Polyarthritis with joint swelling

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Eiman Ghaffarpasand, M.D. [2]

Diseases			Clinical manifestations							Para-clinical findings								Gold standard	Additional findings
			Symptoms				Physical examination
										Lab Findings				Imaging			Histopathology
			Joint Swelling	Fever	Weight loss	Claudication	Morning stiffness	Local erythema	Skin manifestation	CBC	ESR	Synovial fluid	Other	X-ray	CT scan	Other
Polyarthritis	Infectious arthritis	Lyme disease	+	+	+/-	+/-	-	-	Erythema migrans	Leukopenia, Thrombocytopenia	-	Cell counts 500-98,000/µL	Microscopic hematuria, Proteinuria, ↑ALT or AST	-	-	-	Fibrosis of the deeper dermis and hyalinization of collagen bundles	Serologic tests	Erythema migrans
		Bacterial endocarditis	+	+	+	-	-	+/-	Janeway lesions, Osler nodes, Roth spots	Normochromic-normocytic anemia	↑	↑WBC, S. aureus in culture	Hyperglobulinemia, Cryoglobulinemia	Joint erosion and effusion	-	-	Vegetation or intracardiac abscess demonstrating active endocarditis	Echocardiography (TTE)	Vertebral osteomyelitis
	Postinfectious (reactive) arthritis	Rheumatic fever	+	+	-	-	-	+/-	Erythema marginatum rheumaticum	Leukocytosis	↑	Sterile inflammatory reaction with cells<20,000/μL	Streptococcal antibody titer	Cardiomegaly	Valvular or pericardial calcification	Echocardiographic changes in heart valves	Edema, Fibrinoid necrosis, Mononuclear cell infiltrate	Echocardiography	Chorea, Carditis
		Reactive arthritis	+/-	+/-	-	-	-	-	Genital ulceration	Normocytic normochromic anemia	↑	High WBC count (10,000-40,000/µL)	HLA-B27 test	Periosteal reaction and proliferation of tendon insertion site	Sacroiliitis	Enthesitis in ultrasonography	Keratoderma blennorrhagicum, Balanitis circinata	Spondyloarthritis and unequivocal demonstration of preceding infection	Conjunctivitis, Uveitis
	Other seronegative spondyloarthritides	Ankylosing spondylitis	+	-	+/-	+/-	+	-	Dactylitis (sausage digit)	Normocytic normochromic anemia	↑	High WBC count (lymphocyte predominance)	↑Alkaline phosphatase (ALP)	Bony erosions and sclerosis of the joints	Early sacroiliitis, erosions, and enthesitis	Possible cauda equina syndrome secondary to spinal stenosis in MRI	Chronic inflammation with CD4+ and CD8+ T lymphocytes and macrophages	Plain x-rays	Peripheral enthesitis, Uveitis
		Psoriatic arthritis	+	-	-	-	-	+	Scaly erythematous plaques, Guttate lesions, Lakes of pus, Erythroderma	Normal	↑	High WBC count (5000-15,000/µL) with >50% of PMN leukocytes	↑RF, ANA, IgA	Joint-space narrowing, Fluffy periostitis	Pencil-in-cup deformity, Early signs of synovitis	Sacroiliitic synovitis, Enthesitis in MRI	Lack of intrasynovial Ig and RF, Greater propensity for fibrous ankylosis, osseous resorption, and heterotopic bone formation	Clinical findings	Onycholysis, Splinter hemorrhages
		Inflammatory bowel disease	+	+	-	-	+	+/-	Pyoderma gangrenosum (ulcerative colitis), Erythema nodosum (Crohn disease)	Iron deficiency anemia, Leukocytosis, Thrombocytosis	↑	Mild to moderate inflammatory fluid, PMN predominance	↑RF, Antiendomysial Ab, Antitransglutaminase Ab	Bilateral sacroiliitis, Syndesmophytes and apophyseal joint involvement in spine	-	Early detection of spinal and sacroiliac lesions in MRI	-	Clinical findings and history	Acute anterior uveitis
	Rheumatoid arthritis		+	-	+	+	+	-	Rheumatoid nodules	Anemia, Thrombocytosis	↑	WBC count >2000/µL (generally 5000-50,000/µL), with neutrophil predominance (60-80%)	Anti-CCP Ab, Hyperuricemia	Joint-space narrowing	Microfractures	Synovitis in MRI	Influx of inflammatory cells into the synovial membrane, with angiogenesis	Clinical findings coupled anti-CCP antibody	Rheumatoid nodules
	Crystal-induced arthritis		+	+/-	-	-	-	+	Joint erythema	Leukocytosis	↑	Needle shaped urate crystals, WBC count > 2000/µL	Urinary uric acid (>1100 mg in 24h)	Punched-out erosions or lytic areas with overhanging edges	Complementary for recognizing erosions	Tophi or edema in MRI	Large pale pink acellular areas (urate crystals), surrounded by histiocytes and multinucleated giant cells	Synovial fluid assay	Conjunctival nodules
	Systemic rheumatic illnesses	Systemic lupus erythematosus	+	-	+/-	-	-	+	Malar rash, Photosensitivity, Discoid lupus	Leukopenia, Lymphopenia, Anemia, Thrombocytopenia	↑	Cell count from < 25% PMNs (non-inflammatory effusions) to > 50% PMNs (inflammatory effusions)	Creatine kinase, LFT, ANA, Anti-dsDNA, Anti-Sm, Lupus anticoagulant	Periarticular osteopenia and soft-tissue swelling without erosions	Interstitial lung disease, Pneumonitis, Pulmonary emboli, Alveolar hemorrhage	Pericardial effusion, Pulmonary hypertension, Verrucous Libman-Sacks endocarditis in echocardiography	Inflammatory infiltrates at the dermoepidermal junction and vacuolar change in the basal columnar cells	Anti-dsDNA	Rheumatoid arthritis, Serositis, Oral ulcers
		Behçet's syndrome	+	-	-	-	-	-	Erythema nodosum	Normocytic normochromic anemia	↑	Cell count < 25% PMNs (non-inflammatory)	Serum complement levels, Human leukocyte antigen (HLA)-B51	Soft tissue swelling	Non-erosive synovitis	-	Dermal vessels infiltration with lymphocytes and plasma cells, Immune deposits of immunoglobulin M (IgM) and C3	Clinical findings	Oral ulcer, Mucosal erosion
		Relapsing polychondritis	+	-	-	-	-	-	-	Leukocytosis, Anemia	-	Cell count < 25% PMNs (non-inflammatory)	Cryoglobulins, ANA, C-ANCA	Tracheal stenosis in CXR	Calcification of cartilaginous structures	Aortic root dilatation and degree of aortic regurgitation in echocardiography	Chondrolysis, Chondritis, Perichondritis	Clinical findings coupled with imaging	Ear pain and redness, Polyarthritis
	Other systemic illnesses	Sarcoidosis	+	-	-	-	-	-	Mild papules and nodules	Mild anemia	↑	Cell count < 25% PMNs (non-inflammatory)	IL-2 and IFN-γ, ↑ACE, ↑1, 25-dihydroxyvitamin D	Bilateral hilar adenopathy	Active alveolitis or fibrosis	Hepatosplenomegaly in ultrasonography	Noncaseating granulomas (NCGs)	Histological confirmation	Heart block, Ocular lesion
		Palindromic rheumatism	+	-	-	+/-	+	-	Rheumatoid nodules	Anemia	↑	High WBC count (5000-15,000/µL) with >50% of PMN leukocytes	RF, Anti-CCP antibody, ↑Cr or BUN, ↑ALT or AST, ANA	Effusions in joints	Microfractures	Basilar invagination with cranial migration of an eroded odontoid peg in MRI	Influx of inflammatory cells into the synovial membrane, withangiogenesis, proliferation of chronic inflammatory cells	Clinical findings coupled anti-CCP antibody	Rheumatoid nodules
Polyarticular pain	Viral arthritis	Parvovirus	+	+	+/-	-	-	-	Fifth disease/ Erythema infectiosum	Aplastic crisis	↑	Normal	ANA, RF, CRP	Joint swelling	-	-	Immune complex deposition	Parvovirus IgM antibody	Transient aplastic crisis, Fetal infection
	Soft tissue abnormalities		+	-	-	-	-	+/-	Maculopapular rash	Normal	-	Cell count < 25% PMNs (non-inflammatory)	CRP, Ca	Joint swelling	Synovial edema and thickness	Mild joint effusion in ultrasonography	Mild inflammation	Clinical findings	Mucositis, Enthesitis