Crystal induced arthritis

Question 1

3 clinical phases of gout

Answer 1

acute gouty arthritis
intercritical period: Asx
chronic gout: untreated hyperuricemia> chronic tophaceous gout (polyarticular attacks, sxs between attacks, and tophi in soft tissues or joints)

Question 2

Risk factors for gout

Answer 2

medications: thiazide and loop diuretics, cyclosporine, and low-dose aspirin (<1 gram daily)
insulin resistance, metabolic syndrome, and obesity
chronic renal insufficiency, HTN, CHF, organ transplantation, disorders of high cell turnover (hematologic malignancy), high intake of dietary purines (meat and seafood), ethanol (particularly beer and spirits), soft drinks, high-fructose corn syrup

Question 3

Triggers for gout

Answer 3

Recent diuretic use
Alcohol intake
Hospitalization
Surgery
Initially in urate lowering therapy

Question 4

Diagnosis of gout

Answer 4

aspiration of synovial fluid or tophi aspiration

negatively birefringent monosodium urate crystals under polarizing microscopy

Question 5

Txt of acute gout flare

Answer 5

NSAIDs: naproxen, indomethacin (5-7 days)
Colchicine (can use in combo with NSAID or prednisone)
Glucocorticoids: prednisone, taper over 10 days (can use intra-articular or IM if needed)
If resistant can consider using IL-1 inh (anakinra, canakinumab)

Question 6

Who is considered for urate lowering therapy?

Answer 6

tophi, frequent attacks (≥2 per year), polyarticular attacks, CKD 2 or worse, or previous urolithiasis

Question 7

Chronic gout txt

Answer 7

Allopurinol: <100 mg daily and up-titrate every 3-5w until uric acid <6
watch for hypersensitivity rxn in first 3 months, esp with renal insufficiency or genetically susceptible (Asian descent)
Give with low dose colchicine/NSAID/glucocorticoids to prevent acute attack until 3-6 months after goal uric acid reached
Febuxostat only if allergic to allopurinol d/t inc CV events
Probenecid causes excretion in urine, less effective, can cause nephrolithiasis

Question 8

Calcium Pyrophosphate Deposition Disease or pseudogout features

Answer 8

Asx chondrocalcinosis > episodes of arthritis that mimic gout (pseudogout) or even RA (pseudo–rheumatoid arthritis) to accelerated OA
Older patients with multiple comorbidities
Usually knee>wrist
XR: chondrocalcinosis in cartilage of the knee joint, triangular fibrocartilaginous complex of the wrist, or pubic symphysis

Question 9

Pseudogout risk factors

Answer 9

hyperparathyroidism
hypomagnesemia
hypophosphatasia
hemochromatosis
trauma

Question 10

Diagnosis of pseudogout

Answer 10

Arthrocentesis

Synovial fluid analysis: polymorphic rhomboid and rod-shaped crystals that exhibit weak positive birefringence

Question 11

Txt pseudogout

Answer 11

NSAIDs
colchicine
systemic or intra-articular glucocorticoids
Refractory: MTX or hydroxychloroquine but little evidence, IL-1 inh (anakinra) investigational
Prevention: none known to help