**4. Brain tumors symptoms in children**

Symptoms of brain tumors can develop gradually and worsen over time, or they may manifest suddenly and dramatically. Symptoms may be general or specific, resulting from tumor localization. **General symptoms** are manifestation of intracranial hypertension that is caused either by tumor growth, brain swelling or onset of hydrocephalus or a combination of these factors. Symptoms of intracranial hypertension include: headache (especially in the morning after awakening), nausea or vomiting, diplopia and strabismus, disturbances of balance, personality changes, epileptic seizures or loss of consciousness. Infants may experience irritability, loss of appetite, delay or regression of psychomotor development. There is also bulging of the fontanelle and the disproportionate enlargement of the head circumference. Children of school age may suffer from increased fatigue, psychological changes, impairment of school performance, disturbances of memory and impaired concentration. Regarding the localization of the tumor, other locally **specific neurological symptoms** may also occur: visual disturbances, narrowing and outages of visual field, abnormal bulb movements, nystagmus, hearing or speech disorders, paresis or hemiparesis, muscle weakness, loss of sensitivity or coordination, ataxia, posture disorder, walking instability, tingling of body parts, cranial nerves palsy as well as hormonal disorders.

## **5. Brain tumors diagnostics**

Diagnosis of brain tumor is based on a patient history and complete neurological examination. Imaging examination is performed when a brain tumor is suspected. Basic imaging examination is **magnetic resonance imaging (MRI).** It is the most spectacular imaging for intracranial structures that is currently available in medicine. In brain tumor diagnostics the use of contrast media—gadolinium—is essential. **MR-angiography** displays brain vessels alongside with pathological tumor vasculature, what is important for planning of the surgical treatment. **MR-spectroscopy** is a metabolic examination of the brain. The **perfusion MRI** monitors blood flow in the investigated area. Tumors are metabolically active and require greater blood supply. **Functional MRI** and **MR-tractography** are used for planning of surgical approach. Preoperatively, the navigational MRI is performed for the needs of intraoperative navigation. Among the disadvantages of MRI is relatively longer duration, which in smaller children requires general anesthesia. However, a huge advantage is the absence of radiation [13].

**Computer tomography (CT)** is mostly used for the display of bones and their lesions, which do not appear in detail in MRI. Another indication may be **CT-angiography.** Due to the high dose of radiation; however, CT is reserved for cases of sudden changes in the neurological condition when rapid imaging is necessary.

**Positron emission tomography (PET)** uses radioactive fluorodeoxyglucose for visualization of tumor tissue that is metabolically more active. The radioactive load is very low and is excluded in 1 day. It can be used preoperatively for diagnostics as well as for postoperative distinguishing between residues, recurrences and postoperative changes in unclear cases [14].

**Angiography** (mostly DSA) uses vessel imaging after contrast agent administration to assess tumor vascular supply. It is also associated with radiation and though is currently replaced by MR- or CT-angiography. However, it remains reserved for preoperative embolization of the tumor, which is carried out by DSA [13].

Specimen of CSF obtained from **lumbar puncture** is used for cytological examination to detect the presence of tumor cells that occur in CSF in tumor dissemination or in leukemia tumors. It is also used to detect the presence of tumor markers, in particular bHCG and AFP in germ cell tumors. It also serves to verify the presence of infection, especially in the postoperative period [13].

**Biopsy** of brain tumor is essential for definitive diagnosis. In most cases, tissue sample is obtained during surgery. However, there are also cases of inoperable tumors according to their localization or extent. If a tumor resection cannot be performed, a stereotactic biopsy can be useful. In some cases, however, the biopsy is too risky, and therefore the diagnosis is determined only by MRI (e.g., diffuse pontine gliomas).

Also **other examinations** could be useful, such as: EEG, evoked potentials, evaluation of neurocognitive functions, ophthalmological examination (papilledema of optic nerve and perimeter), evaluation of hearing disorder and hormone levels and function [13].
