JIA, Imaging, Labs and Misc

JIA Categories:

Systemic: Stills
PsA
ERA
Oligoarthritis

Persistent
Extended

Polyarthritis Seronegative
Polyarthritis Seropositive
Undifferentiated / Overlap

Radiography: MKSAP 18

Plain Xray can help assess and differentiate inflammatory arthritis, osteoarthritis, and crystal arthropathies. Plain Xray is limited in its ability to visualize soft tissues, and may not detect early or small erosive changes
CT provides multiple views and orientations from a single study but is more useful for bony abnormalities than for soft-tissue inflammation or fluid collections. CT is more sensitive for detecting bone erosions than plain radiographs or MRI
MRI is the most sensitive routine radiologic technique for detecting soft-tissue abnormalities, inflammation, and fluid collections but is less effective than CT in demonstrating bony abnormalities or erosions. MRI is sensitive for detecting early spine and sacroiliac joint inflammation and may be indicated for the evaluation of suspected spondyloarthritis if plain radiographs are negative.
USG can assess soft-tissue abnormalities, including synovitis, tendonitis, bursitis, and effusions; assess disease activity using Doppler; and assist with tendon or joint injections. However, it is operator dependent, and training/practice is needed to achieve competence.

Rheumatologic Disease	Radiographic Findings
Rheumatoid arthritis	Marginal Bony erosions; periarticular osteopenia; subluxations; soft-tissue swelling; MCP, PIP, and wrist involvement
Osteoarthritis	Asymmetric joint-space narrowing; osteophytes; subchondral sclerosis and cystic changes; degenerative disk disease with collapse of disks; degenerative joint disease with facet joint osteophytes; spondylolisthesis (anterior/posterior misalignment of the spine); kyphosis
Diffuse idiopathic skeletal hyperostosis	Calcification of the anterior longitudinal ligament; bridging horizontal syndesmophytes; usually seen in the thoracic spine and more prominent on the right side of the spine
Ankylosing spondylitis	Sacroiliitis; squaring of the vertebral bodies; bridging vertical syndesmophytes; shiny corners; ankylosis does not skip vertebrae
Psoriatic arthritis	Destructive arthritis with erosions and osteophytes; DIP involvement is common; pencil-in-cup deformity on hand radiograph; arthritis mutilans; syndesmophytes
Gout	Punched-out erosions with sclerotic borders and overhanging edges of cortical bones; periarticular soft-tissue swelling with calcifications in tophaceous deposits
Calcium pyrophosphate deposition	Chondrocalcinosis, most commonly of the knees, shoulders, wrists, pubic symphysis; osteoarthritis, including in locations atypical for primary osteoarthritis (MCPs, wrists, shoulders)

Gout:

Punched-out lesions with overhanging edge of cortical bones.

Ultrasounds can show unsuspected tophi or a double contour sign at cartilage surfaces, which is highly specific for urate deposits in joint

The ultrasound double contour sign, the identification of monosodium urate crystal deposition by dual-energy CT, and gout-related joint damage on radiography are all included in the new gout classification criteria.

CPPD

Cartilage calcification appears as a linear opacity below the surface of articular cartilage). It most commonly occurs in the knees, wrists (triangular fibrocartilage), pelvis (pubis symphysis), and metacarpophalangeal (MCP) joints, in descending order.

Radiographic features of OA include asymmetric joint-space narrowing, subchondral sclerosis, osteophytes, and bone cysts; however, these changes may not be present in early disease.

Even in established OA, symptoms may correlate poorly with imaging findings.

Although MRI and ultrasonography can detect subtle OA changes at an earlier stage and are increasingly used in OA research, they are not needed for routine OA diagnosis. MRI may be indicated in the setting of symptoms suggestive of a concomitant mechanical disorder (joint catching, locking, instability), but incidental abnormalities such as meniscal tears are commonly seen on MRI in patients with OA and may prompt unnecessary surgical intervention.

Erosive OA: Diagnosis-defining central erosions (in contrast to marginal erosions seen in rheumatoid arthritis) with a “seagull” or “gull-wing” appearance in the finger joints; joint ankylosis (bony fusion) may also occur.

DISH

Radiographic changes characteristic of DISH include confluent ossification of at least four contiguous vertebral levels, usually on the right side of the spine

Plain radiography of the hands and/or feet is a standard imaging study for RA and can aid in diagnosis and assessing progression, although early radiographs may be normal.

Radiographic changes include periarticular osteopenia, marginal erosions, and joint-space narrowing .

Radiography of the cervical spine with flexion/extension views is appropriate if C1-C2 subluxation is suspected.

MRI and ultrasonography are more sensitive than plain radiography and may have utility in following disease, assessing risk of progression, and determining response to therapy.

Ultrasonography is becoming a standard tool for detecting joint fluid, synovial tissue thickening, early erosions, and increased vascularity.

MRI is used for measuring bone marrow edema, synovitis, and erosions; it is also specifically indicated if atlantoaxial involvement is suspected.

Additional References

Imaging in rheumatology: reconciling radiology and rheumatology doi: 10.1007/s13244-013-0293-1

Dermatological description

Mechanics hand: rough, cracked, scaly skin along the lateral aspects of the digits and palms with horizontal lines resembling the weathered hands of a laborer. Seen in Anti-synthetase syndrome in associated with PM or DM

Gottron rash (Gottron papules and Gottron sign), erythematous to violaceous areas over the metacarpophalangeal and proximal interphalangeal joints seen in DM

Cutaneous Manifestations of Dermatomyositis MKSAP 18
Cutaneous Sign	Location	Clinical Appearance
Gottron rash (Gottron papules and Gottron sign)	Metacarpophalangeal and proximal interphalangeal joints; occasionally on distal interphalangeal joints, elbows, knees	Erythematous to violaceous papules; occasional scale; can ulcerate; atrophic scars may occur
Heliotrope rash	Eyelids	Subtle pink to deep purple or brown discoloration; may be associated with edema of eyelids or periorbital edema
V sign	V of neck	Erythematous to violaceous papules to patches
Shawl sign	Base of posterior neck to upper back	Erythematous to violaceous papules to patches
Fixed erythema	Malar area (may cross nasolabial folds); flanks of trunk	Erythematous to violaceous papules to patches
Nail area changes	Periungual area; cuticles	Periungual erythema; capillary dilatation and dropout; cuticular hypertrophy; cuticular infarcts
Mechanic's hands	Lateral aspects of digits and palms	Hyperkeratotic fissuring of the palmar and lateral surfaces of the fingers resembling the hands of a laborer

Dermatologic Manifestations of Rheumatologic Disease
Rheumatologic Disease	Dermatologic Manifestations
Systemic lupus erythematosus	Butterfly (malar) rash; photosensitive rash; discoid lupus erythematosus; subacute cutaneous lupus erythematosus; oral ulcerations (on the tongue/hard palate; usually painless); alopecia; lupus panniculitis (painful, indurated subcutaneous swelling with overlying erythema of the skin)
Dermatomyositis	Gottron papules (erythematous plaques on extensor surfaces of MCP and PIP joints); photodistributed poikiloderma, including shawl sign (over the back and shoulders) and V sign (over the posterior neck/back or neck/upper chest); heliotrope rash (violaceous rash on the upper eyelids); mechanic's hands (hyperkeratotic, fissured skin on the palmar and lateral aspects of fingers); nailfold capillary abnormalities; holster sign (poikilodermic rash along lateral thigh); can occur in the absence of myositis (amyopathic dermatomyositis)
Systemic sclerosis	Skin thickening and hardening; nailfold capillary changes
Vasculitis	Palpable purpura; cutaneous nodules; ulcers; necrosis
Behçet syndrome	Painful oral and genital ulcers; erythema nodosum; acne/folliculitis; pathergy (skin inflammation/ulceration from minor trauma)
Sarcoidosis	Erythema nodosum; infiltrated plaques; maculopapular and papular lesions; nodules; soft infiltrates of the nose (lupus pernio); on blanching with a glass slide, sarcoid skin lesions reveal “apple jelly” discoloration
Psoriatic arthritis	Plaque psoriasis typically on extensor surfaces, umbilicus, gluteal fold, scalp, and behind ears; pustular psoriasis on palms and soles; nail pitting; onychodystrophy
Reactive arthritis	Keratoderma blennorrhagicum (psoriasiform rash on soles, toes, palms); circinate balanitis (psoriasiform rash on penis)
Adult-onset Still disease	Evanescent, salmon-colored rash on trunk and proximal extremities
Rheumatic fever (secondary to streptococcal infection)	Erythema marginatum (annular pink to red nonpruritic rash with central clearing)
Lyme disease	Erythema chronicum migrans (slowly expanding, often annual lesion with central clearing)

MCP = metacarpophalangeal; PIP = proximal interphalangeal.

Table 3. Ocular Manifestations of Systemic Inflammatory Disease
Systemic Inflammatory Disease	Ocular Manifestations
Ankylosing spondylitis, reactive arthritis, and inflammatory bowel disease (anterior chamber); sarcoidosis and Behçet syndrome (anterior and/or posterior chamber); granulomatosis with polyangiitis (posterior chamber)	Uveitis (inflammation of the anterior and/or posterior chamber and/or retina)
Rheumatoid arthritis; spondyloarthritis; systemic vasculitis	Episcleritis
Rheumatoid arthritis; relapsing polychondritis; inflammatory bowel disease; systemic vasculitis	Scleritis
Systemic vasculitis; antiphospholipid syndrome	Retinal ischemia
Sjögren syndrome	Dryness of the eyes (keratoconjunctivitis sicca)
Giant cell arteritis	Anterior/posterior ischemic optic neuropathy; central retinal artery occlusion; loss of vision
Sarcoidosis; granulomatosis with polyangiitis	Exophthalmos/retrobulbar inflammatory infiltrate
Reactive arthritis	Conjunctivitis

Table 4. Internal Organ Involvement in Rheumatologic Disease
Disease	Type of Involvement
Heart
Kawasaki disease	Coronary artery vasculitis
Systemic sclerosis	Arrhythmia; myocardial fibrosis
SLE	Pericarditis; valvular disease; myocarditis
RA	Pericarditis; myocarditis
Rheumatic fever; antiphospholipid syndrome	Valvular disease
GCA	Aortic aneurysm/dissection; aortitis; large-vessel obstruction
Lung
RA	Serositis; ILD; rheumatoid nodules
SLE; CTDs; Henoch-Schönlein purpura	Serositis; pneumonitis; pulmonary hemorrhage from vasculitis
AAV	Pulmonary hemorrhage; cavitary nodules
Diffuse cutaneous systemic sclerosis	ILD; pulmonary hypertension
Limited cutaneous systemic sclerosis	Pulmonary hypertension
Antiphospholipid syndrome	Pulmonary embolism
Sarcoidosis	Hilar lymphadenopathy; ILD
Goodpasture syndrome	Pulmonary hemorrhage
Kidney
SLE; CTDs; AAV; systemic vasculitis (except PAN)	Glomerulonephritis
PAN	Renal artery vasculitis; pseudoaneurysms
Antiphospholipid syndrome	Renal infarct; renal vein thrombosis
Sjögren syndrome	Acute interstitial nephritis/renal tubular acidosis
Goodpasture syndrome	Glomerulonephritis
Gastrointestinal System
PAN	Mesenteric vasculitis
Henoch-Schönlein purpura	Intestinal vasculitis and ulcerations
Diffuse and limited cutaneous systemic sclerosis	Esophageal and small bowel hypomotility
Behçet syndrome	Mucosal ulcerations
Familial Mediterranean fever	Peritonitis
Nervous System
SLE; CTDs; AAV; systemic vasculitis	Mononeuritis multiplex; peripheral neuropathy
PACNS	CNS vasculitis

ESR

ESR is dictated by characteristics of the erythrocytes themselves and by the presence of specific plasma proteins that alter the normal repulsive forces between erythrocytes and influence their ability to aggregate, form rouleaux, and sediment more quickly. These plasma proteins include acute phase reactants (such as fibrinogen) produced by the liver in response to proinflammatory cytokines occurring in rheumatologic disease, infection, and malignancy that neutralize these negative surface charges and increase ESR. Noninflammatory conditions causing elevated fibrinogen, including kidney disease, diabetes, pregnancy, and obesity, can also result in an elevated ESR. Normal aging can also cause an elevated ESR; for this female patient, an equation to find the estimate of the maximal expected ESR is (age in years + 10)/2, resulting in 42 mm/h

Ref:MKSAP

Autoantibodies in Rheumatologic Disease
Autoantibody	Rheumatologic Disease	Sensitivity/Specificity	Comments
ANA	SLE; also SSc, Sjögren, MCTD	SLE: >95% sensitivity, poor specificity; indirect IFA is the most appropriate methodology	Does not correlate with disease activity
Anti–double-stranded DNA	SLE	SLE: 50%-60% sensitivity, >95% specificity; Crithidia IFA or Farr assays more specific than ELISA	Found in more severe disease, especially kidney disease; antibody levels commonly follow disease activity and are useful to monitor
Anti-Smith	SLE	SLE: 30% sensitivity, 99% specificity	Most specific test for SLE; does not correlate with disease activity
Anti-U1-RNP	MCTD; SLE	High sensitivity for MCTD	High titer seen in MCTD (>1:10,000); does not correlate with disease activity
Anti-Ro/SSA; anti-La/SSB	Sjögren; SLE; RA; SSc	Sjögren: 70% sensitivity; SLE: 20% sensitivity	Sicca symptoms; in SLE, associated with photosensitive rash; offspring of mothers who are positive for anti-Ro/SSA or anti-La/SSB are at increased risk for neonatal lupus erythematosus (rash and congenital heart block)
Antiribosomal P	SLE	15% sensitivity	Associated with CNS lupus and lupus hepatitis
Anti–Scl-70 (antitopoisomerase-1)	DcSSc	10%-30% sensitivity	Seen more often in patients with DcSSc who have pulmonary fibrosis
Anticentromere	LcSSc (CREST)	10%-30% sensitivity	Patients with LcSSc with this antibody are more likely to develop pulmonary arterial hypertension
c-ANCA (antiproteinase-3)	GPA	90% sensitivity when disease is active; high specificity in classic presentations	Correlation with disease activity is unclear
p-ANCA (antimyeloperoxidase)	MPA; EGPA	MPA: 80% sensitivity; EGPA: 60% sensitivity; less specific than c-ANCA	Atypical p-ANCA (antimyeloperoxidase negative) can be seen in inflammatory bowel disease and with positive ANA
Anti–Jo-1	Polymyositis	20%-30% sensitivity	Associated with antisynthetase syndrome, including lung inflammation
Rheumatoid factor	RA; Sjögren; cryoglobulinemia	RA: 70% sensitivity; limited specificity, especially in patients without a classic disease presentation	RF is common in multiple other diseases (e.g., hepatitis C, endocarditis, SLE); 30% with RA are RF negative but may become positive later in RA course
Anti–cyclic citrullinated peptide	RA	RA: 70% sensitivity; 95% specificity	Can be positive in RF-negative RA patients; often present before RF becomes positive; associated with erosions; predicts disease progression in undifferentiated arthritis
Antihistone	DILE	95% sensitivity; poor specificity	Also seen in primary SLE
Cryoglobulins	Vasculitis; hepatitis C; myeloma; SLE; RA	Type II or III cryoglobulins seen in cryoglobulinemic vasculitis	May be present in connective tissue diseases in the absence of vasculitis

ACPA

ELISA : arginine residues are replaced by citrulline in a mixture of CCP, increasing the sensitivity of the assay for ACPA.

69 % sensitivity, 96 % specificity for RA

Other situation when test is positive

SLE : 17 % of 335 patients
SS - 10 % of 155 patients
Best to label as SLE-RA, SS-RA
PsA - 8-16 % esp in the erosive form
Active TB 32-35 % (unmodified Arginine is detected in place of citrulline)
Not seen with Hep C (unlike RF)
AATD (Alpha-1 antitrypsin deficiency) - 3-5 %

Synovial Fluid Analysis
	Normal	Noninflammatory	Inflammatory	Crystal Induced	Infectious	Hemorrhagic
Appearance	Clear/yellow/transparent	Clear/yellow/transparent	Yellow/white/translucent/opaque	Yellow/white/translucent/opaque	Yellow/white/opaque	Red/opaque
Leukocyte count	<200/µL (0.2 × 109/L)	200-2000/µL (0.2-2.0 × 109/L)	2000-20,000/µL (2.0-20 × 109/L) (may be higher)	10,000-50,000/µL (10-50 × 109/L) (may be higher)	>50,000/µL (50 × 109/L) (may be lower)	—
Other studies	Negative Gram stain; negative culture	Negative Gram stain; negative culture	Negative Gram stain; negative culture	Negative Gram stain; positive crystalsa	Positive Gram stainb; positive culturec	Negative Gram stain; negative culture

aCrystal description: Urate crystals are needle shaped and bright. Viewed under polarized light, they are negatively birefringent; they appear yellow when parallel to the axis of the polarized field and blue when perpendicular to the axis. Calcium pyrophosphate crystals are rhomboid, pale, and weakly (not as vividly) positively birefringent; they appear blue when parallel to the axis and yellow when perpendicular.

Misc (Need more references)

Inflammatory Osetoarthritis

Mostly in Middle aged women
PIP and DIP mostly involved

DISH
Late Onset Spondyloarthopathy

Differentiated from PMR by the presence of enthesitis, dactylics, anterior uveitis, Sacrolieitis on imaging, or HLA - B27

Remitting Seronegative Symmetric Synovitis with pitting edema syndrome (RS3PE Syndrome)

Extensor muscle Senovititis is very prominent compared to the flexor muslce synovitis
May respond to low dose steroids
Could progress to RA

Inflammatory Myopathy

Systemic Disease with Arthritis as a symptom

GI Diseases

Autoimmune hepatitis
Primary biliary cirrhosis
Pancreatitis-arthritis syndrome
Whipple’s disease
Gluten-sensitive enteropathy
Inflammatory bowel disease
Hepatitis B/hepatitis C
Intestinal bypass arthritis

Hematological Diseases

Hemophilia
Hemoglobinopathies
Hypogammaglobulinemia
Plasma cell dyscrasias

Endocrinal Diseaseas

Diabetes mellitus
Thyroid disorders
Parathyroid disorders
Acromegaly
Hyperlipoproteinemia
Paget’s disease

Malignant Disorders

Hypertrophic osteoarthropathy
Leukemia and lymphoma
Carcinomatous polyarthritis
Palmar fasciitis and arthritis

Misc

Hemochromatosis
Multicentric reticulohistiocytosis Sarcoidosis
Alkaptonuria
Fabry’s disease
Relapsing polychondritis
Cystic fibrosis
Pigmented villonodular synovitis
Systemic infections

Temporomandibular Disorders

Topics

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JIA, Imaging, Labs and Misc