What is the management approach for paracentral acute middle maculopathy?

Management of Paracentral Acute Middle Maculopathy (PAMM)

There is currently no specific treatment for paracentral acute middle maculopathy, and management focuses on identifying and treating the underlying cause while monitoring for complications.

Understanding PAMM

Paracentral acute middle maculopathy is a relatively new optical coherence tomography (OCT) finding characterized by:

• Hyperreflectivity in the inner nuclear layer of the retina
• Typically presents with acute onset of paracentral scotoma
• Often appears as a dark gray paracentral lesion on near-infrared imaging

Diagnostic Approach

1. Imaging studies:

   • Spectral domain OCT (SD-OCT) is essential for diagnosis, showing hyperreflective bands at the level of the inner nuclear layer
   • En face OCT may demonstrate ovoid focal patches of hyperreflectivity
   • OCT angiography may show flow interruption in the retinal capillary plexus

2. Urgent evaluation for underlying causes:

   • PAMM is often associated with retinal capillary ischemia 1
   • Consider urgent neurovascular workup, particularly if symptoms are acute (within 24 hours) 2, 3
   • Evaluate for giant cell arteritis (GCA), especially in patients over 50 years with elevated CRP/ESR 2, 4

Management Algorithm

Step 1: Urgent Assessment for Vision-Threatening Conditions

• If GCA is suspected (temporal tenderness, jaw claudication, elevated ESR/CRP):
  • Initiate high-dose systemic corticosteroids immediately 2, 4
  • Arrange for temporal artery biopsy for confirmation

Step 2: Evaluation for Vascular Risk Factors

• Assess for:
  • History of migraines with aura 3
  • Cardiovascular disease 5
  • Blood dyscrasias 5
  • Recent cataract surgery 5

Step 3: Referral Considerations

• For acute onset (symptoms within 24 hours):
  • Refer immediately to emergency department or stroke center 2
  • Risk of concurrent stroke is 20-24% in patients with retinal artery occlusions 2

Step 4: Monitoring and Follow-up

• Regular OCT imaging to monitor for progression or resolution
• Follow-up schedule based on underlying etiology:
  • If associated with retinal artery occlusion: follow-up within 1 month 2
  • If stable without complications: follow-up in 3-6 months

Step 5: Management of Complications

• If iris or retinal neovascularization develops:
  • Panretinal photocoagulation (PRP) with or without anti-VEGF therapy 2
  • Consider intravitreal anti-VEGF agent (off-label) to supplement or facilitate PRP treatment 2

Clinical Pearls and Pitfalls

• Key pitfall: PAMM may be missed on routine examination as it can present without significant changes in visual acuity or fundus appearance 3
• Important consideration: Silent brain infarction is frequently found in patients with retinal vascular occlusions, warranting prompt neurological evaluation 2
• Diagnostic challenge: PAMM requires a high level of suspicion since fundus examination may appear normal 3
• Treatment limitation: Currently, there is limited evidence for effective interventional treatments for the ocular condition itself, other than corticosteroids for GCA 2

Special Considerations

• In patients with migraines and persistent visual changes, consider PAMM as a potential complication of retinal vasospasm 3
• Post-cataract surgery patients with unexplained vision loss should be evaluated for PAMM, especially those with cardiovascular risk factors 5
• PAMM may be associated with central nervous system inflammation, requiring evaluation of cerebrospinal fluid in appropriate cases 6