What is the best explanation of stereotactic radiosurgery?

Early detection of brain tumors relies on imaging tests that can visualize small masses and structural changes. A CT scan is often the first diagnostic tool ordered because it provides detailed images of the brain, allowing detection of small tumors, edema, and mass effect. CT scans are quick, widely available, and highly sensitive for structural abnormalities, making them ideal for initial evaluation of new neurological symptoms.

Rationale for correct answer:

A. CT scan: Provides clear structural images that can identify small tumors and associated edema. It is fast and widely available, making it the first-line imaging study in suspected brain tumor cases.

Rationale for incorrect answers:
B. Angiography: Evaluates cerebral blood vessels and tumor vascularity but is not typically used for initial tumor detection. It is reserved for surgical planning or assessing vascular involvement.
C. Electroencephalography (EEG): Records electrical brain activity and is used for seizure evaluation, not structural tumor detection.
D. Positron emission tomography (PET) scan: Identifies areas of metabolic activity or recurrence but is not the primary tool for detecting small, new tumors.

Take home points

• CT scan is the first-line imaging study to detect new or small brain tumors.
• Angiography and PET scans are used for tumor characterization or surgical planning, not initial detection.
• EEG is useful for evaluating seizures but does not visualize structural lesions.

Dexamethasone (Decadron) is a corticosteroid commonly prescribed to clients with expanding brain tumors to reduce cerebral edema. By decreasing swelling and inflammation, it helps relieve intracranial pressure and associated neurological symptoms such as headache or vomiting. Corticosteroids, however, are associated with metabolic and fluid retention side effects that require client education. Monitoring and teaching about weight gain, fluid retention, and hyperglycemia are essential to safe therapy.

Rationale for correct answers:

A. “It is given to reduce swelling of the brain.” Dexamethasone decreases cerebral edema and relieves symptoms of increased ICP. This is the primary therapeutic purpose in brain tumor management.

C. “You may notice weight gain.” Corticosteroids can increase appetite and cause fat redistribution, resulting in weight gain. This is a common, expected side effect of therapy.

E. “It can cause you to retain fluids.” Steroids promote sodium and water retention, which can lead to peripheral edema. Clients should be taught to monitor for swelling or sudden weight changes.

Rationale for incorrect answers:
B. “You will need to monitor for low blood sugar.” Dexamethasone can raise, not lower, blood glucose levels. Hyperglycemia is a more likely concern, especially in clients with diabetes.
D. “Tumor growth will be delayed.” Dexamethasone does not affect tumor growth; it only reduces surrounding edema. Definitive tumor treatment requires surgery, radiation, or chemotherapy.

Take home points

• Dexamethasone reduces cerebral edema but does not shrink the tumor itself.
• Weight gain, fluid retention, and hyperglycemia are key side effects requiring education.
• Client teaching helps ensure early recognition of complications during corticosteroid therapy.