Gout Flashcards
What is gout?
Gout is a syndrome characterised by: hyperuricaemia and deposition of urate crystals causing attacks of acute inflammatory arthritis; tophi around the joints and possible joint destruction; renal glomerular, tubular, and interstitial disease; and uric acid urolithiasis. The disease most commonly affects the first toe (podagra), foot, ankle, knee, fingers, wrist, and elbow; however, it can affect any joint.
Where does gout commonly affect?
The disease most commonly affects the first toe (podagra), foot, ankle, knee, fingers, wrist, and elbow; however, it can affect any joint.
What are the risk factors for gout?
- Older age
- Male sex
- Menopausal state
- Consumption of meat, seafood and alcohol
- Use of diuretics
- Use of ciclosporin or tacrolimus
- Use of aspirin
What are the symptoms of gout?
- Rapid onset severe pain
- Joint stiffness
- Tenderness
What are the signs of gout?
- Foot joint distribution
- Few affected joints
- Swelling and joint effusion
- Tophi
- Rubor
- Calor
Briefly describe tophi
- Deposition of urate crystals in tissue, including bone and soft tissue.
- Manifests as hard painless nodules that may appear yellow and chalky if close to the surface of the skin.
What is shown in the picture?
Tophi
What investigations should be ordered for gout?
- Arthocentesis with synovial fluid analysis
- Serum uric acid level
- Ultrasound
Why investigate using arthrocentesis with synovial fluid analysis? And what may this show?
- WBC count increased; strongly negative birefringent needle-shaped crystals under polarised light.
- Provides definitive diagnosis. Excludes septic arthritis and differentiates gout from pseudogout (calcium pyrophosphate deposition disease).
Why investigate serum uric acid level? And what may this show?
- Increased serum uric acid level.
- Gout can develop with levels lower than the upper limit of normal values. Should be obtained at least 2 weeks after the attack resolves, as it may be falsely low or normal during the attack.
Why investigate using ultrasound? And what may this show?
- Erosions, tophi, double contour line.
What is the goal in management of gout?
The short-term treatment goal for acute gout is rapid resolution of pain and preservation of function. Long-term goals are to prevent recurrent attacks and chronic joint destruction. The earlier treatment is initiated, the better the clinical response.
Briefly describe the treatment of acute gout
- NSAIDs such as naproxen or ibeuprofen are first-line therapy if no contraindications exist. NSAIDs halt the inflammatory cascade of acute gout if they are started early.
- A corticosteroid, such as prednisolone, may be considered if NSAIDs are contraindicated. Corticosteroids can be given either as an intra-articular injection for monoarticular acute gout or parenterally for oligoarticular or polyarticular acute gout.
Briefly describe the treatment of chronic gout
- Urate lowering drugs such as allopurinol and febuxostat.
- Pharmacological anti-inflammatory prophylaxis (e.g., NSAID) is recommended for all gout patients during the initiation and titration of a urate-lowering drug. Anti-inflammatory prophylaxis should be continued for 3 to 12 months after reaching the target level of uric acid.
Briefly describe the use of allopurinol
- A xanthine oxidase inhibitor, reduces the production of uric acid.
- It should be started 2 weeks after the last exacerbation at a low dose. As such agents may increase the risk of recurrence or prolongation of the attacks by rapidly decreasing the serum urate level.
What is the target serum uric acid level for urate lowering drugs?
Urate-lowering drugs are typically prescribed to target serum uric acid levels <360 micromol/L (<6 mg/dL), to prevent supersaturation and crystal formation.
What complications are associated with gout?
- Acute uric acid nephropathy
- Nephrolithiasis
What differentials should be considered for gout?
- Pseudogout
- Septic arthritis
- Trauma
How does gout and pseudogout differ?
- Differentiating signs and symptoms: presentation may be identical to gout. Pseudogout is more likely to affect the wrist and knee joints.
- Differentiaing investigations: the definitive diagnosis is finding calcium pyrophosphate crystals in the synovial fluid.
How does gout and septic arthritis differ?
- Differentiating signs and symptoms: presentetion may be identical to gout. Risk factors for infection, such as intravenous drug use and immunocompromise, may be present.
- Differentiating investigations: synovial fluid microscopy and culture may be Gram positive and show growth. Blood cultures may grow the causal bacteria.
How does gout and trauma differ?
- Differentiating signs and symptoms: a positive history is present. Usually, there are fewer inflammatory signs, such as erythema or warmth, on joint examination than with gout
- Differentiating investigations: synovial fluid is usually bloody and has no monosodium urate crystals.
