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