Autoimmunity and ANA Testing

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What clinical features may indicate a high pre-test probability of rheumatic disease prompting an ANA test?

Photosensitivity and discoid rash (correct)

Joint stiffness and swelling

Fever and fatigue

Migratory pain in the limbs

What does a positive ANA result suggest in the context of autoimmune diseases?

It may prompt further testing for specific antibodies. (correct)

It confirms the diagnosis of rheumatoid arthritis.

It is indicative of high disease activity.

It confirms the absence of rheumatic disease.

What is the significance of a negative ANA test result?

It does not exclude the possibility of rheumatic disease. (correct)

It means the patient has a healthy immune system.

It is definitive for the absence of all autoantibodies.

It confirms that the patient has no rheumatic disease.

Which autoantibody is specifically associated with systemic lupus erythematosus (SLE) but found in less than one-third of cases?

Anti-SM Signup and view all the answers

Which laboratory assessment should be combined with ANA testing for a more complete evaluation of rheumatoid arthritis?

Full blood examination (FBE) Signup and view all the answers

What is the main characteristic of oligoarticular Still's disease?

Affects 4 or fewer joints, usually medium and large joints Signup and view all the answers

What is a potential complication associated with systemic Still's disease?

Amyloidosis Signup and view all the answers

Which type of Still's disease is characterized by symmetrical involvement of 5 or more joints?

Polyarticular (RhF negative) Signup and view all the answers

What does the presence of HLA B27 indicate in enthesitis related arthritis?

A family history of HLA B27 related disease Signup and view all the answers

Which of the following is NOT a common joint affected by oligoarticular Still's disease?

Cervical spine Signup and view all the answers

What additional symptoms are associated with systemic Still's disease?

High fever and transient rash Signup and view all the answers

Which type of Still's disease is most likely to mimic adult rheumatoid arthritis?

Polyarticular (RhF positive) Signup and view all the answers

What characteristic distinguishes psoriatic arthritis from other types of Still's disease?

Associated with dactylitis or nail changes Signup and view all the answers

What is the typical age range for the peak prevalence of polymyalgia rheumatica?

70-80 years Signup and view all the answers

Which of the following is a common laboratory finding in patients with polymyalgia rheumatica?

Elevated CRP Signup and view all the answers

What is the recommendation for treatment if there is not a 70% improvement in symptoms after corticosteroid therapy?

Refer to a rheumatologist Signup and view all the answers

What genetic markers are associated with polymyalgia rheumatica?

HLA-DR4 and HLA-DRB1 Signup and view all the answers

Which imaging technique typically shows bilateral sub-acromial/deltoid bursitis in patients with polymyalgia rheumatica?

Ultrasound (USS) Signup and view all the answers

What is the lifetime risk of developing polymyalgia rheumatica for women?

2.4% Signup and view all the answers

Which of the following conditions is NOT a known increased risk following a diagnosis of polymyalgia rheumatica?

Persistent asthma Signup and view all the answers

What type of anemia is typically found in patients with polymyalgia rheumatica?

Normocytic anemia Signup and view all the answers

What is the primary effect of colchicine in the management of gout?

Preventing future gout attacks by managing inflammation Signup and view all the answers

Which therapy is recommended to lower uric acid levels in gout patients?

Allopurinol Signup and view all the answers

What should be monitored when initiating allopurinol treatment?

Rash, fever, and renal failure Signup and view all the answers

When should allopurinol not be started?

During an acute gout attack Signup and view all the answers

Which medication is specifically indicated for patients with renal impairment?

Febuxostat Signup and view all the answers

How does febuxostat help manage gout?

By inhibiting xanthine oxidase to reduce uric acid levels Signup and view all the answers

What are indications for urate-lowering therapy?

Presence of gouty tophi Signup and view all the answers

What is a potential consequence of initiating allopurinol treatment?

Exacerbation of an existing acute attack Signup and view all the answers

Which of the following viruses is associated with high rates of arthritis?

Parvovirus B19 Signup and view all the answers

What is the most common form of joint involvement in Ross River virus infections?

Symmetrical involvement of the wrists and knees Signup and view all the answers

Which symptom is least commonly associated with Ross River virus infections?

Shortness of breath Signup and view all the answers

Which treatment is commonly recommended for managing symptoms of Ross River virus arthralgia?

Gentle physical therapy Signup and view all the answers

What is the triad of symptoms associated with reactive arthritis?

Urethritis, conjunctivitis, arthritis Signup and view all the answers

Which causative organism is noted to be associated with reactive arthritis?

Chlamydia Signup and view all the answers

Which characteristic is true about the arthritis caused by the Ross River virus?

It may last for years but remains non-destructive Signup and view all the answers

What is the incidence rate of chronic autoimmune inflammatory joint disease in children and adolescents?

1 in 1000 Signup and view all the answers

Which of the following conditions can mimic Juvenile Idiopathic Arthritis (JIA)?

Septic arthritis Signup and view all the answers

What is the most significant complication associated with oligoarticular JIA?

Uveitis Signup and view all the answers

Which laboratory test is not initially included in the investigations for JIA?

Bone density scan Signup and view all the answers

Which treatment has shown dramatic improvement in non-systemic JIA?

Anti-TNF agents Signup and view all the answers

What is the peak incidence age range for rheumatoid arthritis?

60-70 years Signup and view all the answers

Which of the following is NOT a classification criterion for rheumatoid arthritis?

Swelling of fewer than three joint areas Signup and view all the answers

What is the best environmental link found related to rheumatoid arthritis?

Tobacco smoking Signup and view all the answers

Which of the following conditions is most often associated with linear growth abnormalities in children with JIA?

Systemic JIA Signup and view all the answers

Study Notes

Rheumatology For Sports Physicians - Investigations

ANA (Antinuclear Antibodies): Ordered when high pre-test probability of rheumatic disease is suspected.
- Clinical indicators: Includes arthritis, photosensitivity, discoid rash, alopecia, dry eyes, dry mouth, mouth ulcers, sclerodactyly, Raynaud's.
- Lab findings prompting ANA: Hemolytic anemia, thrombocytopenia, lymphoma, hypergammaglobulinemia, hematuria, or proteinuria.
- Significance: Not associated with disease activity.
- Prevalence: 40% of the population has low titers, and 5% of healthy individuals have moderate titers.
- Factors affecting rate: Slightly higher in women and the elderly.
- Negative result implication: A negative result does not rule out rheumatic disease; it is sensitive but not specific.
ENA (Extractable Nuclear Antibodies): If positive speckled ANA.
- Anti-SM antibody: SLE-specific, but only present in less than a third of SLE cases.
- Anti-SSA/SSB (Ro/La antibodies): Associated with Sjögren's syndrome and cutaneous lupus, and can indicate congenital heart block.
- Homogeneous ANA: Anti-dsDNA for SLE, which can fluctuate with disease activity.
Other tests to combine with ANA: Anti-CCP (for rheumatoid arthritis), complete blood count (FBE) to check for cytopenias in SLE, urinalysis for proteinuria (renal manifestations), serum complement (decreased in immune complex-mediated diseases like SLE) and serum immunoglobulins (raised in Sjögren's).

Lyme Arthritis (LA)

Description: First described in 1977; Borrelia burgdorferi isolated in 1982.
Geographic distribution: Most common vector-borne illness in North America and Europe; high prevalence in the Northeast and Upper Midwest United States.
Vector: Ixodes (black-legged deer tick)
Clinical presentation (LA): Occurs 4 days to 2 years after the initial erythema migrans rash. Usually presents as monoarthritis (most commonly knee) or oligoarthritis. Commonly large effusions are present.

Viral Arthritis

General Description: Usually presents as polyarthritis, except for HIV and HCV, in which 20% of cases are oligoarthritis, while 80% of cases are polyarthritis.
Ross River (Group A Arbovirus): Most commonly involves the ankle, knee, wrist, and hands.
- 95% of cases experience Joint pain
- 90% of cases experience >1 month duration of joint pain.
- 90% of cases experience fatigue.
- 80% of cases experience arthralgia
- 60% of cases experience myalgia
- 50% of cases experience rash
- 50% of cases experience fever
Other Viral Arthritis: Parovirus B19 (slap cheek syndrome), Rubella (rash on face, hands, and feet).

Reactive Arthritis

Description: Inflammatory condition.
Etiology: Postbacterial, urogential, or gut infections.
Clinical Characteristics: Asymmetric arthritis usually involving lower limbs. Frequently associated with urethritis, conjunctivitis, and enthesitis.
HLA-B27: Associated with 80–90% Shigella, 79–80% Yersinia, and 40–55% Chlamydia infections.
Duration: Typically 4–12 months, sometimes longer.

Reactive Arthritis - Assessment Criteria

Parameters : Episode of arthritis, urethritis and/or cervicitis, or bilateral conjunctivitis, and multiple episodes of arthritis, conjunctivitis and urethritis.
Sensitivity : Ranges from 51%-86% depending on parameter.
Specificity : Ranges from 96%- 98% depending on parameter.

Juvenile Idiopathic Arthritis (JIA)

Definition: Chronic autoimmune inflammatory joint disease common in children and adolescents.
Duration: Lasting 6 weeks or longer which begins before 16 years of age
Types:
Oligoarticular JIA: Affects 4 or fewer joints. Medium to large joints predominantly
Polyarticular JIA (RhF-negative): Affects 5 or more joints. Predominantly small to large joints
Polyarticular JIA (RhF-positive): Affects 5 or more joints. Predominantly small to large joints
Systemic JIA: Chronic arthritis associated with systemic features. Including high fever, transient rash (salmon), lymphadenopathy, and hepatosplenomegaly, bony ankylosis, and possibly amyloidosis.
Enthesitis-related/associated: Previously called juvenile spondyloarthropathy and can also manifest as lower axial involvement (including Spine, Sacroiliac joints(SIJ)), and bone ankylosis.

Rheumatoid Arthritis (RA)

Prevalence: 1% prevalence.
Clinical Features: Symmetrical arthritis affecting the wrists, metacarpophalangeal (MCP) and proximal interphalangeal (PIP) joints of the hands, and frequently affecting the metatarsophalangeal (MTP) joints of the feet.
Morning stiffness: Often lasting for more than 1 hour, is a cardinal feature.
Systemic features: Flu-like symptoms, fatigue, malaise, and weight loss.
Possible involvement of C-spine: 30-50% of cases.
Clinical signs: swan neck deformity, MCPJ dorsally: Synovial hypertrophy and cysts, hyperextension of IPJ, Z deformity, Ulnar deviation, Boutonniere deformity, and Swan neck deformity.

Additional Notes

Acute-phase reactants (ESR and CRP): Often elevated in active RA
Rheumatoid factor (RF): Present in 60–70% of RA patients, indicative of seropositivity.
Anti-citrullinated protein antibodies (ACPA): More specific for RA than RF, often detected early in the disease.
X-rays: Can reveal joint damage (erosions) and erosions particularly noticeable in the hands and wrist.
MRI and Ultrasound: Detect inflammation, synovitis, and erosions earlier than X-rays.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

This quiz explores key concepts related to antinuclear antibody (ANA) testing in the context of autoimmune diseases. Participants will learn about the clinical features that indicate a high probability of rheumatic disease, the implications of positive and negative ANA results, and the specific autoantibodies associated with conditions like systemic lupus erythematosus. Enhance your understanding of the diagnostic process in rheumatology.