Primary vasculitis that causes chronic granulomatous inflammation predominantly of the aorta and its major branches; the two major categories of large vessel vasculitis are temporal (giant cell) arteritis and Takayasu arteritis (TA)
Takayasu arteritis
Aetiology
Generally occurs < 40 years
More common in females
More prevalent in Asian populations
Clinical presentation
Early features include non specific features - low grade fever, malaise, night sweats, weight loss, arthralgia and fatigue
Following this - claudication in upper and lower limbs
If untreated, vascular stenosis and aneurysms can occur - results in bruit (most commonly carotid), reduced pulses, blood pressure difference of extremities
Investigations
Bloods - raised inflammatory markers
Imaging - MR angiogram can detect thickened vessel walls and stenosis
Giant cell arteritis
Aetiology
Most common cause of systemic vasculitis in adults
Unknown aetiology
Generally occurs > 50 years, most commonly late 60+
Strong association with polymyalgia rheumatica
Clinical presentation
Symptoms:
Unilateral acute temporal headache with focal tenderness on direct palpation
Jaw claudication during chewing of firm foods or speaking (caused by ischaemia of the maxillary artery)
Visual disturbances e.g. blurring
Visual loss (amaurosis fugax)
Constitutional manifestations e.g. fatigue, malaise and fever may also be present
Signs:
Tender enlarged non-pulsatile temporal arteries
GCA should always be considered in the differential diagnosis of a new-onset headache in patients 50 years of age or older with an elevated erythrocyte sedimentation rate (ESR), CRP or plasma viscosity
Investigations
Bloods - raised inflammatory markers
Temporal artery USS (first line)
Temporal artery biopsy (gold standard)
Transmural inflammation of the intima, media, and adventitia of affected arteries
Patchy infiltration by lymphocytes, macrophages, and multinucleated giant cells
Vessel wall thickening can result in arterial luminal narrowing, resulting in subsequent distal ischemia
A positive temporal artery biopsy has 100% specificity but relatively low sensitivity (15-40%) for the diagnosis of GCA due to the presence of skip lesions - biopsy may be taken from a normal segment
PET CT or CT angiogram if other tests inconclusive/negative but high clinical suspicion remains
Management (TA + GCA)
Start at prednisolone 40-60mg daily
TA - more long term, use steriod sparing agents if needed e.g. leflunamide, methotraxate
GCA - gradual reduction in steriod dose over 18 months - 2 years
If patient relapses in early stages of treatment - leflunamide, methotraxate
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