Giant cell arteritis (temporal arteritis) Flashcards
Define temporal arteritis.
Granulomatous inflammation of large arteries, particularly branches of the external carotid artery, most commonly the temporal artery.
What is the aetiology of temporal arteritis?
- Unknown
- Increasing age
- Genetic
- Environmental
- Infection may have causative role
- Both the humoral and cellular immune systems have been implicated in the pathogenesis of GCA.
Which HLA subtypes is GCA associated with?
Associated with HLA-DR3 and HLA-DRB1
How common is giant cell arteritis?
- Annual incidence is 18 in 100,000
- female:male ratio is 2-4:1
- Peak age onset 65-70 years
What is the typical history in GCA?
- Subacute onset, usually over few weeks
- Headache - scalp and temporal tenderness (pain on combing hair), Jaw and tongue claudication
- Visual - blurred vision, sudden blindness in one eye (amaurosis fugax)
- Systemic - malaise, low-grade fever, lethargy, weight loss, depression
- Symptoms of polymyalgia rheumatica (PMR) - early morning pain and stiffness of the muscles of the shoulder and pelvic girdle (40-60% of cases are associated with PMR)
What are the symptoms of polymyalgia rheumatica? (PMR)
early morning pain and stiffness of the muscles of the shoulder and pelvic girdle (40-60% of cases are associated with PMR)
What are the signs of GCA on examination?
- Swelling and erytherma of the overlying temporal artery
- Scalp and temporal tenderness
- Thickened non-pulsatile temporal artery
- Reduced visual acuity
What investigations would you do for GCA?
Bloods
- ESR - raised
- FBC - normocytic anaemia of chronic disease
Temporal artery biopsy
- Within 48hr of starting corticosteroids. Note that a negative biopsy does not exclude the diagnosis because skip lesions occur.
How do you manage GCA?
If no visual/neurological signs or symptoms:
-
PREDNISOLONE - Start high dose oral prednisolone (40-60mg/day) to prevent visual loss* - should have immense symptomatic relief after 48hours
- Reduce dose of prednisolone gradually (according to symptoms and ESR) to a maintenance dose of 7.5-10mg/day
- Many require prednisolone for 1-2 years
- If neurological/visual signs or symptoms:*
- METHYLPREDNISOLONE PULSE THERAPY - If GCA is complicated by visual loss –> IV pulse methylprednisolone (1g for 3 days) followed by oral prednisolone (60mg/day)
Then:
- ASPIRIN + PPI - Low dose aspirin + PPI - to reduce risk of visual loss* , TIA or stroke.
- BONES - Osteoporosis prevention - check adequate calcium and Vit D intake and bisphosphonates
- IMAGING -Annual CXR for up to 10 years to check for thoracic aneurysms - if detected monitor CT every 6-12 months
What are the complications of GCA?
Carotid artery/aortic aneurysms
Thrombosis may occur followed by recanalisation or embolism to the ophthalmic artery –>
- visual disturbances,
- amaurosis fugax
- or sudden monocular blindness.
What is the prognosis with GCA?
Condition usually only lasts ~2 years before complete remission.
What is amaurosis fugax?
condition in which a person cannot see out of one or both eyes due to a lack of blood flow to the eye
What is GCA a type of broadly speaking?
Vasculitis usually in over 50 year olds
What size of vessels are affected by GCA?
Medium and large arteries - mostly branches of carotid but can affect branches of aorta.
What is the pathophysiology of GCA leading to blindness/stroke?
- Inflammatory lesions arranged in granulomas (composed of T cells and macrophages) build up on the arteries.
- Multinucleated giant cells are present in 50% of cases (not required for diagnosis of GCA)
- Initial immune insult occurs on tunica adventitia where local dendritic cells attract and present antigen to T cells
- CD4 T cells then enter the artery through vasa vasorum and multiply in the vessel wall.
- They release IF-gamma –> stimulation of macrophages and formation of multinucleated giant cells.
- Cytokines are released –> systemic inflammation.
- Macrophages release metalloproteinases and reactive oxygen species causing tissue damage.
- Elastic lamina becomes fragmented and giant cells deposit in the media-intima border.
- Artery releases GF and angiogenic factors in response to injury –>
- proliferation of myofibroblasts,
- new vessel formation
- and marked thickening of the intimal/inner layer.
- Process of intimal expansion and hyperplasia leads to narrowing and occlusion of vessels –> tissue ischaemia e.g. blindness and stroke.
From the history alone which of the following is the most likely diagnosis?
- Migraine
- Giant cell arteritis
- Cerebral tumour
- Demyelination
- Subarachnoid haemorrhage
- Stress headache
- Trigeminal neuralgia
- Transient ischaemic attacks
GCA
The combination of frontal headache with tenderness/pain on palpation/brushing over the temporal regions, combined with jaw claudication on eating is highly suggestive of giant cell/temporal arteritis. This is a vasculitis that occurs in the patients > 50 years of age and is more common in the elderly. It tends to involve the external carotid artery (and branches) but can involve other arteries e.g. subclavian, axillary etc. None of the other conditions cause these symptoms. Always ask carefully about visual symptoms e.g. amaurosis fugax as blindness is a major risk. This patient describes this symptom and needs urgent treatment. Also look for evidence of polymyalgia rheumatica e.g. muscle ache and stiffness – 25% of patients have this in association. Trigeminal neuralgia causes intermittent, sharp pain, often in a mandibular/maxillary distribution. Pain can be worsened by eating, talking but is episodic and severe in nature. It is not associated with visual loss.
