it may begin as biliary colic. Less commonly, it may begin de novo, that is, without the pain that is typical of biliary colic, particularly in situations in which the underlying cause is not gallstones (for example, acalculous cholecystitis, vasculitis, etc.).
The pain of cholecystitis is different from biliary colic. It is located in the same area and is constant, but since the cause of the pain is inflammation and not ductal distention, jarring motion, for example, jumping up and down, makes the pain worse. Individuals tend to lie still rather than move about looking for a position of comfort. Other signs of inflammation are tenderness in the right upper abdomen (although this may occur to a lesser degree with distension of the gallbladder without inflammation) and fever.