Reactive arthritis is associated with which one of the following HLA antigens?
Correct Answer A: Reactive arthritis is one of the HLA-B27 associated seronegative spondyloarthropathies. It encompasses Reiter's syndrome, a term which described a classic triad of urethritis, conjunctivitis and arthritis following a dysenteric illness during the Second World War. Later studies identified patients who developed symptoms following a sexually transmitted infection (post-STI, now sometimes referred to as sexually acquired reactive arthritis, SARA).
Reactive arthritis is defined as an arthritis that develops following an infection where the organism cannot be recovered from the joint.
Epidemiology:
The table below shows the organisms that are most commonly associated with reactive arthritis:
Management:
A 47-year-old man with a history of chronic sinusitis presents with shortness of breath to the Emergency Department. Initial investigations reveal:
What is the most likely diagnosis?
Correct Answer C: The combination of pulmonary and renal involvement combined with a history of chronic sinusitis points towards a diagnosis of Wegener's granulomatosis.
Wegener's granulomatosis:
Wegener's granulomatosis is an autoimmune condition associated with a necrotizing granulomatous vasculitis, affecting both the upper and lower respiratory tract as well as the kidneys.
Features:
Investigations:
A 50-year-old female with a history of rheumatoid presents with a suspected septic knee joint. A diagnostic aspiration is performed and sent to microbiology.
Which of the following organisms is most likely to be responsible?
Correct Answer A: In Septic arthritis the most common causative organism is Staphylococcus aureus.
Septic Arthritis:
Overview:
Low levels of which one of the following types of complement are associated with the development of systemic lupus erythematous (SLE)?
Correct Answer A: In SLE: C3 & C4 are low. Low levels of C4a and C4b have been shown to be associated with an increased risk of developing systemic lupus erythematous.
SLE
investigations:
Immunology:
Monitoring:
Which one of the following is not a risk factor for developing osteoporosis?
Correct Answer B: Low body mass, rather than obesity is associated with an increased risk of developing osteoporosis.
Osteoporosis: causes:
Risk factors:
Diseases which predispose to Osteoporosis:
*Research is ongoing as to whether warfarin is a risk factor
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