AKT · Musculoskeletal/Vasculitis, PMR & GCA

Giant cell arteritis

Granulomatous large-vessel vasculitis of the aorta and its branches (esp. temporal/cranial arteries)

Overview

A large-vessel granulomatous vasculitis of those over 50, affecting the cranial branches of the carotid (and the aorta). It is a medical emergency because of the risk of irreversible visual loss from anterior ischaemic optic neuropathy. It strongly overlaps with polymyalgia rheumatica. High-dose steroids must be started immediately on clinical suspicion — before the biopsy.

Recognise

New temporal headache, scalp tenderness (combing hair), jaw claudication (highly specific), tender/thickened/pulseless temporal artery
Visual symptoms: amaurosis fugax or sudden painless visual loss (arteritic AION) — a sight-threatening emergency
Over-50, raised ESR/CRP; overlap with PMR (proximal girdle stiffness); systemic upset

Red flags

Visual symptoms (amaurosis/visual loss) → ophthalmological emergency; the OTHER eye is at risk → immediate high-dose IV/oral steroid
Do NOT wait for the biopsy to start steroids — treat on clinical suspicion to prevent blindness

Differentials & how to tell them apart

Tension/migraine headacheno systemic inflammation, jaw claudication or visual loss; younger

Trigeminal neuralgialancinating facial pain, normal inflammatory markers

Other causes of AIONnon-arteritic AION — no systemic features, normal ESR/CRP

Investigations

Raised ESR/CRP; temporal artery biopsy within ~2 weeks of starting steroids (skip lesions → a negative biopsy does NOT exclude it); temporal/axillary artery ultrasound ('halo' sign); ophthalmology assessment if visual symptoms.

Management

Immediate high-dose corticosteroid (IV methylprednisolone if visual loss) — before the biopsy

1Suspect clinically in over-50s with new headache, jaw claudication, scalp tenderness and raised ESR/CRP. Start a high-dose corticosteroid IMMEDIATELY — do not wait for the temporal artery biopsy.Gate: Any visual symptoms → ophthalmological emergency and IV methylprednisolone to protect the fellow eye; biopsy can be done within ~2 weeks of starting steroids and a negative biopsy (skip lesions) does not exclude GCA.
2Slow steroid taper over 1–2 years with bone/GI protection; add tocilizumab as a steroid-sparing agent for relapsing or refractory disease.

Start high-dose corticosteroid IMMEDIATELY on clinical suspicion — oral prednisolone (40–60 mg) for uncomplicated disease; IV methylprednisolone if visual symptoms — do NOT wait for the biopsy

Long slow steroid taper over 1–2 years — with relapse monitoring; bone and GI protection (PPI, bisphosphonate, calcium/vitamin D)

Tocilizumab (IL-6 inhibitor) as a steroid-sparing agent — for relapsing/refractory disease or to reduce steroid toxicity

Low-dose aspirin (selected) — may reduce ischaemic complications in some

Key points

Over-50 + new headache + jaw claudication + scalp tenderness + raised ESR = GCA → high-dose steroids NOW (IV methylprednisolone if any visual loss) to save sight; biopsy after. A negative biopsy doesn't exclude it (skip lesions). Overlaps PMR.

Monitor & prognosis

Symptoms/ESR-CRP, visual status, steroid taper and its complications (bone, glucose, BP).

Excellent for symptoms with prompt steroids; established visual loss is usually irreversible.

Source: BSR GCA; cross-ref ophthalmology (arteritic AION) & neurology