Pseudo-gout profoma

Question 1

Epidemiology for Pseudo-gout

Answer 1

High prevalence in elderly

Rare under 60

No clear sex predilection

Less common than gout

Question 2

Aetiology of Pseudo-gout

Answer 2

Cause unknown but linked to OA

onset preceded by physical stress, heart attack, intercurrent illness & dehydration.

Likely caused by chondrocyte changes initiated by ageing or injury.

May be mediated through factors such as growth factor-beta

Question 3

Pathophysiology of Pseudo-gout

Answer 3

Calcium pyrophosphate crystals shed from cartilage into articular space = cause an inflammatory response by phagocytes

Cause cytokine production & degrade cartilage = mechanical damage.

NOTE- view diagram on notes!

Question 4

Presentation of Pseudo-gout

Answer 4

Clinical features:
- Sudden onset
- inactivity stiffness- worse after resting
- synovitis- joint effusion, tenderness, redness, warmth, ROM
- Fever & malaise
- Chronic cases present w/ chronic pain which gets progressively worse, early morning stiffness & functional impairment
- Chronic cases have acute inflammatory episodes
- Can present as OA worsening or mimic septic arthritis

Joint pattern:
- Usually mono arthritis (but can be poly)
- systemic distribution & involve non-weight bearing joint
- Order of most commonly affected joint: knee, wrist, shoulder, ankle, elbow

Suspect pseudogout or gout when joints that are affected e.g. shoulders, wrists or metacarpophalangeal joints, are not those commonly seen in OA

Affects more proximal joints than gout & is seen in older patients (over 60)

Question 5

Risk factors for pseudo-gout

Answer 5

1. Advanced age
2. Injury - particularly involving meniscus of knee.
3. Heart attack- pseudo gout usually follows on from heart attack
   4..Hyperparathyroidism - strong association w/ CPPD due to long-standing increased serum calcium. PTH causes bones to release Ca into the blood.
4. Haemochromatosis - where levels of iron in the body slowly build-up over years.
5. Family history
6. Low Magnesium- Mg is an important co-factor for enzymes that degrade pyrophosphate.

Question 6

Investigations for Pseudo-gout

Answer 6

Joint aspiration & synovial fluid analysis:
- Gram stain & cultures to rules out sceptic arthritis.
- Polarised light microscopy- CPPD crystals appear rhomboid & show weak positive birefringence.
- purple & blue In colour

NOTE- view notes for images!

Blood tests:
- FBC - WCC may be elevated = inflammation
- Serum urate - exclude gout (after 2 weeks!)
- Serum calcium & PTH – both may be normal or high in CPPD – both test for hyperparathyroidism.
- Serum ferritin (iron) – normal or high in CPPD – test for haemochromatosis.
- Serum magnesium – normal or low in CPPD – test for hypomagnesaemia.

Question 7

Radiological findings for Pseudo-gout

Answer 7

Has features of OA but w/ unusual distribution:
- Cartilage loss(joint space)
- Osteophytes - larger than OA.
- Sclerosis
- Subscondral cysts - numerous & larger than OA

Cartilage & soft issue calcification: areas have calcific density but no structure e.g. cortex.
-Chondrocalcinosis - both fibrocartilage & hyaline cartilage.
- Capsular & synovium calcification
- Entheseal calcification e.g. achilles tendon.
- Burseal calcification e.g. subacromial, olecranon.

CPPD in the hands tends to involve the Intercarpal & MCP joints.

NOTE- view notes for x-ray images!!

Question 8

Differentials for Pseudo-gout

Answer 8

Gout

Sceptic arthritis

OA

RA

Polymyalgia rheumatica

Question 9

Management of acute Pseudo-gout? Conservative, Pharmacological, Surgical?

Answer 9

Conservative
- Losing weight
- Ice, cool packs & rest
- Physiotherapy – helps to maintain & improve joint mobility.
- Occupational therapy

Pharmacological
- NSAIDs e.g. Naproxen
- Proton Pump Inhibitors e.g. Lansoprazole.
- Colchicine – alternative to NSAIDs or steroids if contraindicated.
- Intra-articular corticosteroid injection – reduce pain & limit inflammation.

Surgical
- Aspiration of joint
- Joint replacement- may be needed if the joint degenerates.

Question 10

Management of chronic Pseudo-gout? Pharmacological & conservative?

Answer 10

• Conservative - same as before

Pharmacological
- Similar management as for OA:
1. NSAIDs used
2. Periodic intra-articular steroid injections.

Prophylaxis using Colchicine hasn’t been proven effective.

Question 11

Prognosis for Pseudo-gout

Answer 11

Most people have improvement in symptoms- some have recurrent episodes

chronic pseudo-gout- have chronic pain & loss of function- may lead to severe joint damage