PLAB 1 Musculoskeletal Medicine & Rheumatology 1 — Questions and Answers
Question 1: A 55-year-old woman presents with pain and stiffness in both hands worse in the morning lasting over 1 hour. X-ray shows erosions and joint space narrowing at the MCP and PIP joints. What is the most likely diagnosis?
- Osteoarthritis
- Rheumatoid arthritis (Correct answer)
- Psoriatic arthritis
- Gout
Correct answer: Rheumatoid arthritis
Rheumatoid arthritis typically presents with symmetrical small joint involvement, prolonged morning stiffness (>1 hour), and erosive changes on X-ray at MCP and PIP joints.
Question 2: A 28-year-old man presents with low back pain and stiffness worse in the morning and improving with exercise. HLA-B27 is positive and MRI shows bilateral sacroiliitis. What is the most likely diagnosis?
- Reactive arthritis
- Psoriatic arthritis
- Ankylosing spondylitis (Correct answer)
- Rheumatoid arthritis
Correct answer: Ankylosing spondylitis
Ankylosing spondylitis presents in young males with inflammatory back pain, HLA-B27 positivity, and sacroiliitis on imaging, with characteristic improvement with exercise.
Question 3: Which investigation is most SPECIFIC for diagnosing rheumatoid arthritis?
- Rheumatoid factor (RF)
- Anti-CCP antibodies (Correct answer)
- ESR
- CRP
Correct answer: Anti-CCP antibodies
Anti-CCP (anti-cyclic citrullinated peptide) antibodies have >95% specificity for rheumatoid arthritis, making them more diagnostically specific than rheumatoid factor.
Question 4: A 68-year-old man presents with sudden onset severe pain, erythema, and swelling of the first metatarsophalangeal joint. Serum uric acid is elevated at 560 µmol/L. What is the most likely diagnosis?
- Septic arthritis
- Pseudogout
- Gout (Correct answer)
- Reactive arthritis
Correct answer: Gout
Gout classically presents with acute monoarthritis of the first MTP joint (podagra) with hyperuricaemia, often triggered by alcohol, dehydration, or diuretics.
Question 5: A patient with SLE develops a butterfly facial rash, joint pains, and proteinuria with red cell casts on urine microscopy. Which antibody best correlates with disease activity and renal involvement in SLE?
- Anti-Ro (SSA)
- Anti-dsDNA (Correct answer)
- Anti-Smith
- Anti-La (SSB)
Correct answer: Anti-dsDNA
Anti-dsDNA antibody titres correlate with SLE disease activity, particularly lupus nephritis, and rising titres predict disease flares.
Question 6: According to UK guidelines, what is the first-line treatment for an acute attack of gout?
- Allopurinol
- Colchicine or NSAIDs (Correct answer)
- Prednisolone
- Febuxostat
Correct answer: Colchicine or NSAIDs
NSAIDs (e.g. naproxen) or colchicine are first-line for acute gout; allopurinol and febuxostat are urate-lowering agents used for prophylaxis, not acute attacks.
Question 7: A 42-year-old woman presents with dry eyes, dry mouth, difficulty swallowing, and symmetrical arthralgia. Blood tests show positive Anti-Ro and Anti-La antibodies. What is the most likely diagnosis?
- Systemic lupus erythematosus
- Sjögren's syndrome (Correct answer)
- Rheumatoid arthritis
- Systemic sclerosis
Correct answer: Sjögren's syndrome
Sjögren's syndrome presents with sicca symptoms (dry eyes and mouth) caused by exocrine gland lymphocytic infiltration and is characterised by Anti-Ro (SSA) and Anti-La (SSB) antibodies.
PLAB 1 Musculoskeletal Medicine & Rheumatology 1
A 55-year-old woman presents with pain and stiffness in both hands worse in the morning lasting over 1 hour.
X-ray shows erosions and joint space narrowing at the MCP and PIP joints.
What is the most likely diagnosis?