Crystal Deposition Diseases

Question 1

What are the 3 common crystal depositions in crystal deposition disease?

Answer 1

Monosodium urate -> Gout

Calcium Phosphate dihydrate (CPPD) -> Pseudogout

Basic calcium phosphate hydroxy-apatite (BCP) -> Calcific Periarthritis/ Tendonitis

Question 2

What will a gout joint look like?

Answer 2

Erythema
Swelling
Shiny

(may look sort of like cellulitis or septic arthritis)

Question 3

What is an accumulation of uric acid called?

Answer 3

Tophus or Tophi (pleural)

Question 4

Where on the face is a classic place to look in gout?

Answer 4

Ears

Question 5

Describe purine input and metabolism

where does our purine source come from and where does it go?

Answer 5

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.

Question 6

What two broad ways can hyperuricaemia occur?

think simple and broad

Answer 6

Overproduction

Under production

Question 7

List causes of overproduction of plasma urate (hyperuricaemia)

Answer 7

Malignancy e.g. lymphoproliferative, tumour lysis syndrome

Severe exfoliative psoriasis

Drugs e.g. ethanol, cytotoxic drugs

Inborn errors of metabolism

HGPRT deficiency

Question 8

List causes of underproduction of plasma urate (hyperuricaemia)

Answer 8

Renal impairment

Hypertension

Hypothyroidism

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

Exercise, starvation, dehydration

Lead poisoning

Question 9

Lesch Nyan Syndrome is caused by a deficiency in what enzyme?

Answer 9

HGPRT

hypoxanthine-guanine phosphoribosyl transferase

Question 10

What is the genotype of Lesch Nyan Syndrome?

Answer 10

X-linked recessive

Question 11

What are the signs and symptoms of Lesch Nyan Syndrome?

Answer 11

Intellectual disability

Aggressive and impulsive behaviour

Self mutilation

Gout

Renal disease

Question 12

What kinds of things precipitate gout?

Answer 12

Being Male (usually older)
Rich red meat diet
Beer
Exercise and dehydration
Out in the sun a lot
Diuretics

Question 13

Why is gout rare in younger women?

Answer 13

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 14

What kind of history does gout give?

Answer 14

Very short onset

Go to bed with joints not feeling quite right

Wake up with joint(s) being red hot and inflamed

Question 15

What is the main diagnostic test for gout?

Answer 15

Aspiration and microscopy

needle shape crystals

Question 16

What blood test can you do in gout?

Answer 16

Serum uric acid

not diagnostic

Question 17

How do you treat an acute flare of gout?

Answer 17

NSAIDs

Colchicine

Steroids I/A, I/M, oral

Question 18

When would you treat hyperuricaemia?

Answer 18

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

Question 19

What treatments can lower uric acid?

Answer 19

Xanthine oxidase inhibitor
-e.g. Allopurinol

Febuxostat

Uricosuric agents
-e.g. sulphinpyrazone, probenecid, benzbromarone

IL-1 antagonist
-Canakinumab

Question 20

What do you need to remember before starting to lower uric acid levels?

Answer 20

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

Question 21

What lifestyle factors need to be addressed in gout?

what can you recommend?

Answer 21

Address cardiovascular risk factors
-Food, alcohol, diabetes etc

Lots of water
Fruit like cheries
Low fat

Question 22

What is the important joint in pseudogout compared to gout?

Answer 22

The knee is to pseudogout as the toe is to gout

Question 23

Who usually gets pseudogout?

Answer 23

Elderly females

gout = elderly males

Question 24

What are the aetiology and triggers of pseudogout?

Answer 24

Aetiology
-idiopathic, familial, metabolic

Triggers
-Trauma, Intercurrent illness

Question 25

What is chondrocalcinosis?

Answer 25

Calcium pyrophosphate dihyrate (CPPD) crystal deposition

Question 26

How do you manage pseudogout?

Answer 26

NSAIDs
I/A steroids

(no prophylactic therapies)

Question 27

Who does polymyalgia rheumatica usually affect?

what is the epidaemiology

Answer 27

Elderly women

• Usually >70
• Rare

Question 28

What is polymyalgia rheumatica associated with?

How many patiens with PMR have this condition?

How many with this condition have PMR?

Answer 28

Giant Cell Arteritis

20% of patients with PMR may have evidence of GCA

50% of patients with GCA may have PMR

Question 29

Polymyalgia rheumatica and giant cell arteritis exist in a spiral with what?

Answer 29

Polymyalgia rheumatica -> giant cell arteritis -> High ESR and Anaemia

Question 30

What are the classic symptoms of polymyalgia rheumatica?

What are the signs?

Answer 30

SUDDEN onset of shoulder +/- pelvic girdle STIFFNESS

ESR usually >45 often 100

• Anaemia
• Malaise; weight loss; fever; depression
• Arthralgia/ synovitis occasionally

Question 31

how do you diagnose polymyalgia rheumatica?

Answer 31

Compatible history

Age >50

ESR >50

Dramatic steroid response
-24-48hrs and feels much much better

No specific diagnostic test

Question 32

What is the differential diagnosis for polymyalgia rheumatica?

Answer 32

Myalgic onset inflammatory joint disease

Underlying malignancy
-e.g. multiple myeloma, lung cancer

Inflammatory muscle disease

Hypo-hyperthyroidism

Bilateral shoulder capsulitis

Fibromyalgia

Question 33

What is the treatment for polymyalgia rheumatica?

Answer 33

Prednisolone 15mg per day initially
-18-24 month course

Bone prophylaxis