Not for the fat, 40 and fertile

MEDICAL MATTERS: In response to a request from a reader, this week's column will look at gallstones and the related condition of acute cholecystitis.

Before the age of political correctness, generations of medical students were taught that gallstones usually occurred in fair-coloured females who were over 40, fat and fertile. And while the phrase may have had it's benefits as a mnemonic, I have treated as many dark-skinned men with gallstones as I have overweight women over the age of 40.

Gallstones affect between 10 and 15 per cent of the population. Although the prevalence of gallstones increases with age, the link between the condition and women who have had a high number of pregnancies remains controversial.

Gallstones are usually made up of cholesterol that has crystallized from bile. This is a greenish, yellow digestive fluid produced by the liver and stored in the gallbladder, a small pear-shaped organ located beneath the liver. When bile is needed, the gallbladder contracts and pushes the fluid through a tube called the bile duct and from there to the small intestine.

When bile becomes oversaturated with cholesterol, it crystallises. The microscopic crystals accumulate to form stones. Most gallstones are of a mixed type and are made up of calcium and bile pigments as well as cholesterol.

As long as the gallstones sit quietly in the gall bladder, they do not cause any symptoms. However, one or more stones may move into the narrow neck of the gallbladder and lodge there. This can cause quite severe pain in the right upper part of the abdomen just under the ribs. Lasting for several hours, the pain classically occurs three to six hours after eating a large fatty meal. The steady pain - called biliary colic - subsides when the stone dislodges and either slips back into the gallbladder or passes into the intestine. Other symptoms include belching, nausea and vomiting.

A family doctor, hearing the classical description of gall stone pain, will send the patient for an ultrasound scan, which can detect 95 per cent of gallstones in the gallbladder. If the biliary colic has been severe and recurrent, it is usual to recommend the surgical removal of the gallbladder (and the offending stones) by means of a procedure called a cholecystectomy. Nowadays, most cholecystectomies are performed laparoscopically, using small incisions in the abdominal wall. Compared with the traditional method of open surgery, using the laparoscope has lessened post operative discomfort and shortened the length of time spent in hospital.

Although gallstones can be dissolved using drugs, it can take up to two years of continuous treatment to remove a large gallstone. Unfortunately, about half of people successfully treated using dissolving drugs will develop gallstones again within five years.

Acute cholecyctitis is the sudden onset of inflammation of the wall of the gallbladder, usually the result of a stone lodging in the duct. It occurs in up to 3 per cent of patients who have developed pain from their gallstones.

Why does it happen? The obstruction at the duct causes pressure to rise within the gallbladder. Together with the build up of bile, this pressure triggers an inflammatory response. Secondary bacterial infection then develops in 20 per cent of people with cholecystitis.

The pain of acute cholecystitis is usually more severe than that of biliary colic. When the doctor presses on the gall bladder, the person feels a sharp pain. That pain may also worsen when the patient breathes in deeply and usually lasts for more than 12 hours. Nausea and vomiting are usual and a high temperature develops in about a third of people with the condition.

Treatment involves admission to hospital, where the patient fasts and is given intravenous fluids and oxygen therapy. This rests the gallbladder until the inflammation subsides. A non steroidal anti-inflammatory drug is given intramuscularly for pain relief. If there is no improvement after 12 to 24 hours, broad spectrum antibiotics are started.

About 20 per cent of people with acute cholecystitis will need emergency surgery because their condition deteriorates. Medical opinion on the best time for surgery for the other 80 per cent has changed.

Traditionally, open cholecystectomy was carried out six to 12 weeks after the acute attack, to allow the inflammation settle down. Trials have now shown that early laparoscopic cholecystectomy carried out after the onset of symptoms results in lower rates of complications and a shorter stay in hospital.

Perhaps the most important point about gallstone disease is that more than 80 per cent of people with gallstones never develop any symptoms. We are more likely to take our gallbladders to the grave than to have them removed during our lifetime.

Dr Muiris Houston is pleased to hear from readers but regrets he cannot answer individual queries.