A health trust in the United Kingdom which serves a population of 100,000 is planning services for patients with rheumatoid arthritis.
How many of the population would be expected to have the disease?
Correct Answer C: The prevalence of rheumatoid arthritis in the UK population is approximately 1%.
Rheumatoid arthritis: epidemiology:
A 31-year-old female intolerant of methotrexate is started on azathioprine for rheumatoid arthritis. Routine blood monitoring shows:
Which of the following factors will predispose her to azathioprine toxicity?
Correct Answer D: Azathioprine - check thiopurine methyltransferase deficiency (TPMT) before treatment.
Thiopurine methyltransferase (TPMT) deficiency is present in about 1 in 200 people and predisposes to azathioprine related pancytopaenia.
Azathioprine: Azathioprine is metabolized to the active compound mercaptopurine, a purine analogue that inhibits purine synthesis. A thiopurine methyltransferase (TPMT) test may be needed to look for individuals prone to azathioprine toxicity.
Adverse effects include:
A significant interaction may occur with allopurinol and hence lower doses of azathioprine should be used.
Which of the following features are not typically seen in a patient with adult onset Still's disease?
Correct Answer B: Adult onset Still's disease is typically rheumatoid factor negative.
Still's disease in adults: Adult Still's disease:
Features:
A 34-year-old woman with a history of antiphospholipid syndrome presents with a swollen and painful leg. Doppler ultrasound confirms a deep vein thrombosis (DVT). She had a previous DVT 4 months ago and was taking warfarin (with a target INR of 2-3) when the DVT occurred.
How should her anti-coagulation be managed?
Correct Answer A: The evidence base is scanty here but most clinicians would increase the target INR to 3-4 if a patient has had a further thrombosis with an INR of 2-3. Please see the BCSH guidelines.
Antiphospholipid syndrome:
Antiphospholipid syndrome is an acquired disorder characterized by a predisposition to both venous and arterial thromboses, recurrent fetal loss and thrombocytopenia. It may occur as a primary disorder or secondary to other conditions, most commonly systemic lupus erythematosus (SLE).
A key point for the exam is to appreciate that antiphospholipid syndrome causes a paradoxical rise in the APTT.
This is due to an ex-vivo reaction of the lupus anticoagulant autoantibodies with phospholipids involved in the coagulation cascade.
Associations other than SLE:
Management - based on BCSH guidelines:
A 41-year-old man with a past history of asthma presents with pain and weakness in his left hand. Examination findings are consistent with a left ulnar nerve palsy. Blood tests reveal an eosinophilia.
Which one of the following antibodies is most likely to be present?
Correct Answer C: This patient has Churg-Strauss syndrome as evidenced by the asthma, mononeuritis and eosinophilia.
Churg-Strauss syndrome: Churg-Strauss syndrome is an ANCA associated small-medium vessel vasculitis.
Leukotriene receptor antagonists may precipitate the disease.
Click to expand