Crystal Arthropathies and Polymyalgia Rheumatica (PMR) Flashcards
What are crystal deposition diseases characterised by?
Deposition of mineralised material within joints and peri-articular tissue
Which crystal deposition diseases are commonly seen in practice?
Gout
Pseudogout
Calcific periarthritis/tendonitis
Which crystal is deposited in gout?
Monosodium urate
Which crystal is deposited in pseudogout?
Calcium pyrophosphate dihydrate (CPPD)
Which crystal is deposited in calcific periarthirits/tendonitis?
Basic calcium phosphate hydoxy-apatite (BCP)
In gout, what is there excess of in the blood?
High levels or purines/uric acid
->uric acid is the end product of metabolised purines
How does the body get purines?
Through the diet
Hyperuricaemia?
Overproduction of uric acid in the blood
In which conditions is hyperuricaemia commonly seen?
Lymph proliferative malignancies
Tumour lysis syndrome
Severe exfoliative psoriasis
Renal impairment
Which drugs can cause hyperuricaemia?
Ethanol (alcohol)
Cytotoxic drugs
Where are purines excreted from?
Approx 75% from kidneys
25% from GIT
What is a major source of purines?
Alcohol
Lesch Nyan Syndrome?
HGPRT deficiency (type of enzyme) so uric acid overproduction
Intellectual disability with aggressive and impulsive behaviour
What kind of inherited condition is Lesch Nyan syndrome?
X-linked recessive
Which other health issues can occur with Lesch Nyan syndrome?
Self mutilation (self harm)
Gout
Renal disease
Who more commonly gets gout?
Older men
->think of GP case I saw cos that was an old man
also note, very rare in premenopausal women so if see this in diagnosis, look again and make sure
Is there a link to family history in gout?
Yes, v strong FH association
Signs of gout?
Red and swollen joint
->look for scalp psoriasis as well, as previously mentioned, can be caused by psoriasis
Risk factors for gout?
Hypertension
Diabetes
Hyperlipidaemia
Family history
->often lifestyle driven by a lifestyle of excess e.g. excess eating and drinking but can be caused by medications too
Some of the differential diagnosis or gout?
Any inflammatory joint condition
Infection- e.g. if swollen knee, aspirate to rule out infection
What is the gold-standard investigation for gout?
Fluid sample from joint to look under microscope
Would you test urate in bloods in someone with suspected gout?
Can be difficult as if acute attack of gout, urate levels will be low
->if cannot identify gout from a joint aspirate, check urate blood levels again in a few weeks
What are x-rays good for regarding joints?
To see if there is any damage to joint but not useful in an acute attack
Basically- are x-rays and US good for gout?
Not really as would need to be really advanced before seeing anything so by that point, will have been missed
Which joint does gout classically start?
First MCP joint
Does gout start suddenly or build up?
Starts very suddenly
Tophi build up in gout. What are they?
Deposit of the monsodium urate crystals
->very painful
Tophus tophi?
Massive accumulations of uric acid
->check pinna of ear as can accumulate here too
How many joints tend to be affected by gout?
Typically one but can occur in more than one
Gold standard management of gout?
Aspirate the joint and then inject steroids
What is used in the management of an acute flair of gout?
NSAIDs
Colchicine
Steroids
Sometimes gout doesn’t need to be treated. The first attack of gout is only treated if….
- Single attack of polyarticular gout
- Tophaceous gout
- Urate calculi
- Renal insufficiency
Who cannot have anti-inflammatory durgs?
Patients with renal insufficiency
What is the first line of treatment for lowering uric acid?
Xanthine oxidase inhibitors e.g. Allopurinol
->can be used in renal impairment too
If not tolerated, Febuxostat is next line of action
What are the rules to follow when lowering uric acid levels?
- Wait until acute attack has stopped
- Use prophylactic NSAIDs or low dose steroids until uric acid levels are normal
- Adjust allopurinol dose according to renal function
What lifestyle factors help in gout management?
Smoking cessation
Lower consumption of highly processed foods
Reduce alcohol consumption
Increase water intake
->lots of people get a flare up of gout when on holidays because they don’t drink enough water and too much alcohol
Gout usually affects toes.
Where does pseudogout usually affect?
Knee, can affect wrist but mostly knee
Who is more likely to develop pseudogout?
Elderly females
What are some of the causes of pseudogout?
Idiopathic
Familial
Metabolic
What are some of the triggers of pseudogout?
Trauma
Intercurrent illness
What is important to note about sending off urate crystals to the labs?
They disintegrate very quickly so need to be sent off immediately
Management of pseudogout?
NSAIDs
Intra-articular steroids
Polymyalgia Rheumatica is very difficult to diagnose as very similar to many other conditions.
Which condition in particular if you suspected Polymyalgia Rheumatica would you also have to screen for?
Giant Cell Arteritis
->very important not to miss as risks of stokes and blindness associated with GCA,
What is the most important part of a presentation which are indicative of polymalgai rheumatica?
SUDDEN onset of shoulder +/- pelvic girdle STIFFNESS
What age do people tend to get polymyalgia rheumatica?
> 70
->rare <50 so be suspicous of underlying condition e.g. malignancy
What are some of the features/symptoms of polymyalgia rheumatica?
ESR usually >45, often even 100
Anaemia
Malaise
Weight loss
Fever
Depression
How is a diagnosis of polymyalgia rheumatica made?
No blood test or test for definite diagnosis
Based on history, age >50, ESR >50
Will have a dramatic steroid response
->looks like many other conditions, DD = inflam joint disease, underlying malignancy, inflam muscle disease, hypo/hyperthyroidism
Treatment for polymyalgia rheumatica?
Prednisolone
Bone prophylaxis
->bone proph is because course of steroids is for 18-24 months and anyone on steroids for >5 months need bone protection
