Sunday, July 26, 2015

Chemical Eye Exposure

Chemical Eye Exposure

Case presentation:

A 34 - year - old female is seen in the emergency department after having an unknown chemical
splashed in her face and eyes. She is complaining of burning, tearing, decreased vision, and light sensitivity.

Gross inspection reveals first - degree burns to the periorbital skin and lids. The globes are intact.
On physical examination, the visual acuity is 20/200 in each eye.

The bulbar and palpebral conjunctiva is markedly injected with a watery mucous discharge (illustrated).
chemical eye exposure
The corneas are hazy with blurred iris detail.
There is a 6 mm oval area of blanched bulbar conjunctiva inferiorly near the limbus. The anterior chambers are deep, and the pupils are round.

Question: What emergent action should be initiated prior to completing the ophthalmic examination?

A. Emergent ophthalmology consultation
B. Litmus test
C. Irrigation of the eye with copious fluids such as saline or lactated Ringer ’ s solution
D. Tetanus prophylaxis
E. Neutralization with a weak acid or base for a base - or acid - offending agent, respectively

Answer: C
Diagnosis: Chemical injury to the eye
Discussion: Chemical injuries to the eye range from mild irritation to devastating destruction of the ocular surface resulting in visual impairment or even loss of the eye. Most chemical injuries affect young patients, with exposure occurring at home, in industrial or agricultural accidents, or in criminal assault. The offending chemical may be in the form of a solid, liquid, powder, or vapor. The severity of the injury depends on the offending agent, the  surface area of contact, and the degree of penetration. The most important step in the initial management of chemical injuries is immediate and copious irrigation of the ocular surface with lactated Ringer ’ s solution or normal saline solution, even before testing vision. This may be facilitated using a topical anesthetic and handheld intravenous tubing or a Morgan lens. Irrigation should be continued for a minimum of 30 minutes until the conjunctival sac pH is neutral. The conjunctival pH can be easily checked with a urinary pH strip. Sweeping the conjunctival fornices with a moistened cotton - tipped applicator
for solid particles should be performed for a persistently elevated pH.

Alkali injuries occur most frequently and are the most devastating. These agents elevate the pH and
readily penetrate the ocular tissues. Blanching of the conjunctiva indicates penetration, vascular ischemia, and necrosis, which are often the result of severe alkali injuries. On the other hand, acid injuries tend to remain confined to the surface of the eye and produce superficial damage.


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