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  Intravenous Mannitol to reduce raised intra-ocular pressure (Guidelines)

Eyedrops will probably not work if IOP >40. Preferred method - IVPB 20% Mannitol in 250cc run at 60 cc/hr over 4 hours - Bud Kurwa MD. When IOP <40 start eyedrops. Usual method - Mannitol 10%, 500ml by intravenous infusion over 60 minutes.

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Blind, Aching and Vomiting

The mainstays of urgent management are: head up — at least 30 degrees topical b-blocker — e.g. timolol 0.5% 1-2 drops as a single dose (caution if bronchospasm or heart failure) topical cholinergic (miotic) — e.g pilocarpine 2 or 4 % eyedrops — one-two drops q15min until pupillary constriction occurs (a 2% solution may be better in blue-eyed patients and a 4% solution in brown-eyed patients); especially if angle crowding is suspected. topical alpha2-agonist — e.g., apraclonidine 1% 1-2 drops as a single dose. acetazolamide 500mg IV, or PO if IV not available (not if topiramate or sulfonamide-induced acute closed angle glaucoma)

Angle Closure Glaucoma

Acute management of acute ACG in the ED is targeted at reducing the intraocular pressure. There are three mechanisms by which this is achieved: prevention of aqueous humor production, decreasing the volume of vitreous humor and increasing aqueous humor outflow. Reduction of aqueous humor production at the ciliary body decreases pressure build up. Beta-blockers (timolol drops), Alpha-2 adrenergic agonists (apraclonidine or brimonidine drops), and carbonic anhydrase inhibitors (both topical dorzolamide or systemic acetazolamide) decreases humor production, and can all be given in concert to maximize effect. In refractory or severe cases, osmotic diuresis with IV mannitol decreases volume of vitreous humor in the eye, further decreasing pressure.

Glaucoma Emergency: Acute angle closure glaucoma

The most common form of angle closure glaucoma involves blockage of the pupil by the lens (pupillary block) and occurs in eyes that have narrow drainage angles. Pupillary block occurs when the lens comes in close contact with the iris around the pupil and prevents aqueous fluid from moving through the pupil. Aqueous fluid collects behind the iris and causes it to bow forward and close the drainage angle. Three classes of medications reduce the production of aqueous fluid (beta blockers, alpha adrenergic agonists, and carbonic anhydrase inhibitors) and thereby lower pressure in the eye. These aqueous suppressant medications are useful in lowering the pressure in acute angle closure glaucoma. Rapid application of a series of beta blockers, alpha adrenergic agonists, and carbonic anhydrase inhibitors eye drops will often lower intraocular pressure sufficiently to to allow definitive treatment with a laser Once the eye pressure has been lowered with other medications, cholinergic eye drops may be used to pull the iris centrally in preparation for a laser treatment.

Medical Concepts: Acute Angle Closure Glaucoma

Be aware that pilocarpine may be ineffective at causing the iris to contract in the early stages of an acute attack because the elevated intraocular pressure can cause pressure-induced ischemic paralysis of the iris It is effective only once the pressure in the affected eye is reduced, leading to controversy regarding when pilocarpine should be administered. Some experts recommend initiating pilocarpine only after the intraocular pressure falls below 40 mmHg, while others recommend initiating it immediately upon diagnosis. Most experts recommend immediate administration to ensure availability once the ischemic paralysis has resolved.

Acute Angle Closure Glaucoma: ED-Relevant Management

Start with a topical β blocker and alpha 2 agonist +/- diamox. Diamox can be given by mouth if IOP is not excessively elevated (i.e. less than 40). If highly elevated, IV Diamox is preferred. Topical pilocarpine can be considered but should be used with caution 1-2 hours after IOP is reduced for the reasons stated earlier. If IOP is not significantly reduced by 25% at 30-60 minutes, an osmotic agent should be strongly considered. The goal IOP should be 35 or less. Pilocarpine should be given after other eye drops.

Angle Closure: A Bad Connection

Therapeutic agents used for acute angle attacks include topical beta blockers, alpha-2 agonists, carbonic anhydrase inhibitors and prostaglandin analogs—even though their onset of action may be delayed. Topical drops are given every five minutes for 30 minutes and the pressure is rechecked in one hour. Additionally, oral carbonic anhydride inhibitors, such as 1,000mg oral acetazolamide, are given as long as the patient does not have kidney disease or a sulfa allergy. Oral acetazolamide should be given as the immediate release tabs and not the extended release version. If the pressure is still not down at the one-hour check, apply more drops and check the pressure in another hour.

Angle-closure Glaucoma: Are You Ready?

Often used as initial treatment, eye drops that can quickly reduce IOP include beta blockers, alpha agonists, carbonic anhydrase inhibitors and pilocarpine. Beta blockers, alpha agonists and carbonic anhydrase inhibitors all quickly reduce aqueous production, making them ideal to use when rapid IOP reduction is desired. Pilocarpine constricts the pupil, which is helpful for subsequent laser PI. Oral or intravenous acetazolamide or hyperosmotics can also help relieve elevated IOP. Because quick reduction is warranted, acetazolamide sequels are less effective, as they reduce pressure slowly.

Diagnostics: Elevated Intraocular Pressure

Due to rapidly increasing IOP, the patient with AACG typically presents to the emergency department with a chief complaint of an acutely painful red eye. Risk factors include age greater than 55, hyperopia, being of Inuit or Asian descent and female sex.

Emergency management: angle-closure glaucoma

Acute angle-closure glaucoma is an ophthalmic emergency as it can lead to irreversible blindness if not identified and treated immediately. Treatment goal: immediate lowering of IOP and alleviation of inflammation, pain, nausea.

REBEL Core Cast 19.0 – Acute Angle Closure Glaucoma

Physical exam will reveal conjunctival redness, corneal haziness or cloudiness due to edema and a pupil that is mid sized and minimally reactive to light, a rock hard globe and IOP >/= 21. These patients require emergent ophthalmology evaluation but treatment should be started empirically while waiting for the evaluation. Initial treatment to decrease IOP usually includes a topical BB such as timolol and topical AB such as apraclonidine and either IV or PO acetazolamide.

Resources

American Academy of Ophthalmology

In patients where angle closure is thought to be secondary to pupillary block or plateau iris syndrome, cholinergic agents (such as pilocarpine)... should be started after IOP decreases to < 40 mm Hg... Hyperosmotic agents are also used initially when pressures are exceedingly high.

IOP Measurement

IOP is considered one of the “eye vital signs” and should be measured in every patient with an eye complaint or in whom the clinician suspects glaucoma - Gavin Gorrell

WikEM

Reduce volume of aqueous humor. These therapies are usually reserved for failure of other treatments. Hyper osmotic agents such as mannitol are effective but are contraindicated in renal failure and can cause hypotension in the volume depleted patient.

Zero to Finals

Acute angle closure glaucoma occurs when the iris bulges forward and seals off the trabecular meshwork from the anterior chamber, preventing aqueous humour from draining and leading to a continual increase in intraocular pressure. The pressure builds in the posterior chamber, pushing the iris forward and exacerbating the angle closure.