Giant Cell Arteritis (GCA) and Arteritic AION Management

Algorithm Steps

1. ▶

   Start

   Suspected Giant Cell Arteritis

   Age ≥50 with: new headache, jaw claudication, scalp tenderness, visual symptoms, PMR symptoms, unexplained elevated ESR/CRP

   1. ◆

      Decision

      Visual Symptoms Present?

      Any: vision loss, amaurosis fugax, diplopia, RAPD, optic disc edema/pallor

      1. ●

         Action

         OPHTHALMIC EMERGENCY

         Vision-threatening GCA requires immediate high-dose IV steroids

         • IV Methylprednisolone 500-1000mg/day x 3 days
         • THEN oral prednisone 1mg/kg/day (max 60-80mg)
         • DO NOT delay treatment to obtain biopsy
         • Admit for IV therapy if outpatient not feasible
         1. ●

            Action

            Laboratory Workup

            Send immediately - do not delay steroids for results

            • ESR - typically elevated >50mm/hr (often >100)
            • CRP - sensitive marker, usually markedly elevated
            • CBC - normocytic anemia, thrombocytosis common
            • LFTs - may see elevated ALP
            • Note: ~5% have normal ESR/CRP
            1. ●

               Action

               Consider Imaging

               Temporal artery ultrasound or other modalities

               • Temporal artery ultrasound: 'halo sign' suggestive
               • MRI/MRA: vessel wall enhancement
               • PET-CT: for large vessel involvement
               • Imaging does NOT replace biopsy
               1. ◆

                  Decision

                  Clinical Response to Steroids?

                  Most patients improve markedly within 24-72 hours

                  1. ●

                     Action

                     Good Response - Taper Steroids

                     Gradual taper with monitoring

                     • After 2-4 weeks at initial dose, begin taper
                     • Typical: reduce by 10mg every 2 weeks until 40mg
                     • Then slower: 5mg every 2-4 weeks until 15-20mg
                     • Then very slow: 1-2.5mg/month
                     • Monitor ESR/CRP with each reduction
                     • Total treatment usually 1-2+ years
                     1. ●

                        Action

                        Consider Steroid-Sparing Therapy

                        For relapsing disease or unable to taper

                        • Tocilizumab 162mg SC weekly - FDA approved for GCA
                        • Significantly reduces relapse and cumulative steroid dose
                        • Screen for latent TB, hepatitis before starting
                        • Monitor LFTs, lipids, neutrophils
                        • Alternative: Methotrexate 15-25mg/week
                        1. ●

                           Action

                           Long-term Monitoring

                           GCA requires prolonged follow-up

                           • Monitor for steroid side effects (glucose, BP, osteoporosis)
                           • Start PPI, calcium/vitamin D, consider bisphosphonate
                           • ESR/CRP with each taper step
                           • Watch for aortic aneurysm (annual CXR or CT if concerning)
                           • Relapse common - may need re-escalation
                           1. ✓

                              Outcome

                              Remission Achieved

                              Steroids tapered/stopped, continued monitoring for relapse

                           2. ✓

                              Outcome

                              Rheumatology Co-management

                              Complex/refractory cases benefit from rheumatology involvement

                  2. ●

                     Action

                     Poor/No Response

                     Reconsider diagnosis or add steroid-sparing agent

                     • Re-evaluate: is this truly GCA?
                     • Consider other causes of visual loss
                     • Tocilizumab (IL-6 inhibitor) - ACR recommended for relapsing/refractory
                     • Methotrexate as alternative
                     1. ⚠

                        Warning

                        ⚠️ Vision Loss Can Progress

                        Up to 10% of patients may have further vision loss despite steroids, especially in first 1-2 weeks

            2. ●

               Action

               Temporal Artery Biopsy

               Gold standard for diagnosis

               • Arrange within 2 weeks of starting steroids
               • Sensitivity decreases after 2-4 weeks of treatment
               • Unilateral adequate; bilateral if high suspicion and negative
               • Specimen length ≥1-2cm
               • Negative biopsy does not rule out GCA
      2. ●

         Action

         GCA Without Visual Loss

         Start oral corticosteroids promptly

         • Prednisone 40-60mg daily (1mg/kg, max 60mg)
         • Or equivalent glucocorticoid
         • Most patients respond within 24-72 hours