What is Brain Tumors?

Brain Tumors

Intracranial tumors are all masses that develop anatomically and clinically within the cranial cavity and impinge on brain tissue or exert pressure on the brain from the outside. These include tumors (neoplasms) in the narrow sense, granulomas (tuberculomas, gomas) and parasitic cysts. Intracranial tumors can arise from elements of the nervous tissue itself and from elements outside this tissue (vascular and meningeal tumors). Foci caused by the spread of tumors from other organs (sarcoma, carcinoma) are also common. Tumors arising from nerve tissue vary greatly in cell type and maturity.

• Causes: The origin of these tumors is still unknown, although there are efforts to identify factors such as trauma, viruses and familial predisposition. Some tumors are distinctly “embryonal” or “congenital”; others appear later in life.

• Symptoms: Intracranial tumors cause two types of symptoms. The first group are called general symptoms. These are symptoms common to all intracranial tumors, regardless of their location. The second group of symptoms depends on the location of the tumor. These symptoms are useful in identifying the parts of the brain destroyed by the tumor. These are called localization symptoms because they help to determine the location of the tumor in the brain. A definitive diagnosis of a brain tumor can be made when both types of symptoms are present, but one group may be more prominent than the other.

In some cases, general symptoms may not be present for a long time; they only appear after the tumor has grown. This is characteristic of tumors located in areas of the brain that are very sensitive to pressure and injury, such as the cortex. In some cases, only general symptoms dominate the picture; localized symptoms are either very mild or absent. These can only be detected by careful, patient and detailed examinations.

In these cases, the diagnosis of the tumor is based on the characteristics and severity of the general symptoms and the course of the disease; the clinical diagnosis of the localization of the tumor can be approximate when local symptoms cannot be detected. The forehead and right temporal lobes used to be considered the “quiet zone” of the brain. This is because they are not the centers of movement or sensory functions like the lateral and occipital lobes. Therefore, tumor pressure on these areas can be asymptomatic for a long time.

With the development of methods for diagnosing tumors on the basis of a nervous system examination, it has been proven that tumors in the “silent zone” also produce symptoms that more or less reveal their location. The diagnosis may be complicated by the fact that general symptoms of mental origin, such as mental lethargy, mask the symptoms of localization. In other words, the unconscious patient is unable to cooperate adequately with the physician and it becomes impossible to detect these very sensitive symptoms.

Localization symptoms may not always directly indicate the location of the tumor. The tumor may press on a nearby brain area, causing symptoms related to that area to become prominent. It can also cut the connecting fibers that link the primary area of involvement to distant areas, causing related symptoms (the most well-known example is the typical symptoms of cerebellum lesions in tumors of the frontal lobe).

The tumor can press on the cranial nerves from a distance. For example, temporal lobe tumors can press downwards, affecting the brain stem and the cranial nerves that exit from it. The hemisphere of the brain where the tumor is located may also be severely edematous. As a result, the local symptoms of brain tumors are not only a direct reflection of the involvement of the area where the tumor develops, but also a result of distant effects.

General Symptoms

These symptoms are due to increased intracranial pressure; they are caused both by the tumor mass and by disturbances in cerebrospinal fluid circulation. The same symptoms also occur in diseases in which there is increased intracranial pressure due to overproduction of cerebrospinal fluid and obstruction of its flow (obstructive hydrocephalus [excessive accumulation of cerebrospinal fluid in the cerebral ventricles]). All of these symptoms together are called increased intracranial pressure syndrome (ICPPS). The most important general symptoms are headache, vomiting and stasis of the papillae (blind spot). Less common but highly significant symptoms include mental lethargy, tendency to sleep and decreased pulse rate.

Headache: The most common and earliest symptom, usually severe. It can be constant, and rarely comes in seizures in the initial phase. The intensity of the headache may vary depending on the position of the body; it usually intensifies when standing upright and decreases when lying down.

Vomiting: Vomiting due to increased intracranial pressure is not related to food; there is no nausea, it is in the form of gushing. Because of these characteristics, brain-induced vomiting is also called easy vomiting (nausea-free vomiting); however, these characteristics may vary. Brain-induced vomiting is more common in the morning on an empty stomach.

Papillae stasis: Almost all intracranial tumors cause changes in the papilla (blind spot) of the eye. As the papilla swells and bulges outwards, its edges are erased and the surrounding retinal vessels protrude in an elbow-shaped projection. Dizziness: Subjective or objective dizziness induced by head movements is seen in tumors of the cerebellum and auditory nerve. Complaints such as transient disturbance of consciousness, fainting and sudden weakness observed in tumors of other regions may be mistakenly identified as dizziness by the patient.

Epilepsy (epileptic seizures): convulsive seizures, which used to be considered a general symptom, are not actually due to increased intracranial pressure. The generalized convulsive seizures that occur in cases of brain tumors should be considered as a local symptom of the tumor. In tumors of the posterior cranial cavity, where the increase in intracranial pressure is early and severe, convulsive seizures are very rare. In tumors of the temporal lobe, however, convulsive seizures may occur long before the symptoms of increased intracranial pressure (sometimes years before).

Mental lethargy: Mental lethargy is characterized by coarsening of emotions, delayed perception and slowed intellectual functioning. The patient appears apathetic, apathetic and inattentive, with reduced cognitive ability and delayed responses to questions. Mental lethargy is less common in tumors of the cerebellum and is a constant symptom in tumors of the cerebral hemispheres, especially the frontal lobe. However, in tumors of the frontal lobe, mental disorders are much more severe than mental lethargy. Yawning is a common symptom in cases with more mental lethargy.

In summary, the symptoms of intracranial tumors include headache, vomiting, stasis of the papillae, rarefaction of the pulse and mental lethargy.

Examinations

Technological examinations are mandatory and effective methods for the diagnosis and localization of intracranial tumors. The most common of these are advanced examination methods such as computed tomography and magnetic resonance imaging.