🧠 Quiz: Inflammatory Markers in Giant Cell Arteritis
Giant Cell Arteritis (GCA) remains a diagnostic challenge, especially when systemic symptoms are subtle or absent. While temporal artery biopsy (TAB) is the gold standard, its limitations—false negatives, procedural risks, and delayed access—have pushed clinicians to rely heavily on inflammatory markers. But how reliable are they, really?
A new study published in the American Journal of Ophthalmology (2025) offers a fresh perspective, leveraging the Rochester Epidemiology Project to assess the real-world performance of CRP, ESR, and platelets in diagnosing GCA.
🧪 Study Snapshot
- Design: Retrospective, population-based cross-sectional study
- Cohort: 553 patients who underwent TAB (1995–2019)
- 143 diagnosed with GCA
- 410 without GCA
- Markers analyzed: CRP, ESR, platelets (excluding those on systemic steroids)
📊 Diagnostic Performance
| Marker(s) | Sensitivity | Specificity | Negative Predictive Value (NPV) |
|---|---|---|---|
| CRP | 96% | 21% | 95% |
| ESR | 80% | 43% | 85% |
| Platelets | 49% | 79% | 80% |
| CRP + ESR | 77% | 54% | 87% |
| CRP + ESR + Platelets | 41% | 84% | 80% |
🔹 Notably, 3% of GCA patients had normal CRP, ESR, and platelets—reminding us that normal labs do not exclude the diagnosis.
👁️ Clinical Pearls
- CRP is king: With the highest sensitivity and NPV, CRP is the most reliable screening tool.
- Platelets add precision: Their high specificity makes them valuable in borderline cases.
- ESR is not enough: Despite tradition, ESR alone lacks diagnostic robustness.
- Ocular-only GCA exists: 12% of patients had visual symptoms without systemic signs—highlighting the need for vigilance in ophthalmic settings.
🧠 Practice Implications
- Use CRP as your frontline marker, especially in primary care or emergency settings.
- Combine CRP, ESR, and platelets for better specificity when diagnostic certainty is needed.
- Don’t dismiss GCA in patients with normal labs but classic symptoms—especially headache or visual changes.
- Consider early imaging or biopsy in high-risk cases, even if markers are normal.
📚 Final Thought
This study reinforces the nuanced role of inflammatory markers in GCA. CRP shines as a screening tool, but no marker is infallible. Clinical judgment, supported by multimodal evaluation, remains the cornerstone of timely diagnosis.
Castillejo Becerra CM, Crowson CS, Langenfeld HE, Tajfirouz D, Chodnicki KD, Koster MJ, Warrington KJ, Chen JJ. Population-Based Performance of Inflammatory Markers in Giant Cell Arteritis. Am J Ophthalmol. 2025;275:47–51. doi:[10.1016/j.ajo.2025.03.022]
🧠 Case Overview
- An 89-year-old man presented with sudden, painless vision loss in his left eye.
- Despite normal inflammatory markers (ESR and CRP), clinical suspicion for Giant Cell Arteritis (GCA) led to corticosteroid treatment and bilateral temporal artery biopsies (TABs).
- Surprisingly, the biopsy was negative on the symptomatic (left) side but positive for arteritis on the contralateral (right) side.
🔍 Diagnostic Challenges
- GCA can present without systemic symptoms—known as occult GCA.
- Normal ESR and CRP do not rule out GCA; combined sensitivity is high but not absolute.
- Profound vision loss and pallid optic disc edema raised concern for arteritic anterior ischemic optic neuropathy (AAION).
🧪 Temporal Artery Biopsy Insights
- Bilateral TABs can be crucial: ~5% of cases show discordance between sides.
- Histopathologic features of GCA include:
- Transmural inflammation
- Giant cells
- Disruption of the elastic lamina
- Consensus guidelines recommend:
- Biopsy within 2 weeks of steroid initiation
- Minimum 2 cm specimen length
- Avoid terms like “temporal arteritis”; prefer “healed arterial injury”
💊 Treatment & Follow-Up
- Initial treatment: oral prednisone → IV methylprednisolone → tocilizumab
- Despite therapy, vision in the left eye deteriorated to no light perception.
- Long-term management included monthly tocilizumab and prophylactic antibiotics.
🧩 Broader Implications
- Highlights diagnostic complexity of GCA, especially in seronegative cases.
- Supports bilateral TABs in select patients to avoid missed diagnoses.
- Reinforces the urgency of treatment despite inconclusive initial tests.
Jean-Charles, S., Shoji, M. K., Kikkawa, D. O., & Bhatti, M. T. (2025). The mirrored arterial dilemma. Survey of Ophthalmology, 70(5), 1029–1033.
