Acute angle-closure glaucoma

Revision as of 20:34, 3 June 2015 by Rossdonaldson1 (talk | contribs) (Treatment)

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

Clinical Features

  • Abrupt onset of severe eye pain
  • Blurred vision
  • Frontal or supraorbital headache
  • Nausea / vomiting / abdominal pain

Differential Diagnosis

Unilateral red eye

^Emergent diagnoses ^^Critical diagnoses

Diagnosis

  • Fixed, midposition pupil
  • Hazy cornea
  • Conjunctival injection most prominent at limbus (ciliary flush)
  • Rock-hard globe
  • IOP >20 mm Hg
  • SLIT LAMP exam shows Cell and Flare which represents visualization of individual cells in the shallow anterior chamber

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

Treatment

  • Emergent ophthalmology consult
  • Decrease production of aqueous humor:
  1. timolol 0.5% drop: blocks beta receptors on ciliary epithelium
  2. apraclonidine 1% drop: alpha-2 adrenergic receptor agonist which increases trabecular outflow
  3. acetazolamide 500mg IV or PO: blocks productions of HCO3-, which draws Na+ into the eye; water follows by osmosis to form aqueous humour
  • Facilitate outflow of aqueous humor:
  1. 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
  • Reduce volume of aqueous humor:
  • mannitol 1–2gm/kg IV: if no contraindications
  • Recheck IOP hourly

See Also

References