Temporal Arteritis (Giant cell Arteritis)

Definition | Aetiology | Pathophysiology | Risk Factors | Signs and Symptoms | Investigations | Management

Definition

Temporal arteritis, also known as giant cell arteritis (GCA), is a systemic vasculitis that affects medium and large arteries, particularly the temporal arteries. It can lead to vision loss if untreated.

Aetiology

  • Exact cause unknown but thought to be an autoimmune response.
  • Triggered by environmental factors in genetically predisposed individuals.
  • Strong association with polymyalgia rheumatica (PMR).

Pathophysiology

  • Inflammation of the arterial walls leads to granulomatous infiltration.
  • Predominantly affects the external carotid artery and its branches.
  • Results in vessel narrowing, ischaemia, and potential occlusion.
  • Can cause sudden irreversible vision loss due to ophthalmic artery involvement.

Risk factors

  • Age >50 years (peak incidence in 70s).
  • Female sex (2:1 ratio compared to males).
  • History of polymyalgia rheumatica (PMR).
  • Genetic predisposition (HLA-DR4 association).
  • Scandinavian or Northern European ancestry.
  • Smoking.

Signs and symptoms

Systemic Symptoms:

  • Fever, fatigue, weight loss.
  • Night sweats.

Vascular Symptoms:

  • Temporal headache: localised, severe, throbbing pain.
  • Tender, thickened temporal artery: palpable and non-pulsatile.
  • Jaw claudication: pain when chewing due to masseter muscle ischaemia.

Ophthalmic Symptoms (Emergency Features):

  • Amaurosis fugax: temporary vision loss.
  • Sudden, painless permanent vision loss: due to anterior ischaemic optic neuropathy.
  • Diplopia (double vision).

Investigations

  • Blood tests:
    • Elevated ESR & CRP: markers of inflammation, usually very high (>50 mm/hr).
    • Full blood count: may show normocytic anaemia.
    • Liver function tests: can show raised alkaline phosphatase.
  • Temporal artery biopsy:
    • Gold standard for diagnosis.
    • Shows granulomatous inflammation with giant cells.
    • Can be negative due to skip lesions.
  • Ultrasound of temporal artery:
    • Shows a “halo sign” (indicative of vessel inflammation).
  • Fundoscopy:
    • May show optic disc swelling if there is ischaemic optic neuropathy.

Management (referral to rheum generally)

1. Immediate Corticosteroids (Prevent Vision Loss):

  • Oral prednisolone: 40–60 mg daily if no visual symptoms.
  • IV methylprednisolone: 500–1000 mg daily for 3 days if visual loss is present.
  • Start treatment immediately if suspected – do not wait for biopsy results.

2. Additional Therapy:

  • Aspirin 75 mg daily: reduces ischaemic complications.
  • Calcium & vitamin D: prevent steroid-induced osteoporosis.
  • Proton pump inhibitor (PPI): to protect gastric mucosa from steroid side effects.

3. Tapering & Long-Term Immunosuppression:

  • Gradual steroid tapering over months to years.
  • Consider steroid-sparing agents (e.g., methotrexate, tocilizumab) in relapsing cases.

4. Monitoring:

  • Regular ESR & CRP monitoring.
  • Monitor for steroid side effects (diabetes, osteoporosis, hypertension).
  • Ophthalmology referral if visual symptoms develop.
NeurologymypanotesTemporal Arteritis (Giant cell Arteritis), GCA