Olecranon Bursitis - Gout

General Considerations

• Deposition of sodium urate monohydrate crystals in synovial membranes, articular cartilage, ligaments, bursae leading to destruction of cartilage
• Age of onset is usually greater than 40 years; males much more often than females
• Radiologic features usually not seen until 6-12 years after initial attack
• Radiologic features present in 50% of affected patients

Causes:

• Idiopathic Gout

• M:F = 20:1
• Overproduction of uric acid
• Abnormality of renal urate excretion

• Secondary Gout

• Rarely cause for radiographically apparent disease
• Myeloproliferative disorders, e.g. polycythemia vera, leukemia, lymphoma, multiple myeloma
• Blood dyscrasias
• Myxedema, hyperparathyroidism
• Chronic renal failure
• Glycogen storage disease
• Myocardial infarction
• Lead poisoning

Stages:

• Asymptomatic hyperuricemia
• Acute mono-articular gout
• Polyarticular gout
• Chronic tophaceous gout = multiple large urate deposits

Location:

• Joints: hands + feet (1st MTP joint most commonly affected = podagra), elbow, wrist
  • Carpometacarpal compartment especially common), knee, shoulder, hip, sacroiliac joint (15%, unilateral)
• Ear pinna > bones, tendon, bursa

Soft tissue findings

• Calcific deposits in gouty tophi in 50% (only calcium urate crystals are opaque)
• Eccentric juxta-articular lobulated soft-tissue masses (hand, foot, ankle, elbow, knee)
• Bilateral olecranon bursitis
• Aural calcification

Joint findings

• Preservation of joint space initially
• Absence of periarticular demineralization
• Erosion of joint margins with sclerosis
• Cartilage destruction late in course of disease
• Periarticular swelling (in acute mono-articular gout)
• Chondrocalcinosis (menisci, articular cartilage of knee) resulting in secondary osteoarthritis

Bone findings

• "Punched-out" lytic bone lesion ± sclerosis of margin
• "Mouse / rat bite" from erosion of long-standing soft-tissue tophus
• "Overhanging margin" (40%)
• Ischemic necrosis of femoral / humeral heads
• Bone infarction

Coexisting disorders:

• Psoriasis
• Glycogen storage disease Type I
• Hypo- and hyperparathyroidism
• Down’s syndrome
• Lesch-Nyhan syndrome (choreoathetosis, spasticity, mental retardation, self-mutilation of lips + fingertips)

Treatment

• Colchicine, allopurinol (effective treatment usually does not change x-ray findings)

Olecranon Bursitis-Gout. The olecranon bursa is enlarged white arrow) and there is a large erosion in the olecranon process of the ulna (yellow arrow).
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