Brain tumors: going over the basics

Recently I have seen many patients with brain tumors in my office and that shall be the focus of my post.  Brain tumors are tumors (cancers) that arise in the brain or spread to the brain. We call these primary brain tumors (tumors arising in the brain itself) or metastatic tumors to the brain (the primary tumor/ cancer is somewhere else for example in the lung or breast but then spreads to the brain).

Let us now spend a moment to talk about how brain tumors present clinically. Many of you shall be surprised to learn that the brain itself is insensitive to pain (meaning if I was to put a knife through your brain tissue, you shall feel no pain!!!).  So a small brain tumor may be silent, causing no pain or discomfort. It is usually when the brain tumor increases in size and starts involving (stretching the blood vessels in the brain) or the covering of the brain (meninges) that the patient may complain of headache. Blood vessels and covering of the brain (meninges) are richly supplied by nerves and hence are exquisitely pain sensitive.  So first and foremost not all brain tumors present with headache. The corollary to that is that not all headaches are due to brain tumors. Most of the times when patients present to a doctor for evaluation of headache, a “benign” cause such as migraine or tension headache is found and not a brain tumor.

If I am examining a patient with headache, there are certain red-flags in the history and the examination which shall make me think about a possible brain tumor.

Laterality of the headache:  Headaches associated with brain tumors are usually holocranial (the whole head hurts). Remember migraines are typically hemicranial (patient complains of a throbbing headache on one side of the head). This though is not a hard and fast rule and I would not base my opinion on the laterality of the headache.

Is the headache associated with projectile vomiting: Because a large brain tumor  shall lead to an increase in the intracranial pressure (pressure inside the brain),  patients with brain tumors may have projectile vomiting. This again is not a hard and fast rule as patients with migraines are frequently nauseated and may throw up.

Does the headache awaken the patient at night from sleep? Headache associated with brain tumor may awaken the patient from sleep. Classically the headache is worst when lying down and abates in the morning when the patient gets up and starts to move around. Migraines usually do not awaken a patient from sleep, infact sleep frequently helps to abort a mgraine attack. Again a weak point and I would not base my opinion on this alone.

History! History! History!: 

Let us compare two different histories in two patients:

Patient number 1 (age=53 years male)

“Dr Sethi, I have never had a headache in my life, never had a headache in my adolescence but recently I am waking up with a severe headache.”–THE THOUGHT OF BRAIN TUMOR DOES CROSS MY MIND WHEN I HEAR THIS

Compare this to:

Patient number 2 (age 26 years female)

“Dr Sethi, I have headaches since my college days. Frequently I shall get a throbbing headache on one side of my head and at that time bright lights shall bother me. I used to feel nauseated when I had my headaches and at times threw up. My headaches went away in my 30s but now I am again having bad headaches” –MIGRAINE IS THE FIRST THOUGHT THAT CROSSES MY HEAD AND NOT BRAIN TUMOR.

Other presentations of brain tumors: brain tumors at times may present more dramatically. Patients may present with a generalized convulsion. When these patients are imaged (via a CT scan or a MRI brain scan) the brain tumor may be detected. At times patients present with progressive neurological deficits. The type of neurological deficit depends frequently on the location of the brain tumor. Let me explain this further. Let us assume the brain tumor is pressing on the optic nerve or other nerves which control eye-movements: patients may present with visual problems (such as blurring of vision, double vision or diplopia, cuts in their visual fields and so forth). If the tumor presses on the motor or sensory system: patients may present with weakness or numbness on the contralateral side of the body. If the tumor is in the cerebellum, they shall complain of balance problems or lack of coordination. If the tumor involves the auditory nerve, their presenting complaint shall be of hearing loss (usually though unilateral hearing loss may not be appreciated by the patient).

Finally the neurological examination is of great help. Patients with migraines, tension type headaches and other “benign” headaches have a normal (we call this non-focal) neurological examination. On the other patients with brain tumors may have some subtle and other more prominent neurological findings. Thus your doctor shall examine you: check your cranial nerves (does the patient have a symmetrical smile, are eye-movements intact, is the visual field intact, do thay have any sign of increased pressure inside the brain (this is determined by looking into the eye to visualize the optic nerve head), is motor strength and sensory system intact,  are there any signs of cerebellar dysfunction (incoordination, ataxia–balance is off and so forth).

Patients with headaches who have an abnormal neurological examination should be imaged. Your doctor may then recommend either a CT scan of the head or a MRI scan. Frequently this is done with and without contrast. I shall dwell into different types of brain tumors and their management in my next post.

Nitin Sethi, MD