First Encounter With a Patient: Examination and Formulation

Examination

Neurologists usually begin by noting a patient’s age, sex, and handedness before reviewing the primary symptom, present illness, medical history, family history, and social history. They explore the primary symptom, associated symptoms, and possible etiologic factors. If a patient cannot relate the history, the neurologist might interrupt the process to look for language, memory, or other cognitive deficits. Many chapters in Section II contain outlines of standard questions related to common symptoms.

After obtaining the history, the neurologist should be able to anticipate the patient’s deficits and prepare to look for disease primarily affecting the central nervous system (CNS) or the peripheral nervous system (PNS). At this point, without succumbing to rigid preconceptions, the physician should have developed some sense of the problem at hand.

Then neurologists should look for the site of involvement (i.e., “localize the lesion”). The art of localization, one of the initial goals of most neurologic examinations, is valuable in the majority of cases. However, it is largely inapplicable in several important neurologic illnesses, such as Alzheimer disease.

The examination is not only of historical interest but irreplaceable in diagnosis. It consists of a survey of neuroanatomical function: mental status, cranial nerves, motor system, reflexes, sensation, cerebellar system, and gait ( Box 1.1 ). This format should be followed during most examinations. Trainees still mastering this structure may find it helpful to bring a printed copy to the patient’s bedside to serve both as a reminder and as a place to record neurologic findings.

The examination usually starts with an assessment of the mental status because cognition is the most fundamental neurologic function and cognitive impairments may preclude an accurate assessment of other neurologic functions. The examiner should consider specific intellectual deficits, such as language impairment (see Aphasia, Chapter 8 ) and general cognitive impairment (see Dementia, Chapter 7 ). Tests of cranial nerves may reveal malfunction of nerves either individually or in groups, such as the ocular motility nerves (III, IV, and VI) or the cerebellopontine angle nerves (V, VII, and VIII) (see Chapter 4 ).

The examination of the motor system defines the anatomic pattern of weakness as well as its severity. Whether weakness is partial (paresis) or complete (plegia) , the pattern offers reliable clues to localization. On a practical level, the severity of the paresis determines the patient’s functional capacity (e.g., whether a patient walks, requires a wheelchair, or stays bedridden).

Neurologists frequently speak of three patterns of paresis. If the lower face, arm, and leg on one side of the body are paretic, they call the pattern hemiparesis . They usually attribute hemiparesis to damage in the contralateral cerebral hemisphere or brainstem. They call weakness of both legs paraparesis , and weakness of all four limbs quadriparesis . In both cases, neurologists may ascribe the weakness to either PNS or CNS injury depending on any accompanying findings and test results.

Eliciting two categories of reflexes assists in determining whether paresis—or other neurologic abnormality—originates in CNS or PNS injury. Deep tendon reflexes (DTRs) are normally present with uniform reactivity (speed and forcefulness) in all limbs, but neurologic injury typically alters their activity or symmetry. In general, CNS injury that includes corticospinal tract damage makes DTRs hyperactive, whereas PNS injury makes DTRs hypoactive.

In contrast to DTRs, pathologic reflexes are not normally elicitable beyond infancy. If found, they are a sign of CNS damage. The most widely recognized pathologic reflex is the famous Babinski sign . After plantar stimulation, the great toe normally moves downward (i.e., it has a flexor response), but with corticospinal tract damage, whether in the brain or spinal cord, plantar stimulation typically causes the great toe to move upward (i.e., to have an extensor response). This reflex extensor movement, the Babinski sign (see Fig. 19.3 ), is thus a manifestation of CNS damage. Neurologists say that the Babinski sign and other pathologic reflexes are “present,” “found,” or “elicited,” but not “positive” or “negative.” The terminology is similar to describing a traffic stop sign: it may be present or absent, but not positive or negative.

Frontal release signs , which are also pathologic reflexes, reflect frontal lobe injury; when present, they reflect loss of the inhibitory capacity of the frontal lobes. Thus, they point to an “organic” or structural basis for a change in personality and sometimes correlate with cognitive impairment (see Chapter 7 ).

Unlike abnormal DTRs and Babinski signs, which are reproducible, objective, and difficult to mimic, the sensory examination relies almost entirely on the patient’s report. Its subjective nature has led to the practice of disregarding reports of disturbances inconsistent with the rest of the examination. Under most circumstances, the best approach is to test the major sensory modalities in a clear anatomic order and tentatively accept the patient’s report.

Depending on the nature of the suspected disorder, physicians may first test light touch sensation with their fingertips or a cotton swab, and then two sensations carried by the posterior columns of the spinal cord: position and vibration. Neurologists might test pain (pinprick) sensation, which is carried in the spinothalamic tracts, but only in a careful manner with a nonpenetrating, disposable instrument, such as a broken wood shaft of the cotton swab.

Neurologists evaluate cerebellar function by observing several standard maneuvers that include the finger-to-nose test and rapid alternating movement test (see Chapter 2 ). These tests may demonstrate intention tremor or incoordination.

If at all possible, neurologists watch the patient walk because a normal gait requires intact and well-integrated CNS and PNS motor pathways, coordination, proprioception, and balance. Examining the gait is probably the single most valuable assessment of non-cognitive functions of the nervous system. Neurologists watch for gait abnormalities that characterize many neurologic illnesses (see Table 2.1 ). In addition, they expect certain gait abnormalities to be comorbid with cognitive impairment. Whatever the underlying abnormality, gait impairment is not merely a neurologic sign but a condition that routinely leads to fatal falls and permanent incapacity for numerous people each year.