3. Vascular diseases of the brain and spinal cord, paroxysmal state headaches, sleep disorders, neurointoxications. Traumatic injuries of the nervous system.
TOPIC22. Tumor of the brain and spinal cord. Brain abscess.
IV, semester VIIІ
- Learn: classification of brain tumors.
- Learn: clinic of brain, focal and dislocation syndromes.
- Navigate the differential diagnosis of tumors of the brain and spinal cord. Extra-and intra-medullary tumors. Diagnostic value of ophthalmoscopy, CSF studies, EEG, MRI and CT.
- Learn - principles of surgical and conservative treatment of tumors of the brain and spinal cord. Psychological assistance.
- An abscess of the brain. Foci of abscess formation. Clinical diagnosis, differential diagnosis.
Brain metastasis in the right cerebral hemisphere from lung cancer shown onmagnetic resonance imaging.
A brain tumor or intracranial neoplasm occurs when abnormal cells form within the brain. There are two main types of tumors: malignant or cancerous tumors and benign tumors. Cancerous tumors can be divided into primary tumors that started within the brain and those that spread from somewhere else known asbrain metastasis tumors. All types of brain tumors may produce symptoms that vary depending on the part of the brain involved. These may include headaches, seizures, problem with vision, vomiting, and mental changes. The headache is classically worst in the morning and goes away with vomiting. More specific problems may include difficulty in walking, speaking and with sensation. As the disease progressesunconsciousness may occur.
The cause of most cases is unknown. Risk factors that may occasionally be involved include a number of genetic syndromesuch as neurofibromatosis as well as exposure to the chemicalvinyl chloride, Epstein-Barr virus, and ionizing radiation. While concern has been raised about mobile phone use the evidence is not clear. The most common types of primary tumors in adults are: meningiomas and astrocytomas such asglioblastomas. In children the most common type ismedulloblastomas. Diagnosis is usually by medical examination along with computed tomography or magnetic resonance imaging. This is then often confirmed by biopsy. Based on the finding the tumors are divided into different grades or severity.
Treatment may include some combination of surgery, radiation therapy and chemotherapy. Anticonvulsantmedication is needed in those who have a seizure. Dexamethasone and furosemide may be used to decrease swelling around the tumor. Some tumors grow sufficiently slowly that all that is required is keeping an eye on it. Treatments that use a person's immune system are being studied. Outcome depends on the type of tumor. Gliobastomas usually have poor outcomes while meningiomas usually have good outcomes. The average five year survival rate for brain cancer in the United States is 33%.
Metastatic brain tumors are more common than primary brain tumors, with about half of metastasis coming from lung cancer. Primary brain tumors occur in around 250,000 people a year globally, making up less than 2% of cancers. In children less than 15, brain tumors are second only to acute lymphoblastic leukemia as a cause of cancer. In Australia the average economic costs of a case of brain cancer is $1.9 million, the greatest of any type of cancer.
Visibility of signs and symptoms of brain tumors mainly depends on two factors: the tumor size (volume) and tumor location. The moment of symptom onset, when symptoms become apparent either to the person or people around them, is an important milestone in the course of the diagnosis and treatment of the tumor. The symptom onset – in the timeline of the development of the neoplasm – depends in many cases, on the nature of the tumor but in many cases is also related to the change of the neoplasm from "benign" (i.e. slow-growing/late symptom onset) to more malignant (fast growing/early symptom onset).
Symptoms of solid neoplasms of the brain (primary brain tumors and secondary tumors alike) can be divided into three main categories:
Consequences of intracranial hypertension: The symptoms that often occur first are those that are the consequences of increased intracranial pressure: Large tumors or tumors with extensive perifocal swelling (edema) inevitably lead to elevated intracranial pressure (intracranial hypertension), which translates clinically into headaches, vomiting (sometimes without nausea), altered state of consciousness(somnolence, coma), dilation of the pupil on the side of the lesion (anisocoria), papilledema (prominentoptic disc at the funduscopic eye examination). However, even small tumors obstructing the passage ofcerebrospinal fluid (CSF) may cause early signs of increased intracranial pressure. Increased intracranial pressure may result in herniation (i.e. displacement) of certain parts of the brain, such as the cerebellar tonsils or the temporal uncus, resulting in lethal brainstem compression. In very young children, elevated intracranial pressure may cause an increase in the diameter of the skull and bulging of the fontanelles.
Dysfunction: depending on the tumor location and the damage it may have caused to surrounding brainstructures, either through compression or infiltration, any type of focal neurologic symptoms may occur, such as cognitive and behavioral impairment (including impaired judgment, memory loss, lack of recognition, spatial orientation disorders), personality or emotional changes, hemiparesis, hypoesthesia,aphasia, ataxia, visual field impairment, impaired sense of smell, impaired hearing, facial paralysis, double vision, dizziness, but more severe symptoms might occur too such as: paralysis on one side of the bodyhemiplegia or impairment to swallow. These symptoms are not specific for brain tumors – they may be caused by a large variety of neurologic conditions (e.g. stroke, traumatic brain injury). What counts, however, is the location of the lesion and the functional systems (e.g. motor, sensory, visual, etc.) it affects. A bilateral temporal visual field defect (bitemporal hemianopia—due to compression of the optic chiasm), often associated with endocrine dysfunction—either hypopituitarism or hyperproduction of pituitaryhormones and hyperprolactinemia is suggestive of a pituitary tumor.
Irritation: abnormal fatigue, weariness, absences and tremors, but also epileptic seizures.
The above symptoms are true for all types of neoplasm of the brain (including secondary tumors). It is common that a person carries a primary benign neoplasm for several years and have no visible symptoms at all. Many present some uncertain and intermittent symptoms like headaches and occasional vomiting or weariness, which can be easily mistaken for gastritis or gastroenteritis. It might seem strange that despite having a mass in his skull exercising pressure on the brain the patient feels no pain, but as anyone who has suffered a concussion can attest, pain is felt on the outside of the skull and not in the brain itself. The brain has no nerve sensors in the meninges (outer surface) with which to feel or transmit pain to the brain's pain center; it cannot signal pain without a sensory input. That is why secondary symptoms like those described above should alert doctors to the possible diagnosis of a neoplasm of the brain.
Aside from exposure to vinyl chloride or ionizing radiation, there are no known environmental factors associated with brain tumors. Mutations and deletions of so-called tumor suppressor genes, such as TP53, are thought to be the cause of some forms of brain tumors. People with various inherited diseases, such as Von Hippel-Lindau syndrome, multiple endocrine neoplasia, neurofibromatosis type 2 are at high risk of developing brain tumors.
Although studies have not shown any link between cell phone radiation and brain tumors, the World Health Organization has classified mobile phone radiation on the IARC scale into Group 2B – possibly carcinogenic. That means that there "could be some risk" of carcinogenicity, so additional research into the long-term, heavy use of mobile phones needs to be conducted.
The main areas of the brain and limbic system
For the purpose of understanding this article some summary notes about the human brain and its different types of organic tissues will be provided. When looking at the human brain in the picture on the right, only a few of the areas are really of interest to us. The first type of tissue encountered beneath the skullbone in the intracranial cavity is actually not shown on this picture: the meninges. This is what is inflamed in meningitis.
Human brains are surrounded by a system of connective tissuemembranes called meninges that separate the skull from the brain. This three-layered covering is composed of (from the outside in) the dura mater ("hard mother"), arachnoid mater ("spidery mother"), and pia mater ("soft mother"). The arachnoid and pia are physically connected and thus often considered as a single layer, the pia-arachnoid. Below the arachnoid is the subarachnoid space which contains cerebrospinal fluid, which circulates in the narrow spaces between cells and through cavities called ventricles, and serves to nourish, support, and protect the brain tissue. Blood vessels enter the central nervous system through the perivascular space above the pia mater. The cells in the blood vessel walls are joined tightly, forming the blood–brain barrier which protects the brain from toxins that might enter through the blood. Tumors of the meninges are meningioma and are often benign neoplasms.