Spondyloarthropathies - AS; Reactive Arthritis; PsA Flashcards
Asymmetric arthritis
Define ankylosing spondylitis (AS) [1]
Which joints are mostly affected? [1]
Ankylosing spondylitis (AS) is an inflammatory condition affecting the axial skeleton (mainly the spine and sacroiliac joints), causing progressive stiffness and pain.
The main affected joints are the sacroiliac joints and the vertebral column joints - causes spine and sacroiliac joint fusion
Describe the basic pathophysiology of AS [2]
initial inflammatory stage:
- activation of the immune system leading to inflammation within the entheses.
reparative stage:
- ongoing inflammation leads to new bone formation in an attempt to repair the damage caused in the earlier phase
- However, this process is dysregulated in AS resulting in pathological bone formation.
Describe the clinical features of AS [+]
Hallmark features:
- Pain and stiffness in the lower back AND Sacroiliac pain (in the buttock region)
- The stiffness takes at least 30 minutes to improve in the morning (symptoms improve with activity and worsen with rest)
Other symptoms:
- Neck pain
- Fatigue
- Arthritis
- Achilles tendon pain
- Positive Schober test
- EAM
Describe diagnositic criteria for AS
Limited lumber movement
Reduced chest expansion
Radiological changes:
- Progressive loss of joint space –> sclerosis –> fibrosis of joints
- CXR: apical fibrosis
- Syndesmophytes: formation of bony bridges that fuse - causes bamboo spine
Complete fusion of sacro-iliac joint on right photo
What is the name for the sign shown here in AS here? [1]
Dagger sign
- ossification of the supraspinous and interspinous ligaments leading to a central radiodense line running up the spine.
The [] is a commonly used scoring system in AS that helps to evaluate disease activity and ultimately can be used to assess response to treatment. The BASDAI is a six-part questionnaire where each question is scored 1-10. It is a subjective assessment of severity.
The Bath Ankylosing Spondylitis Activity Index (BASDAI) is a commonly used scoring system in AS that helps to evaluate disease activity and ultimately can be used to assess response to treatment. The BASDAI is a six-part questionnaire where each question is scored 1-10. It is a subjective assessment of severity.
What are the 7As of AS EAM? [7]
Apical fibrosis
Anterior uveitis
Aortic regurgitation
Achilles tendonitis
AV node block
Amyloidosis
and cauda equina syndrome
How do you different AS from mechincal back pain?
AS:
- Young men
- Lower back pain that can be so intense that wakes people up
- > 3 months
- Exercise improves pain
- More insidious onset
MBP:
- > 40 yrs
- typically acute pain
- excerise worsens the pain
- Pain uncommon at night
- No morning stiffiness
Describe the test used to quantify AS [1]
Schober’s test:
- Patient stands straight; L5 vertabrae is located
- Point is marked at 10cm above and 5cm below L5
- Patient bends forward
- A length of less than 20cm indicates a restriction in lumbar movement a supports a dx.
Describe the medical management of AS [3]
- Regular exercise like swimming
- First line treatment: NSAIDS
- Physiotherapy
- Second line: Anti-TNF: for patients with persistently high disease activity; e.g. adalimumab
- Third line: IL-17 antibodies: Secukinumab or ixekizumab
- DMARDs only useful in peripheral joint involvement
Which neurological complications are associated with AS? [1]
Which GI complications are associated with AS? [1]
Neurological complications:
- Atlantoaxial subluxation and cauda equina syndrome are rare but serious neurological complications associated with AS.
GI:
- Increased risk of IBD
Which CV complications are AS patients at risk of? [4]
aortitis, aortic regurgitation, conduction abnormalities and ischemic heart disease.
What are syndesmophytes? [1]
Syndesmophytes formation of bony bridges that fuse
- Syndesmophytes are calcifications or heterotopic ossifications inside a spinal ligament or of the annulus fibrosus.
OA osteophytes DONT fuse
Upper
Define reactive arthritis [1]
Reactive arthritis is a sterile inflammatory synovitis following an infection by organisms that infect mucosal surfaces, especially urogenital or enteric infections”
Reactive arthritis: involves synovitis in one or more joints in response to an infective trigger.
There is a link with the HLA B27 gene
NB: Patients with reactive arthritis do NOT have an infection in the joint (unlike septic arthritis)
Infection from which organisms typically causes reactive arthritis? [1]
The most common triggers of reactive arthritis are gastroenteritis or sexually transmitted infections. - Chlamydia may cause reactive arthritis.
NB: Gonorrhoea typically causes septic arthritis rather than reactive arthritis.
What are the typical features of reactive arthritis? [3]
This post-infectious spondyloarthropathy is described classically as a triad of asymmetric oligoarthritis, urethritis, and conjunctivitis ‘Can’t see, pee or climb a tree’
Symptoms typically occur around 4 weeks after infection
- symptoms themselves last around 4-6 months
Other symptoms:
- Dactylitis
- Skin manifestations: keratoderma blennorrhagicum; circinate balanitis
NB: about 70% of patients do not present with the classic triad
Investigations for ReA? [+]
Blood tests
- ongoing inflammation (raised ESR and CRP)
- ANA and RF: to rule out other forms of arthritis
- HLA B27 - present in 40% patients
Urine test:
- NAAT to detect Chlamydia trachomatis
Stool test:
- Test for Salmonella, Shigella, Campylobacter, and Yersinia
Radiological changes:
- Early stages - no specific changes
- chronic ReA - radiographic changes in 70%
Synovial fluid analysis:
- to exclude alternative diagnoses like septic arthritis; gout and pseudogout
- Synovial cultures are always negative.
NB - Stool cultures are usually negative by the time arthritis occurs, but should be considered if diarrhoea present or recently resolved.
Describe the treatment used for ReA [+]
Treatment of arthritis
- first-line therapy for acute phase: NSAIDs
- Corticosteroids: during an acute flare, or unresponsive to NSAIDs.
- DMARDs: Sulfasalazine is effective in peripheral disease and has little or no effect on spinal disease; Methotrexate is effective in treating both acute and chronic ReA especially, in patients with spinal involvement.
- Anti-TNF-α therapy: Etanercept is an emerging therapy,
Antibiotics for acute Chlaymdia infection
- doxycycline or azithromycin
NB - Antibiotics may be given until septic arthritis is excluded.
How would you treat cicinate balanitis or keratoderma blennorrhagica in ReA? [1]
topical steroids.
Which factors predict a worse outcome in ReA? [3]
- Nature of infection: ReA caused due to genitourinary pathogen have a worse outcome than those caused by gastrointestinal pathogens.
- Presence of HLA-B27 gene
- Heel and foot pain at the beginning of the disease is an adverse prognostic factor and is associated with poor functional outcomes and disability.
- Elevated ESR
- Unresponsiveness to nonsteroidal anti-inflammatory drugs (NSAIDs)
A 25-year-old man develops a painful and swollen knee associated with dysuria and conjunctivitis
keratoderma blenorrhagica
