Seronegative Spondyloarthropathies Flashcards
What is Spondyloarthritis?
An umbrella term for a group of inflammatory disorders that involve the joints and the entheses
What does seronegative mean?
Negative for rheumatoid factor
Name some seronegative spondyloarthropathies.
Ankylosing Spondylitis Psoriatic arthritis Reactive arthritis Juvenile Idiopathic arthritis Enteropathic arthritis
What are entheses?
The sites where ligaments and tendons attach to the bones
The seronegative spondyloarthropathies are associated with a particular tissue type. Which one?
HLA B27
What is HLA B27?
Human Leukocyte Antigen type B27
HLA class I antigens are found on all cells of the human body? True or false?
False, not on red blood cells
Do all people with HLA B27 get seronegative spondyloarthropathies?
No
Name the theories that explain why HLA B27 is linked with seronegative spondyloarthropathies?
- Molecular mimicry
- Misfolding
- Heavy Chain theory
What is the ‘molecular mimicry’ theory?
Infection with an agent with similar shaped antigens to B27 molecules
The body makes antigens against the pathogen’s antigens
But they attack the (very similar) B27 antigen
Immune system is attacking its own cells
What is the ‘misfolding’ theory?
Unfolded proteins get trapped in the endoplasmic reticulum of macrophages
This causes a response involving IL-23 and IL-17
These cause inflammation and damage to joints
What is the ‘heavy chain’ theory?
B27 chains tend to dimerise and accumulate in the ER
This initiates a response involving IL-23 and IL-17
These cause inflammation and damage to joints
What are the general features of the seronegative spondyloarthropathies?
HLA B27 association
Axial arthritis: axial skeleton
Asymmetrical large joint affecting a few or 1 joint
Enthesitis
Dactylitis
Extra-articular manifestations
What is meant by ‘axial arthritis’?
Affecting the axial skeleton:
- spine
- ribs
- pelvis
- sacroiliac joints
What is enthesitis?
Inflammation of the entheses (attachments of tendons + ligaments to bone)
What is dactylitis?
Inflammation of the entire digit
Featuring soft tissue oedema, tenosynovial + joint inflammation
Sausage digit
What is sausage digit?
A digit affected by dactylitis: oedema and swelling make the digit resemble a sausage shape
Painful
What are some extra-articular manifestations of the seronegative spondyloarthropathies?
Anterior uveitis Psoriaform rash Oral ulcers Aortic valve incompetencies IBD
What is a good mnemonic to remember the general features of the seronegative spondyloarthropathies?
SPINEACHE
S - sausage digit P - psoriasis I - inflammatory back pain N- NSAIDs good response E - enthesitis A - arthritis C - crohn’s / colitis (or family history of it) / raised CRP H - HLA B27 E - eye (uveitis)
What is anterior uveitis?
Inflammation of the uvea
Uvea = middle part of the eye that consists of the iris, ciliary body and choroid
What is ankylosing spondylitis?
Chronic inflammation of the spine + sacro-iliac joints
Who is affected with ankylosing spondylitis?
Young adults, peak onset 20-30 years
Men more than women
90% of patients are HLA B27
Clinical features of ankylosing spondylitis?
Gradual onset of low back pain
Pain worse at night
Spinal morning stiffness relived by exercise
Pain in sacroiliac joints radiates to hips + buttocks
In time, rigid spine - bone has fused together after years of inflammation
If severe: stooped posture, neck hyperextension
Anterior uveitis
Asymmetric peripheral arthritis
Osteoporosis
What are the symptoms + signs of anterior uveitis?
Painful red eye Irregular pupil White cells floating in vitreous fluid Photophobia Cloudy vision
What is the pathogenesis of ankylosing spondylitis?
Inflammation caused by auto-immune response against body cells
Bone marrow oedema in anterior corners of the vertebrae
Excessive + erosive repair process is triggered by the inflammation
Syndesmophytes (bony growths)form, they grow and ultimately fuse together
What are syndesmophytes?
Small growths of bone on corners of bone
Like stalactites and stalagmites
The grow and ultimately fuse together
Investigations of ankylosing spondylitis?
MRI: best choice of imaging
Imaging: look for fusion of spine, bamboo spine
Bloods:
- raised ESR and CRP
- are they HLA B27?
Management of ankylosing spondylitis?
Exercise not rest!
- physiotherapy
- hydrotherapy
Anti-inflammatories, NSAIDs
Methotrexate not useful
Anti-TNF drugs are very effective
Surgery: replacement of fused hip joint
Name some anti-TNF drugs?
Adalimumab
Golimumab
Is methotrexate used in ankylosing spondylitis?
Patients don’t respond to methotrexate very well
What is psoriatic arthritis?
Inflammatory arthritis linked with the autoimmune skin condition psoriasis
How many patients with psoriasis get psoriatic arthritis?
About 20%
What are the clinical features of psoriatic arthritis?
Symmetrical polyarthritis
Sacroiliac joints affected: unilateral or bilateral
Distal interphalangeal joints affected
Arthritis mutilans (telescoping)
Dactylitis
Spinal arthritis
Psoriasis rash
Nails are affected
What is arthritis mutilans?
Bone completely loses its architecture and telescopes
Painless
Which areas can a psoriasis rash be hiding?
Behind ears
Umbilical region
Vulval / penile
What happens to the nails in psoriatic arthritis?
Pitting of nails (dimples)
Hyperkeratinitis: keratin build up, nails lift up
Creamy white lesions in corners of nails
Investigation of psoriatic arthritis?
If they have psoriatic rash its likely to be psoriatic arthritis
If they have dactylitis, this is a classic sign of psoriatic arthritis
X-ray:
- signs of erosion
- pencil in cup deformity (erosion has caused the bone to become pointed)
http://i1.wp.com/boneandspine.com/wp-content/uploads/2008/03/pencil-in-cup-deformity-psoriatic-artthritis.jpg
Management of psoriatic arthritis?
Physio, joint support
NSAIDs
DMARDs: methotrexate good for skin as well
Anti-TNF drugs
What is reactive arthritis?
What is another name for it?
An autoimmune condition that develops in response to an infection in another part of the body
The arthritis and synovitis itself is sterile
Formerly known as Reiter’s disease
Which infections trigger reactive arthritis?
Gut infections:
- salmonella, Shigella
GU infections:
- chlamydia
How long does it take for reactive arthritis to develop after an infection?
Anytime between 2 days and 2 weeks post-infection
What are the clinical features of reactive arthritis?
Can’t see: conjunctivitis
Can’t pee: urethritis
Can’t climb a tree: arthritis
What skin lesions occur with reactive arthritis?
Keratoderma blenorrhagica
Lesions which resemble psoriasis lesions
Investigations of reactive arthritis?
Blood:
- ESR and CRP raised
- serology shows evidence of recent infection
X-ray
- shows inflammatory effects on the bone
Management of reactive arthritis?
Steroids to manage short term
If persistent DMARDs
What is enteropathic arthritis?
Arthritis linked with IBD
Clinical features of enteropathic arthritis?
Asymmetrical lower limb arthritis
Usually reflects IBD activity, so in a flare up of IBD you’ll get a flare up of arthritis
Management of enteropathic arthritis?
DMARDs
Don’t give NSAIDs as they will set off IBD
