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Flashcards in Crystal arthropathies Deck (21):
1

Two main conditions

Gout and pseudogout.

2

What is gout?

Inflammatory arthritis associated with monosodium urate crystal depositation in the joint.

3

Aetiology of gout

More common in men.
Prevalence increases with age.

4

Pathogenesis of gout

Uric acid is the final compound in the breakdown of purines in DNA metabolism (adenine & guanine). Hyperuricaemia may be due to renal underexcretion (which can be exacerbated by diuretics or renal failure) or due to excessive intake of alcohol, red meat and seafood

5

Hyperuricaemia

Uric acid level of greater than 7mg/dL (0.42mmol.L

6

Causes of uric acid underexcretion

Renal insufficiency
Starvation
Dehydration
Hypothyroidism
Hyperparathyrodism
Drugs (diuretics, levodopa, cyclosporin A, pyrazinamide)
Alcohol abuse

7

Causes of uric acid overproduction

Could be genetic e.g. Lesch Nyhan
Could be due to high cell turnover e.g. psoriasis
Dietary- e.g. red meat, seafood, alcohol.

8

Diagnosis of gout

Diagnosis of gout is based on identification of crystals or classic radiographic findings, not hyperuricemia alone

9

Clinical presentation of gout

Rapid onset (hours, often overnight)
Red, hot joint
Severe pain
Duration- up to 2 weeks
Site-
1st MTPJ>ankle>knee> upper limb joints>spine

10

Differential diagnosis of gout

Septic arthritis
Trauma
Seronegative arthritis

11

Chronic polyarticular gout

Chronic joint inflammation
Usually after having recurrent acute attacks > 10 years
Often diuretic associated
High serum uric acid
Tophi
May get acute attacks

12

Investigations into gout

JOINT ASPIRATION
Inflammatory markers( CRP, PV/ESR)-raised
WCC may be raised ( difficult to differentiate from infection)
X ray:
normal in acute attack
chronic/repeated attacks-
erosions, overhanging osteophytes,
joint destruction

13

Management of gout in acute attacks

NSAIDs ( if no contraindication)
or
Colchine
or
corticosteroids.

14

Long term management of gout

Allopurinol.
start 2-4 weeks after acute attack
-Start low dose and titrate
-Aim for target serum urate <0.30mmol/L
(British Society of Rheumatology guidelines

15

Lifestyle modifications needed in gout

Restrict red meat, offal, beans, shellfish
Reduce Alcohol ( 3 alcohol free days/ week, but still overall keep within limits)
Lose weight
Fluids- 2L /day ( not fizzy drinks with fructose!)

16

Pseudogout/Calcium Pyrophosphate Dihydrate Deposition Disease (CPPD)

More common in elderly
Chondrocalcinosis increases with age
Related to osteoarthritis
Affects fibrocartilage - knees, wrists, ankles

17

What shape are psuedogout crystals

Rhomboid/envelope shaped crystals
Weakly positive birefringence

18

What shape are gout crystals

Needle shaped- negatively birefringence.

19

Pseudogout/Calcium Pyrophosphate Dihydrate Deposition Disease (CPPD) associations

Aging
Hyperparathyroidsim
Familial hypocalciuric
hypercalcaemia
Haemochromatosis
Haemosiderosis
Hypophosphatasia

20

Treatment of psuedogout

NSAIDS
Colchicine
Steroids
Rehydration

21

Hydroxyapatite

“Milwaukee shoulder”
Hydroxyapatite crystal deposition in or around the joint.
Acute and rapid deterioration.
Females, 50-60 years
Crystals not detected under light or polarised microscopy- Alizarin stain show red clumps