Giant Cell Arteritis

Biopsy

• Temporal artery biopsy is the gold standard.
  • Biopsy often shows findings of arteritis even after more than 14 days of steroid therapy.
  • Ideally obtained within 14 days of starting steroids, although positive biopsy may be seen for several months
  • Need about 1.5-2 cm length of tissue, as skip lesions can occur

Imaging

• Ultrasound of temporal artery – halo sign is consistent with GCA (view image) but dependent on skill of ultrasonographer
• MRA, CTA, or PET-CT may identify large vessel vasculitis lesions.

Lab Workup

• ESR, CRP, or other nonspecific markers of inflammation

• Other vasculitides
  • Takayasu arteritis
    • Also affects aorta and primary branches, but typically under 40 yo and F
  • Granulomatosis with polyangiitis (GPA)
  • Polyarteritis nodosa (PAN)
  • Microscopic polyangiitis (MPA)
• Ischemic vascular disease, ischemic optic neuropathy, retinal artery/vein occlusion, migraine headaches, TMJ OA, dental disease
• Other causes of headache
• Other causes of vision loss
• Malignancies (especially in patients with elevated inflammatory markers)

Glucocorticoid Therapy

• Initial dosing 1 mg/kg daily in divided doses
• Do not delay by waiting to confirm by biopsy or imaging if clinical suspicion is high, especially in the setting of threatened or acute vision loss 
• If threat of acute visual loss at diagnosis, should be treated with IV methylprednisolone 1 g daily X 3 days
• High dose therapy is usually continued for 1 month or until ESR/CRP normalize and then is tapered slowly
  • Taper can last 6 months-2 years

Aspirin

• Aspirin may be added for GCA patients with critical or flow-limiting involvement of the vertebral or carotid arteries.

Adjunctive Immunosuppressive Therapy

• Consult rheumatology to consider start of tocilizumab (anti-IL6) for any new or relapsing GCA patient, if no contraindications

Bone Health

• Treat to prevent glucocorticoid-induced osteoporosis, given need for long-term steroids

Exercise and Nutrition Counseling

• To prevent falls, steroid myopathy and frailty

• Regular follow-up every 3 months
• Monitor based on symptoms:
  • Worsening headaches
  • Increased temporal artery tenderness
  • Scalp tenderness
  • Jaw/tongue claudication
  • PMR symptoms
• Monitor for signs of AAA or TAA
  • Needs to be urgently evaluated in a GCA patient
  • Yearly abdominal ultrasound should be considered
• Monitor with ESR and CRP (which should decrease and normalize with treatment)
• Very important to monitor for steroid complications for patients with GCA (steroid-induced osteoporosis is very common early on in steroid therapy)

Clinical Presentation

• GCA is most common among 70-80 yo, although younger or older presentation is possible.
• Jaw claudication, fatigue after chewing for several minutes, is a highly specific symptom for GCA.
  • Jaw pain that starts upon opening/closing mouth is more indicative of TMJ OA/pain.
• Evaluate for signs and symptoms of GCA in a patient with symptoms of PMR (morning stiffness affecting neck, shoulders, pelvic girdle)

Diagnostic Workup

• Ultrasound has utility (halo sign indicates temporal arteritis – view image), but it is very operator dependent.
• Although possible, GCA rarely presents with normal inflammatory markers.
• Temporal artery biopsy can yield diagnosis/show inflammation even 2 weeks after steroid start.

Treatment & Monitoring

• Treatment should not be delayed for diagnostic purposes, as vision loss is a concerning complication.
• Mainstay of therapy: systemic steroids and IL6 axis inhibitors
• Very important to monitor for steroid complications
  • Steroid-induced osteoporosis is very common early on in steroid therapy.