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:

1. timolol 0.5% drop: blocks beta receptors on ciliary epithelium
2. apraclonidine 1% drop: blocks alpha-2 adrenergic receptors
3. 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:

1. mannitol 1–2gm/kg IV: if no contraindications

To facilitate outflow of aqueous humor, give:

1. pilocarpine 1%–2% drop: parasympatholytic alkaloid acts on muscarinic receptors found on iris sphincter muscle ==> causes muscle to contract ==> miosis
   1. In USA - green top
   2. Use one drop every 15 minutes x 2 doses, then every 4 to 6 hours
   3. Only effective when IOP <40 mm Hg

Recheck IOP hourly

See Also

• Eye Algorithm (Main)

Source

Tintinalli