Seronegative arthritis Flashcards
Seronegative arthritis - definition
Group of chronic diseases which are negative for rheumatoid factor - no autoantibody linked to the disease
but positive for the HLA-B27 gene which runs in families.
HLA-B27 gene : Pathophysiology
- MHC Class 1 molecule : Cell surface protein which presents molecules within it, to the immune system
- CD8+ T cell binds to the antigen presented by the MHC Class 1 molecule.
- HLA -B27 gene : Codes for a specific type of MHC Class 1 molecule
- T cell recognises the MHC Class 1 molecule as foreign
- Resulting in : Inflammation and Cytokine release
Seronegative arthritis : Inflammation causes -
- Destroys the joints : fibroblasts replace the destroyed joint with fibrous tissue which limits range of movement.
- Syndesmophytes : Osteoblasts get activated and process of ossification resulting in small bony outgrowths at joint edges
Seronegative arthritis : Conditions
- Ankylosing spondylitis,
- Psoriatic arthritis
- Reactive arthritis
- Enteropathic arthritis
Seronegative arthritis : Clinical features
Affects bone, spine and nearby joints
1. Peripheral arthritis
2. Enthesitis - inflammation where tendons/ligaments insert to the bone
3. Extra-articular sx :
* Eyes : anterior uveitis
* Skin : psoriasis
* CVS : Aortic regurgitation / Pericarditis
* GI : Crohns disease or Ulcerative colitis.
Ankylosing Spondylitis : Definition
- Chronic inflammatory disease that affects the vertebral joints and increases stiffness of the joints
- Also associated with blood vessel inflammation
Ankylosing Spondylitis : Pathophysiology
- Intervertebral disc between the vertebra which is made up of type 1 and type 2 collagen
- Autoimmune inflammation of Collagen (T1 +T2)
- Collagen gets destroyed and is replaced by fibrin and ultimately ossification.
- Resulting in inflammation and reduction in ROM
Ankylosing Spondylitis : Associated conditions
- A – Anterior uveitis
- A – Aortic regurgitation
- A – Atrioventricular block (heart block)
- A – Apical lung fibrosis (fibrosis of the upper lobes of the lungs)
- A – Anaemia of chronic disease
Ankylosing Spondylitis : Incidence
Presents in males between 20-30 years of age
Ankylosing Spondylitis : Clinical features
‘Young man presents with lower back pain’
* Onset : Insidious, slow onset of stiffness
* Main affected joints :
the sacroiliac joints + the vertebral column joints
1 . Stiffness in Lower back
* Worse in the morning
* improved with exercise / pain at night which improves on getting up.
2 . Area of inflammation
* sacroiliac joint : Pain in buttocks } most common
* cervical region : neck pain
* Ribs and vertebra effects : shortness of breath
- Systemic inflammatory disease - weightless, fevers, fatigue
Ankylosing Spondylitis : Clinical examination
- Schober’s test :
line is drawn 10cm above and 5cm below
The distance between the line must increase more > 5cm when patient bends as far forward as possible
- Reduced Forward Flexion
- Reduced Lateral Flexion
- Reduced Chest expansion
Ankylosing Spondylitis : Investigations
-
Bloods -
* Raised inflammatory makers ESR, CRP a -
X-ray :
Most commonly effects sacroiliac joint, therefore X-ray of sacroiliac joint is the most useful investigation in diagnosis.
- Squaring of lumbar vertebrae
- Bamboo spine : fusion of joints
- Syndesmophytes : areas of bone growth where ligaments insert into bone
- Ossification : ligament, discs and joints start to turn to bone
MRI - if XR is negative but high suspicion, consider MRI as it shows early inflammation of the joints.
- **CXR **- apical fibrosis
Ankylosing Spondylitis : Management
- Life style advice : Regular exercise
- First line : NSAIDs
- Second line (severe disease) : Anti-TNF disease e.g. Infliximab
Psoriatic arthritis : Definition
inflammatory arthritis associated with psoriasis.
It can vary in severity from mild stiffening and soreness in the joints to complete joint destruction in arthritis mutilans
Psoriatic arthritis : Patterns of disease
Psoriatic arthritis : Patterns of disease
1 . Symmetric polyarthritis } most common
* > 4 joints are affected - such as the hands, wrists and ankles.
* presents similarly to rheumatoid arthritis.
2 . Asymmetrical oligoarthritis} 2nd most common
* 1-4 joints on one side of the body
3 . Distal interphalangeal predominant pattern*
* DIP joints } mostly affected
4 . Spondylitis
* Back stiffness and pain
5 . Arthritis Mutilans
* Phalanges of the fingers and toes
* Severe destruction of bone - causing digit shortening
Psoriatic arthritis : Clinical features
* most likely cause of asymmetrical polyarthritis in an afebrile patient*
1 . Arthritis :
* Distal interphalangeal joints and axial skeleton
2 . Skin changes
* Plaques of psoriasis on the skin
3 . Nail changes
* Nail pitting - indents in nails
* Onycholysis -separation of the nail from the nail bed
* Dactylitis - inflammation of the entire finger
3 . Enthesitis
* inflammation at the points of insertion of tendons into bone
* Dactylitis inflammation of the entire finger
* Achilies Tendonitis
Psoriatic arthritis : Ix
unusual combination of coexistence of erosive changes and new bone formation
1. X-ray : Pencil in cup’ appearance
* Assoc with : arthritis mutilans
* Cup-like appearance.: central erosion on one side of the joint
* ‘Pencil’ : The other bone becomes pointed and looks like a pencil in the cup.
Psoriatic arthritis : Mx
Smilar to RA management
1. Mild peripheral / Axial disease : NSAID
2. Moderate/Severe : Methotrexate
Reactive arthritis : Definition
- Reactive arthritis involves synovitis in joints in response to an infective trigger.
- Typically it causes acute monoarthritis- affecting a single joint - most often the knee
- Presenting with a warm, swollen and painful joint.
Reactive arthritis : Cause
Autoimmune response to an infectious trigger such as;
1. Gastroenteritis or Sexually transmitted infections
* Chlamydia may cause reactive arthritis
* Associated in patients with HIV
Reactive arthritis : Clinical features
“can’t see, pee or climb a tree”.
* Arthritis : single, hot swollen and painful joint
* Bilateral conjunctivitis -non-infective
* Anterior uveitis
* Urethritis
* Circinate balanitis (dermatitis of the head of the penis)
keratoderma blenorrhagica (waxy yellow/brown papules on palms and soles)
Reactive arthritis : Management
- Joint aspiration of synovial fluid
* R/o septic arthritis - Tx underlying triggering infection
- NSAID therapy
Most cases resolve within 6 months and do not recur
