Acute angle-closure glaucoma

Revision as of 01:02, 3 August 2015 by Ostermayer (talk | contribs) (TreatmentCare of the Patient with Primary Angle Closure Glaucoma. Optometric Clinical Practice Guideline. American Optometric Association. PDF Accessed 06/17/15)

Background

Pathophysiology

  • Obstructed aqueous outflow tract → aqueous humor builds up → 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 (usually unilateral) 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 shallow anterior chamber and Cell and Flare (visualization of individual cells in the 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[1]

Goal of medical therapy is to 'break the attack' in order to prepare the patient for laser iridotomy.[2]

  1. Emergent ophthalmology consult
  2. Decrease production of aqueous humor:
    • timolol 0.5%: Blocks beta receptors on ciliary epithelium
      • 1 drop in affected eye, repeat in 1 hour if needed.
    • acetazolamide: blocks productions of HCO3-, which draws Na+ into the eye; water follows by osmosis to form aqueous humour
      • 500mg IV or PO (PO preferred unless pt is nauseated)
      • Can substitute methazolamide 100mg if pt has renal failure.
    • Dorzolamide (Trusopt) 2%: topical carbonic anhydrase inhibitor
      • 1 drop in affected eye
    • Brimonidine (Alphagan) 0.2% OR Apraclonidine 1%: alpha-2 agonist, which also increases trabecular outflow
      • 1 drop in affected eye
  3. Facilitate outflow of aqueous humor:
    • pilocarpine 1%–2%: parasympatholytic alkaloid acts on muscarinic receptors found on iris sphincter muscle → causes muscle to contract → miosis → pulls iris away from trabecular network
      • 1 drop in affected eye every 15 minutes x 2-4 doses, then every 4 to 6 hours
      • Likely does not work until IOP drops below 40-50 mmHg, but still give immediately upon diagnosis
  4. Reduce volume of aqueous humor:
    • Hyperosmotic agents: Single most effective treatment, but watch for contraindications (e.g. renal failure) and systemic effects.
      • mannitol: 1-2 g/kg IV (most common)
      • 50% glycerin (Osmoglyn) OR 45% isosorbide (Ismotic): 1.5 mL/kg PO (rarely used)
      • May need to give repeat doses
  5. Recheck IOP at least hourly

Topical steroids not indicated during acute attack, but may help inflammation after IOP under control.

See Also

References

  1. Care of the Patient with Primary Angle Closure Glaucoma. Optometric Clinical Practice Guideline. American Optometric Association. PDF Accessed 06/17/15
  2. Primary Angle Closure Preferred Practice Pattern Guideline. American Academy of Ophthalmology. Angle Closure PPP Accessed 06/17/15.