MSK/Rheumatology - Gout - Exam 3 Flashcards
How does gout develop?
- Uric acid precipitates into monosodium urate (MSU) crystals
- Deposits in and around joints, bones, and soft tissues
- Pain and inflammation
What types of food can trigger a gout flare and why?
High purine diet (red meat and seafood)
Uric acid is the breakdown product of purine metabolism
What is the hallmark clinical feature of gout and how is it classified?
Hyperuricemia
Uric acid level exceeding 6.8 mg/dL
What are possible causes of hyperuricemia overproducers?
Inherited enzyme defects
High cell turnover
Increased purine consumption
What are possible causes of hyperuricemia underexcretors?
90% of all hyperuricemia cases Renal insufficiency Diuretics Volume depletion Lead nephropathy
What population is gout most prevalent in?
Males age 30-60
What are some modifiable risk factors for gout?
Obesity, HTN, hyperlipidemia, CKD, diabetes, diet, ETOH, medications
What are the four stages of gouty arthritis?
- Asymptomatic hyperuricemia
- Acute gouty arthritis
- Intercritical gout (asymptomatic interval between gout attacks)
- Chronic gouty arthritis (chronic swelling and tophi)
What are white chalky material consisting of dense concentration of MSU crystals that are indicative of the duration of severity of hyperuricemia?
Tophi
What are complications of gout?
Uric acid nephrolithiasis
Urate nephropathy
What is the clinical presentation of an acute gout flare?
Monoarticular 1st MTP joint "Podagra" Rapid onset, often at night Severe pain Erythema Warmth Edema Recurrent Self limiting
What can trigger an acute gout flare?
Acute increase OR decrease in uric acid levels
What medications can trigger an acute gout flare?
Thiazide or loop diuretics
Urate-lowering medications
What will appear on imaging of established gout disease?
“punched out” with sclerotic margin, overhanging edges (rat bite erosions)
How is gout diagnosed with an ultrasound?
Double contour sign
What test provides a definitive diagnosis of gout?
Arthrocentesis/synovial fluid analysis
What technique is used to test the arthrocentesis/synovial fluid analysis and what would be a positive test for gout?
Polarized Light Microscopy
Needle shaped
Negatively birefringent
What test can be helpful to monitor effect of urate-lowering therapy?
Serum Uric Acid (sUA)
What test can be used to determine if a patient is a candidate for uricosuric therapy?
24h urinary uric acid
What is the first line treatment for an acute gout flare?
NSAIDs- Indomethacin or Naproxen
Glucocorticoids (must exclude infection)
If a patient is already on ULT, and comes in with an acute gout flare, should you continue or discontinue the medication?
Continue without interruption
What can be used for treatment for an acute gout flare if patients have a contraindication to NSAIDs and glucocorticoids?
Colchicine
How does urate-lower therapy (ULT) work to lower serum uric acid levels?
How long is the course of tx?
- Decreases urate synthesis (XOIs)
- Enhances renal excretion of uric acid (uricosuric agents)
Continued indefinitely
What are the two types of Xanthine Oxidate Inhibitors (XOIs) used to treat gout?
How do they work?
Who are they indicated for?
Allopurinol 100mg/day
Febuxostat 40mg/day
MOA: Decreases Urate Synthesis
Indicated for overproducers and underexcretors
What is the uricosuric agent used to treat gout?
How does it work?
Who is it indicated for?
Probenecid 250mg bid
MOA: Enhances renal excretion of uric acid
Indicated for underexcretors
What is the first line XOI tx for gout? What is its main side effect?
Allopurinol
Severe cutaneous adverse reactions
What is the FDA warning for Febuxostat?
Mortality risk for patients at high cardiovascular risk
Why should ULTs not be used to treat an acute gout flare? When is it safe to initiate tx?
Initiation may precipitate an acute flare
2 weeks after flare has resolved
During initiation of ULT, what can be used to reduce the risk of flares?
NSAIDs or colchicine can be used for ~6mo to reduce the risk of flares
What is the treat-to-target goal of long term gout tx?
Achieve target serum urate levels
sUA of 6.0mg/dL or less
sUA of 5.0mg/dL or less for tophaceous gout
What is another name for calcium pyrophosphate crystal deposition disease (CPPD)?
Pseudogout
What are some disease association of CPPD/pseudogout?
Hemochromatosis
Hyperparathyroidism
What is the clinical presentation of CPPD/pseudogout?
Severe acute inflammation
Knee is most commonly affected
What may you find on radiograph of CPPD/pseudogout?
Chrondrocalcinosis “cartilage calcification”
What test provides a definitive diagnosis of CPPD/pseudogout?
Arthrocentesis/synovial fluid analysis
What technique is used to test the arthrocentesis/synovial fluid analysis and what would be a positive test for pseudogout?
Polarized Light Microscopy
Rhomboid shaped
Positively birefringent
What is the acute treatment of CPPD/pseudogout?
NSAIDs or Colchicine
Intraarticular glucocorticoid injection (rule out infection)
When is prophylactic treatment of CPPD/pseudogout recommended? What is the prophylatic tx?
3 or more attacks/yr
Colchicine
What is spondyloarthritis (SpA)?
Family of inflammatory rheumatic diseases that cause arthritis
What are shared clinical features of SpA?
Inflammatory back pain Peripheral arthritis Dactylitis Enthesitis Uveitis HLA-B27 association Seronegative
How does inflammatory back pain caused by SpA present?
Age of onset < 40 years Improvement with exercise No improvement with rest Pain at night Often have morning stiffness
How does peripheral arthritis caused by SpA present?
Predominantly involves the lower extremities, frequently asymmetrical and often affects only 1-3 joints (oligoarthritis)
How does enthesitis caused by SpA present?
Inflammation around the entheses—site of insertion of ligaments, tendons, joint capsule, or fascia
Most commonly on the achilles tendon or the plantar fascia at the calcaneus
What is the triad saying for reactive arthritis (ReA)?
Can’t see: Conjunctivitis/uveitis
Can’t pee: Urethritis
Can’t climb a tree: peripheral arthritis, enthesitis, dactylitis, inflammatory low back pain
What is reactive arthritis?
An acute aseptic inflammatory arthritis triggered by a preceding GI or GU infection
What is the clinical presentation of reactive arthritis?
Acute onset
Typically present with an asymmetrical oligoarthritis
Occurs usually 1-4 weeks following the inciting infection
How is reactive arthritis diagnosed?
Antecedent or concomitant infection
Positive HLA-B27 antigen
What is the 1st line management of reactive arthritis?
Refer to rheumatology
1st line- NSAIDs
What can use to treat reactive arthritis if the patient has an inadequate response to NSAIDs?
Glucocorticoids
What can use to treat reactive arthritis if the patient is resistant to NSAIDs and glucocorticoids?
Disease-modifying antirheumatic drugs (DMARDs)
What is ankylosing spondylitis (AS)?
Chronic inflammatory disease of the axial skeleton, particularly the sacroiliac (SI) joints and spine
What is the clinical presentation of ankylosing spondylitis?
Inflammatory back pain and progressive stiffness of the spine Enthesitis Peripheral arthritis Sx worse in the morning or with activity Good response to NSAIDs
What is the disease pathology of ankylosing spondylitis?
- Enthesitis with chronic inflammation
- Structural damage
- New bone formation (ossification)
- Anklosis (fusion)
What may imaging of ankylosing spondylitis show?
Fusion of the spine
“bamboo spine”
Sacroiliitis
What may physical findings of ankylosing spondylitis show?
Limited spinal mobility (and chest expansion)
Hyperkyphosis
Loss of lumbar lordosis
What is the physical diagnostic test for ankylosing spondylitis and what would be an abnormal finding?
Modified Schober
On forward flexion, distance <5 cm is abnormal
When should you refer to rheumatology?
In patients with ≥ 3 months back pain and age at onset < 45 years
