Gout

Question 1

What is crystal arthropathy?

Answer 1

joint disorder characterised by accummulation of small crystals in 1 or more joints

Question 2

What are 2 types of crystal arthropathy?

Answer 2

Gout

Pseudogout

Question 3

Define gout

Answer 3

syndrome characterised by:

• hyperuricaemia and deposition of urate crystals causing attacks of acute inflammatory arthritis;
• tophi around the joints and possible joint destruction;
• renal glomerular, tubular and interstitial disease;
• uric acid urolithiasis.

The disease most commonly affects the first toe (podagra), foot, ankle, knee, fingers, wrist, and elbow; however, it can affect any joint.

Question 4

What are some risk factors of gout?

Answer 4

• age
• male > female
• post-menopausal females > pre
• meat, seafood, alcohol consumption
• drugs:
  
  • diuretics e.g. thazide and loop diuretics
  • ABx e.g. ciclosporin or tacrolimus
  • pyrazinamides
  • aspirin ≤325 mg elevates urate levels
• genetics
• high cell turnover rate
  
  • haematological malignancies,
  • myeloproliferative disorders,
  • psoriasis,
  • chemotherapy-induced cell death

Question 5

Summarise the epidemiology of gout

Answer 5

• older age
• males > females
• in females: more common post-menopause

Question 6

What are the presenting symptoms of gout?

Answer 6

• podagra –> pain in first metatarsophalangeal joint on waking
• joint stiffness
• joint swelling & effusion
• joint tenderness

Question 7

What are the signs of gout on examination?

Answer 7

• monoarticular or oligoarticular (<4 joints affected)
• mainly feet > hands affected
• tophi = hard subcutaneous nodules
  
  • extensor surfaces of joints e.g. elbows, knees, Achilles

Question 8

What primary investigations must be conducted for a case of suspected gout?

Answer 8

Arthrocentesis with synovial fluid analysis = definitive.

• synovial fluid WCC count usually exceeds 2.0 x 10^9/L (2000/mm^3 or 2000/microlitre)
• Monosodium urate crystals (intracellular and/or extracellular needle-shaped crystals strongly negative for birefringence under polarised light) confirm the diagnosis.

Synovial fluid analysis should be considered in most patients, but the diagnosis can often be made clinically.

Question 9

Once gout has been diagnosed, what secondary investigations should be considered?

Answer 9

• uric acid level after gout attack (2 weeks post)
• X ray/ US of affected joint –> look for gouty erosions

Question 10

What is another name for pseudogout?

Answer 10

Calcium pyrophosphate arthritis

Question 11

Define pseudogout

Answer 11

Acute psuedogout= acute inflammatory arthritis of one or more joints.

• Knees, wrists, shoulders, ankles, elbows, or hands can be affected.

Chronic psuedogout arthritis mimics osteoarthritis or rheumatoid arthritis & is associated with variable degrees of inflammation.

Question 12

What are the risk factors for pseudogout?

Answer 12

• old age
• previous joint injuries
• hyperparathyroidism
• haemachromatosis
• FH
• hypomagnesaemia
• hypophosphatasia

Question 13

What are the presenting symptoms of pseudogout?

Answer 13

• joint pain
• joint tenderness
• osteoarthritis type involvement of joints i.e. wrists & shoulders
  
  • involvement of shoulders, wrists, MCPs = suggestice of pseudogout
• sudden worsening of osteoarthritis

Question 14

What are the signs of pseudogout on physical examination?

Answer 14

same as the symptoms

Question 15

What primary investigations must be conducted for a case of suspected gout?

Answer 15

• arthrocentesis with synovial fluid analysis
• x ray of affected joints
• serum calcium & PTH
  
  • excludes primary hyperparathyroidism
• Iron studies: serum ferritin, iron, total iron-binding capacity
  
  • ​excludes haemachromatosis
• serum alk phos
  
  • ​excludes hypophosphatasia