Gout

Introduction

A monosodium urate crystal deposition disorder
- primary gout
  - an idiopathic disorder of nucleic acid metabolism that leads to hyperuricemia and deposition of monosodium urate crystals in joints (a purine breakdown product).
- secondary gout
  - is associated with a disease with high metabolic turnover (psoriasis, hemolytic anemia, leukemia, chemotherapy)
Epidemiology
- demographics
  - recurrent attacks seen in men from ages 40-60 years
- location
  - usually seen in lower limb
    - podagra (arthritis attacks of great toe)
  - crystal deposition as tophi
    - ear helix, eyelid olecranon, Achilles tendon
- risk factors
  - chemotherapy
Pathophysiology
- dysfunctional nucleic acid metabolism causing hyperuricemia
- deposition of monosodium urate crystals in synovium of joint
- crystals lead to an inflammatory response activating
  - proteases
  - prostaglandins
  - leukotriene B4
  - free oxygen radicals
Associated conditions
- renal stones

Presentation

Symptoms
- pain in joint
- can resemble septic arthritis
- symptoms of renal stones
Physical exam
- may have decreased range of motion due to pain
- white toothpaste-like appearance of tophus aspirate

Imaging

Radiographs
- recommended views
  - AP and lateral of affected joint
- findings
  - may see punched out periarticular erosion with sclerotic overhanging borders
  - may see soft tissue crystal deposition (tophi)

Studies

Labs
- serum uric acid
  - elevated uric acid is not diagnostic (80% of people with an elevated uric acid will never have a gout attack)
Crystal analysis
- diagnosis made by joint aspiration and crystal analysis
- crystals are
  - thin , tapered, needle shaped intracellular crystals
  - strongly negatively birefringent

Treatment

Acute gout
- anti-inflammatory drugs
  - indications
    - first line of treatment
  - modalities
    - indomethacin (indocin)
      - 50mg three times daily
      - inhibits phagocytosis
    - colchicine
      - indicated in acute attacks if patient has a history of peptic ulcers
      - inhibits inflammatory mediators
      - can be given intravenously
Chronic gout
- allopurinol
  - xanthine oxidase inhibitor
- colchicine
  - indicated for prophylaxis after recurrent attacks

TAG

(OBQ08.47) A 60-year-old man has had intermittent pain in his right great toe for the past 2 years. What is the most likely cause for the lesions indicated by the arrows in Figure A? Topic

Review Topic

FIGURES: A

1. Monosodium urate crystal deposition
2. Calcium pyrophosphate deposition
3. Renal osteodystrophy
4. Tuberculosis
5. Sarcoidosis

PREFERRED RESPONSE ▶

DISCUSSION: Gout is a disorder of nucleic acid metabolism that leads to monosodium urate crystal deposition in the joints. The most common area of the body to be affected by gout is the first toe. The radiograph in Figure A demonstrates joint space narrowing of the 1st metarsalphalangeal joint and the arrows show medial soft tissue swelling at the 1st MTP with soft tissue radio-densities and some erosive changes consistent with gout.

Weinfeld et al report their experience over a 7 year period with hallux MTP arthritis in 439 patients they treated. Surgical indications included pain, shoewear problems, and failure of non-operative management.

Reber et al describe a rare case of tophaceous gout in the medial sesamoid of the hallux and review the diagnosis, pathophysiology, and suggested management.

Eggebeen reports "gout is caused by monosodium urate crystal deposition in tissues leading to arthritis, soft tissue masses (i.e., tophi), nephrolithiasis, and urate nephropathy. The biologic precursor to gout is elevated serum uric acid levels (i.e., hyperuricemia). The diagnosis is confirmed if monosodium urate crystals are present in synovial fluid."

Incorrect Answers:
Answer 2: Calcium pyrophosphate deposition is found with pseudogout and tophaceous depositions are rare in this disease.
Answer 3: Renal osteodystrophy is a spectrum of disease seen in patients with chronic renal disease. It is characterized by bone mineralization deficiency due to the electrolyte and endocrine abnormalities associated with chronic kidney disease. It is common cause of hypocalcemia, but does not present with the "tophi" seen in Figure A.
Answer 4: Extrapulmonary manifestations of tuberculosis include CNS infection, vertebral body involvement (Potts Disease), renal disease, and GI symptoms. It does not present with tophi of the first MTP joint.
Answer 5: Sarcoidosis is a multisystem, chronic, inflammatory/fibrosing disease of unknown etiology. It is characterized by noncaseating granulomas that affects the lungs (90% of the cases) and other organ symptoms. It does not present with tophi of the first MTP joint.

REFERENCES:

1. Weinfeld SB, Schon LC. Hallux metatarsophalangeal arthritis. Clin Orthop Relat Res. 1998 Apr;(349):9-19. Review. PMID:9584362 (Link to Abstract)

2. Reber PU, Patel AG, Noesberger B. Gout: rare cause of hallucal sesamoid pain: a case report. Foot Ankle Int. 1997 Dec;18(12):818-20. PMID:9429885 (Link to Abstract)

3. Eggebeen AT. Gout: an update. Am Fam Physician. 2007 Sep 15;76(6):801-8. Review. PubMed PMID: 17910294. PMID:17910294 (Link to Abstract)

Question Authors:

Patrick O'Donnell MD/PhD, Derek Moore, Patrick McCulloch MD,

Please Rate Educational Value!

3.0

Average 3.0 of 7 Ratings

TAG

(OBQ04.265) Which of the following foot radiographs is most consistent with the diagnosis of gout? Topic

Review Topic

FIGURES: A

1. A
2. B
3. C
4. D
5. E

PREFERRED RESPONSE ▶

DISCUSSION: In their study, Egan et al describe the characteristic radiographic findings of gout in the foot which include: asymmetric polyarthropathy, well-defined erosions with sclerotic margins, overhanging bony edges, and tophi. Figure B above displays well-defined punched out periarticular erosion with sclerotic overhanging borders within the forefoot, consistent with a diagnosis of gout. Figure A shows an example of arthritis mutilans in psoriatic arthritis. Figure C shows an example of Freiberg's infraction. Figure D shows an example of a Charcot foot. Figure E shows an example of a rheumatoid foot.

REFERENCES:

1. Coughlin MJ: Arthritides, in Coughlin MA, Mann RA (eds): Surgery of the Foot and Ankle, ed 7. St Louis, MO, Mosby, 1999, pp 560-650.

2. Egan R, Sartoris DJ, Resnick D. Radiographic features of gout in the foot. J Foot Surg. 1987 Sep-Oct;26(5):434-9. PMID:3316363 (Link to Abstract)

Question Authors:

David Abbasi MD, John Badylak MD, Patrick McCulloch MD,

Please Rate Educational Value!

3.0

Average 3.0 of 5 Ratings

Level of Evidence 4 (Case Series)

Egan R, Sartoris DJ, Resnick D. Radiographic features of gout in the foot. J Foot Surg. 1987 Sep-Oct;26(5):434-9. PMID:3316363 (Link to Abstract)

Level of Evidence 5 and Other Journal Articles (includes Case Reports, Expert Opinions, Personal Observations, and Biomechanic Studies)

Weinfeld SB, Schon LC. Hallux metatarsophalangeal arthritis. Clin Orthop Relat Res. 1998 Apr;(349):9-19. Review. PMID:9584362 (Link to Abstract)
Reber PU, Patel AG, Noesberger B. Gout: rare cause of hallucal sesamoid pain: a case report. Foot Ankle Int. 1997 Dec;18(12):818-20. PMID:9429885 (Link to Abstract)

Textbooks

Review of Orthopaedics, 6th Edition, Mark D. Miller MD, Stephen R. Thompson MBBS MEd FRCSC, Jennifer Hart MPAS PA-C ATC, an imprint of Elsevier, Philadelphia, Copyright 2012
AAOS Comprehensive Orthopaedic Review, Jay R. Leiberman. Published by American Academy of Orthopaedic Surgeons, Rosemont IL. Copyright 2009
Orthopaedic Knowledge Update 10, John M Flyn. Published by American Academy of Orthopaedic Surgeons, Rosemont IL. Copyright 2011
Hoppenfeld SP. Surgical Exposures in Orthopaedics: The Anatomic Approach. Lipponcott, Williams, and Wilkins, Philadelphia, PA, Copyright 2009
Orthopaedic In-training Examination (OITE) Questions 2004-2012, American Academy of Orthopaedic Surgeons, Rosemont IL. Copyright 2004-2012
Self-Assessment Examination (SAE) Questions 2004-2012, American Academy of Orthopaedic Surgeons, Rosemont IL. Copyright 2004-2012
Coughlin MJ: Arthritides, in Coughlin MA, Mann RA (eds): Surgery of the Foot and Ankle, ed 7. St Louis, MO, Mosby, 1999, pp 560-650.

Undefined

Eggebeen AT. Gout: an update. Am Fam Physician. 2007 Sep 15;76(6):801-8. Review. PubMed PMID: 17910294. PMID:17910294 (Link to Abstract)

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