Crystal Athropathy Flashcards
(44 cards)
What is the mineral that forms gout
Monosodium urate
What is the mineral that forms pseudogout
Calcium pyrophosphate dihydrate (CPPD
What is the mineral that forms calcific periarthritis/tendonitis
Basic calcium phosphate hydroxy-apatite (BCP
What is gout
Gout is a common and complex form of arthritis that can affect anyone. It’s characterized by sudden, severe attacks of pain, swelling, redness and tenderness in one or more joints, most often in the big toe.
What happens to uric acid that is produced in the body?
Of the uric acid produced daily, the majority (∼ 70%) is excreted via the kidney and the remainder is eliminated into the biliary tract and subsequently converted by colonic bacterial uricase to allantoin.
What is usually the underlying cause of gout
reduced efficiency of renal urate clearance
What is the aetiology of gout
Alcohol
Genetic
- Lesch Nyan Syndrome
What is Lesch Nyan Syndrome
Lesch Nyhan syndrome is a condition characterized by neurological and behavioral abnormalities and the overproduction of uric acid in the body. It occurs almost exclusively in males. Signs and symptoms may include inflammatory arthritis (gout), kidney stones, bladder stones, and moderate cognitive disability.
How can you categorise the pathophysiology of gout
Overproduction
Underproduction
What are causes of over production of uric acid
¥ Malignancy e.g lymphoproliferative, tumour lysis syndrome ¥ Severe exfoliative psoriasis ¥ Drugs e.g. ethanol, cytotoxic drugs ¥ Inborn errors of metabolism ¥ HGPRT deficiency
What are causes of under production of uric acid
Renal impairment
Hypertension
Hypothyroidism
Drugs e.g. alcohol, low dose aspirin, diuretics, cyclosporin
Exercise, starvation, dehydration
Lead poisoning (rare)
How does alcohol increases the risk of gout
Some alcoholic drinks are rich in purines, notably beer which contains guanosine. Alcohol is thought to increase the risk of gout because the metabolism of ethanol to acetyl CoA leads to adenine nucleotide degradation, resulting in increased formation of adenosine monophosphate, a precursor of uric acid.
Alcohol also raises the lactic acid level in blood, which inhibits uric acid excretion.
What is the epidemiology of gout
Men have higher urate levels than women and an increased prevalence of gout at all ages, though less pronounced in older age
Why do men get more gout than females
Oestrogen has a uricosuric effect, making gout very rare in younger women. However, after the menopause, urate levels rise and gout becomes increasingly prevalent.
What are classic symptoms of gout
Classically appears overnight Classically on big toe (first mtp) Usually last 5-7 days Erythema of skin Very painful
Can get accumuulations of uric acid
What are accumuulations of uric acid under the skin called?
Tophus
What are the investigations for gout
NEED TO EXCLUDE SEPTIC ARTHRITIS
Aspirate joint
- Look for crytals (needle shaped negatively birofingent crystals)
- Look for sepsis (send away for culture and microscopy)
- S
What is management of an acute flare of gout
- NSAIDs
- Colchicine
- Steroids
I/A, I/M, oral
Why do you need to be careful with colchicine
Careful with renal problems
When do you treat a first a gout attack
Single attack of polyarticular gout
Tophaceous gout
Urate calculi
Renal insufficiency
When do you treat a second gout attack
Treat if 2nd attack within 1 yr
How to you prprophylactically treat GOUT
lower uric acid
Xanthine oxidase inhibitor e.g. Allopurinol
Febuxostat
- Metabolised in liver not kidney (good for renal impairment)
Uricosuric agents (very difficult to get hold of) - sulphinpyrazone, probenecid, benzbromarone,
Canakinumab
What are CI for Febuxostat
Be careful with CVD history as increased risk of CVD death when taken
Metabolised in liver not kidney (good for renal impairment)
What are the rules for lowering uric acid levels (x4)
Wait until the acute attack has settled before attempting to reduce the urate level
Use prophylactic NSAIDs or low dose colchicine/steroids until urate level normal
Adjust allopurinol dose according to renal function
Address cardiovascular and lifestyle factors
