Brain tumors

Intracranial  pressure

Intracranial pressure (ICP) refers to the pressure within the skull caused by the volume of three main components:

  1. Brain tissue

  2. Cerebrospinal fluid (CSF)

  3. Blood (mainly venous)

Monroe-Kelly doctrine: the volume of the intracranial components - brain tissue, blood, CSF - is constant. 

Increase of any of them is possible only at the expense of the other two, and that increases the intracranial pressure. 

Symptoms of increased intracranial pressure

  • Headache (diffuse, continous, progressive in character)

  • Nausea, vomitus 

  • Disturbances of consciousness 

  • Cushing phenomenon: bradycardia, increased systolic blood pressure

  • Bilateral edema of the optic disc

  • Diplopia (due to bilateral abducent nerve palsy)

Increased intracranial pressure

  • Space-occupying lesions: tumors, brain oedema, inflammation, abscess, haemorrhage, brain infarction, brain contusion, occlusive hydrocephalus, parasites, etc.

  • Changes in CSF  flow:  subarachnoideal hemorrhage, meningitis. 

  • Circulatory disturbances: extremely high arterial blood pressure, thrombosis of the cerebral veins or venous sinuses.

brain tumors

Brain tumors charaterised by:

  • Insidious development of symptoms is typical for brain tumors.

  • Sudden worsening or onset of new symptoms may be a consequence of intratumoral haemorrhage or herniation. 

Brain tumors - symptoms

  • Focal signs: Direct effect of the tumor leads to damaged function (e.g. paresis, hypaesthesia, visual field defect). Positive symptoms - focal or generalized epileptic seisures 

  • Compression signs: Effects on surrounding structures, tracts, cranial nerves, CSF pathways resulting in hydrocephalus.

  • General symptoms caused by the increased intracranial pressure, mass effect of the tumor, independent from its nature. 

  • Psychiatric signs: cognitive, behavioural or personality changes (sometimes leading or only features of the tumor)

  • Hormonal changes - result of dysfunction of the pituitary gland

  • Sometimes tumor may be exactly localized by the findings of the physical examination. 

  • In the suspicion of brain tumor imaging methods are indicated.

Brain tumors - diagnostics

  • Brain CT: Administration of contrast media (containing iodine) is necessary. CT is not proper for small tumors, mainly in the posterior fossa (bony artefacts). CT is prior to MR in evaluation of intratumoral calcification an bone destruction. Some tumors have characteristic CT features (e.g. meningiomas)

  • Brain MR: The proper method of diadnostics of brain tumors. More detailed spatial resolution,  multi-planar imaging,  all parts of the brain are well visualized. The best method for surgical planning 

  • Angiography: Disclosing of the blood supply of some hyper-vascularized tumors (e.g. angiomas, meningiomas

  • Brain SPECT and PET:  Evaluation of circulation and metabolism of tumors. Differentation between tumors and lesions of other nature in controversary cases. 

  • Brain biopsy: CT assisted, „stereotaxic” procedure. Exact histological classification of tumors (grading)

 

  • Additional tests: 

    • CSF examination

    • EEG

    • Evoked potentials 

    • Hormonal tests

    • Genetics

Brain tumors - classification

  • Neuroepithelial tumors

  • Tumors of the peripheral nerves

  • Tumors originated from the meninges

  • Metastatic tumors

Neuroepithelial tumors 

  • Astrocytomas (graded I-IV)

  • The most malignant form is Glioblastoma multiforme 

  • High malignancy, rapid growth, infiltrative 

  • Symptoms: seisures, focal signs, elevated intracranial pressure, headache, 

  • psychiatric disorders (depression, behavioural or personality changes)

  • Diagnosis: CT, MR 

  • Treatment:  surgical; total removal is not possible. Irradiation and chemotheraby mav be added. High rate of recurrence, poor survival (maximum 1,5 year)

Tumors originated from the meninges  

  • Meningiomas: any age. Slow growth (20-30 years), but may reach extreme sizes. Rarely turns into malignancy. May destroy bones of skull. 

  • Originated from cells of the arachnoidea. 

  • Symptoms: depending on localisation. Epileptic seisures may occur. 

  • Diagnosis: CT, MR 

  • Treatment:  surgical, total removal if possible.  Total recovery may be achieved. 

Metastatic brain tumors

In many cases the brain metastasis is diagnosed before the recognition of the primary tumor.  Sometimes the origin is not found at all. 

  • Metastatic brain tumors in order of frequency: 

    • Lung 64%

    • Breast   14%

    • Unknown origin               8%

    • Malignant melanoma       4%

  • Symptoms: not different than the primary tumors: focal epileptic seizures are quite frequent 

  • Diagnosis: CT, MR and biopsy

  • Treatment: Solitary metastasis: surgical removal is possible. Multiplex metastasis: irradiation or chemotherapy. 

  • Brain tumors are not frequent, but we have to consider them. 

  • The symptoms of brain tumors are not specific.

  • New onset headache or epileptic seisures always indicate a search for brain tumor. 

  • Some types of brain tumors recognized in time have good outcome.