You are working in a rural ED without an ophthalmologist on call. A 70 year-old female presents to your ED with severe headache and eye pain. She states that she is seeing “halos” around objects. She feels nauseous. On exam, you notice injection of the eye with a fixed, mid-dilated pupil. Intraocular pressure (IOP) is measured and found to be 54. You need to transfer the patient to a facility with ophthalmology, but what treatment should you provide the patient prior to transfer?
Glaucoma encompasses the group of eye diseases that results in optic neuropathy usually associated with elevated IOP. The two major forms are open angle glaucoma and closed angle glaucoma. Open angle is usually associated with elevated IOP, but not always, and has to do with increased aqueous production and decreased outflow. Closed angle glaucoma results from a narrowed or closed anterior chamber angle which results in the inability of aqueous humor to leave the anterior chamber. Untreated, this results in elevated IOP and optic neuropathy.
ED management of the acute undifferentiated glaucoma patient:
If you have an ophthalmologist readily available, emergent consultation is needed. However if unavailable, initial treatment by the ED provider is warranted, as if left untreated, the patient could develop permanent vision loss.
Unfortunately, we are unlikely to be able to tell in the ED what type of glaucoma the patient has without an ophthalmologist’s assistance. Because of the threat to vision this disease poses, our initial management should focus on lowering the IOP while attempting to arrange for transfer to a facility with an ophthalmologist.
Medications to reduce IOP:
The two major ways to reduce IOP with medications are to reduce the production of aqueous humor and to increase aqueous humor outflow.
Reduction of aqueous humor production:
- Topical beta blockers
- Topical alpha agonists
- Systemic carbonic anhydrase inhibitors
- Systemic osmotics
- Topical alpha agonists
- Topical prostaglandin analogues
- Topical muscarinic agonists
- Topical steroids
Multiple sources recommend giving one of each drug class listed above (with the exception of systemic osmotics, except in refractory cases) for an acute glaucoma crisis if ophthalmology is unavailable for guidance. If IOP remains elevated one hour after medication administration, mannitol can be given if no contraindications.
Example drug regimen for acute management:
- Timolol 0.5% 1 gtt (topical beta blocker)
- Apraclonidine 1% 1 gtt (topical alpha agonist)
- Pilocarpine 2% 1 gtt q15 min x 2 (muscarinic agonist)
- Latanoprost 0.005% 1 gtt (prostaglandin analogue)
- Prednisone acetate 1% 1 gtt q15 min x4 (topical steroid)
- Acetazolamide 500mg PO (carbonic anhydrase inhibitor)
- If needed, mannitol 1g/kg IV can be given
Since many smaller hospitals may not have these medications readily available, it’s helpful to remember the different classes of medications used to treat acute glaucoma. That way you can ask your pharmacist which medications are available to you when you need them and give some combination of drops from the various classes depending on what is available to you.
A 3-drop regimen (only timolol, pilocarpine, and prednisone acetate available at your hospital) and acetazolamide are used after discovering the patient’s IOP to be 54. 1 hour after dosing, a recheck of the IOP shows it has decreased to 25. The patient feels much better. You secure transport to a facility with an on call ophthalmologist so the patient can receive definitive management.
Note: the featured image is from Wikimedia Commons, by author CNX OpenStax