Crystal Deposition Diseases Flashcards
What are the 3 common crystal depositions in crystal deposition disease?
Monosodium urate -> Gout
Calcium Phosphate dihydrate (CPPD) -> Pseudogout
Basic calcium phosphate hydroxy-apatite (BCP) -> Calcific Periarthritis/ Tendonitis
What will a gout joint look like?
Erythema
Swelling
Shiny
(may look sort of like cellulitis or septic arthritis)
What is an accumulation of uric acid called?
Tophus or Tophi (pleural)
Where on the face is a classic place to look in gout?
Ears
Describe purine input and metabolism
where does our purine source come from and where does it go?
Purines make DNA and RNA
These can be broken down to purines. This source can be supplemented by diet.
Purines are broken down to hypoxanthine. This can either be converted back into purines by HGPRT or can be broken down further to xanthine.
Xanthine is broken down into plasma urate which is excreted by the kidneys as uric acid.
What two broad ways can hyperuricaemia occur?
think simple and broad
Overproduction
Under production
List causes of overproduction of plasma urate (hyperuricaemia)
Malignancy e.g. lymphoproliferative, tumour lysis syndrome
Severe exfoliative psoriasis
Drugs e.g. ethanol, cytotoxic drugs
Inborn errors of metabolism
HGPRT deficiency
List causes of underproduction of plasma urate (hyperuricaemia)
Renal impairment
Hypertension
Hypothyroidism
Drugs e.g. alcohol, low dose aspirin, diuretics, cyclosporin
Exercise, starvation, dehydration
Lead poisoning
Lesch Nyan Syndrome is caused by a deficiency in what enzyme?
HGPRT
hypoxanthine-guanine phosphoribosyl transferase
What is the genotype of Lesch Nyan Syndrome?
X-linked recessive
What are the signs and symptoms of Lesch Nyan Syndrome?
Intellectual disability
Aggressive and impulsive behaviour
Self mutilation
Gout
Renal disease
What kinds of things precipitate gout?
Being Male (usually older) Rich red meat diet Beer Exercise and dehydration Out in the sun a lot Diuretics
Why is gout rare in younger women?
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 kind of history does gout give?
Very short onset
Go to bed with joints not feeling quite right
Wake up with joint(s) being red hot and inflamed
What is the main diagnostic test for gout?
Aspiration and microscopy
needle shape crystals
What blood test can you do in gout?
Serum uric acid
not diagnostic
How do you treat an acute flare of gout?
NSAIDs
Colchicine
Steroids I/A, I/M, oral
When would you treat hyperuricaemia?
1st attack not treated unless:
- Single attack of polyarticular gout
- Tophaceous gout
- Urate calculi
- Renal insufficiency
2nd attack treated if within 1yr
Prophylactically prior to treating certain malignancies
DO NOT treat asymptomatic hyperuricaemia
What treatments can lower uric acid?
Xanthine oxidase inhibitor
-e.g. Allopurinol
Febuxostat
Uricosuric agents
-e.g. sulphinpyrazone, probenecid, benzbromarone
IL-1 antagonist
-Canakinumab
What do you need to remember before starting to lower uric acid levels?
Wait until the acute attack has settles before attempting to reduce the urate level
-i.e. couple of weeks
Use prphylactic NSAIDs or low dose colchicine until urate level normal
What lifestyle factors need to be addressed in gout?
what can you recommend?
Address cardiovascular risk factors
-Food, alcohol, diabetes etc
Lots of water
Fruit like cheries
Low fat
What is the important joint in pseudogout compared to gout?
The knee is to pseudogout as the toe is to gout
Who usually gets pseudogout?
Elderly females
gout = elderly males
What are the aetiology and triggers of pseudogout?
Aetiology
-idiopathic, familial, metabolic
Triggers
-Trauma, Intercurrent illness
What is chondrocalcinosis?
Calcium pyrophosphate dihyrate (CPPD) crystal deposition
How do you manage pseudogout?
NSAIDs
I/A steroids
(no prophylactic therapies)
Who does polymyalgia rheumatica usually affect?
what is the epidaemiology
Elderly women
- Usually >70
- Rare
What is polymyalgia rheumatica associated with?
How many patiens with PMR have this condition?
How many with this condition have PMR?
Giant Cell Arteritis
20% of patients with PMR may have evidence of GCA
50% of patients with GCA may have PMR
Polymyalgia rheumatica and giant cell arteritis exist in a spiral with what?
Polymyalgia rheumatica -> giant cell arteritis -> High ESR and Anaemia
What are the classic symptoms of polymyalgia rheumatica?
What are the signs?
SUDDEN onset of shoulder +/- pelvic girdle STIFFNESS
ESR usually >45 often 100
- Anaemia
- Malaise; weight loss; fever; depression
- Arthralgia/ synovitis occasionally
how do you diagnose polymyalgia rheumatica?
Compatible history
Age >50
ESR >50
Dramatic steroid response
-24-48hrs and feels much much better
No specific diagnostic test
What is the differential diagnosis for polymyalgia rheumatica?
Myalgic onset inflammatory joint disease
Underlying malignancy
-e.g. multiple myeloma, lung cancer
Inflammatory muscle disease
Hypo-hyperthyroidism
Bilateral shoulder capsulitis
Fibromyalgia
What is the treatment for polymyalgia rheumatica?
Prednisolone 15mg per day initially
-18-24 month course
Bone prophylaxis
