This chapter deals with four diseases affecting the central nervous system (CNS) for which neurologists are primarily involved as consultants. It follows the same approach as the chapters that focus on single diseases but does so more briefly. Brain tumors are estimated to have an incidence of 12/100,000 per year (Scharre, 2000). The incidence is highest in old age, peaking between 60 and 80 years of age. Almost 50% of intracranial tumors are gliomas, 10% to 15% are meningiomas, 5% to 7% are pituitary adenomas, and 5% to 6% are metastatic tumors. Brain tumors produce signs and symptoms in a variety of ways, including direct invasion, compression, hemorrhage, and edema. Motor, sensory, visual, and gait disturbances are frequent manifestations of brain tumors. In addition, headache and focal or generalized seizures are quite common. The psychiatric manifestations of brain tumors reflect their location; the type of brain damage they produce; patients’ reactions to their symptoms or diagnosis; and the effects of treatments such as steroids, chemotherapy, and radiation. Tumors in specific brain regions have been linked to specific psychiatric manifestations. Frontal lobe tumors are most closely associated with behavioral changes,sometimes referred to as the frontal lobe syndrome or executive dysfunction syndrome. Temporal lobe tumors are most closely associated with personality change, irritability, and hallucinations (especially auditory), as well as with a variety of language disorders. Patients with language disorders associated with temporal lobe tumors can experience catastrophic reactions when their deficits interfere with communication. Parietal lobe tumors typically are associated with cognitive deficits such as apraxia, neglect syndromes of the contralateral body or space, and unformed visual hallucinations such as streaks or flashes of light. When evaluating brain tumor patients with psychiatric symptoms and signs, careful evaluation and differential diagnosis are critical. In hospitalized and seriously ill patients, it is especially important to rule out delirium, particularly when the psychiatric phenomena are intermittent and vary in intensity. Serial observations and repeated mental status examinations are the basis for the diagnosis of delirium, but an electroencephalogram (EEG) is also helpful, because in most cases of delirium it reveals generalized slowing involving brain areas far from the location of the brain tumor.
Brain Tumor Presenting with Parkinsonism
