How to… spot serious medical symptoms?

Like red-light warnings on the dashboard, the human body sends out a flare when something's awry. Chest pain, shortness of breath, dizziness - those are some familiar medical symptoms. But other problems can creep up on you, too - aches and pains, lumps and bumps. It's necessary to know when they are important and when they are not.

Neil Shulman, MD and a professor of internal medicine at Emory University School of Medicine in Atlanta, calls it a serious and likens to "terrorists inside our bodies." The symptoms are "killing way too many people. There's tremendous suffering and horrible death which could be avoided, but people don't know that something's wrong."

In fact, it happens all the time, a symptom is missed and it leads to a tragic ending. Or it's caught just in time, and a life is saved. Quite literally, it's that dramatic, Shulman tells.

Here are "five flags" - five medical symptoms - you should keep in mind:

1. If you have unexplained weight loss and/or loss of appetite , you may have a serious underlying medical illness.

"If you're on a diet, you're expecting this to happen. But if you're eating the same way - and now have to adjust your belt a few notches tighter - you could have a serious problem, so you should see a doctor." Shulman says.

2. Slurred speech, paralysis, weakness, tingling, burning pains, numbness, and confusion are signs of a stroke, and you should get to an appropriate emergency centre immediately. Early treatment may prevent permanent damage to the brain or even save your life.

3. Black, tarry stools may indicate a haemorrhage from an ulcer of the stomach or the small intestine. It is important to stop the bleeding and to rule out cancer as a cause.What you eat changes the colour of stools. But black, tarry stools mean there may be bleeding higher in the digestive tract, says Shulman. It could be a sign of a bleeding ulcer or cancer.

4. A headache accompanied by a stiff neck and fever is an indicator of a serious infection called meningitis. In fact, if you can't put your chin on your chest, that's a sign you may have bacterial meningitis, says Shulman. With bacterial meningitis, you need antibiotics immediately to kill the bacteria before it infects and scars the brain.

5. A sudden, agonizing headache, more severe than any you have felt before, could mean you are bleeding in the brain. Go to an emergency room immediately. A brain aneurysm is rare, but it can happen - even in people under 40. If you have a severe, crushing headache, you may have an aneurysm, which is a blood-filled pouch bulging out from a weak spot in the wall of a brain artery. If treated before it bursts, it could save your life.