Disorders of Consciousness
807
tent with the diagnosis of coma. Spontaneous eye opening can be associ-
ated with awareness (i.e., locked-in state) or lack of awareness (i.e., veg-
etative state).
Examination of Pupils
The conditions that affect pupillary size and light reactivity are shown in
Table 44.3 (21,22,24).
(
+
) and (–) indicate a reactive and nonreactive pupil, respectively. From References 21, 22, and 24.
Pupillary findings can be summarized as follows:
1. Dilated, reactive pupils can be the result of drugs (anticholinergics,
CNS stimulants, or adrenergic agonists) or nonconvulsive seizures,
while dilated, unreactive pupils are a sign of diffuse brain injury or
brainstem compression (e.g., from an expanding intracranial mass).
2. A unilateral, dilated and fixed pupil can be the result of ocular trau-
ma or recent ocular surgery, or can be evidence of third cranial nerve
dysfunction from an expanding intracranial mass.
3. Midposition, reactive pupils can be the result of a metabolic enceph-
alopathy, a sedative overdose, or neuromuscular blocking drugs,
while midposition, unreactive pupils can be seen with acute liver
failure, postanoxic encephalopathy, or brain death.
e
Pupil Size & Reactivity
Associated Conditions
Atropine, anticholinergic toxicity, adrenergic
agonists (e.g., dopamine), stimulant drugs (e.g.,
(
+
)
(
+
)
amphetamines), or nonconvulsive seizures
Diffuse brain injury, hypothermia (
<
28°C), or
brainstem compression from an expanding
(–)
(–)
intracranial mass or intracranial hypertension
Expanding intracranial mass (e.g., uncal hernia-
(–)
(
+
)
tion), ocular trauma or surgery, or focal seizure
Toxic/metabolic encephalopathy, sedative over-
(
+
)
(
+
)
dose, or neuromuscular blockade
Acute liver failure, postanoxic encephalopathy,
(–)
(–)
or brain death
(
+
)
(
+
)
Horner’s Syndrome
Opiate overdose, toxic/metabolic encephalopathy,
(
+
/–) (
+
/–)
hypercapnia or pontine injury
Table 44.3
Conditions That Affect Pupillary Size and Reactivity
