102 Intracranial and Other Central Nervous System Lesions
Key Points• A comprehensive patient history is imperative to narrow the differential diagnosis when a new mass lesion is discovered on radiographic imaging.
• A complaint of dizziness requires cerebellar testing, including finger-nose, heel-shin, dysdiadochokinesia, and gait evaluation.
• Fever in the setting of a neurologic complaint requires both a neurologic examination and consideration of neuroimaging.
• Any patient with a first-time seizure warrants a non–contrast-enhanced computed tomography (CT) scan of the head regardless of age (Box 102.1).
• CT scans reliably demonstrate lesions 1.0 cm or larger.
• Magnetic resonance imaging should be performed if there is significant concern for a central nervous system lesion in patients with negat ive CT findings.
Box 102.1
Indications for Computed Tomography of the Brain in Patients with First-Time Seizures
Adapted from guidelines developed by the U.S. Headache Consortium, American College of Emergency Physicians, and the American College of Radiology. American College of Emergency Physicians. Clinical policy: critical issues in the evaluation and management of patients presenting to the emergency department with acute headache. Ann Emerg Med 2002;39:108.
Epidemiology
Patients with intracranial lesions typically have headaches, seizures, focal neurologic changes, weakness, fatigue, or any combination of these findings. Headaches occur in approximately 50% of patients with central nervous system (CNS) tumors; however, brain tumors are uncommon in patients with a headache and normal findings on neurologic examination (<1% of the time).1 Thus emergency physicians should always consider the presence of a brain tumor in the differential diagnosis but should use neuroimaging judiciously (Table 102.1).2,3 Focal neurologic changes always warrant further investigation, including laboratory tests, radiographic imaging, and neurologic or neurosurgical consultation (or both).
Table 102.1 Guidelines for Neuroimaging in Patients with a Headache
| CLINICAL FINDING | RECOMMENDATION |
|---|---|
| “Thunderclap” headache with abnormal neurologic findings | Emergency neuroimaging recommended |
| Signs of increased intracranial pressure; fever and nuchal rigidity | Safe performance of lumbar puncture recommended |
| “Thunderclap” headache | Neuroimaging should be considered |
| Headache radiating to the neck | |
| Temporal headache in an older individual | |
| New-onset headache in a patient who: | |
| Is HIV positive | |
| Has a previous diagnosis of cancer | |
| Is in a population at high risk for intracranial disease | |
| Accompanied by an abnormal neurologic findings, including but not limited to papilledema, unilateral loss of sensation, weakness, and hyperreflexia | |
| Migraine and normal neurologic findings | Neuroimaging not usually warranted |
| Headache worsened by the Valsalva maneuver, wakes the patient from sleep, or is progressively worsening | No recommendation (some data revealing increased risk for intracranial abnormality, not sufficient for recommendation) |
| Tension headache with normal neurologic findings | No recommendation (insufficient data) |
Adapted from guidelines developed by the U.S. Headache Consortium, American College of Emergency Physicians, and American College of Radiology. American College of Emergency Physicians. Clinical policy: critical issues in the evaluation and management of patients presenting to the emergency department with acute headache. Ann Emerg Med 2002;39:108.
Pathophysiology
Autopsy diagnosis reveals that nearly 25% of patients who die of cancer had intracranial metastasis (Fig. 102.1). The lung is the most common origin of brain metastases. Breast cancer (especially ductal carcinoma) has a propensity to metastasize to the cerebellum and the posterior pituitary gland; however, breast cancer that metastasizes to bone tends to not metastasize to the brain.
