Gallbladder is an organ placed just below the liver. It is therefore located in the right part of the abdomen, under the ribs. It is a small pear-shaped vesicle. The task of the gallbladder is to store and thicken bile that flows in from the liver through the bile duct system. The bile is created in the liver. It is a dense fluid of yellow-brown colour; its main function is decomposition of fat drops during fat digestion.
Anatomy of the Gallbladder
The gallbladder is composed of three parts - fundus, body, and neck. The neck connects the gallbladder to the biliary tree via cystic duct. The cystic duct then joins the common hepatic duct to become the common bile duct that ends in the duodenum. The wall of the gallbladder consists of several layers. The innermost layer is the epithelium, formed by one row of cylindrical cells. On the surface of the epithelium there are wrinkles, visible above all in empty gallbladder. The second layer of the gallbladder wall is so-called lamina propria, a thin layer of loose connective tissue. The epithelium and the lamina propria form the mucous membrane. Lamina muscularis is a layer of smooth muscular tissue that follows the mucous membrane. On the outside surface of the gallbladder, there is the perimuscular layer formed again by fibrous tissue and serosa, the outer shiny covering of the gallbladder that comes from the peritoneum.
The function of the gallbladder is closely associated with food consumption. Within 30 minutes after eating, especially food rich in fat, the gallbladder shrinks and squeezes certain amount of bile into the duodenum, where it mingles with the food. The place where the common bile duct empties in the duodenum is called ampulla of Vater. It is surrounded by the sphincter of ampulla (or sphincter of Oddi), a smooth muscle organ that regulates the common bile duct outlet.
Function of the Gallbladder
Under normal circumstances, the gallbladder contains about 50ml of bile. The bile is thickened by epithelium cells that derive water contained in the bile; up to 90% of bile water including ions is absorbed. The gallbladder wall is not permeable for lipids, though. The bile is composed of different substances. The main constituent parts are bile acids, bile pigments, cholesterol, anorganic substances, fatty acids, and lecithin. The liver produces 600 to 1000ml of unconcentrated bile every day. As mentioned above, the bile is helpful in the digestion process. However, in the final processing of fats pancreatic enzyme called lipase is essential. The bile has other functions, too. It helps excretion of vast cholesterol and other substances that cannot be excreted by the kidney; it helps to absorb fat-soluble vitamins and neutralize the intestinal contents. The bile is excreted by the stool, only the bile acids are in 95% re-absorbed in the large intestine. The bile acids therefore constantly circulate between the liver and the gut.
Diseases of the Gallbladder
Diseases of the gallbladder and the bile ducts are quite common; the mortality is relatively low in these diseases. In some of the diseases it is necessary to surgically remove the gallbladder; however, the digestive system is not significantly affected by this surgery. The bile produced in the liver is not collected in the gallbladder but runs directly from the liver into the duodenum. For normal digestion this is fairly sufficient. Digestive problems occur only when the recommended regime measures are not followed, i.e. too much fatty food is consumed in one meal and more bile is therefore needed. Among the most common diseases of the gallbladder, there are gallstones, inflammation of the gallbladder, and gallbladder cancer.
Gallstones, or cholecystolithiasis, are the most common gallbladder disease. The term choledocholithiasis indicates on the contrary presence of stones in the biliary tree. Gallstones occur in up to 30% of the population, more often in women. The increase in the incidence of gallstones in recent years is associated with worsening living habits of the people, especially unhealthy eating.
The symptoms of gallstones include dyspepsia, feelings of fullness, intermittent pressure on the right side under the ribs, fat foot intolerance, nausea and bloating. In some people, biliary colic appears. It is caused by a gallstone impaction in the neck of the gallbladder or in the common bile duct. Around the impacted gallstone, the muscle tissue clenches and substances causing inflammation are released. This causes a very severe pain that typically comes in waves; it is located in the right hypochondrium and often spreads to the backbone or to the shoulder blade. Typical time of the day for a biliary colic to occur is early evening. The patient suffering biliary colic is usually restless, pale, feverish, in time can become slightly yellowed. In more than half of the cases pain and vomiting are present; however the vomiting does not bring relief. A biliary colic is often caused by fatty foods ingestion, at times it can also be provoked by physical exertion or cold.
Diagnosis of gallstones is based on patient's detailed history and description of typical symptoms. To confirm the diagnosis, ultrasound is used. An ultrasound can visualize the gallstones and evaluate the ability of the gallbladder wall to contract. After some time, the gallbladder wall becomes clearly widespread due to ongoing inflammation. If necessary, CT scan can be used to provide more detailed image. It is a painless method that uses several X-rays in a tunnel device to display the examined structure.
In some cases, the gallstones leave the biliary tract spontaneously is a series of biliary colics. In most cases, however, treatment is necessary. The permanent treatment of gallstones comprises surgical removal of the gallbladder; nowadays performed mostly laparoscopically. Laparoscopy is a method that uses special small instruments and several small incisions to enter the abdominal cavity, which significantly reduces the risk of this operation. Non-surgical treatment for gallstones, especially dietary measures, is not widely used.
Inflammation of the Gallbladder
Inflammation of the gallbladder, or cholecystitis, is most often connected with the presence of gallstones. Other, less frequent causes for gallbladder inflammation are the effect of certain corrosive substances and the presence of micro organisms in the gallbladder. The inflammation of the gallbladder is a serious disease that constitutes a relatively high percentage of acute abdomens. This disease can occur at any age in both sexes but typically occurs in obese women aged 20-50 years.
As for symptoms, acute inflammation of the gallbladder manifests as strong persistent pain on the right side under the ribs, fever and signs of peritoneal irritation, such as abdominal wall tension. Pain increases with movement and deep inspiration. The problems have a short duration, several days the maximum. On the contrary, chronic inflammation of the gallbladder is rather inconspicuous, presenting no clear symptoms. The patient might complain of tension on the right side below the ribs, nausea, indigestion, and intolerance to certain foods. The wall of the gallbladder becomes more wrinkled and calcium is stored in the wall due to the inflammation.
Diagnosis of the inflammation of the gallbladder is based on a careful history, physical examination and imaging methods. During the examination, the physician detects the Murphy's sign (the patient feels a sharp pain during inspiration when the doctor pushes his hand on the right side below the ribs). If the gallstone obstructs the gallbladder or the gallbladder duct permanently, the gallbladder grows bigger, which is called hydrops of the gallbladder. The gallbladder can be palpated on the right side of the abdomen, like a large pyriform-shaped vesicle. Gallbladder is usually imaged by ultrasound or CT; scintigraphy can reveal its malfunction. Scintigraphy is performed using contrast agent that is applied to the bile system and later displayed.
Treatment of acute inflammation of the gallbladder includes bed rest, fasting, antibiotics and medications to control pain. Later, the patient is recommended gallbladder diet. If the patient's condition is serious, immediate surgical removal of the gallbladder, called cholecystectomy, is necessary. The risk of complications of the inflammation of the gallbladder is higher when no gallstones are present; in such a case it is recommended to perform cholecystectomy without unnecessary delay. Chronic inflammation of the gallbladder is also treated by surgical removal.
Cancer of the Gallbladder
Gallbladder cancer is a malignant tumour; among digestive system cancers it is on the fifth place. Gallbladder carcinoma is a malignant tumour based on the epithelial cells that form the inner surface of the gallbladder. Malignant tumours generally tend to spread to the surrounding tissues and disrupt its function. Due to the close relationship between the gallbladder and the liver, in the later stages the gallbladder cancer often spreads into the liver. It can also penetrate into the intestine, the pancreas or spread among the peritoneum. Gallbladder cancer metastasizes primarily to the nearest lymph nodes and to the liver.
Manifestations of gallbladder cancer are in the early stages usually hidden behind prolonged bile problems. Typical are especially uncharacteristic problems with digestion, sometimes the tumour may manifest as a sudden inflammation of the gallbladder. In later stages, there is persistent pain in the right upper part of the abdomen, jaundice, loss of appetite, weight loss and vomiting.
Diagnosis of gallbladder cancer is next to a careful history verified by physical examination and imaging techniques. The physician may during the examination discover enlargement of the liver and palpable solid gallbladder. Blood tests reveal changes typical for bile stasis (elevated bilirubin above all). Among imaging methods, ultrasound is usually the first to point to the possibility of gallbladder cancer. In suspicious cases CT scan follows and sometimes even endoscopic retrograde cholangiopancreatography, shortened to ERCP. It is a test performed by a flexible tubular instrument introduced through the mouth into the biliary tract of the patient. Bile duct and gallbladder is filled with contrast material during the examination, the contrast material is afterwards displayed by X-rays. It is also essential in obtaining tissue samples for histological examination, necessary to prove tumour cells.
The only effective treatment is surgical removal of the tumour, usually the whole gallbladder and surrounding tissue together with lymph nodes. This operation is only suitable for patients in early stage of the gallbladder tumour. In other patients, chemotherapy and radiation are used. Gallbladder cancer is a serious disease; its symptoms must not be underestimated. As in other cancer types, early detection of the disease is key to successful treatment.