Case Id: JSSMCRADC0026

 

 

AP radiograph of foot
   

 

 

 

Lateral radiograph of foot

 

 

 

The great toe demonstrates extensive juxta-articular erosions with soft tissue swelling and little osteoporosis
Lateral radiograph showing juxta-articular erosions with soft tissue swelling

DIAGNOSIS:
GOUT

 

                                                                                             

                                                                               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
  • 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 monarticular gout
    • Polyarticular gout
    • Chronic tophaceous gout = multiple large urate deposits
    • Gouty nephropathy
  • 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
  • Radiologic features usually not seen until 6-12 years after initial attack
  • Radiologic features present in 50% of inflicted patients
  • 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 monarticular 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


MRI
Tophi


Signal characteristics of gouty tophi are usually

  • T1 : iso intense
  • T2 : variable with the majority of lesions being heterogeneously hypointense
  • T1 C+ (Gd) : the tophus usually enhances

References:

  1. Dähnert W. Radiology review manual. Lippincott Williams & Wilkins. (2007)
  2. Carter JD, Kedar RP, Anderson SR et-al. An analysis of MRI and ultrasound imaging in patients with gout who have normal plain radiographs. Rheumatology (Oxford). 2009;48 (11): 1442-6
  3. Oaks J, Quarfordt SD, Metcalfe JK. MR features of vertebral tophaceous gout. AJR Am J Roentgenol. 2006;187 (6)

 

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