A 62-year-old woman is brought to the emergency department because of sudden, severe pain in her left eye and a frontal headache that began 2 hours ago while she was watching a movie. She also reports several episodes of vomiting and seeing "rainbow-colored halos" around lights. Her medical history is significant only for farsightedness, for which she wears corrective lenses. On physical examination, her left eye is diffusely injected, the cornea appears hazy, and the pupil is mid-dilated and non-reactive to light. The globe feels firm to palpation compared to the right side.
Which of the following is the most appropriate next step in the management of this patient?
The correct answer is:
C) Measurement of intraocular pressure.
This patient is presenting with a classic case of acute angle-closure glaucoma (AACG). The combination of sudden eye pain, nausea, halos, and a mid-dilated, non-reactive pupil is highly suggestive of this ophthalmologic emergency. While the clinical suspicion is high, the most appropriate next step to confirm the diagnosis is the measurement of intraocular pressure (IOP) via tonometry. In AACG, the IOP is typically significantly elevated (often >50 mmHg). Rapid confirmation is essential because prolonged elevation of IOP can lead to irreversible optic nerve damage and permanent vision loss.
Answer choice A: Intravenous mannitol, is incorrect. Mannitol is an osmotic diuretic used to rapidly lower intraocular pressure, but it is typically reserved as a second-line treatment when the IOP does not respond to initial medical therapy such as topical beta-blockers, alpha-agonists, or acetazolamide) Diagnosis should be confirmed before initiating such systemic therapy.
Answer choice B: Laser peripheral iridotomy, is incorrect. This is the definitive treatment for acute angle-closure glaucoma as it creates a permanent opening in the iris to allow aqueous humor to bypass the pupil and enter the anterior chamber. However, it is performed once the acute attack has been medically stabilized and the corneal edema has cleared enough to allow visualization of the iris.
Answer choice D: Oral acetazolamide, is incorrect. Carbonic anhydrase inhibitors like acetazolamide are used in the acute medical management of glaucoma to decrease aqueous humor production. While often part of the initial treatment cocktail, the most appropriate next step in a patient presenting with these symptoms is to confirm the elevated IOP via tonometry.
Answer choice E: Topical prednisolone, is incorrect. Topical corticosteroids are used to treat inflammatory conditions of the eye, such as uveitis. While uveitis can present with a red, painful eye, it typically features a constricted (miotic) pupil and "cells and flare" in the anterior chamber, rather than the mid-dilated pupil and corneal haziness seen in AACG.
Key Learning Point
Acute angle-closure glaucoma is an ophthalmologic emergency characterized by sudden eye pain, headache, nausea, and halos around lights. Clinical signs include a mid-dilated, non-reactive pupil and a hazy cornea. The most appropriate next step in management is the measurement of intraocular pressure by tonometry. Once confirmed, treatment involves immediate pressure-lowering medications followed by definitive laser peripheral iridotomy.
