Rheumatoid arthritis and SLE/systemic manifestations Flashcards
CONNECTIVE TISSUE DISORDERS
Key conditions
RHEUMATOID ARTHRITIS
- Chronic joint inflammation that can result in joint damage
- Site of inflammation is the synovium
- Associated with autoantibodies:
- Rheumatoid factor
- Anti-cyclic citrullinated peptide (CCP) antibodies
Synovitis is main pathology here
Ankylosing spondylitis
- Chronic spinal inflammation that can result in spinal fusion and deformity
- Site of inflammation includes the enthesis
- No autoantibodies (‘seronegative’)
Key pathology is attacking the anthesis where the ligmanet tendons insert into bone
SYSTEMIC LUPUS ERYTHEMATOSUS (SLE)
- Chronic tissue inflammation in the presence of antibodies directed against self antigens
- Multi-site inflammation but particularly the joints, skin and kidney
- Associated with autoantibodies:
- Antinuclear antibodies
- Anti-double stranded DNA antibodies
- Anti-phospholipid antibodies
Production of immune complexes due to antibodies being formed against self antigens. Multisystem disease as the immune complexes formed can affect anywhere in body.
CONNECTIVE TISSUE DISORDERS-there are similarities between the connective tissue disorders
Key points:
Arthralgia-pain but no obvious inflammation ie no heat, redness or swelling
Arthalgia is very common in CT disorders
Raynaud’s phenomenon
Trigger-cold, but can occur in normal temp
Ischaemic changes affecting fingers-white, blue then red and painful
CT disorders often have this so ask about it!
SYSTEMIC LUPUS ERYTHEMATOSUS (SLE)
Condition of young people, typically women (9:1)
- Raynaulds phenomenon, athralgia, mouth ulcers found in lupus and other connective tissue disorders
- Malar rash is specific to lupus, spares nasolabial folds
SYSTEMIC LUPUS ERYTHEMATOSUS (SLE) pathogenesis:
Note: square brackets on slides mean we don’t need to know ie this one!
Immune complexes bind to antibody or Fc rceeptors mediating inflammation
Autoantibodies in rheumatology-need to learn
Seronegative-no antibodies
SLE-anti-phospholipid antibodies are associated with arterial and venous thrombosis, so if detected in treatment need to give anti-thrombotic agents. This can lead to miscarriages as can cause thrombosis of the placenta.
ANTINUCLEAR ANTIBODIES:
Just be aware
Autoantibodies in SLE:
SYSTEMIC LUPUS ERYTHEMATOSUS investigations:
Break down into daignosis, so we have antibody screens and then we break into organ systems. Very important to investigate kidney function so look at protein in urine as causes glomerular damage causing inappropriate protein leaking into urine.
ESR is high like in Rheumatoid arthritis
But in absence of infection CRP is normal UNLIKE rheumatoid which has both high
Only if infection or inflammation ie serosistis which will cause CRP to be high in lupus.
In SLE: ESR high (often driven by high immunoglobulin levels), CRP typically normal *except* if there is significant joint inflammation or serositis (inflammation of pleural or pericardial membranes). I think exact reason unclear but must be due to nature of the inflammation. If the CRP is up in SLE, you first suspicion should be an infection rather than the SLE. Remember these patients are often immunosuppressed due to medications and so are vulnerable to infection.
Disease activity in SLE
Measure component of immune complexes, so as immune complexes rise, the amount of Anti double stranded DNA rises.
Took many immune complexes, trigger this pathway so it uses up C3 and C4 so these levels decrease. We measure C3 and C4. Complement drops and DNA rises
Disease activity in SLE
Complement drifts down as DNA goes up. The patient’s lupus is active so we need to meet this patient, have they got symptoms, is there evidence of kidney involvement etc.
On right, circled in albumin to creatinine ratio, measuring protein in urine. These are high ie abnormal.
This is lupus glomerular nephritis
Look how insensitive measuring renal function is in these patients eg creatine etc. Must do urine protein measurement, not just basic kidney screen.
Disease activity in SLE
Can get autoimmune haemolytic anaemia driven by lupus.