9. PROGNOSIS IN COMA AND RELATED DISORDERS OF
CONSCIOUSNESS, MECHANISMS UNDERLYING
OUTCOMES, AND ETHICAL CONSIDERATIONS 341
INTRODUCTION 342
PROGNOSIS IN COMA 343
PROGNOSIS BY DISEASE STATE 344
Traumatic Brain Injury
Nontraumatic Coma
Vascular Disease
Central Nervous
System Infection
Acute Disseminated Encephalomyelitis
Hepatic Coma
Depressant
Drug Poisoning
VEGETATIVE STATE 357
Clinical, Imaging, and Electrodiagnostic Correlates of Prognosis in the Vegetative State
MINIMALLY CONSCIOUS STATE 360
Late Recoveries From the Minimally Conscious State
LOCKED-IN STATE 363
MECHANISMS UNDERLYING OUTCOMES OF SEVERE
BRAIN INJURY: NEUROIMAGING STUDIES AND
CONCEPTUAL FRAMEWORKS 364
FUNCTIONAL IMAGING OF VEGETATIVE
STATE AND MINIMALLY CONSCIOUS STATE 365
Atypical Behavioral Features in the Persistent Vegetative State
Neuroimaging
of Isolated Cortical Responses in Persistent Vegetative State Patients
POTENTIAL MECHANISMS UNDERLYING RESIDUAL
FUNCTIONAL CAPACITY IN SEVERELY DISABLED PATIENTS 372
Variations of Structural Substrates Underlying Severe Disability
The Potential Role of
the Metabolic ‘‘Baseline’’ in Recovery of Cognitive Function
The Potential Role of
Regionally Selective Injuries Producing Widespread Effects on Brain Function
ETHICS OF CLINICAL DECISION MAKING AND
COMMUNICATION WITH SURROGATES (J.J. FINS) 376
Surrogate Decision Making, Perceptions, and Needs
Professional Obligations and
Diagnostic Discernment
Time-Delimited Prognostication and Evolving Brain States:
Framing the Conversation
Family Dynamics and Philosophic Considerations
INDEX 387
xiv
Contents
PLUM AND POSNER’S DIAGNOSIS
OF STUPOR AND COMA
Fourth Edition
Chapter
1
Pathophysiology of Signs
and Symptoms of Coma
ALTERED STATES OF CONSCIOUSNESS
DEFINITIONS
Consciousness
Acutely Altered States of Consciousness
Subacute or Chronic Alterations of
Consciousness
APPROACH TO THE DIAGNOSIS OF
THE COMATOSE PATIENT
PHYSIOLOGY AND
PATHOPHYSIOLOGY
OF CONSCIOUSNESS
AND COMA
The Ascending Arousal System
Behavioral State Switching
Relationship of Coma to Sleep
The Cerebral Hemispheres and Conscious
Behavior
Structural Lesions That Cause Altered
Consciousness in Humans
ALTERED STATES OF
CONSCIOUSNESS
And men should know that from nothing else but
from the brain came joys, delights, laughter and
jests, and sorrows, griefs, despondency and lamen-
tations. And by this, in an especial manner, we ac-
quire wisdom and knowledge, and see and hear and
know what are foul, and what are fair, what sweet
and what unsavory . . .
—The Hippocratic Writings
Impaired consciousness is among the most diffi-
cult and dramatic of clinical problems. The an-
cient Greeks knew that normal consciousness
depends on an intact brain, and that impaired
consciousness signifies brain failure. The brain
tolerates only limited physical or metabolic in-
jury, so that impaired consciousness is often a
sign of impending irreparable damage to the
brain. Stupor and coma imply advanced brain
failure, just as, for example, uremia means renal
failure, and the longer such brain failure lasts,
3
the narrower the margin between recovery and
the development of permanent neurologic in-
jury. The limited time for action and the mul-
tiplicity of potential causes of brain failure
challenge the physician and frighten both the
physician and the family; only the patient es-
capes anxiety.
Many conditions cause coma. Table 1–1 lists
some of the common and often perplexing
causes of unconsciousness that the physician
may encounter in the emergency department
of a general hospital. The purpose of this mono-
graph is to describe a systematic approach to
the diagnosis of the patient with reduced con-
sciousness, stupor, or coma based on anatomic
and physiologic principles. Accordingly, this
book divides the causes of unconsciousness
into two major categories: structural and meta-
bolic. Chapter 1 provides background informa-
tion on the pathophysiology of impaired con-
sciousness, as well as the signs and symptoms
that accompany it. In Chapter 2 this infor-
mation is used to define a brief but informa-
tive neurologic examination that is necessary to
Table 1–1 Cause of Stupor or Coma in 500 Patients Initially Diagnosed as
‘‘Coma of Unknown Etiology’’*
Subtotals
I. Supratentorial lesions
101
A. Rhinencephalic and subcortical
destructive lesions
2
1. Thalamic infarcts
2
B. Supratentorial mass lesions
99
1. Hemorrhage
76
a. Intracerebral
44
(1) Hypertensive
36
(2) Vascular anomaly
5
(3) Other
3
b. Epidural
4
c. Subdural
26
d. Pituitary apoplexy
2
2. Infarction
9
a. Arterial occlusions
7
(1) Thrombotic
5
(2) Embolic
2
b. Venous occlusions
2
3. Tumors
7
a. Primary
2
b. Metastatic
5
4. Abscess
6
a. Intracerebral
5
b. Subdural
1
5. Closed head injury
1
II. Subtentorial lesions
65
A. Compressive lesions
12
1. Cerebellar hemorrhage
5
2. Posterior fossa subdural or
extradural hemorrhage
1
3. Cerebellar infarct
2
4. Cerebellar tumor
3
5. Cerebellar abscess
1
6. Basilar aneurysm
0
Subtotals
B. Destructive or ischemic lesions
53
1. Pontine hemorrhage
11
2. Brainstem infarct
40
3. Basilar migraine
1
4. Brainstem demyelination
1
III. Diffuse and/or metabolic
brain dysfunction
326
A. Diffuse intrinsic disorders of brain
38
1. ‘‘Encephalitis’’ or
encephalomyelitis
14
2. Subarachnoid hemorrhage
13
3. Concussion, nonconvulsive
seizures, and postictal states
9
4. Primary neuronal disorders
2
B. Extrinsic and metabolic
disorders
288
1. Anoxia or ischemia
10
2. Hypoglycemia
16
3. Nutritional
1
4. Hepatic encephalopathy
17
5. Uremia and dialysis
8
6. Pulmonary disease
3
7. Endocrine disorders
(including diabetes)
12
8. Remote effects of cancer
0
9. Drug poisons
149
10. Ionic and acid-base disorders
12
11. Temperature regulation
9
12. Mixed or nonspecific
metabolic coma
1
IV. Psychiatric ‘‘coma’’
8
A. Conversion reactions
4
B. Depression
2
C. Catatonic stupor
2
*Represents only patients for whom a neurologist was consulted because the initial diagnosis was uncertain and in whom a
final diagnosis was established. Thus, obvious diagnoses such as known poisonings, meningitis, and closed head injuries,
and cases of mixed metabolic encephalopathies in which a specific etiologic diagnosis was never established are under-
represented.
4
Plum and Posner’s Diagnosis of Stupor and Coma