Week 12 - spinal disorders Flashcards
What is ankylosing spondylitis? (LO1)
Inflammatory arthritis of the sacroiliiac joints and axial skeleton characterised by ankylosing and enthesitis. This comes under a larger group of arthritis’ called seronegative spondyloarthropathies (SpA).
What is enthesitis? (LO1)
Inflammation at tendon insertions.
Describe the epidemiology of ankylosing spondylitis. (LO1)
- 0.1%-1% of the population.
- Varies with prevalence of the HLA-B27 and ethnicity.
- It is more prevalent in those with positive family history of spondyloarthropathy.
- Males are 3 times more likely to have it.
- 15-35 year olds.
- Symptoms will appear before the age of 45 in the majority of people.
Describe the pathophysiology of ankylosing spondylitis. (LO1)
- The result of interaction between environmental pathogens and the host immune system in genetically susceptible individuals.
- Increased faecal carriage of Klebsiella aerogenes has been reported in established AS.
- Increasing evidence that axSpA and AS are due to abnormal host response to intestinal microbiota and involvement of Th17 cells (cells with a key role in mucosal immunity).
- This reaction leads to the production of various inflammatory cytokines, e.g. IL-12, IL-23, IL-17 and TNF-α.
List the genes that increase susceptibility to ankylosing spondylitis. (LO1)
- HLA-B27: 95% of patients with ankylosing spondylitis are positive for this gene, an MHC class 1 molecule.
- ERAP-1: an endoplasmic reticulum protein which facilitates intracellular antigen processing and binds with its presenting MHC molecule, HLA-B27.
- IL-23 receptor.
- Molecules involved in directing Th17 cell responses, e.g. STAT13.
Describe the musculoskeletal presentation of ankylosing spondylitis. (LO1)
- Prolonged morning stiffness of insidious onset, lasting >3 months.
- Bilateral sacroiliac joint tenderness (sacroiliitis).
- Inflammatory back pain - IMPROVES WITH EXERCISE, WORSENS WITH REST.
- Limited lumbar spine motion.
- Tenderness at enthesis, especially Achilles’ tendons and plantar fascia.
- Rib cage involvement: limited chest expansion.
- Possible peripheral joint arthritis, usually involving lower extremities.
Describe the presentation of advanced ankylosing spondylitis. (LO1)
- Compensatory hyperextension of the neck.
- Fixed flexion of the hips.
- Compensatory flexion of the knees.
List the non-musculoskeletal manifestions of ankylosing spondylitis. (LO1)
- Iritis and uveitis.
- Aortic insufficiency.
- Cardiovascular disease.
- Pulmonary fibrosis.
- Increased risk of osteoporosis.
What two types of investigations can be carried out for ankylosing spondylitis? (LO1)
- Bloods.
- Radiological.
List the blood tests that can be done to investigate ankylosing spondylitis. (LO1)
- FBC.
- ESR.
- CRP.
- Serological rheumatoid factor.
- Genotyping for HLA-B27.
Describe the interpretation of blood results in a patient with ankylosing spondylitis. (LO1)
- FBC - showing anaemia of chronic disease.
- ESR - often elevated during active phases of the disease.
- CRP - often elevated during active phases of the disease.
- RF - negative.
- HLA-B27 genotyping - positive in 95% of patients with AS but not required for a diagnosis. May be useful where the clinician has doubts.
List the radiological investigations that can be done to investigate ankylosing spondylitis. (LO1)
- X-ray - can appear normal.
- MRI - first choice.
Describe the advantages of using MRIs to investigate ankylosing spondylitis over x-rays. (LO1)
- Able to detect inflammatory back disease in cases where x-rays appear normal.
- Prevents x-ray exposure to the pelvis which is particularly important in young patients.
Describe the potential results of MRIs in patients with ankylosing spondylitis. (LO1)
- Sacroiliitis and bone oedema highlight ongoing inflammation.
Despite MRIs being first choice for ankylosing spondylitis imaging, how can x-rays also be helpful? (LO1)
- They can help assess damage where substantial mechanical change has occurred.
- Views of the lumbar spine may show bamboo spine: squaring of vertebrae and formation of syndesmophytes (due to ossification of the longitudinal ligaments).
- At other sites: enthesitis erosions, e.g. at plantar fascia of Achilles’ tendon.
Describe the conservative management of ankylosing spondylitis. (LO1)
- Physiotherapy: long-term exercise programme with the aim of maintaining normal posture and exercise activity.
- Hydrotherapy - can be beneficial.
Describe the drug treatment side of management for ankylosing spondylitis. (LO1)
Initial treatment:
- NSAIDs.
Continuous therapy is needed where there is ongoing evidence of inflammation:
- NSAIDs.
- COX-1 inhibitors.
- COX-2 inhibitors.
Anti-TNFs:
- Secukinumab: anti-IL17.
- Good efficacy in treating and preventing ankylosing spondylitis progression.
When can DMARDs (methotrexate, sulphasalazine) be used for ankylosing spondylitis? (LO1)
- These immunosuppressive drugs are less beneficial in ankylosing spondylitis unless there is peripheral arthritis.
Describe the prognosis of ankylosing spondylitis. (LO1)
- Prognosis for any AxSpA disorder not fully understood yet.
- They can remain mild and/or episodic in many patients for many years.
- HLA-B27 positivity, persistently high CRP and high functional incapacity are markers of poor prognosis and markers of extension to ankylosing spondylitis (if not already developed).
What are two main classifications of back pain? (LO2)
- Inflammatory.
- Non-inflammatory.
List the possible causes of non-inflammatory back pain. (LO2)
- Mechanical/low back pain +/- sciatica.
- Osteoarthritis.
- Spinal stenosis.
- Spondylolisthesis.
- Scoliosis.
- Vertebral fracture.
List the possible causes of inflammatory back pain. (LO2)
- Infection, e.g., disciitis, osteomyelitis, abscess.
- Axial spondyloarthropathies.
- Malignancy.
List the terms commonly used when talking about back pain. (LO2)
- Discogenic pain.
- Degenerative disc disease.
- Lumbar disc herniation.
- Secondary to lumbar degenerative disease.
- Facet joint pain.
List some alternative terms for sciatica. (LO2)
- Sciatica/lumbago.
- Radicular pain/radiculopathy.
- Pain radiating to the leg.
- Nerve root compression/irritation.
- Neurogenic claudication.
- Spinal stenosis.