GCA and PMR

Question 1

Serum markers in GCA and PMR which have the strongest assoication with disease activity

Answer 1

• BAFF and IL-6

Question 2

Epidemiology and symptoms of GCA

Answer 2

• Most common vasculitis of elderly
• Patients > 50 years (>75), peaks at 80 years
• F:M 2.5:1
• Incidence highest in Scandinavian populations, infrequent in African, Asian, Hispanic

Symptoms

• Systemic inflammation related symptoms → scalp tenderness, low grade fever, weight loss and fatigue
• Ischaemic symptoms → jaw claudication, vision loss, limb claudication, sometimes posterior circulation stroke

Visual symptoms in GCA

• Vision loss → partial or complete
• Transient blurring
• Sudden loss of vision (usually permanent)
• Eye pain
• Diplopia
• Ptosis, nystagus, INO

Question 3

Causes of vision loss in GCA

Answer 3

1. Anterior ischaemic optic neuropathy → occlusion of posterior ciliary arteries → most common cause in GCA 80% cases (GCA only makes up 5% causes AOIN)
2. Branch retinal vein occlusion
3. Posterior ischaemic optic neuropathy
4. Central retinal artery occlusion
5. Choroidal ischaemia

Question 4

Pathogenesis of GCA and vascular distribution

Answer 4

Pathogenesis

• Activation dendritic cells in adventitia blood vessel, TLR7 → cascade of events → significant inflammatory cell infiltrate in the media and smooth muscle proliferation → luminal narrowing → ischaemia
• Also formation of tissue giant cells

Vascular distribution

Affects medium and large sized arteries with internal elastic lamina

• External carotid branches e.g. temporal and occipital
• Ophthalmic
• Vetebral
• Distal subclavian and axillary arteries
• Thoracic aortia

Question 5

Four different clinical patterns of GCA

Answer 5

1. Isolated cranial GCA - 80%
2. Symptomatic large vessel vasculitis - claudication, pulseless limb with or without associated cranial signs - 9%
3. Isolated fever or inflammatory response - 9%
4. Isolated PMR with vasculitis on imaging - 2%

Large vessel GCA

Aorta, axillary, subclavian

• More likely to be younger
• Less likely to present with headaches
• Less likely to have a positive temporal artery biopsy
• Lower risk of visual loss
• Required higher steroid doses
• Higher risk of relapse

Question 6

Differential diagnosis GCA

Answer 6

Headache main symptoms

Cluster/migraine/tension headache

sInusitis

Trigeminal neuralgia

Ophthalmic shingles

Skull metsastasis, occipital condyle syndrome

TMJ disorder

High ESR/CRP & systemic features

PMR

Small, medium vessel vasculitis - GPA/PAN

Endocarditis

Malignancy

CPPD

Question 7

Investigations for GCA

Answer 7

• FBC, U&Es, ESR, CRP, urine dip, CXR (aortic aneursym, parenchymal infiltrates), CT Head (other headache causes)

Temporal artery biopsy

Sensitivity 70-90% cranial GCA, 52% large vessel GCA

Biopsy negative GCA → skip lesions, specimen too short, extra-cranial large vessel GCA

Imaging

1. Ultrasound → superficial temporal arteries and branches, axillary arteries. Useful for large vessel phenotype. Sensitivity decreased after 2 days steroids. Hypoechoic halo
2. 3T MRI scalp arteries with GAD
3. 18FDG PET
4. CT Angiogram

Question 8

Management of giant cell arteritis

Answer 8

• Visual symptoms → methylprednisolone 1g daily for 3/7
  
  • Development or progression of visual loss after initiation glucocorticoids rare
• Prednisone orally if no visual symptoms → initial dose >40mg daily more likely to reach dose of <5mg/discontinue steroids than those initially on <40mg day
  
  • Glucorticoid related adverse effects high rate - 86% at 10 years, High risk of infection in 1st year
• Tocilizumab → associated with sustained remission, reduced cumulative prednisone dose, lower rate of relapse. No increase in visual complications
  
  • Funded in Australia - requires positive biopsy or imaging (PET/MRI/CT) consistent with large vessel vasculitis
• Aspirin not currently recommended
• Methotrexate also associated with reduction in risk of first relapse and second relapse

Question 9

Complications of GCA and its treatment

Answer 9

• Infection - high in first year
• Osteoporosis
• Cataracts
• Impact on diabetes control
• Cancer risk apparently not increased
• Monitoring for development of aortic aneursym required (usually ascending aorta)
  
  • Makes and smokers

Question 10

Features, differential diagnosis and investigations for polymyalgia rheumatica

Answer 10

• One of the most common systemic rheumatic conditions
• Lifetime risk - 2.4% women, 1.6% men
• > 50 years
• ½ GCA patients will be affected. 10% with PMR will develop GCA

Clinical features

• Aching and stiffnes around the neck, shoulders, hips
• Prolonged morning stiffness (key feature)
• Muscle strength normal but testing limited by pain
• Can be associated with depression, fatigue, weight loss

Differential diagnosis

• Seronegative rheumatois arthritis
• Regional soft tissue rheumatism
• Subacromial bursitis/supraspinatus tendinitis
• Myeloma, other malignancy
• Myositis
• Drug-induced myopathy and myalgia
• Fibromyalgia
• Parkinson’s

Investigations

• ESR/CRP → almost always elevated
• RF/CCP to exclude seropositive RA
• Protein electrophoresis - myeloma, MGUS
• CK - exclude myositis

Question 11

Classification criteria for polymyalgia rheumatica

Answer 11

Question 12

Management and prognosis of PMR

Answer 12

• Most respond to prednisone 15-25mg/day within 48-72 hours
  
  • Relapses recur during steroid reduction and may require return to previous effective dose
  • Mean treatment duration approximately 20 months
• Tocilizumab associated with steroid free remission at week 16
• General → bone health, infection risk → vaccination, glycaemic control , cataracts

Prognosis

• Most patients require treatment > 1 year → may need low dose steroid for years
• 50% relapse rate
• PMR associated synovitis is non-erosive