Written by admin on 2009-03-11T13:11:13+0000">March 11, 2009 – 1:11 pm
Probably the most common fear of patients with prolonged or severe headaches is that they have a tumour. Thankfully, the answer they hardly ever do, although rarely headaches can be a symptom of a growth in the brain or skull.
However, it is very uncommon for a headache to be the first indication of a brain tumour; paralysis, stroke-like attacks or fits, yes. Headache, no. On the other hand, headaches are common symptoms of brain tumours, but only as a late event, long after the diagnosis has been made.
Tumours form when cells don’t know how to stop dividing; essentially, a tumour is an overgrowth of cells. There are two main types of tumours – benign and malignant. In benign tumours the cells overgrow, but don’t invade the tissue surrounding them, and there is often a layer of squashed normal tissue around the tumour. Often a benign tumour can be shelled out of the tissue it’s buried in, almost as one would shell the kernel out of a mil.
Benign tumours cause problems because they press on other tissues and organs in the body; and because benign tumours are very similar to the tissues they are derived from, they can produce the same chemicals – so it is quite possible for a benign tumour at a hormone-producing site (like the thyroid gland) lo produce an uncontrolled excess of hormone.
Basically, these are the only two ways that benign tumours can exert any unpleasant effects; simply by their physical presence, and sometimes by secreting excess hormones. Benign tumours never spread to distant parts of the body, and they seldom change into malignant ones.
What sort of tumours are commonly benign? Often breast lumps are found to be harmless; those little skin tags that often come round the neck are small benign tumours; and, as mentioned above, deeper in the body the thyroid can have benign tumours that may secrete extra thyroid hormone. The gut may have small benign growths in it.
Malignant tumours are a different kettle of fish altogether. These are cells which have really got out of control. As well as not knowing when to stop dividing, they also infiltrate the tissues surrounding them. Whereas a benign tumour frequently has a cyst-like shell around it, a malignant tumour doesn’t – which is why it is frequently difficult to remove, because there is no clear borderline between normal and abnormal tissue.
As well as spreading locally malignant tumours also spread to distant sites. A primary tumour (i.e., the tumour at the original site) throws off cells into either the bloodstream or, more commonly, the lymphatic system (a drainage system in the body, rather like the veins, that runs parallel to the circulatory system). Cells seeding off from the main cancerous tumour become deposited in areas of the body remote from the primary site. Once they have lodged in distant tissue they start to grow, forming a secondary tumour. Each type of cancer has a tendency to form secondary tumours in certain types of tissue. For example, cancer in the bowel tends to cause secondary growths in the liver; cancer of the breast often moves to the bones; cancer of the lung tends to form secondary tumours in the brain. However, these are not hard and fast rules, and a particular type of cancer can spread to a number of different sites.
Malignant tumours are fatal in a number of ways. Firstly, and most importantly, they seem to have an ability to suck the nutrients out of the system so that they grow at the body’s expense – the cancer gets bigger as the patient gets thinner. Secondly, they can erode into important organs, preventing them working properly; and, finally, they can exert the same pressure and hormonal effects that benign tumours also exert, often made more complex because, being more primitive tissue, they can produce hormones that are wildly different from those normally produced by the tissue they come from.
Malignant tumours also cause problems because they invade and destroy the tissues that they have formed in. Frequently they cause more pain in the secondary site than they do in the original site – bone pain from secondaries can be particularly severe.
What sorts of cancers give rise to headaches? The answer is actually quite complex. Any tumour inside the skull can cause pressure on the brain, both locally and by obstructing the outflow of cerebro-spinal fluid – and in raising the pressure within the skull, benign tumours can be just as bad as malignant ones. A rise in pressure causes dull persistent headaches, but by the time headaches happen, other symptoms have usually occurred – such as weakness in an arm or leg, or changes in vision or speech. In addition, with a malignant abnormality there may be loss of weight, together with a general feeling of exhaustion and malaise.
Tumours inside the skull can be primary; in other words, they arise from the tissues inside the skull, such as the brain or its surrounding coverings; but more often brain tumours are secondary. Cancers which commonly manifest themselves in the brain include cancers of the breast and the lungs.
Don’t forget that there’s more to the head than just the brain. Malignancies can also affect the bones of the skull – usually secondary cancers, though primary tumours can arise in the sinuses. Secondary cancers can affect the bones of the spine, and primary tumours, both benign and malignant, can also affect the pituitary gland, which is a gland underneath the main part of the brain. The pituitary’s job is to secrete hormones which control growth, reproduction, and water balance, among other things. Headaches are common with pituitary tumours, both benign and malignant.
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