Gout
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
· Causes:
o Idiopathic Gout
§ M:F = 20:1
§ Overproduction of uric acid
§ Abnormality of renal urate excretion
o 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:
o Asymptomatic hyperuricemia
o Acute monarticular gout
o Polyarticular gout
o Chronic tophaceous gout = multiple large urate deposits
· Location:
o Joints: hands + feet (1st MTP joint most
commonly affected = podagra), elbow, wrist
§ Carpometacarpal compartment especially common), knee, shoulder, hip, sacroiliac joint
(15%, unilateral)
o Ear pinna >
bones, tendon, bursa
· Radiologic features usually not seen until
6-12 years after initial attack
· Radiologic features present in 50% of
inflicted patients
· Soft tissue findings
o Calcific deposits in gouty tophi in 50% (only
calcium urate crystals are opaque)
o Eccentric juxta-articular lobulated soft-tissue masses (hand, foot,
ankle, elbow, knee)
o Bilateral olecranon bursitis
o Aural calcification
· Joint findings
o Preservation of joint space initially
o Absence of periarticular demineralization
o Erosion of joint margins with sclerosis
o Cartilage destruction late in course of
disease
o Periarticular swelling (in acute monarticular gout)
o Chondrocalcinosis (menisci, articular
cartilage of knee) resulting in secondary osteoarthritis
The great toe demonstrates extensive juxta-articular erosions
with soft tissue swelling and little osteoporosis
· Bone findings
o "Punched-out" lytic bone lesion ± sclerosis of margin
o "Mouse / rat bite" from erosion of
long-standing soft-tissue tophus
o "Overhanging margin" (40%)
o Ischemic necrosis of femoral / humeral
heads
o Bone infarction
· Coexisting disorders:
o Psoriasis
o Glycogen storage disease Type I
o Hypo- and hyperparathyroidism
o Down’s syndrome
o Lesch-Nyhan syndrome (choreoathetosis, spasticity, mental retardation,
self-mutilation of lips + fingertips)
· Treatment: colchicine, allopurinol (effective treatment usually
does not change x-ray findings)
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