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Fifth stage
Medicine
Lec-1
د.بشار
12/10/2015
Evaluation of the Neurologic Patient
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 pelvic 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
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Traumatic
Toxic-metabolic
Immune mediated
1- History
The history is the most important part of the neurologic evaluation. Patients should be
put at ease and allowed to tell their story in their own words. Usually, a clinician can
quickly determine whether a reliable history is forthcoming or whether a family member
should be interviewed instead
Specific questions clarify the quality, intensity, distribution, duration, and frequency of
each symptom. What aggravates and attenuates the symptom and whether past
treatment was effective should be determined. Asking the patient to describe the order
in which symptoms occur can help identify the cause.
Specific disabilities should be described quantitatively (eg, walks at most 25 ft before
stopping to rest), and their effect on the patient's daily routine noted. Past medical
history and a complete review of systems are essential because neurologic
complications are common in other disorders, especially alcoholism, diabetes, cancer,
vascular disorders, and HIV infection.
Family history is important because migraine and many metabolic, muscle, nerve, and
neurodegenerative disorders are inherited. Social, occupational, and travel history
provides information about unusual infections and exposure to toxins and parasites
Sometimes neurologic symptoms and signs are functional or hysterical, reflecting a
psychiatric disorder. Typically, such symptoms and signs do not conform to the rules of
anatomy and physiology, and the patient is often depressed or unusually frightened.
However, functional and physical disorders sometimes coexist, and distinguishing them
can be challenging.
2- Neurological examination
3- Diagnostic procedures
Diagnostic procedures should not be used for preliminary screening, except perhaps in
emergencies when a complete neurologic evaluation is impossible. Evidence uncovered
during the history and physical examination should guide testing
Lumbar puncture is used to evaluate intracranial pressure and CSF composition (see see
Cerebrospinal Fluid Abnormalities in Various Disorders ), to therapeutically reduce
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intracranial pressure (eg, pseudotumor), and to administer intrathecal drugs or a
radiopaque dye for myelography
CT provides rapid, noninvasive imaging of the brain and skull: MRI provides better
resolution of neural structures than CT. This difference is most significant clinically for
visualizing cranial nerves, brain stem lesions, abnormalities of the posterior fossa, and
the spinal cord; CT images of these regions are often marred by bony streak artifacts.
Also, MRI is better for detecting demyelinating plaques, early infarction, subclinical brain
edema, cerebral contusions, incipient transtentorial herniation, abnormalities of the
craniocervical junction, and syringomyelia. MRI is especially valuable for identifying
spinal abnormalities (eg, tumor, abscess) compressing the spinal cord and requiring
emergency intervention
Myelography
X-rays are taken after a radiopaque agent is injected into the subarachnoid space via
lumbar puncture
EEG
Electrodes are distributed over the brain to detect electrical changes associated with
seizure disorders, sleep disorders, and metabolic or structural encephalopathies. Twenty
electrodes are distributed symmetrically over the scalp
Measurement of evoked responses (potentials): Visual, auditory, or tactile stimuli are
used to activate corresponding areas of the cerebral cortex, resulting in focal cortical
electrical activity. Ordinarily, these small potentials are lost in EEG background noise,
but computer processing cancels out the noise to reveal a waveform. Latency, duration,
and amplitude of the evoked responses indicate whether the tested sensory pathway is
intact
Electromyography and nerve conduction studies
When determining whether weakness is due to a nerve, muscle, or neuromuscular
junction disorder is clinically difficult, these studies can identify the affected nerves and
muscles
Biopsy
Nerve and muscle biopsy are usually done simultaneously