Jeremy

Woodward

Gastroenterologist

crestes70

“In biology, nothing is clear, everything is too complicated, everything is a mess, and just when you think you understand something, you peel off a layer and find deeper complications beneath. Nature is anything but simple.” Richard Preston

Gallstones

What does the gallbladder do? The gallbladder stores bile. Bile is a fluid that is made in the liver which serves a number of purposes. It is a means of excreting substances that are detoxified by the liver but it also contains bile salts which are chemcials that are soluble in both water and in fat. This property means that bile salts are able to help with the absorption of fat and certain vitamins in the intestine. Bile drains from the liver via the bile ducts that join into one - the 'common bile duct' - before entering the intestine. There is a muscle that encircles the bottom of the common bile duct that prevents the bile from draining into the intestine. As a result, bile flow up the 'cystic duct' which is a tube that links the gallbladder to the bile duct. The accumulation of bile leads to gradual filling and distension of the gallbladder (which is highly elastic and able to expand significantly). When a meal - particularly one containing fat - is taken, the intestine senses the presence of the fat and secretes a hormone chemical called CCK that acts to both relax the muscle at the bottom of the bile duct and to make the gallbladder contract. The effect is like that of a detergent bottle being squirted into the washing up as it helps the fat to be absorbed into the body...

What are gallstones? Gallstones are hard accretions that form within the gallbladder. They can be small and multiple or large and solitary. Gallstones are made of cholesterol - that is secreted in bile - and also from bile acids and pigments. The majority of gallstones are made of a mixture of these chemicals, but some are predominantly cholesterol or pigment based. Gallstones can form for a variety of reasons - if there is too much cholesterol in the bile for it to dissolve for instance. However, the commonest causes relate to the function of the gallbladder - if it is contracting regularly and effectively then gallstones do not form easily. Conditions that result in reduced contractions of the gallbladder include starvation or frequently missing meals, rapid weight loss, or operations that require a patient to be starved for a period of time. If there is a large amount of pigment in the bile - made from the breakdwon of blood cells - then this can lead to gallstones in conditions such as 'haemolytic anaemia' or hereditary spherocytosis where the abnormal shape of the blood cells makes them more fragile. Women are more at risk of gallstones than men and gallstones can be detected in as many as one in 20 adult women.

What symptoms are caused by gallstones? Gallstones are usually silent and cause no problems whatsoever. Therefore finding them incidentally can cause more problems than it solves by leading to worry and unecessary operations. About 1-2% of patients with gallstones found coincidentally experience symptoms each year.
Gallstones can lead to problems within the gallbladder itself or if they spill out into the tubing that drains bile into the intestine. Within the gallbladder, the gallstones can lead to inflammation and 'chronic cholecystitis' (cholecystitis = inflammation of the gallbladder). This can lead to nausea and chronic pain in the upper right part of the abdomen which may be worse after eating and can radiate around to the right shoulder blade. An acute infection of the gallbladder may also occur and present with severe constant pain in the same place, and can make the patient extremely unwell. This 'acute cholecystitis' may occur if the tube draining teh gallbladder itself is blocked by a gallstone. If gallstones spill over into the tubing that drains bile into the intestine, they may cause a blockage - resulting in a back pressure of bile into the liver that causes the bile to flow back into the blood stream and cause a yellow colour to the skin and eyes - 'jaundice'. Worryingly, gallstones in the bile duct can act as a source of infeciton that can be severe or on occasion life threatening.
Finally, chronic inflammation in the gallbladder or bile ducts due to gallstones that have been present without causeing symptoms for many years can rarely result in the development of cancer of the gallbladder or bile ducts.

How are gallstones diagnosed? Gallstones are easily detected by using ultrasound scans - a safe, non-invasive test using a probe that is placed in jelly on the abdomen wall to look through it using high frequency sound waves. About 10% of gallstones contain enough calcium to show up on normal X-rays, but they notoriously do not show up well on CT ('CAT') scans, although complications due to gallstones may show up well on these scans. It is sometimes necessary to use a magnetic resonance ('MRI') scan to visualise gallstones that have spilled out into the tubing.

What treatments are available for gallstones? If gallstones are detected, it is very important to decide whether they are responsible for the symptoms or merely coincidental, and whether they should be left alone or removed.
Gallstones present in the gallbladder that are causing symptoms require an operation to remove the gallbladder along with the stones - merely removing the stones would simply allow new ones to form very quickly as the gallbladder is usually damaged by the chronic inflammation and does not contract well. The operation can be performed by 'keyhole' surgery in the majority of instances and requires only one to two days in hospital.
Gallstones that are present in the tubing - the bile ducts - always need removing as they are much more likely to cause symptoms and potentially life-threatening complications than gallstones that are merely present in the gallbladder itself. Gallstones in the bile ducts can usually be removed using a endoscopic procedure called ERCP - explained on a separate page on this site.
Many patients ask whether they can take tablets to dissolve the stones. By taking large doses of bile acids by mouth, it is indeed probably possible to do this. However this only works in patients with many small stones that do not contain calcium and are found in a normally functioning gallbladder,which is very rare and can take up to two years.

What happens if the gallbladder is removed? The gallbladder is not essential in humans and there are relatively few consequences of removing it - bile still flows out into the intestine by overcoming the pressure in the muscle at the bottom of the bile ducts. However, by steadily trickling out rather than being absorbed along with the fat in the diet, it can reach the large bowel (colon) where is can cause fluid to be secreted and cause diarrhoea. This 'bile acid malabsorption' syndrome can be easily treated by taking a powder called 'Questran' that binds to the bile and stops it from causing the diarrhoea. This powder has the useful side effect of reducing cholesterol levels as well!

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