Marino The ICU Book 4e, IE

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Disorders of Consciousness

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).

e Pupil Size & Reactivity Table 44.3

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 Conditions That Affect Pupillary Size and Reactivity

( + )

( + )

(–)

(–)

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

( + /–) ( + /–)

( + ) 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.