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 Post subject: BRAIN TUMORS
PostPosted: 16 Jul 2018 09:16 
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Joined: 19 Dec 2017 14:21
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OVERVIEW
Brain tumors occur when the brain cells multiply in an abnormal and uncontrolled manner. They can be benign (slow growing) or malignant (cancerous and aggressive). However unlike other organs, even benign and slow growing tumors can cause considerable mortality and morbidity by pressing on important brain structures and affecting vital functions.

● Brain tumors are said to be primary when they form from the brain cells. Secondary brain tumors are those that spread to the brain from a cancer in some other organ and are termed “metastases”.

Secondary brain tumors are at least 10 times more common than primary brain tumors

● Brain tumours may occur at any age in adults but are most common between 50 and 70 years.

● Adult brain tumors are mostly located supratentorially. The most common types are high grade gliomas and meningiomas

CAUSES AND RISK FACTORS
The exact etiology of brain tumors is not clear but there are certain risk factors that have been associated with an increased chance of developing brain tumors

• Presence of specific inherited conditions - Neurofibromatosis, von Hippel-Lindau disease, Li-Fraumeni syndrome, tuberous sclerosis, Cowden’s disease

• Exposure to ionising radiation – for example as treatment for head and neck cancer

• Increasing age

• Immunosuppression – Immunosuppressed conditions such as AIDS are associated with increased risk of brain lymphoma

• ?Mobile phone use – needs more investigation

HISTOLOGICAL TYPES OF BRAIN TUMORS
Primary brain tumors are named according to the cell of origin within the brain. They can be classified into

High grade tumors – more aggressive and fast growing
• Gliomas (arises from glial cells)
• Medulloblastoma (arise from immature or embryonal cells)
• Lymphomas (from lymphocytes)

Low grade tumors – Slow growing and more often benign
• Meningioma (arise from the coverings of the brain)
• Pituitary tumors (from the cells of the pituitary gland)
• Acoustic neuroma (tumors arising from Schwann cells of the vestibulocochlear N (VIII cranial nerve)
• Neurofibroma
• Pineal tumors (pineal gland)
• Craniopharyngioma (arise in the stalk of the pituitary gland from remnants of the craniopharyngeal duct and/or Rathke's cleft)

CLINICAL FEATURES OF BRAIN TUMORS
The symptoms of brain tumor will depend on the size of the tumour and exact location in the brain.

Symptoms due to compression of nearby structures (pressure symptoms)
• Headaches – often worse at night and early in the morning but may improve as the day goes on
• Blurred vision
• Projectile vomiting (due to raised intracranial pressure caused by tumor)

Symptoms caused by location of tumor in brain
• Seizures (fits) – may be associated with loss of consciousness
• Difficulty in walking
• Weakness on one side of the body
• Problems with speaking, vision, hearing, or sense of smell
• Changes in behaviour and personality, memory or mental ability

COMPLICATIONS OF BRAIN TUMORS
• Hemorrhage into tumor
• Obstruction to flow of CSF – may result in death due to blockage of the third ventricle
• Increased intracranial pressure causing brain herniation
• Complications due to radiotherapy – intellectual impairment and drowsiness

DIAGNOSIS OF BRAIN TUMORS
Diagnosis largely relies on brain imaging

• CT scan (with or without contrast) – obtains 3 dimensional x-ray images of the brain

• MRI (with or without contrast) is more sensitive. Spinal cord imaging may be required to rule out spread of tumor to the spine

• Positron emission tomography (PET) is helpful in grading gliomas or to detect an occult primary.

• Technetium brain scan - is useful in the diagnosis of destructive skull base lesions and destructive lesions of the skull vault

• Electroencephalogram (EEG) – this uses electrodes that are attached to your scalp to record your brain activity to look for anything unusual.

• Biopsy – Occasionally a sample of tumor may be obtained to know the type and grade (aggressive nature) of tumor. A stereotactic biopsy of the lesion using CT and MRI imaging scans and 3D imaging technology is done and sent for histopathological examination

GRADING AND STAGING OF BRAIN TUMORS
Grading of brain tumors is done looking at the magnified tumor cells under the microscope. The sample will be graded I to IV. Grade I means it is a low-grade, less aggressive, slow-growing tumour, least likely to spread and grade IV is fast growing, aggressive and most likely to spread

There is no standard clinical staging system for brain tumours. Although brain tumors can spread to other parts of the brain and spinal cord, distant spread to other organs is rare

TREATMENT OF BRAIN TUMORS
Treatment will depend on tumor type, how advanced or aggressive it is, and location in the brain

Watchful waiting
If the tumour is slow-growing and not causing much symptoms, treatment may not be required straight away. The doctor will monitor the tumor closely with routine check-ups and scans. This is called watchful waiting or active monitoring

Surgery
Tumors should be removed whenever feasible. The aim of surgery is to remove as much of the growth as possible. In some cases, removal of the brain tumour can be curative. In others, it can reduce symptoms due to the pressure effects of the tumor

The type of surgery may be open surgery (or craniotomy), or a keyhole surgery. This will depend on the type of tumour as well as its size and position. A pituitary tumour can be removed via the nose, which is called transsphenoidal surgery.

Radiotherapy
A targeted beam of radiation is employed to destroy the tumour with minimal damage to surrounding healthy tissue. Radiotherapy may be given after surgery to kill any remaining tumour cells, but occasionally as an alternative to surgery.

Chemotherapy
Chemotherapy uses drugs to kill cancer cells. The most commonly used agents are temozolomide, or combination of procarbazine, lomustine and vincristine. Again chemotherapy may be used alone or in combination with surgery and radiotherapy

Miscellaneous measures
Steroids may be useful to reduce brain swelling caused by tumor as well as surgery or radiation. Antiseizure medications, pain killers and blood thinners may be prescribed as appropriate.

DIFFERENTIAL DIAGNOSIS
Other conditions that have to be considered in the diagnosis during work-up include
• Cerebrovascular event
• Idiopathic intracranial hypertension
• Seizure disorder
• Brain infections and brain abscess
• Arteriovenous malformations
• Neurosyphilis

PROGNOSIS OF BRAIN TUMORS
Brain tumours, whether benign or malignant, are associated with morbidity relating to pressure effect if they continue to enlarge. Malignant brain tumours are the leading cause of death in children due to solid tumors and the third leading cause in adolescents and young adults


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 Post subject: Re: BRAIN TUMORS
PostPosted: 19 Jul 2018 16:48 
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Joined: 26 Feb 2013 10:59
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This poster is a helpful reminder.


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