Gout, pseudogout and septic arthritis

Question 1

Pathophysiology of gout

Answer 1

Excess uric acid (final metabolite of purine) crystallises and forms deposits in joints

Question 2

Causes of hyperuricaemia (3)

Answer 2

1. Diet 2. Genetics 3. Underexcretion by kidney

Question 3

Percentage of people with hyperuricaemia that develop gout

Answer 3

10%

Question 4

Risk factors for gout (7)

Answer 4

(OLD FARM) 1. Obesity 2. Lead exposure 3. Diabetes 4. Family history 5. Alcohol 6. Renal failure 7. Metabolic syndrome (abdominal obesity, HT, insulin resistance, high lipids)

Question 5

Precipitants of acute gout flare-ups (5)

Answer 5

(CRAP + drugs) 1. Cool temperature (promotes urate precipitation) 2. Rapid changes in uric acid levels 3. Acidosis 4. Physical trauma/surgery 5. Drugs (allopurinol, diuretics, niacin, aspirin, immunosuppressants)

Question 6

Signs and symptoms of gout, including most often affected joint

Answer 6

1. Red, tender, hot, swollen joint (most commonly first metatarsal-phalangeal) 2. May have fever/fatigue

Question 7

Definitive investigation for gout

Answer 7

Synovial fluid analysis for monosodium urate crystals and a gram stain to rule out septic arthritis

Question 8

Normal uric acid levels in blood

Answer 8

3.5-7.2 mg/dL

Question 9

Management of acute gout flare-up

Answer 9

1. NSAIDs 2. Prednisolone 3. Colchicine

Question 10

Management of chronic gout

Answer 10

1. Lifestyle (dietary modification, weight loss, hydration) 2. Allopurinol/probenecid

Question 11

Complications of gout (3)

Answer 11

1. Tophi (common sites: helix of the hear, olecranon process, Achilles tendon) 2. Chronic arthritis 3. Kidney urate sontes, urate nephropathy

Question 12

Prognosis of gout (resolution time, recurrence rate, increased risks)

Answer 12

1. 5-7 day resolution without treatment 2. 60% annual recurrence rate 3. Increased risk of HT, DM, renal disease and CVD

Question 13

Pathophysiology of pseudogout most affected joint, risk factors, investigation, management)

Answer 13

Calcium pyrophosphate crystals deposit in joints, causing inflammation. Also called crystal arthritis.

Question 14

Signs and symptoms of pseudogout, including the most affected joint

Answer 14

1. Red, tender, hot, swollen joint (most commonly knee) 2. May have fever/fatigue i.e. same as gout, but most common joint in the knee.

Question 15

Risk factors for pseudogout (5)

Answer 15

1. Old age 2. Past joint trauma 3. Genetics 4. Electrolyte imbalance (hypercalcaemia, high iron, low magnesium) 5. Hypothyroidism

Question 16

How do you differentiate gout and pseudogout on investigation?

Answer 16

Crystals in pseudogout are positive birefringent.

Question 17

Management of pseudogout

Answer 17

NSAIDs, prednisolone and colchicine (same as for gout)

Question 18

Risk factors for septic arthritis (5)

Answer 18

1. Trauma 2. Previous joint issues (RA, OA, prostheses) 3. Intra-articular corticosteroids 4. IV drug use 5. Alcoholism

Question 19

Common causative organisms in septic arthritis

Answer 19

1. Staph. aureus 2. Strep. pyogenes 3. Haemophilus influenzae

Question 20

Signs and symptoms of septic arthritis

Answer 20

1. Acute onset pain, loss of movement, loss of weight-bearing ability, redness and swelling of a joint 2. May have fever, hypotension and/or tachycardia

Question 21

Management of septic arthritis

Answer 21

1. Urgent aspiration +/- arthrotomy and washout 2. Elevate and immobilise limb 3. IV flucloxacillin