T&O: Gout

Question 1

Outline the pathophysiology of gout

Answer 1

Disorder of metabolism = uric acid or urate accumulation in blood and tissues

Monosodium urate (MSU) monohydrate crystals

Uric acid is an end-stage by-product of purine metabolism

Question 2

Outline the aetiology of gout

Answer 2

Low renal excretion of uric acid = renal insufficiency

Over consumption of purines

Disorders that cause high cell turn over and therefore release purines = myeloproliferative and lymphoproliferative disorders, psoriasis, and haemolytic anaemias

Conditions associated with higher incidence of gout = HTN, DM, renal insufficiency, hypertriglyceridemia, hypercholesterolemia, obesity, anaemia

Question 3

What are the symptoms of gout?

Answer 3

Arthritis

Monoarticular involvement – big toe (podagra), knee

Inflam = swelling, warmth, erythema, tenderness

Fever

Tophi in soft tissues = helix of the ear, fingers, toes, prepatellar bursa, olecranon

Question 4

How would you investigate gout?

Answer 4

Joint aspiration = Gram stain, culture, sensitivity, microscopic analysis (-ve birefringent)

Synovial fluid analysis

Serum uric acid measurement

24-hour urinary uric acid evaluation

Bloods = FBC, TG, HDL, U+E, LFTs

X-ray = erosions with overhanging edges

US = bone erosions, double contour sign (hyperechoic, irregular line of MSU crystals on the surface of articular cartilage overlying an adjacent hyperechoic bony contour)

Question 5

How would you manage gout?

Answer 5

1. Treating the acute attack = NSAIDs, corticosteroids, ACTH
2. Prophylaxis = colchicine
3. Lowering excess stores of urate = allopurinol (xanthine oxidase antagonist) (started 2 weeks after settled)
   - High level of hydration with water (≥8 glasses of liquids daily)
   - Low-cholesterol, low-fat diet, if such a diet is otherwise appropriate for the patient
   - Weight reduction in patients who are obese
   - Avoid = high purine foods, beer, high-fructose corn syrup, sweet fruit juices, table salt

Question 6

What are the complications of gout?

Answer 6

Severe degenerative arthritis

Secondary infections

Urate nephropathy

Renal stones

Nerve or spinal cord impingement

Fractures in joints with tophaceous gout