Symptoms & Investigations
Limb weakness and any abnormal sensation in the limbs can be a symptom of a tumour in certain parts of the brain especially in and around the motor or sensory cortex. Generally the opposite side is affected i.e right-sided weakness by a tumour in the left motor cortex.
Unsteady walking or imbalance (ataxia) may occur if the tumour is in the cerebellum or some other parts of the brain.
Vision may become blurred or sometimes lost if the optic nerve is compressed or swollen (Papilloedema). Sometimes a squint or double vision (diplopia) may develop if the nerves moving the eyes are affected.
Recent or long term memory may become weak.
Speech: Ability to understand (sensory aphasia) or express (motor aphasia) may be affected by tumours in certain parts of the brain. Sometimes the person is able to understand but is not able to express properly and may not get the right words.
Hormonal Effects: Some tumours in and around the pituitary / hypothalamus region (sellar and suprasellar region) can cause either excess or deficiency of many hormones. This may affect the growth, fertility, libido, body weight, mental functions, etc.
Changed behaviour, lethargy, drowsiness, and loss of consciousness are some of the other symptoms of brain tumours.
Methods of detecting a brain tumour:
Most of the symptoms described above are non-specific and can be caused by many other diseases. A detailed history and medical examination is first done by the doctor and if a brain tumour is suspected then further tests like CT or MRI scan, angiogram, CSF test, hormonal blood test or EEG may be done.
CT or MRI Scan produce special X-ray pictures that show the detailed structure of the brain and spine and pick up any abnormality. To get a clearer picture, Iodine or Gadolinium contrast dyes are given intravenously. Some people can develop an allergic reaction to the iodine contrast agent and you should always tell the doctor if you have any allergies. Newer non-ionic contrast agents reduce the risk of allergic reaction.
There is a strong magnetic field during the MRI scan and you should inform the doctor if you have any Pacemaker or metallic clip or prostheses inside your body. For these scans which take about half an hour, the patient lies down on the couch of these CT or MRI machines. The couch moves the patient through the large aperture or tunnel of these machines. The whole procedure is painless but the noise created by the MRI machines can be disturbing for some patients. During the scan the patient should not move and for small children who may move a lot, sometimes a minor anaesthesia is given.
Angiogram is an X-ray taken after injecting an iodine dye through catheters placed into the arteries. This shows the details of the blood supply to the tumour. For vascular malformation like AVM it is essential to plan embolisation, surgery or stereotactic radiation.
Cerebro Spinal Fluid (CSF) Study is done after removing the CSF from the spine by a long needle (lumbar puncture). This is done in certain tumours which have a high chance of spreading to the spine or to rule out infections or bleeding.
Hormonal Blood Tests are done for tumours like pituitary adenoma, craniopharyngioma, optic chiasmal or hypothalamic glioma.
Electroencephalogram (EEG) is occasionally done to study the pattern of seizures.