There’s that headache again. The one you had yesterday. And the day before. And the day before that. What makes you finally decide to see your GP? Fear. A headache is a typical example of a symptom where your main agenda is to seek reassurance about what you haven’t got rather than to receive a label for what you have. And what you haven’t got is a brain tumour, unless you’ve been incredibly unlucky in the great medical lottery.

The chances We GPs see tension headaches almost every day and a brain tumour about once every ten years.

The giveaways Tension headaches may recur for months or years. They feel like a pressure on, or a band around, the head and are aggravated by stress. During a phase of tension headaches, the ache may be present most of the time, typically worsening through the day. Brain tumours cause headaches of that start out of the blue and rapidly worsen over weeks, and which are particularly bad first thing in the morning and on stooping or straining. They may wake you at night and there are nearly always other symptoms such as repeated vomiting, constantly blurred vision, severe unsteadiness, fits, or weakness or numbness down one side of the body.

PULLED MUSCLE v HEART ATTACK

Heart attacks are easily confused with some other symptoms; just ask all those poor souls who convinced themselves that they were just having a bad attack of indigestion. Except you can’t, because they’re dead. But distinguishing a pulled muscle from a heart attack should be a no-brainer. The problem is that panic overwhelms common sense and the resulting frightened helplessness leads to an urgent appointment with your GP or even an unnecessary ride in an ambulance.

The chances We see a handful of pulled muscles each week — and about the same number of heart attacks a year.

The giveaways A pulled muscle hurts when you prod your rib cage, take a deep breath, cough, laugh or tense the relevant muscles. It’s usually sharp but mild, recurrent and localised to a small part of your chest. A heart attack is a one-off pain of such severity that you’re likely to realise that something is seriously wrong. Odds on you’re probably 40 or more and a smoker. You feel as if there’s a heavy weight crushing the centre of your chest and the pain may spread to your neck or left arm. It lasts more than half an hour and may make you feel sick, short of breath or sweaty.

PILES v COLON CANCER

Campaigns such as “Don’t blush, look before you flush” have reinforced the nation’s traditional bowel obsession and helped to overcome squeamishness about looking for blood. As a result, your toilet ritual may now include peering down the pan in an attempt to read your medical future. Anything red spells danger, which is why you’re hammering on my door.

The chances Rectal bleeding is actually very common, though it rarely crops up during dinner party conversation. In the absence of other symptoms, it points to cancer in only about one in a thousand cases.

The giveaways Piles are simply varicose veins. Being in your anus, though, they’re prone to trauma when you open your bowels. The result is episodic bright red bleeding in the pan, on the motions and on the paper — and no accompanying symptoms. Colon cancer, on the other hand, can result in all sorts of additional problems, including abdominal pain, weight loss, persistent or recurrent diarrhoea, and a mucus-like discharge from the back passage. Any blood passed may be mixed in with the stool. But cancers can also just cause pile-type bleeding. So you’ve no real choice but to make an appointment — and if you’re over 40, it’s recurrent or you have other symptoms, you may well need a check-up from a specialist armed with a pleasant smile but unpleasant probes.

TRAPPED NERVE v STROKE