APPROACH TO THE PATIENT Tumors of the Nervous System Clinical Presentation
Brain tumors can present with general and/or focal symptoms and signs. Nonspecific symptoms include headache with or without nausea and vomiting, cognitive difficulties, personality change, and gait disorder. The classic brain tumor headache predominates in the morning and improves during the day, but this pattern is seen only in a minority of pts. Papilledema may suggest elevated intracranial pressure. Focal symptoms and signs include hemiparesis, aphasia, or visual field deficit; these are typically subacute and progressive. Seizures are common, occurring in ∼25% of pts with brain metastases or malignant glioma, and are the presenting symptom in up to 90% of pts with low-grade glioma. Evaluation
Primary brain tumors, unlike metastases, have no serologic features of malignancy such as an elevated ESR or tumor-specific antigens. Cranial MRI with contrast is the preferred diagnostic test for any pt suspected of having a brain tumor; CT should be reserved for pts unable to undergo MRI. Malignant brain tumors typically enhance with contrast and may have central areas of necrosis; they are characteristically surrounded by edema of the neighboring white matter. Low-grade gliomas typically do not enhance. Meningiomas have a typical appearance on MRI because they are dural-based enhancing tumors with a dural tail that compress but do not invade the brain. Additional testing such as cerebral angiogram, EEG, or lumbar puncture is rarely indicated or helpful.
TREATMENT Tumors of the Nervous System SYMPTOMATIC TREATMENT
Glucocorticoids (dexamethasone 8–16 mg/d PO or IV) to temporarily reduce edema
Anticonvulsants (levetiracetam, topiramate, lamotrigine, valproic acid, or lacosamide) for pts who present with seizures (Chap. 184); there is no role for prophylactic anticonvulsant drugs
Low-dose SC heparin for immobile pts
PRIMARY INTRACRANIAL TUMORS
Astrocytomas Including Glioblastomas
Infiltrative tumors with a presumptive glial cell of origin. Most common primary intracranial neoplasm. Only known risk factors are ionizing radiation, uncommon hereditary syndromes (neurofibromatosis, tuberous sclerosis), and immunosuppression (primary CNS lymphoma). Infiltration along white matter pathways often prevents total resection. Imaging studies (Fig. 75-1) fail to indicate full tumor extent. Grade I tumors (pilocytic astrocytomas) are the most common tumor of childhood, typically in the cerebellum; can be cured if completely resected. Grade II astrocytomas usually present with seizures in young adults; if feasible should be surgically resected. In pts at higher risk for recurrence (subtotal resection or above the age of 40 years), radiation therapy (RT) followed by PCV (procarbazine, (cyclohexylchloroethylnitrosourea [CCNU]), and vincristine) chemotherapy may possibly be of benefit. The tumor transforms to a malignant astrocytoma in most pts, leading to variable survival with a median of about 5−10 years. Grade III (anaplastic astrocytoma) and grade IV (glioblastoma) astrocytomas are treated similarly with maximal safe surgical resection followed by ...