Clinical Investigations, Autoantibodies

Front 1

What is a Rheumatoid Factor?

Back 1

An antibody directed against specific region of Fc fragment of human IgG

Front 2

Associations with positive Rh.Factor:

Back 2

RA (75%)
Lupus, scleroderma, Sjogren’s syndrome, Dermatomyositis.
Chronic infection : bacteria endocrditis, parasites, CMV.
Neoplasms: after irradiation or chemotherapy
Cryoglobulinaemia
Chronic liver disease.
Normal subject.

Front 3

factors associated with worse prognosis in RA

Back 3

positive Rh factor
Extra articular features – nodules, eye involvement, respiratory involvement etc.
HLA-DRB1 (shared epitope)
Female sex
Early erosions
Insidious onset
Severe disability at presentation.

Front 4

what clinical features may suggest SLE?

Back 4

Clinical history of Raynaud’s phenomenon, migratory non erosive polyarthritis, oral ulcer, possible malar rash, thrombocytopaenia and leukopaenia may suggest

Front 5

What is ANA?

Back 5

ANA is any autoantibody directed against one or more components of the nucleus.
Higher titre is more significant but does not necessarily imply more severe disease.
For lupus, it has a high sensitivity (virtually 100%) but low specificity (10-40%). This means a positive result does not make the diagnosis and negative ANA virtually excludes the diagnosis.

Front 6

Which ANA is specific for lupus?

Back 6

ANA directed against double stranded DNA (Anti-dsDNA) is highly specific for lupus. Unfortunately it only present in minority of patients and those in whom it is positive often have classic severe lupus and a clear clinical diagnosis.

Front 7

List other rheumatological conditions which can cause positive ANA besides lupus?

Back 7

Rheumatological conditions:
1. RA 2. Sjogren’s syndrome
3. Polymyositis 4. Polyarteritis Nodosa
5. Drug induced lupus
6. Scleroderma
7. MCTD

Front 8

List other non-rheumatological conditions which can cause positive ANA besides lupus?

Back 8

1. Juvenile idiopathic arthritis
2.Chronic active hepatitis
3.Autoimmune thyroid disease
4.Myasthenia gravis
5.Extensive burns
6.Normal subject.

Front 9

What antibody other than ANA is specific for lupus?

Back 9

Antibodies to Sm (Anti-Sm) are found in only 20% of lupus but very specific. Usually patients with this antibody has a high risk of renal lupus.

Front 10

What is antiphospholipid anitibody and the significance to SLE?

Back 10

Antiphospholipid antibodies occur in 40% of patients with SLE. Only a minority have a thrombotic event.
Can cause arterial or venous occlusion and recurrent miscarriage.
Mechanism causing thrombosis unclear. Probably maintaining platelet in activated state or inhibit fibrinolysis.

Front 11

what is primary antiphospholipid antibody syndrome?

Back 11

Antiphospholipid antibodies may be present without features of SLE

Front 12

What are the constellation of symptoms and signs suggestive of Sjogren’s syndrome

Back 12

Xerostomia (dry mouth)
Keratoconjunctivitis sicca – dry eyes due to lack of tears and lubrications.
Raynaud’s phenomenon
Dental caries.
Non erosive arthritis

Front 13

what is sjogrens syndrome?

Back 13

Autoimmune disorder of unknown aetiology characterised by lymphocytic infiltration of salivary and lacrimal glands, leading to fibrosis and exocrine failure

Front 14

what are the less common features of sjorgens syndrome?

Back 14

low grade fever,
interstitial lung disease, parotitis,
anaemia,
peripheral neuropathy lymphadenopathy
and other A/I disease

Front 15

What is Extractable Nuclear Antigen (ENA)?

Back 15

This are specific nuclear antigens.
Therefore usually associated with positive ANA test.