Connective Tissue Diseases

Diagnosis

Indications for Testing

  • Patient with systemic symptoms, including arthralgias, arthritis, skin rashes, anemia, renal dysfunction, pleuritis, pericarditis

Laboratory Testing

  • Nonspecific testing
    • CBC – rule out infection
    • Erythrocyte sedimentation rate or C-reactive protein – monitor inflammation
  • ANA testing
    • Antinuclear antibodies (ANA), IgA, by ELISA
      • Negative – possible scenarios
        • No connective tissue disease (CTD) present
        • False negative result – consider scleroderma (SSc), polymyositis/dermatomyositis (PM/DM), inactive systemic lupus erythematosus (SLE)
        • Positive – ANA HEp-2, IgG, by IFA (result pattern suggests underlying disease)
          • ANA reported patterns and diagnoses
            • Centromere – limited cutaneous scleroderma (lcSSc), CREST (calcinosis, Raynaud phenomenon, esophageal dysmotility, sclerodactyly, telangiectasia)
            • Cytoplasmic – PM, DM, SLE, SSc
            • Peripheral/rim/homogenous – SLE, drug-induced lupus erythematosus (DIL)
            • Nucleolar – SLE, SSc, PM/DM
            • Speckled – antibodies detected
              • Sm+  – SLE
              • SS-A/SS-B+  – Sjögren syndrome, SLE
              • U1RNP+  – mixed connective tissue disease (MCTD) /undifferentiated connective tissue disease (UCTD)
              • Scl-70+  – diffuse cutaneous scleroderma (dcSSc)
              • No specificity – unidentified specificities or markers of low prevalence in CTD
          • False-positive results may be induced by age, certain infections, cancers, and drugs
          • ANA may be positive in inflammatory diseases such as autoimmune liver diseases
          • Titer level has no bearing on diagnosis or disease severity once it is above established normal level
  • Other testing
    • Rheumatoid factor IgM antibodies – if musculoskeletal complaints are present
    • If suspicion for connective tissue disease is low, consider drug-induced lupus erythematosus (DIL), chronic autoimmune disease, chronic hepatitis C virus
    • Urinalysis – rule out glomerulonephritis associated with connective tissue disease
    • ANCA – rule out vasculitis associated with connective tissue disease

Differential Diagnosis

Monitoring

  • Once diagnosis is made, use monitoring tests based on organ involvement
    • Urinalysis acceptable screen for renal disease
    • If cytopenias present, follow with sequential CBCs
    • Certain treatment drugs require liver function testing

Clinical Background

Several autoimmune connective tissue diseases may present with similar features. These diseases include systemic lupus erythematosus, Sjögren syndrome, mixed connective tissue disease, scleroderma (systemic sclerosis), progressive systemic sclerosis, inflammatory myopathies (polymyositis/dermatomyositis [PM/DM]), and undifferentiated connective tissue disease.

Epidemiology

  • Incidence – 15-50/100,000, depending on disease
  • Age – onset is 15-40 years; peak onset in 20s
  • Sex – M<F, 1:6-10  

Pathophysiology

  • Circulating antigen-antibody complexes affect a variety of organs
  • Multisystem disease presentation

Clinical Presentation

  • Constitutional – fever, anorexia, weight loss
  • Musculoskeletal – arthralgias, arthritis, synovitis, myopathy
  • Dermatologic – skin rashes, Raynaud phenomenon, photosensitivity
  • Cardiopulmonary – pleuritis, pericarditis, fibrosis, chest pain
  • Renal – proteinuria, glomerulonephritis
  • Otorhinolaryngologic – sicca syndrome, oral ulcers
  • Gastrointestinal – gastroesophageal reflux disease
  • Neurologic – seizures, encephalopathy
  • Hematologic – cytopenias (involving neutrophils, erythrocytes, and platelets)

Treatment

  • Anti-inflammatory therapies – glucocorticosteroids and other drugs (eg, methotrexate and mycophenolate)

Pediatrics

Clinical Background

Epidemiology

  • Incidence – varies by disease but lower than in adults
  • Sex – M<F for most disorders
  • Age – presents more often >10 years

Clinical Presentation

  • Constitutional – fever, anorexia, weight loss (most common)
  • Musculoskeletal – arthralgias, arthritis, synovitis, myopathy, weakness
  • Dermatologic – skin rash, Raynaud syndrome, photosensitivity
  • Cardiopulmonary – chest pain, pericarditis, pleuritis
  • Gastrointestinal – abdomen pain, diarrhea, hepatitis

Diagnosis

Indications for Testing

  • Appropriate clinical presentation, including arthritis, arthralgias, skin rashes, anemia, pleuritis, pericarditis

Laboratory Testing

  • Nonspecific testing
    • Refer to Diagnosis tab
  • ANA testing
    • Refer to Diagnosis tab and Connective Tissue Disease Testing algorithm
  • Other testing
    • Rheumatoid factor IgM antibodies – rule out juvenile idiopathic arthritis if musculoskeletal complaints are present

Differential Diagnosis

Indications for Laboratory Testing

  • Tests generally appear in the order most useful for common clinical situations
  • Click on number for test-specific information in the ARUP Laboratory Test Directory
Test Name and Number Recommended Use Limitations Follow Up
CBC with Platelet Count and Automated Differential 0040003
Method: Automated Cell Count/Differential

Nonspecific initial test to evaluate connective tissue disease and rule out infection

If cytopenias present, use sequentially for monitoring

   
Sedimentation Rate, Westergren (ESR) 0040325
Method: Visual Identification

Nonspecific initial test to evaluate connective tissue disease and monitor inflammation

   
C-Reactive Protein 0050180
Method: Quantitative Immunoturbidimetry

Nonspecific initial test to evaluate connective tissue disease and monitor inflammation

   
Anti-Nuclear Antibodies (ANA), IgG by ELISA with Reflex to ANA, IgG by IFA 0050080
Method: Qualitative Enzyme-Linked Immunosorbent Assay/Semi-Quantitative Indirect Fluorescent Antibody

Initial screen for connective tissue diseases

Detects antibodies against dsDNA, histone, SS-A (Ro), SS-B (La), Sm, RNP, Scl-70, Jo-1, centromere, and an extract of lysed HEp-2 cells

ELISA results reported as "Detected" are further evaluated by IFA

Results are not disease specific

ANA ELISA assays have lower sensitivities for antibodies associated with nucleolar and specked ANA-IFA patterns

 
Anti-Nuclear Antibody (ANA), IgG by IFA with Reflex by IFA Pattern 2008467
Method: Semi-Quantitative Indirect Fluorescent Antibody/Qualitative Enzyme-Linked Immunosorbent Assay/Semi-Quantitative Enzyme-Linked Immunosorbent Assay/Semi-Quantitative Multiplex Bead Assay/Semi-Quantitative Immunoblot

Initial screen for connective tissue diseases

Test begins with IFA IgG; depending on findings, one or more reflexive tests may be added:

  • Double-stranded DNA (dsDNA) antibody, IgG, by ELISA
  • Double-stranded DNA (dsDNA) antibody, IgG, by IFA (using Crithidiae luciliae)
  • Chromatin antibody, IgG
  • Extractable nuclear antigen antibodies (RNP, Smith, scleroderma, SSA, & SSB)
  • PM/Scl-100 antibody, IgG, by immunoblot
  • RNA polymerase III antibody, IgG
   
Connective Tissue Diseases Profile 0051668
Method: Semi-Quantitative Multiplex Bead Assay

Order to follow up positive ANA result

Components include Sm (ENA) antibody, RNP (U1) (ribonucleic protein), SSA (Ro), SSB (La), Jo-1, ribosomal P protein, centromere, scleroderma (Scl-70)

   
Rheumatoid Arthritis Panel 2003277
Method: Semi-Quantitative Enzyme-Linked Immunosorbent Assay/Immunoturbidimetry

Rule out rheumatoid arthritis

Components include cyclic citrullinated peptide (CCP) antibody, IgG, and rheumatoid factor

   
Anti-Neutrophil Cytoplasmic Antibody with Reflex to Titer and MPO/PR-3 Antibodies 2002068
Method: Semi-Quantitative Indirect Fluorescent Antibody/Semi-Quantitative Multiplex Bead Assay

Rule out vasculitis

If screen is positive, titer and MPO/PR-3 antibodies testing will be added

   
Urinalysis, Complete 0020350
Method: Reflectance Spectrophotometry/Microscopy

Screen for renal disease; rule out glomerulonephritis

   
Hepatic Function Panel 0020416
Method: Quantitative Enzymatic/Quantitative Spectrophotometry

Monitor drug treatment

   
Additional Tests Available
 
Click the plus sign to expand the table of additional tests.
Test Name and NumberComments
Cyclic Citrullinated Peptide (CCP) Antibody, IgG 0055256
Method: Semi-Quantitative Enzyme-Linked Immunosorbent Assay

Diagnose rheumatoid arthritis (RA) or evaluate likely development of RA in patients with undifferentiated arthritis

RNP (U1) (Ribonucleic Protein) (ENA) Antibody, IgG 0050470
Method: Semi-Quantitative Multiplex Bead Assay

Secondary screen based on ANA test

High titers associated with SSc/SLE/polymyositis overlap syndromes

Extractable Nuclear Antigen Antibodies (RNP, Smith, Scleroderma, SSA, & SSB) 0050653
Method: Semi-Quantitative Multiplex Bead Assay
Anti-Nuclear Antibodies (ANA), IgG by ELISA with Reflexes to ANA, IgG by IFA and to dsDNA, RNP, Smith, SSA, and SSB Antibodies, IgG 0050317
Method: Qualitative Enzyme-Linked Immunosorbent Assay/Semi-Quantitative Indirect Fluorescent Antibody/Semi-Quantitative Multiplex Bead Assay

If ELISA screen is positive, then IFA using HEp-2 substrate will be added; if positive by IFA, titer and pattern will be reported and testing for dsDNA antibody and ENA antibodies will be added

Extractable Nuclear Antigen Antibodies (RNP, Smith, SSA, & SSB) 0050652
Method: Semi-Quantitative Multiplex Bead Assay
Jo-1 Antibody, IgG 0099592
Method: Semi-Quantitative Multiplex Bead Assay
SSA (Ro) (ENA) Antibody, IgG 0050691
Method: Semi-Quantitative Multiplex Bead Assay
PM/Scl-100 Antibody, IgG, by Immunoblot with Reflex to ANA IFA 2003040
Method: Semi-Quantitative Immunoblot/Semi-Quantitative Indirect Fluorescent Antibody
SSB (La) (ENA) Antibody, IgG 0050692
Method: Semi-Quantitative Multiplex Bead Assay
Double-Stranded DNA (dsDNA) Antibody, IgG by ELISA with Reflex to dsDNA Antibody, IgG by IFA 0050215
Method: Qualitative Enzyme-Linked Immunosorbent Assay/Semi-Quantitative Indirect Fluorescent Antibody

dsDNA antibodies are screened using an ELISA assay

If dsDNA antibodies are detected, then dsDNA Antibody IgG by IFA (using Crithidia luciliae) will be added

Smith (ENA) Antibody, IgG 0050085
Method: Semi-Quantitative Multiplex Bead Assay
Ribosomal P Protein Antibody 0099249
Method: Semi-Quantitative Multiplex Bead Assay
ssDNA Antibody, IgG 0099528
Method: Semi-Quantitative Enzyme-Linked Immunosorbent Assay
Histone Antibody, IgG 0050860
Method: Semi-Quantitative Enzyme-Linked Immunosorbent Assay
Neutrophil-Associated Antibodies 0055506
Method: Qualitative Flow Cytometry
Lupus Comprehensive Reflexive Panel 0050119
Method: Quantitative Immunoturbidimetry/Semi-Quantitative Enzyme-Linked Immunosorbent Assay/Semi-Quantitative Indirect Fluorescent Antibody/Quantitative Chemiluminescent Immunoassay/Semi-Quantitative Multiplex Bead Assay
Scleroderma (Scl-70) (ENA) Antibody, IgG 0050599
Method: Semi-Quantitative Multiplex Bead Assay
Centromere Antibody, IgG 0050714
Method: Semi-Quantitative Multiplex Bead Assay
Uric Acid, Body Fluid 0020513
Method: Quantitative Spectrophotometry