Giant cell arteritis: Prevalent in moderate and large arteries that are well stratified and have epicardial intrinsic arteries, such as the superficial temporal artery, occipital artery, ophthalmic artery, vertebral artery, distal subclavian artery, axillary artery, and thoracic aorta.
Rheumatic polymyalgia: predominantly myalgia, stiffness, distributed in the neck, shoulder, upper arm, pelvic girdle, etc..
Both may appear with each other (may be implicitly accompanied) or sequentially, or after hormone reduction after treatment.
It occurs mostly in elderly people over 50 years old, with a peak of 70-80 years old and 60-75% of women.
1. Laboratory tests
Increased sedimentation (s/s: 84%/30%), increased CRP (s/s: 86%/30%), only 4% negative for both, increased platelet count, may have anemia.
Anti-neutrophil cytoplasmic antibodies (ANCA): to exclude other rheumatic disorders.
serum protein electrophoresis: to exclude monoclonal gamma disease.
blood culture: to exclude other fever-causing infectious agents.
2. Imaging
MRA/CTA: inflammatory changes in the aortic arch and major branches, wall thickening, enhancement, stenosis, dilatation, coarctation, aneurysm and other changes.
Color Doppler ultrasound: vascular wall edema in the form of “halo sign” (s/s: 75%/83%).
Soft tissue ultrasound: rheumatic polymyalgia can be seen as subacromial, subdeltoid, humeral rotor, humeral neck and other parts of the bursitis, biceps long head tenosynovitis; periarticular synovitis suggests rheumatoid and other inflammatory osteoarthropathies.
3.Pathology
Biopsy of the superficial temporal artery is an important diagnostic criterion, usually 1.5-2.0 cm long artery is taken; those with high suspicion of the disease and negative biopsy may be considered for a second site. The positive biopsy rate decreases after about a few weeks of hormone therapy.
Diagnosis
Giant cell arteritis and rheumatic polymyalgia classification and diagnostic criteria
I. ACR classification criteria for giant cell arteritis (1990)
At least 3 of the following criteria are met
Age of onset ≥ 50 years.
New onset of headache, new onset or new form of limited headache.
Abnormal superficial temporal artery, with tenderness or diminished pulsation.
increased blood sedimentation, >50 mm/h (Westergren method).
biopsy-confirmed mononuclear cell-dominated inflammatory infiltrate or granulomatous inflammation, usually with multinucleated giant cells.
II. ACR-EULAR provisional rheumatic polymyalgia classification criteria (2012)
Required criteria
Age ≥ 50 years.
Bilateral shoulder pain.
Abnormalities in one or both of CRP and ESR.
Additional criteria
Morning stiffness lasting more than 40 minutes (2 points).
Hip pain or decreased range of motion (1 point).
Negative rheumatoid factor and anti-cyclic citrullinated peptide antibodies (2 points).
absence of periarticular synovitis (1 point).
Ultrasonographic findings
subdeltoid bursitis, biceps tendon tenosynovitis, glenohumeral synovitis on at least one shoulder, or synovitis or rotor bursitis on at least one hip (1 point)
Bilateral subdeltoid bursitis, biceps tendon tenosynovitis, or glenohumeral synovitis (1 point).
【Treatment
I. Giant cell arteritis
Induction therapy: prednisone 1 mg/kg/d orally for 2-4 weeks, and methylprednisolone 1 g/d intravenously for 3 days for those with clinical signs of optic nerve ischemia.
Dose reduction: when clinical symptoms disappear and ESR and CRP are normal, daily dosage is reduced by 10%-20% every 2 weeks; after reaching <10mg/d, the dosage is reduced by 1mg/d per month.
Reignition: manifesting as recurrent rheumatic polymyalgia, increase the daily dosage of hormone by 10%-20%, and re-induce treatment if the symptoms are severe.
II. rheumatic polymyalgia
Induction therapy: prednisone 15-20 mg/d orally for 1-2 months.
Dose reduction: clinical and laboratory improvement, 10%-20% reduction in dosage every 2 weeks; to <10mg/d later, reduce daily dosage by 1mg per month.
III. Non-corticosteroid therapy: uncertainty of effect may be tried.
IV. Follow-up: inflammatory index, 1 time/month x 1 year, 1 time/2 months in the 2nd year, and then every 6 months