Presenting signs and symptoms in brain tumors

Focal symptoms and signs occurring during brain tumor clinical presentation are dependent on a number of factors. Location and rate of growth are the most critical, followed by overall lesion size and nature, whether infiltrating or causing the displacement of neural structures, but also the presence or extent of associated pathology, including edema, hemorrhage, vascular compromise, and cerebrospinal fluid obstruction. Mechanisms of presenting symptomatology can be divided into tumor and peritumoral factors. Tumor factors include histology, for example, in that seizures are common in patients with certain low-grade gliomas. Peritumoral factors, including regional hypoxia and ionic changes in the peritumoral zone, may influence neuronal activity and extracellular glutamate may be associated with neuronal hyperexcitability. Blood-brain barrier breakdown may predispose to seizure and localized neuronal dysfunction. Finally, signs and symptoms in brain tumors can be generalized, associated with increased intracranial brain pressure, but can also be localized, based on the involvement of the major structures of the central nervous system.