neurologic disorders
Approach to the Neurologic Patient
Introduction
Patients with neurologic symptoms are approached in a stepwise manner termed the neurologic method, which consists of the following: Identifying the anatomic location of the lesion or lesions causing symptoms Identifying the pathophysiology involved Generating a differential diagnosis Selecting specific, appropriate tests Identifying the anatomy and pathophysiology of the lesion through careful history-taking and an accurate Introduction to the Neurologic Examination markedly narrows the differential diagnosis and thus the number of tests needed. The history is important in identifying the likely site of neurologic dysfunction, and the neurologic examination is used to corroborate the suspected location. This approach should not be replaced by reflex ordering of CT, MRI, and other laboratory testing; doing so leads to error and unnecessary cost. To identify the anatomic location, the examiner considers questions such as Are all the symptoms and signs referable to a single lesion in the nervous system or to multiple lesions? Is the central or peripheral nervous system involved, or are both involved? Specific parts of the nervous system to be considered include the cerebral cortex, subcortical white matter, basal ganglia, thalamus, cerebellum, brain stem, spinal cord, brachial or lumbosacral plexus, peripheral nerves, neuromuscular junction, and muscle. Once the location of the lesion is identified, categories of pathophysiologic causes are considered; they include those originating primarily in the nervous system and those originating elsewhere in the body and affecting the nervous system secondarily (eg, vascular, infectious, immune-mediated). General categories of causes for neurologic disorders include the following: Vascular Infectious Neoplastic Degenerative Traumatic Toxic-metabolic Congenital Immune-mediated When appropriately applied, the neurologic method provides an orderly approach to even the most complex case, and clinicians are far less likely to be fooled by neurologic mimicry—eg, when symptoms of an acute stroke are actually due to a brain tumor or when rapidly ascending paralysis suggesting Guillain-Barré syndrome is actually due to spinal cord compression. 