not respond to the physician’s voice, the phy-
sician may speak more loudly or shake the pa-
tient. When this fails to produce a response,
the physician begins a more formal coma eval-
uation.
The examiner must systematically assess the
arousal pathways. To determine if there is a
structural lesion involving those pathways, it is
necessary also to examine the function of brain-
stem sensory and motor pathways that are ad-
jacent to the arousal system. In particular, be-
cause the oculomotor circuitry enfolds and
surrounds most of the arousal system, this part
of the examination is particularly informative.
Fortunately, the examination of the comatose
patient can usually be accomplished very quickly
because the patient has such a limited range of
responses.However, theexaminermust become
conversant with the meaning of the signs elic-
ited in that examination, so that decisions that
may save the patient’s life can then be made
quickly and accurately.
The evaluation of the patient with a reduced
level of consciousness, like that of any patient,
requires a history (to the extent possible), phys-
ical examination, and laboratory evaluation.
These are considered, in turn, in this chapter.
However, as soon as it is determined that a
patient has a depressed level of consciousness,
the next step is to ensure that the patient’s
brain is receiving adequate blood and oxygen.
The emergency treatment of the comatose pa-
tient is detailed in Chapter 7. The physiology
and pathophysiology of the cerebral circulation
and of respiration are considered in the para-
graphs below.
HISTORY
In patients with nervous system dysfunction,
the history is the most important part of the
examination (Table 2–1). Of course, patients
with coma or diminished states of conscious-
ness by definition are not able to give a history.
Thus, the history must be obtained if possible
from relatives, friends, or the individuals,
usually the emergency medical personnel, who
brought the patient to the hospital.
The onset of coma is often important. In a
previously healthy, young patient, the sudden
onset of coma may be due to drug poisoning,
subarachnoid hemorrhage, or head trauma; in
the elderly, sudden coma is more likely caused
by cerebral hemorrhage or infarction. Most pa-
tients with lesions compressing the brain either
have a clear history of trauma (e.g., epidural
hematoma; see Chapter 4) or a more gradual
rather than abrupt impairment of conscious-
ness. Gradual onset is also true of most patients
with metabolic disorders (see Chapter 5).
The examiner should inquire about previous
medical symptoms or illnesses or any recent
trauma. A history of headache of recent onset
points to a compressive lesion, whereas the his-
tory of depression or psychiatric disease may
suggest drug intoxication. Patients with known
diabetes, renal failure, heart disease, or other
chronic medical illness are more likely to be
suffering from metabolic disorders or perhaps
brainstem infarction. A history of premonitory
signs, including focal weakness such as dragging
Table 2–1 Examination of the
Comatose Patient
History ( from Relatives, Friends, or Attendants)
Onset of coma (abrupt, gradual)
Recent complaints (e.g., headache, depression,
focal weakness, vertigo)
Recent injury
Previous medical illnesses (e.g., diabetes,
renal failure, heart disease)
Previous psychiatric history
Access to drugs (sedatives, psychotropic drugs)
General Physical Examination
Vital signs
Evidence of trauma
Evidence of acute or chronic systemic illness
Evidence of drug ingestion (needle marks,
alcohol on breath)
Nuchal rigidity (assuming that cervical trauma
has been excluded)
Neurologic Examination
Verbal responses
Eye opening
Optic fundi
Pupillary reactions
Spontaneous eye movements
Oculocephalic responses (assuming cervical
trauma has been excluded)
Oculovestibular responses
Corneal responses
Respiratory pattern
Motor responses
Deep tendon reflexes
Skeletal muscle tone
Examination of the Comatose Patient
39
of the leg or complaints of unilateral sensory
symptoms or diplopia, suggests a cerebral or
brainstem mass lesion.
GENERAL PHYSICAL
EXAMINATION
The general physical examination is an im-
portant source of clues as to the cause of
unconsciousness. After stabilizing the patient
(Chapter 7), one should search for signs of
head trauma. Bilateral symmetric black eyes
suggest basal skull fracture, as does blood be-
hind the tympanic membrane or under the
skin overlying the mastoid bone (Battle’s sign).
Examine the neck with care; if there is a pos-
sibility of trauma, the neck should be im-
mobilized until cervical spine instability has
been excluded by imaging. Resistance to neck
flexion in the presence of easy lateral move-
ment suggests meningeal inflammation such as
meningitis or subarachnoid hemorrhage. Flex-
ion of the legs upon flexing the neck (Brud-
zinski’s sign) confirms meningismus. Examina-
tion of the skin is also useful. Needle marks
suggest drug ingestion. Petechiae may suggest
meningitis or intravascular coagulation. Pres-
sure sores or bullae indicate that the patient
has been unconscious and lying in a single
position for an extended period of time, and
are especially frequent in patients with barbitu-
rate overdosage.
1
LEVEL OF CONSCIOUSNESS
After conducting the brief history and exami-
nation as outlined above and stabilizing the
patients’ vital functions, the examiner should
conduct a formal coma evaluation. In assessing
the level of consciousness of the patient, it is
necessary to determine the intensity of stim-
ulation necessary to arouse a response and the
quality of the response that is achieved. When
the patient does not respond to voice or vigor-
ous shaking, the examiner next provides a source
of pain to arouse the patient. Several methods
for providing a sufficiently painful stimulus to
arouse the patient without causing tissue dam-
age are illustrated in Figure 2–1. It is best to
begin with a modest, lateralized stimulus, such
as compression of the nail beds, the supraor-
bital ridge, or the temporomandibular joint.
These give information about the lateralization
of motor response (see below), but must be
repeated on each side in case there is a focal
lesion of the pain pathways on one side of the
brain or spinal cord. If there is no response to
the stimulus, a more vigorous midline stimulus
may be given by the sternal rub. By vigorously
pressing the examiner’s knuckles into the pa-
tient’s sternum and rubbing up and down the
chest, it is possible to create a sufficiently pain-
ful stimulus to arouse any subject who is not
deeply comatose.
The response of the patient is noted and
graded. The types of motor responses seen are
considered in the section on motor responses
(page 73). However, the level of response is
important to the initial consideration of the
depth of impairment of consciousness. In des-
cending order of arousability, a sleepy patient
who responds to being addressed verbally or
light shaking, or one who responds verbally to
more intense mechanical stimulation, is said to
be lethargic or obtunded. A patient whose best
response to deep pain is to attempt to push the
examiner’s arm away is considered to be stu-
porous, with localizing responses. Patients who
A
B
C
D
Figure 2–1. Methods for attempting to elicit responses from unconscious patients. Noxious stimuli can be delivered with
minimal trauma to the supraorbital ridge (A), the nail beds or the fingers or toes (B), the sternum (C) or the temporo-
mandibular joints (D).
40
Plum and Posner’s Diagnosis of Stupor and Coma