USMLE Prep - Medical Reference Library

Acute Angle-Closure Glaucoma — Emergency Management

System: Ophthalmology • Reviewed: Aug 31, 2025 • Step 1Step 2Step 3

Synopsis:

Sudden painful red eye with halos and vision loss; treat immediately with topical and systemic agents to lower IOP; definitive therapy is laser peripheral iridotomy.

Key Points

  • Stabilize ABCs; begin targeted evaluation without delaying life-saving therapy.
  • Use system-specific risk tools to guide testing and disposition.
  • Order high-yield tests first; escalate imaging when indicated.
  • Start evidence-based initial therapy and reassess frequently.

Algorithm

  1. Primary survey and vitals; IV access and monitors.
  2. Focused history/physical; identify red flags and likely etiologies.
  3. Order system-appropriate labs and imaging (see Investigations).
  4. Initiate guideline-based empiric therapy (see Pharmacology).
  5. Reassess response; arrange consultation and definitive management.

Clinical Synopsis & Reasoning

For Acute Angle Closure Glaucoma, frame the differential by acuity and pathophysiology, then align diagnostics to the leading hypotheses. Prioritize stabilization while obtaining high‑yield studies such as CBC (Baseline hematology), BMP (Electrolytes/renal). Incorporate bedside imaging and targeted labs to define severity and identify complications; synthesize results with clinical trajectory to refine the working diagnosis and disposition needs.


Treatment Strategy & Disposition

Initiate disease‑directed therapy alongside supportive care, titrating to objective response. Pharmacologic options commonly include Analgesia/Antipyretics. Use validated frameworks (e.g., Initial Medication Set (Example)) to guide escalation and site of care. Address precipitating factors, de‑escalate empiric therapies with data, and arrange follow‑up for monitoring and risk‑factor modification; admit patients with instability, high risk of deterioration, or needs for close monitoring.


Epidemiology / Risk Factors

  • Risk factors vary by condition and patient profile

Investigations

TestRole / RationaleTypical FindingsNotes
CBCBaseline hematologyAbnormal counts
BMPElectrolytes/renalDerangements

Initial Medication Set (Example)

ClassExample
Beta blocker (topical)Timolol
Alpha agonist (topical)Brimonidine
Carbonic anhydrase inhibitorDorzolamide (topical) or acetazolamide (systemic)
Miotic (after IOP falls)Pilocarpine

Pharmacology

MedicationMechanismOnsetRole in TherapyLimitations
Acetazolamide (IV/PO)Carbonic anhydrase inhibitionHoursLower IOP quicklyMetabolic acidosis; avoid in sulfa allergy
Timolol (gtt)β-blocker (topical)MinutesReduce aqueous productionBradycardia
Prednisolone acetate (gtt)Topical steroidHoursReduce inflammation↑ IOP
Pilocarpine (gtt after IOP lowered)Muscarinic agonistMinutesFacilitate outflowMiosis; use after IOP ↓
Apraclonidine/Brimonidine (gtt)α2 agonistMinutesReduce aqueous productionDry mouth

Prognosis / Complications

  • Prognosis depends on severity, comorbidities, and timeliness of care

Patient Education / Counseling

  • Explain red flags and when to seek emergent care.
  • Reinforce medication adherence and follow-up plan.

Notes

Avoid acetazolamide in sulfa allergy with caution and severe renal failure. Check for precipitating meds (anticholinergics, sympathomimetics).


References

  1. AAO Preferred Practice Pattern — Link
  2. Royal College of Ophthalmologists — Link