Crystal arthopathies and polymalgia rheumatic

Question 1

What are common crystal deposition diseases?

Answer 1

> Monosodium urate - gout

> Calcium pyrophosphate dihydrate (CPPD) - Pseudogout

> Basic calcium phosphate hydroxy-apatite (BCP) – calcific periarthritis/tendonitis

Question 2

Which crystals are found in gout?

Answer 2

Monosodium urate

Question 3

Monosodium urate crystals?

Answer 3

Gout

Question 4

Which crystals are found in pseudogout?

Answer 4

Calcium pyrophosphate dihydrate (CPPD)

Question 5

Which crystals are found in calcific periarthritis/tendonitits?

Answer 5

Basic calcium phosphate hydroxy-apatite (BCP)

Question 6

Calcium pyrophosphate dihydrate (CPPD) crystals?

Answer 6

Pseudogout

Question 7

Basic calcium phosphate hydroxy-apatite (BCP)?

Answer 7

Calcific periarthritis/tendonitis

Question 8

What are typhus-tophi?

Answer 8

Massive accumulations of uric acid

Question 9

What is the main contributor to the bodies rate pool?

Answer 9

> 2/3rds come from the production of uric acid when purines are degraded

> The rest comes from diet

Question 10

How is uric acid excreted?

Answer 10

> 70% is excreted via the kidneys

> The rest is eliminated into the biliary tract

Question 11

What is uric acid in the colon converted to?

Answer 11

Converted by colonic bacterial uricase to allantoin

Question 12

What is the main cause of hyperuricaemia in gout usually?

Answer 12

Decreased efficiency of renal urate clearance

Question 13

Where do purines come from?

Answer 13

> Diet
DNA/RNA
Recycled HGPRT (Hypoxanthine)

Question 14

Why can alcohol increase the risk of gout?

Answer 14

> The metabolism of ethanol to acetylene CoA leads to adenine nucleotide degradation, resulting in increased formation of adenosine monophosphate, a precursor of uric acid.

> Alcohol also increases the lactic acid level in blood, which inhibits uric acid excretion

Question 15

What can lead to hyperuricaemia - Overproduction?

Answer 15

Overproduction:
> Malignancy e.g lymphoproliferative, tumour lysis syndrome

> Severe exfoliative psoriasis

> Drugs e.g. ethanol, cytotoxic drugs

> Inborn errors of metabolism

> HGPRT deficiency

Question 16

What can lead to hyperuricaemia - under excretion?

Answer 16

Under excretion:
> Renal impairment

> Hypertension

> Hypothyroidism

> Drugs e.g. alcohol, low dose aspirin, diuretics, cyclosporin

> Exercise, starvation, dehydration

> Lead poisoning

Question 17

What is Lesch syndrome caused by?

Answer 17

Deficiency of the enzyme hypoxanthine-guanine phosphoribosyl transferase (HPRT)

Question 18

What is the role of hypoxanthine-guanine phosphoribosyl transferase (HPRT)?

Answer 18

HPRT normally plays a key role in the recycling of the purine bases, hypoxanthine and guanine, into the purine nucleotide pools

In the absence of HPRT, these purine bases cannot be salvaged; instead, they are degraded and excreted as uric acid

The synthetic rate for purines is accelerated, presumably to compensate for purines lost by the failure of the salvage process.

Question 19

How is Lesch Nyan syndrome inherited?

Answer 19

X-linked recessive

Question 20

How does someone present with Lesch Nyan syndrome?

Answer 20

> Intellectual disability

> Aggressive and impulsive behaviour

> Self mutilation

> Gout

> Renal disease

Question 21

Which population group is at highest risk of gout?

Answer 21

Older men

Question 22

Why are men at higher risk for gout than women?

Answer 22

Men have higher urate levels than women and an increased prevalence of gout at all ages, though less pronounced in older age.

Oestrogen has a uricosuric effect, making gout very rare in younger women. However, after the menopause, urate levels rise and gout becomes increasingly prevalent.

Question 23

When are woman at a higher risk of having gout and why?

Answer 23

Post menopause as Oestrogen has a uricosuric effect, this allows rate levels to rise and gout becomes increasingly prevalent

Question 24

Why is increased age related with increased gout prevalence?

Answer 24

> An increase in sUA levels (mainly due to reduced renal function);

> Increased use of diuretics and other drugs that raise sUA;

> Age-related changes in connective tissues, which may encourage crystal formation;

> An increased prevalence of OA.

Question 25

What is diagnosis of gout based on?

Answer 25

> History
Examination
Differential Diagnosis
Investigations

Question 26

How do you manage acute flare of gout?

Answer 26

> NSAIDs
Colchicine
Steroids I/M, oral

Question 27

When is hyperuricaemia treated (If asymptomatic it is not treated)?

Answer 27

If the context of gout:
> 1st attack not treated unless:
- Single attack of polyarticular gout
- Tophaceous gout
- Urate calculi
- Renal insufficiency

> Treat if 2nd attack within 1 yr

Or Prophylactically prior to treating certain malignancies

Question 28

Which drugs are used to lower uric acid?

Answer 28

> Xanthine oxidase inhibitor e.g. Allopurinol

> Febuxostat

> Uricosuric agents e.g. sulphinpyrazone, probenecid, benzbromarone (Used rarely)

> Canakinumab - IL-1 antagonist (Almost never used)

Question 29

What are the rules in lowering uric acid levels?

Answer 29

> 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

Question 30

Other than drugs what is important in gout management?

Answer 30

> Lifestyle (Diet)
Hydration
Cardiovascular disease

Question 31

Which part of the body is most commonly affected by gout?

Answer 31

The MTP joint of the big toe

Question 32

Which part of the body is most commonly affected by pseudogout?

Answer 32

The knee

Question 33

Who is most likely to be affected by pseudogout?

Answer 33

Elderly females

Question 34

What is the aetiology of pseudogout?

Answer 34

> Idiopathic
Familial
Metabolic

Question 35

What triggers are there in pseudogout?

Answer 35

> Trauma

> Intercurrent illness

Question 36

What is the pattern for flares in pseudogout?

Answer 36

Erratic flares

Question 37

How is Pseudogout managed?

Answer 37

> NSAIDs
I/A steroids

There are no prophylactic therapies

Question 38

What is polymyaligia rheumatica?

Answer 38

An inflammatory condition in the elderly (>50yrs)

Question 39

What is chondrocalcinosis?

Answer 39

Cartilage calcification seen on X-ray (Can occur in pseudogout, calcium pyrophosphate deposition)

Question 40

What does calcium pyrophosphate deposition lead to?

Answer 40

> Acute inflammation = Pseudogout

> Chronic degeneration = Pseudo-osteoarthritis

Question 41

What condition is associated with polymyalgia rheumatica?

Answer 41

Giant cell (Temporal) arteritis:
- 20% patients with PMR have evidence of GCA

• 50% patients with GCA have evidence PMR

Question 42

What findings are there in polymalgia rheumatica?

Answer 42

> Rise in ESR (>45 often 100) and CRP
Anaemia
Normal CK

Question 43

How do you treat polymyalgia rheumatica?

Answer 43

Rapid response to low-dose corticosteroids

Question 44

How does someone present with Polymyalgia rheumatica?

Answer 44

> SUDDEN onset of shoulder +/- pelvic girdle STIFFNESS

> Anaemia

> Malaise ; Weight loss ; fever; depression

> Arthralgia / synovitis occasionally

Question 45

Who is most commonly affected by polymyalgia rheumatica?

Answer 45

> 50yrs, usually > 70yrs

F:M = 2:1

Question 46

How is Polymyalgia rheumatica diagnosed?

Answer 46

• History
• Age > 50yrs
• ESR > 50
• Dramatic response to steroids

Question 47

Differential diagnosis in polymyalgia rheumatica?

Answer 47

> Myalgic onset Inflammatory joint disease

> Underlying malignancy
e.g Multiple myeloma, lung cancer

> Inflammatory muscle disease

> Hypo/ hyperthyroidism

> Bilateral shoulder capsulitis

> Fibromyalgia

Question 48

Treatment of polymylagia rheumatica?

Answer 48

Rapid response to corticosteroids e.g. prednisolone 15mg day initially for 18-24 months

Bone prophylaxis