Gout / Pseudogout

Question 1

Gout

Uric Acid (UA) end‐product of purine degradation

Monosodium urate monohydrate crystals (MS)

Needle shape crystals, negative birefringent by polarizing microscopy

Usually joint (1st MTP‐Podagra) can be polyarticular

Tophi-White chalky masses of uric acid

Answer 1

Acute Gouty Arthritis

‒ Pain, erythema, warmth, tender, swollen; often occurs at night

‒ Triggers‐ red meats/sea foods, purines, alcohol, trauma, seasonal weather extremes, dehydration, excessive exercise

‐ feet, ankles, knees – (any joint)

Chronic Arthritis

‒ Tophi (ears, forearms, Achilles tendon)

‒ Renal insufficiency (urate stones); radiolucent

-Radiopaque tissues/objects appear more white and radiolucent tissues/objects appear more black

Differential Diagnosis:

‐ Infectious arthritis (septic arthritis)

‐ Reactive A.

‐ Pseudo gout ‐ CPPD disease (Ca Pyrophosphate Dihydrate)

Treatment

Do not treat asymptomatic hyperuricemia, Exception‐ patent about to receive cytotoxic therapy for neoplasm

no single best agent for all patient with Acute Gouty Flare

Question 2

Acute Gouty Flare

• Treat ASAP (12‐36 hours)
• NSAID‐ Naproxen 500mg BID/Indomethacin 50mg TID
• Incr. risk GI bleed/ulcer/renal disease/fluid retention/interfere with anticoag/HF/HT

Answer 2

gout treatment

Steroids

• Oral, parental, Intraarticular
• steroids are a Reasonable 1st line treatment
• Safe, effective, anti‐inflammatory agent
• Prednisone 40mg PO/day x5‐7 days‐ taper

Caution: HF, HT, poorly controlled DM, Sepsis, CKD

Colchicine

• Effective within 1st 24 hrs. of attack
• .6mg q8hrs with taper or 1.2mg initially, then .6mg/hr. later
• Side effects (GI‐N/V/D (biggest side effect); Liver, Renal impairment)

Biologics

• Inhibitors of interleukin‐ 1B (antagonist)
• Anakinra 100mg subcut. daily

Uric Acid Lowering Agents

Indications

• Recurrent gouty attacks, tophi, kidney stones, cytotoxic therapy
• Do not start during acute attack; can precipitate flare

Xanthine oxidase inhibitors (allopurinol) dec. UA Synthesis

Uricouric drugs (probenecid, sulfinpyrazone)‐ inc. UA excretion by inhibiting tubular reabsorption Don’t use with CKD or stones

Question 3

Pseudogout

(Calcium Pyrophosphate Dehydrate Depostion Disease) ‐ CPPD

• Large joints, knee; older patient
• Can be polyarticular; warm, swollen, erythematous, painful
• If chronic‐ resembles OA
• Chondrocalcinosis‐ calcium deposits in articular cartilage

Answer 3

CPPD Crystals

• Short blunt rods, rhomboids/cuboids
• Weak POSITIVE birefringence by polarizing microscopy

Differential Diagnosis: OA, RA, Gout, Septic A.

Associated with CPDD‐ aging

In younger patients – consider primary hyperparathyroidism, hemochromatosis, hypomagnesemia, chronic gout, Gitelman’s syndrome

treatment

• NSAID
• Steroids (intra‐articular injections)
• Colchicine (variable)