pseudogout

Question 1

definition of pseudogout

Answer 1

Calcium pyrophosphate deposition (CPPD) is associated with both acute and chronic arthritis. Acute CPP crystal arthritis is an acute inflammatory arthritis of one or more joints. Knees, wrists, shoulders, ankles, elbows, or hands can be affected. The chronic form of CPP arthritis mimics osteoarthritis or rheumatoid arthritis and is associated with variable degrees of inflammation.[1] CPPD typically occurs in older people but can occur in younger people with associated metabolic conditions, such as hyperparathyroidism and haemochromatosis.[2] Familial forms of the disease have been reported.

Question 2

what’s the difference between pseudogout and other rheumatic bone diseases

Answer 2

• gout vs pseudogout: main difference is in the type of crystals that are causing the problem (clacium pyrophosphate in pseudogout, urate in gout). gout mainly happens in the big toe and feet first, pseudogout mainly in hand, wrist, shoulder, knee
• osteoarthritis: can be a risk factor for pseudogout, but pseudogout usually in shoulders, wrists, or metacarpophalangeal joints, osteoarthritis usually in hips, knees, spine.

Question 3

risk factors

Answer 3

• hypophosphatasia, hypercalcaemia, hypothyroid, hyperparathyroidism, haemachromatosis
• other metabolic disorders
• old age, injury, surgery, fmaily history of CPPD

Question 4

symptoms and signs

Answer 4

red and swollen joints
joint effusion and fluctuance 
painful and tender joints
osteoarthritis-like involvement of joints
sudden worsening of osteoarthritis 

could present with fever and malaise

Question 5

investigations

Answer 5

1st investigation: arthrocentesis with synovial fluid analysis

• x ray of affected joint
• serum calcium, PTH, magnesium, alkaline phosphatase, iron studies

others to consider: ultrasonography, CT scan

Question 6

pseudogout vs gout attack

Answer 6

gout:
More likely to affect small joints of the lower extremity, particularly the first metatarsophalangeal joint.

Onset is sudden and attack duration is frequently shorter than in acute CPP arthritis.[46]

Risk factors for hyperuricaemia, such as renal insufficiency, are more common.

Synovial fluid microscopy is negative for CPP crystals and positive for urate crystals.

Question 7

pseudogout vs septic arthritis

Answer 7

septic arthritis:
Presentation may be identical to that of gout.
Patients are typically immunocompromised.

Synovial fluid microscopy is negative for CPP crystals.
Positive Gram stains or fungal stains, and cultures of synovial fluid.

Question 8

pseudogout vs osteoarthritis

Answer 8

osteoarthritis:
Typically affects large weight-bearing joints, the cervical and lumbar spine, and the base of the first metatarsophalangeal joint. In the hands, it involves the first carpometacarpal, distal interphalangeal, and proximal interphalangeal joints.

Synovial fluid microscopy is negative for CPP crystals.
X-rays show no evidence of cartilage calcification.

Question 9

pseudogout vs RA

Answer 9

RA:
Joints flare simultaneously. Affected joints tend to be in a symmetrical pattern.

Synovial fluid microscopy is negative for CPP crystals.
X-rays show typical changes of erosive rheumatoid arthritis.

Question 10

pseudogout vs polymyalgia rheumatica

Answer 10

polymyalgia rheumatica:
Patients complain of prolonged morning stiffness involving the hips and shoulders.

This is typically symmetrical and accompanied by signs and symptoms of systemic inflammation, such as weight loss and malaise.

There is usually little or no synovitis.

Synovial fluid microscopy is negative for CPP crystals.

Erythrocyte sedimentation rate is high.