A tumor is an abnormal growth of cells. This growth happens when the cells of a particular organ start dividing in an uncontrolled manner. The human brain is enclosed in the cranium, a strong and hard cavity made of bone. The brain floats in the cerebrospinal fluid which both nourishes the brain tissues and protects the brain from impact whenever we toss our head about or hit it against a surface.
When the cells start abnormally dividing, the tumor grows in size and mass and there is very less room in the cranial cavity to accommodate this growth. The tumor then ends up squeezing the healthy cortical tissue. This leads to the buildup of pressure inside the cranium which is called Intracranial Pressure (ICP) or Intracranial Hypertension (IH).This pressure buildup can be slow or fast and can block the flow of the cerebrospinal fluid. Tumors that originate in the brain are called Primary Brain Tumors. Depending on their grade, they can spread to the brainstem and spinal cord as well.
Types of Adult Brain Tumor
The tumors are classified in different ways:
- One way of labeling tumors is according to the type of cell they originate from. Tumors of the glial cells are called Gliomas. Those of the pituitary gland are called Pituitary Adenomas, those of the meninges are called Meningiomas and those of the nerves are called Neuromas.
- The second way to classify tumors is according to their grading. They are usually graded according to the speed of their growth. Grade1 and Grade 2 tumors are Benign Tumors. They are slow growing tumors and are less likely to spread to other tissues. They mostly only require surgery and are not in need of radiation or chemotherapy. They are also less likely to grow back after surgery. Grade 3 and Grade 4 tumors are Malignant Tumors. These spread faster in an aggressive manner and will require radiation and chemotherapy for treatment. They may also grow back post treatment. Sometimes a tumor can grow from a benign one into a malignant one. This is called Malignant transformation and is rare.
Causes of Brain Tumor
- Genetics – Tumors can have a hereditary component but genetic tumors only account for about 5% of the tumors out there.
- Exposure to radiation – This has shown to be a major cause for primary brain tumors.
- Exposure to cell phones, chemicals, and magnetic fields have been studied as causal factors for brain tumors but there are no strong conclusive links discovered.
- Immunosuppression – When the immune system is suppressed due to various factors such as in the case of AIDS, the anti-tumor immune response lowers in productivity. This is often seen in fighting glioblastomas, which could prove to be fatal.
Symptoms of Brain Tumor
The raised intracranial pressure can lead to the presence of certain symptoms. These symptoms often need to be examined along with diagnostic scans to prove the existence of the tumors. Most of the symptoms get aggravated when the patient changes posture suddenly.
- Headaches – These headaches tend to be severe and throbbing sensations which are easily aggravated by any physical strain or even by coughing. The individual is usually asked to stand so that the pressure increases and the headaches reduce in intensity.
- Vision changes – these changes can range from fleeting vision to blurry vision. These changes usually occur when the individual changes posture suddenly. The optic nerve which connects the retina to the brain has usually bulged in these cases as the tumor puts pressure on it.
- Seizures – Brain tumors can cause seizures or convulsion. They can be subtle or severe. Severe seizures are often painful and can result in loss of consciousness. Subtle seizures result in twitches of the limbs but do not cause loss of consciousness.
- Nausea – The patient may feel uncomfortable abdominal sensations which could result in hiccups, vomiting or worse.
- Fatigue- Drowsiness is very common in the later stages. The patient sleeps more than normal or may fall asleep during the day.
Related Read: Different types of headaches you didn’t know
Effects of Brain Tumor
The effects of tumor vary according to where the tumor is localized and what functions are carried out by that portion of the brain:
- If the tumor is in the frontal lobe, it affects the association abilities such as communication, reasoning, concentration, impulsive emotions, and new learning.
- If the tumor is in the temporal lobe, it affects auditory responses such as hearing and speaking and also identifying emotions in others.
- If the tumor is in the parietal lobe, it affects sensations related to touch, coordinated movements, and spatial responses.
- If the tumor is in the occipital lobe, it affects visual responses and identifying colors and objects.
- If the tumor is in the cerebellum, it affects balance and coordination
- If the tumor is in the brain stem, it causes double vision and difficulties in walking, speaking and swallowing.
Diagnosis – The person suspecting a brain tumor will be required to undergo a physical examination first. The tumors can only be detected through scans such as an MRI or a CT. Sometimes, a neurological examination will also be carried out to test the senses and to scan for any bulges. If a tumor is detected, a piece of its tissue is sent for biopsy to check its grade and the possible effects.
Treatment-Treatment is usually done according to the type and size of the tumor:
- Surgery is required for most primary brain tumors. This would involve completely removing the tumor or debulking the ones that are in deeper. This helps reduce pressure and hence, relieve the symptoms.
- Radiation therapy – This involves exposure to radiation that can kill or shrink the cells. Gamma knife therapy is one such radiation that is for tumors that are deep in the brain and are hard to reach.
- Chemotherapy – It is often used in the case of CNS lymphoma as an adjunct method to supplement the above.