Brain Tumor: Types, Grades, Causes, Signs, Symptoms, Treatment
While everyone suffers from a headache now and then, persistent or worsening headache should not be ignored as it could be a symptom of brain tumor. Brain tumors, though rare, do occur and the headache from brain tumor should be distinguished from those headaches which are caused due to less serious conditions like migraines, allergies, cold, flu, or common vision problems that require glasses or contact lenses.
Headache from brain tumor results from increased intracranial pressure (IICP). This is caused due to excess fluid, brain swelling, or a mass. Human skull can accommodate only the brain and normal amount of fluid. In brain tumors, the extra fluid, swelling and mass causes increased pressure leading to headache. Brain tumors can develop irrespective of age.
The exact reason of brain tumors is not absolutely clear. Brain tumor symptoms are dependent on the size of tumor and its location. General symptoms of brain tumor include headaches, numbness in upper or lower extremities, seizure, memory impairments, personality changes, ambulation difficulties, nausea, vomiting; speech impediment, and impaired vision.
Brain tumor is diagnosed after a detailed medical history and a physical examination conducted along with a battery of tests related to nervous system and brain. Based on the results, brain tumors are diagnosed. Treatment is dependent on type of tumor and its location and also its size. Treatment for brain tumor also depends on age as well as overall health of patient.
Treatment options for brain tumor are surgery, radiation, chemotherapy and sometimes even all the above.
Classification and Types of Brain Tumor
Normally when cells in the body become old or are damaged, they die and new cells replace them. In some instances, this process goes haywire and new cells start forming even when not required and the damaged cells do not die. This collection of surplus cells starts to form a mass of tissue called tumor.
Brain Tumors Can Be:
Primary Brain Tumors: These tumors can be benign or malignant. These are generally seen in children. These tumors stem from the brain and are usually named after the part of brain or the type of brain cell from which they are forming. Most of them are benign and can be excised. As these tumors around brain are not cancerous, the chances of them recurring are miniscule. These tumors have clear defined edge. Cells of these tumors very rarely invade tissues around them. They also do not invade other parts of body. However, they can compress sensitive areas of brain and cause serious health problems. When these brain tumors become malignant, they get life threatening. Benign brain tumor grows slowly putting pressure on surrounding parts of brain whereas malignant tumors grow very quickly and infiltrate the brain. The most common primary brain tumors are gliomas named after their place of origination that is the glial cells.
The Following Are The Types of Gliomas :
- Brain stem glioma
Primary Tumors That Do Not Begin In The Glial Cells Are:
- Medulloblastoma or primitive neuroectodermal tumor
- Pituitary tumors
- Germ cell tumor of the brain
- Pineal region tumor
Malignant Brain Tumors: These are also called as brain cancer as they have cancerous cells in them. Malignant brain tumors are quite serious and pose a threat to life of an individual. These tumors grow very quickly and invade nearby healthy brain tissues. The cancer cells from malignant brain tumors may break away and spread to other parts of brain or spinal cord. They very seldom spread to other parts of body.
Secondary Brain Tumors: Secondary brain tumors or metastatic tumors occur when cancer cells from other parts of the body, such as the lung, breast, skin, kidney, and colon leak from their primary tumor and enter the lymphatic system and blood vessels, circulate through the bloodstream and get lodged in the brain. These cells then continue growing and dividing, becoming invasive and malignant. Secondary tumors in the brain are more common than primary brain tumors. About 25% of tumors elsewhere in the body metastasize to the brain.
Childhood Brain Tumor: Children more commonly have brain tumors presented as common solid tumors. Children of any age may be affected. Boys are affected more often than girls. Medulloblastoma and ependymoma are the two types of brain tumors that are more common in children than in adults. Treatment and chance of recovery from childhood brain tumor depend on the type of tumor, its location within the brain, the extent to which it has spread and the child's age and general health.
Brain Tumor Grades
Doctors group brain tumors by grade. The grade of a brain tumor indicates the way the cells look under a microscope:
- Grade I Brain Tumor: The tissue is benign. The cells grow slowly and look almost like normal brain cells.
- Grade II Brain Tumor: The tissue is malignant. The cells look less like normal brain cells when compared to the cells in a Grade I brain tumor.
- Grade III Brain Tumor: The tissue is malignant and the cells look very different from normal cells. These abnormal cells are actively growing (anaplastic).
- Grade IV Brain Tumor: The tissue is malignant and its cells look very abnormal and multiply and grow very quickly.
Causes And Risk Factors of Brain Tumor
The Cause Of Brain Tumors Is Uncertain, But There Are Several Risk Factors Present Which May Cause Brain Tumor Such As:
- Ionizing Radiation: Such as high dose x-rays, people exposed to ionizing radiation may have an increased risk of a brain tumor.
- Family History: It is uncommon for brain tumors to run in family but some inherited disorders increase its risk. These disorders are neurofibromatosis, Von Hippel-Lindau syndrome, and Turcot syndrome.
There may be other risk factors like using cell phones, having had a head injury, or having been exposed to certain chemicals at work or to magnetic fields, but they are very much debatable and still undergoing research.
Pathophysiology of Brain Tumor
The skull of adults can accommodate only the brain and the normal amount of fluid. It cannot spread to accommodate the increasing tumor size, swelling etc. and this causes increased intracranial pressure. This increase in intracranial pressure is due to increase in tumors mass, edema that accompanies the tumor and because of obstacles in the flow of cerebrospinal fluid. The brain can adapt to a large tumor if it grows very slowly, but smaller tumors that grow rapidly cause severe symptoms.
Edema is a result of expansive process of the brain. Edema principally affects the white mass of the hemispheres and is less pronounced in the internal capsule, corpus callosum and optic radiation. Even edema acts as a mass that increases the volume of the brain causing increased intracranial pressure and headache.
Signs and Symptoms of Brain Tumor
- The symptoms of brain tumors depend on their size, type, and location. People with brain tumors more often present with other symptoms such as seizures, changes in vision or hearing, weakness of the arms and legs, or cognitive decline etc. before presenting with a headache.
- General symptoms of brain tumors are headaches, numbness of the extremities, seizure, memory issues, personality changes, ambulation disorders, nausea and/or vomiting, speech impediments, vision problems. Some patients suffer from morning headaches.
- Sometimes these headaches can be so painful that they awaken the patient from their sleep, though this can also be caused by conditions other than brain tumor. Brain tumor pain can be described as dull, aching, or throbbing. As time passes, the headaches may become more frequent, intense, increasing in severity, and eventually be a constant occurrence that is not easily relieved. Changes in body position can make them worse, especially when lying down. They can also be worsened by coughing or sneezing.
- Focal neurologic symptoms like cognitive function impairment, including judgmental issues, memory impairment, impaired recognition, spatial orientation problems, emotional problems, hemiparesis, loss of speech, problems with ambulation, visual field problems, loss of sense of smell, problems with hearing, facial paralysis, diplopia, and dizziness may occur but other symptoms like paralysis on one side of body or dysphagia may also occur. These symptoms may also be present in conditions other than brain tumor.
Treatment Options for Brain Tumor
Following Are The Options For Treating Brain Tumor:
- Surgery for Removal of Brain Tumor: The most sought after treatment is surgical removal or resection of the brain tumor through craniotomy. It can be a complete or partial resection of the brain tumor with main objective of excising as many tumor cells as can be from around the brain. Most of the meningiomas, save for tumors located at skull base, can be successfully excised with surgery. Postoperative radiotherapy and chemotherapy is done for malignant brain tumors.
- Radiotherapy For Brain Tumor: This is the most commonly used treatment for brain tumors. The aim of this radiotherapy is to selectively eliminate tumor cells while leaving normal brain tissue intact. The tumor is targeted with alpha and beta rays to shrink the brain tumor size. The tumor is targeted with the rays in a circular motion to minimize damage to the surrounding cells. Radiotherapy is commonly used for treatment of secondary brain tumors. The amount of therapy to be received is dependent on the size of tumor. Whole brain radiotherapy treatment or whole brain irradiation can be done if there are risks of development of secondary brain tumors later.
- Chemotherapy For Brain Tumor: Chemo is also one of the treatment options, but is seldom used to treat brain tumors because of its toxicity, side effects and uncertain outcome. In chemotherapy, drugs that are made to exterminate tumor cells are administrated. In people with malignant primary brain tumors, chemotherapy has the capacity to improve overall survival rate but it does so in only 25% of people. Chemotherapy is generally given to young children in lieu of radiation, as radiation may have adverse effects on their brain development. Chemotherapy administration depends on patients overall health, tumor type, and degree of cancer. For brain tumor, surgery and radiation therapy are preferred to chemotherapy because of its toxicity, side effects and uncertain outcome.
- Other Treatment Options For Brain Tumor: A shunt can be used for relief of symptoms by reduction of hydrocephalus caused due to blocking of cerebrospinal fluid. It is definitely not curative but only designed to provide relief from symptoms. A number of novel treatments such as gene therapy, highly focused radiation therapy etc. are in the process of ongoing research.
Investigations For Diagnosis of Brain Tumor
- Neurologic Exam: Doctor checks the patient's vision, hearing, alertness, muscle strength, coordination, and reflexes and also examines patient's eyes to look for swelling caused by brain tumor pressing on the nerve that connects the eye and the brain.
- MRI: Is used to take pictures of areas inside the patient's head. These pictures can show abnormal areas, such as a brain tumor.
- CT Scan: This is used to take a series of detailed pictures of the patient's head. Patient may receive contrast material by injection into a blood vessel in either arm or hand. The contrast material makes the abnormal areas or brain tumors visible.
- Angiogram: In this procedure, a dye is injected into the bloodstream that makes blood vessels or tumor in the brain show up on an x-ray.
- Spinal Tap: In this procedure, the doctor removes a sample of cerebrospinal fluid (the fluid that fills the spaces in and around the brain and spinal cord). This is done under local anesthesia using a long, thin needle to remove fluid from the lower part of the spinal column. The collected cerebrospinal fluid is sent to the laboratory, where it is checked for cancer cells or other abnormalities. This procedure takes about 30 minutes and the patient is required to lie flat for several hours afterwards to prevent from getting a headache.
- Biopsy: In this procedure, tissue is removed to look for tumor cells and this tissue is sent to a pathologist who looks at the cells under a microscope to check for abnormal cells. A biopsy can show cancer, any changes in the tissue that can lead to cancer, and other abnormal conditions. Biopsy is the most reliable and the only sure way to diagnose a brain tumor, know what grade it is, and formulating a treatment plan accordingly. Biopsy can be done in 2 ways:
- Biopsy at the Same Time as Treatment: The doctor takes tissue sample during surgery itself.
- Stereotactic Biopsy: In this procedure, after local or general anesthesia, a surgeon drills a small hole into the skull and guides the needle to the tumor (with the help of MRI or CT scan) and takes a small tissue sample with the needle.
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