See Table 16-14, Metabolic and Structural Coma (p. 620), and Table 3-12, Abnormalities in Rate and Rhythm of Breathing (p. 93).
See Table 16-15, Pupils in Comatose Patients (p. 621).
Structural lesions such as stroke may lead to asymmetrical pupils and loss of light reaction.
In structural hemispheric lesions, the eyes "look at the lesion" in the affected hemisphere.
In irritative lesions due to epilepsy or early cerebral hemorrhage, the eyes "look away" from the affected hemisphere.
In a comatose patient with absence of doll's eye movements, shown below, the ability to move both eyes to one side is lost, suggesting a lesion of midbrain or pons.
In a comatose patient with an intact brainstem, as the head is turned the eyes move toward the opposite side (the doll's eye movements). In the adjacent photo, for example, the patient's head has been turned to the right; her eyes have moved to the left. Her eyes still seem to gaze at the camera. The doll's eye movements are intact.
OCULOVESTIBULAR REFLEX (WITH CALORIC STIMULATION). If the oculocephalic reflex is absent and you seek further assessment of brainstem function, test the oculovestibular reflex. Note that this test is almost never performed in an awake patient.
Make sure the eardrums are intact and the canals clear. You must elevate the patient's head to 30° to perform the test accurately. Place a kidney basin under the ear to catch any overflowing water. With a large syringe, inject ice water through a small catheter that is lying in (but not plugging) the ear canal. Watch for deviation of the eyes in the horizontal plane. You may need to use up to 120 ml of ice water to elicit a response. In the comatose patient with an intact brainstem, the eyes drift toward the irrigated ear. Repeat on the opposite side, waiting 3 to 5 minutes if necessary for the first response to disappear.
POSTURE AND MUSCLE TONE. Observe the patient's posture. If there is no spontaneous movement, you may need to apply a painful stimulus (see p. 595). Classify the resulting pattern of movement as:
■ Normal-avoidant—the patient pushes the stimulus away or withdraws.
■ Stereotypic—the stimulus evokes abnormal postural responses of the trunk and extremities.
■ Flaccid paralysis or no response
Test muscle tone by grasping each forearm near the wrist and raising it to a vertical position. Note the position of the hand, usually only slightly flexed at the wrist.
No response to stimulation suggests brainstem injury.
See Table 16-16, Abnormal Postures in the Comatose Patient (p. 622).
Two stereotypic responses predominate: decorticate rigidity and decerebrate rigidity (see Table 16-16, Abnormal Postures in the Comatose Patient, p. 622).
No response on one side suggests a corticospinal tract lesion.
The hemiplegia of sudden cerebral accidents is usually flaccid at first. The limp hand drops to form a right angle with the wrist.
Then lower the arm to about 12 or 18 inches off the bed and drop it. Watch how it falls. A normal arm drops somewhat slowly.
A flaccid arm drops rapidly, like a flail.
Support the patient's flexed knees. Then extend one leg at a time at the knee and let it fall (see next page). Compare the speed with which each leg falls.
In acute hemiplegia, the flaccid leg falls more rapidly
Flex both legs so that the heels rest on the bed and then release them. The normal leg returns slowly to its original extended position.
As you complete the neurologic examination, check for facial asymmetry and asymmetries in motor, sensory, and reflex function. Test for meningeal signs if indicated.
In acute hemiplegia, the flaccid leg falls rapidly into extension, with external rotation at the hip.
Meningitis, subarachnoid hemorrhage.
As you proceed to the general physical examination, check for unusual odors. Alcohol, liver failure, uremia
Look for abnormalities of the skin, including color, moisture, evidence of bleeding disorders, needle marks, and other lesions.
Examine the scalp and skull for signs of trauma.
Examine the fundi carefully.
Check to make sure the corneal reflexes are intact. (Remember that use of contact lenses may abolish these reflexes.)
Inspect the ears and nose, and examine the mouth and throat.
Be sure to evaluate the heart, lungs, and abdomen.
Tables 16-1 through 16-7 summarize the manifestations of selected disorders. They show how the data collected can be used diagnostically, and will help you to recognize and think about certain patterns of illness.
Tables 16-1, 16-3, and 16-4 are based, with permission, on the Diagnostic and Statistical ManualofMentalDisorders, Fourth Edition, Text Revision (DSM IV-TR) Washington, D.C., American Psychiatric Association, 2000. For further details and criteria, the reader should consult this manual, its successor, or comprehensive textbooks of psychiatry.
Jaundice, cyanosis, cherry red color of carbon monoxide poisoning
Bruises, lacerations, swelling
Papilledema, hypertensive retinopathy
Reflex loss in coma and lesions affecting CN V or CN VII
Blood or cerebrospinal fluid in the nose or the ears suggests a skull fracture; otitis media suggests a possible brain abscess.
Tongue injury suggests a seizure.
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