USMLE Prep - Medical Reference Library

Acute Angle-Closure Glaucoma — Emergent IOP Reduction

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

Synopsis:

Severe eye pain with halos and nausea; emergent therapy to lower IOP with topical and systemic agents followed by definitive laser 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 Urgent Iop, 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., Medication Sequence (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

Medication Sequence (Example)

StepAgent
1Topical beta blocker + alpha agonist
2Acetazolamide 500 mg PO/IV
3Pilocarpine when IOP falls
4Mannitol IV if refractory

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
Pilocarpine (gtt after IOP lowered)Muscarinic agonistMinutesFacilitate outflowMiosis; use after IOP ↓
Apraclonidine/Brimonidine (gtt)α2 agonistMinutesReduce aqueous productionDry mouth
Prednisolone acetate (gtt)Topical steroidHoursReduce inflammation↑ IOP

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 epinephrine-containing drops and anticholinergics. Control nausea and pain to improve cooperation.


References

  1. AAO Eye Emergencies — Angle Closure — Link
  2. RCEM/EM Ophthalmology Guides — Link