Another scare for the Prime Minister, but Downing Street plays down health concerns

Uncertainty about the state of the Prime Minister's health persisted yesterday, 24 hours after he was seen by two doctors, having complained of stomach pains.

Downing Street said the problem had passed quickly and he had required no treatment, but released no other details. The GP who attended Tony Blair suspected appendicitis and called in a consultant, David Nott, a general surgeon at the Chelsea and Westminster Hospital, for a second opinion. Mr Nott appears to have ruled out appendicitis and to have reassured Mr Blair, 50, who did not interrupt his normal schedule.

Pain caused by appendicitis normally starts in the right lower side of the abdomen in a region of the gut known as the iliac fossa. Once appendicitis has been ruled out the most likely cause is constipation because the iliac fossa marks the start of the colon.

Jeremy Sanderson, consultant gastroenterologist at St Thomas' Hospital, said: "We see loads of people from the City working at full tilt like Tony Blair. They often eat too fast and on the run and they don't have time to drink enough water. The body pinches the water back from the bowel and leaves it with bricks."

Mr Sanderson said the colicky pain could be intense and come in waves while the gut tried to move its contents. But Mr Blair's doctors would have wanted to rule out other possible causes, including cancer, before giving him a clean bill of health. "Fifty is the crossover age where you start to think about cancer in the bowel - but it doesn't usually present with pain," he said.

Another possibility, though unlikely, was Crohn's disease - an inflammatory condition of the gut. Gall bladder stones and kidney stones may also have been suspected though they do not normally cause pain in the same area as the appendix.

Acid reflux, one of the most common diagnoses in people who lead high-pressure lifestyles and eat irregularly, is also a cause of intense pain but it is felt in the upper abdomen. It is caused by the regurgitation of acid in the stomach which burns the lower part of the oesophagus. Downing Street gave no details on the nature of the stomach pain - whether it was sharp, burning or cramping - or its location.

Mr Blair's GP did not consider his symptoms indicative of a return of the heart trouble he experienced weeks ago. Had he done so he would have sent for a cardiologist, not a general surgeon. Although stomach discomfort can be a symptom of a heart problem, it is rarely linked in the absence of other symptoms.

Specialists said yesterday that the exact nature of Mr Blair's heart trouble remained unclear. He was taken ill at Chequers, in Buckinghamshire, on 19 October with an irregular heartbeat and taken first to Stoke Mandeville Hospital near by. He was then transferred to Hammersmith Hospital in west London where he was given cardioversion, an electric shock which jolts the heart back into a normal rhythm. Downing Street described his condition at the time as paroxysmal supraventricular tachycardia (SVT), in which the heart beats at more than twice its normal speed. But Professor John Camm, heart specialist at St George's hospital, Tooting, south London, said cardioversion was not the usual treatment for SVT. Professor Camm said it was more likely to be atrial fibrillation, the same condition that struck George Bush Snr when he was US President in 1992. The White House gave full details of the incident at the time which was later traced to a thyroid problem and easily treated.

Professor Camm said: "I don't really understand why Downing Street has not given a more sensible and complete statement. We don't really know what the problem was." A spokesman for the Prime Minister said yesterday: "When the Prime Minister is admitted to hospital or is taken unwell then we will give the full background to that.

"Equally, there is a difference when the Prime Minister sees a doctor and nothing results from that. Even the Prime Minister is entitled to some privacy in respect of his medical history."

So what could be the PM's problem?

Appendicitis: Symptom ­ sharp pain in the lower right side

Constipation: Symptom ­ colicky, cramping pain in lower or upper abdomen

Acid reflux: Symptom ­ burning pain in upper abdomen

Gall stones: Symptom ­ severe pain that doubles you up and then passes

Kidney stones: Symptom ­ similar to gall stones but the pain normallyaffects the patient's back

Other possible causes of the Prime Minister's abdominal pain include cancer, Crohn's disease and trapped air