Pupils, nonreactive
Nonreactive (fixed) pupils fail to constrict in response to light or to dilate when the light is removed. The development of a unilateral or bilateral nonreactive response indicates an important change in the patient's condition and may signal a life-threatening emergency and possibly brain death. It also occurs with the use of certain optic drugs.
To evaluate pupillary reaction to light, first test the patient's direct light reflex.Darken the room, and cover one of the patient's eyes while you hold open the opposite eyelid. Using a bright penlight, bring the light toward the patient from the side and shine it directly into his opened eye. If normal, the pupil will promptly constrict. Next, test the consensual light reflex.Hold the patient's eyelids open and shine the light into one eye while watching the pupil of the opposite eye. If normal, both pupils will promptly constrict. Repeat both procedures in the opposite eye. A unilateral or bilateral nonreactive response indicates dysfunction of cranial nerves (CNs) II and III, which mediate the pupillary light reflex. (See Innervation of direct and consensual light reflexes, page 516.)
Action stat!
If the patient is unconscious and develops unilateral or bilateral nonreactive pupils, quickly take his vital signs. Be alert for decerebrate or decorticate posture, bradycardia, elevated systolic blood pressure, widened pulse pressure, and the development of other changes in the patient's condition. A unilateral dilated, nonreactive pupil may be an early sign of uncal brain herniation. Emergency surgery to decrease intracranial pressure (ICP) may be necessary. If the patient isn't already being treated for increased ICP, insert an I.V. catheter to administer a diuretic, an osmotic, or a corticosteroid. You may also need to start the patient on controlled hyperventilation.
History and physical examination
If the patient is conscious, obtain a brief history. Ask him what type of eyedrops he's using, if any, and when they were last instilled. Also ask if he's experiencing pain and, if so, try to determine its location, intensity, and duration. Check the patient's visual acuity in both eyes. Then test the pupillary reaction to accommodation: Normally, both pupils constrict equally as the patient shifts his glance from a distant to a near object.
Next, hold a penlight at the side of each eye and examine the cornea and iris for abnormalities. Measure intraocular pressure (IOP) with a tonometer, or estimate IOP by placing your second and third fingers over the patient's closed eyelid. If the eyeball feels rock-hard, suspect elevated IOP. Ophthalmoscopic and slit-lamp examinations of the eye will need to be performed. If the patient has experienced ocular trauma, don't manipulate the affected eye. After the examination, be sure to cover the affected eye with a protective metal shield, but don't let the shield rest on the globe.
Medical causes
Botulism.Bilateral mydriasis and nonreactive pupils usually appear 12 to 36 hours after eating tainted food. Other early findings include blurred vision, diplopia, ptosis, strabismus, and extraocular muscle palsies, along with anorexia, nausea, vomiting, diarrhea, and dry mouth. Vertigo, deafness, hoarseness, a nasal voice, dysarthria, and dysphagia follow. Progressive muscle weakness and absent deep tendon reflexes usually evolve over 2 to 4 days, resulting in severe constipation and paralysis of respiratory muscles with respiratory distress.
Encephalitis.As encephalitis progresses, initially sluggish pupils become dilated and nonreactive. Decreased accommodation and other symptoms of cranial nerve palsies, such as dysphagia, develop. Within 48 hours after onset, encephalitis causes decreased level of consciousness, high fever, headache, vomiting, and nuchal rigidity. Aphasia, ataxia, nystagmus, hemiparesis, and photophobia may occur with seizures.
Glaucoma (acute angle-closure).With acute angle-closure glaucoma, an ophthalmic emergency, examination reveals a moderately dilated, nonreactive pupil in the affected eye. Conjunctival injection, corneal clouding, and decreased visual acuity also occur. The patient experiences a sudden onset of blurred vision, followed by excruciating pain in and around the affected eye. He commonly reports seeing halos around white lights at night. Severely elevated IOP commonly induces nausea and vomiting.
Oculomotor nerve palsy.Commonly, the first signs of oculomotor nerve palsy are a dilated, nonreactive pupil and loss of the accommodation reaction. These findings may occur in one or both eyes, depending on whether the palsy is unilateral or bilateral. Among the causes of total CN III palsy is life-threatening brain herniation. Central herniation causes bilateral midposition nonreactive pupils, whereas uncal herniation initially causes a unilateral dilated, nonreactive pupil. Other common findings include diplopia, ptosis, outward deviation of the eye, and an inability to elevate or adduct the eye. Additional findings depend on the underlying cause of the palsy.
Uveitis.A small, nonreactive pupil that appears suddenly with severe eye pain, conjunctival injection, and photophobia typifies anterior uveitis. With posterior uveitis, similar features develop insidiously, along with blurred vision and a distorted pupil shape.
Other causes
Drugs.Instillation of a topical mydriatic and a cycloplegic may induce a temporarily nonreactive pupil in the affected eye. Opiates, such as heroin and morphine, cause pinpoint pupils with a minimal light response that can be seen only with a magnifying glass. Atropine poisoning produces widely dilated, nonreactive pupils.
Nursing considerations
▪ If the patient is conscious, monitor his pupillary light reflex to detect changes.
▪ If he's unconscious, close his eyes to prevent corneal exposure using tape to secure the eyelids, if needed.
▪ Monitor neurologic status.
Patient teaching
▪ Explain the underlying disorder and treatment plan.
▪ Teach proper methods for instilling eye drops.
▪ Explain methods of reducing photophobia.
▪ Stress the importance of follow-up care to check IOP.
Pictures
Book Source Details
- Book Title: Nursing: Interpreting Signs and Symptoms
- Author(s): Springhouse
- Year of Publication: 2007
- Copyright Details: Nursing: Interpreting Signs and Symptoms, Copyright © 2007 Lippincott Williams & Wilkins.
Other Book Chapters Related to Pupil symptoms
Read excerpts from these other book chapters related to Pupil symptoms:
Medical Books Excerpts
- Mydriasis
- "Handbook of Signs & Symptoms (Third Edition)" (2006)
- [ read ]
- Mydriasis
- "Professional Guide to Signs & Symptoms (Fifth Edition)" (2006)
- [ read ]
- Mydriasis
- "Signs & Symptoms: A 2-in-1 Reference for Nurses" (2007)
- [ read ]
- Mydriasis
- "Nursing: Interpreting Signs and Symptoms" (2007)
- [ read ]
Copyright Details: Nursing: Interpreting Signs and Symptoms, Copyright © 2008 Williams & Wilkins.
More About Causes of Pupil symptoms
» Next page: Pupils, sluggish (Nursing: Interpreting Signs and Symptoms)
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