Acute angle-closure glaucoma
Background
Pathophysiology
- Obstructed aqueous outflow tract ==> aqueous humor builds ==> increased intraocular pressure (IOP) ==> optic nerve damage ==> vision loss
- Increased posterior chamber pressure causes iris to bulge forward (iris bombé) ==> further obstruction of outflow tract ==> further increase IOP
- Acute attack is usually precipitated by pupillary dilation
Definition: 3 signs + 2 symptoms
- At least 3 of these signs
- IOP >21 mm Hg
- Conjunctival injection
- Corneal epithelial edema
- Mid-dilated nonreactive pupil
- Shallow anterior chamber with occlusion
- At least 2 of these symptoms
- Ocular pain
- Nausea/vomiting
- History of intermittent blurring of vision with halos
Clinical Features
- Abrupt onset of severe eye pain
- Blurred vision
- Frontal or supraorbital headache
- Nausea / vomiting / abdominal pain
Diagnosis
- Fixed, midposition pupil
- Hazy cornea
- Conjunctival injection most prominent at limbus (ciliary flush)
- Rock-hard globe
- IOP >20 mm Hg
Treatment
Emergent opthalmology consult
To decrease production of aqueous humor, give:
- timolol 0.5% drop: blocks beta receptors on ciliary epithelium
- apraclonidine 1% drop: blocks alpha-2 adrenergic receptors
- acetazolamide 500mg IV or PO: blocks productions of HCO3-, which draws Na+ into the eye; water follows by osmosis to form aqueous humour
To reduce volume of aqueous humor, give:
- mannitol 1–2gm/kg IV: if no contraindications
To facilitate outflow of aqueous humor, give:
- pilocarpine 1%–2% drop: parasympatholytic alkaloid acts on muscarinic receptors found on iris sphincter muscle ==> causes muscle to contract ==> miosis
- In USA - green top
- Use one drop every 15 minutes x 2 doses, then every 4 to 6 hours
- Only effective when IOP <40 mm Hg
Recheck IOP hourly
See Also
Source
Tintinalli