Approach to the neurologic patient

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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 neurologic examination markedly narrows the differential diagnosis and thus the number of tests needed. 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

Is the lesion in one or multiple locations?
Is the lesion confined to the nervous system, or is it part of a systemic disorder?
What part of the nervous system is affected?

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

Vascular
Infectious
Neoplastic
Degenerative
Traumatic
Toxic-metabolic
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-Barr#233; syndrome is actually due to spinal cord compression.