Let's talk about a common problem seen on Internal Medicine - Crystal Arthropathy
CPPD - Weakly positive rhomboid crystals
- Most are idiopathic; inflammation due to calcium deposit in the joint
- Remember 3 Hs
- Hypomagnasemia (Gittelmans, Bartters)
- Some more H's - hypothyroidism, hypophosphatemia, hypomagnesemia
- Hemochromatosis - 2nd + 3rd MCP/PIP
- Suspect CPPD when the presentation sounds like OA in odd locations (eg MCP) with chrondrocalcinosis
- Basic Calcium Phosphate (BCP) - Milwaukee shoulder - destructive, acute, older females, associated with prior trauma
- Arthrocentesis: WBC 2000 - 10000. PMNS greater than 50%.
- Acute treatment: Joint aspiration/steroid injection is first line
- NSAID is second line
- Colchicine, steroids (systemic or intra-articular) also used
- Prophylaxis with colchicine if more than 2 attacks/year
- PRV, hemolysis, TLS
- Diet - beer, red meat, seafood
- Increased meat, seafood, alcohol
- Male, obesity
- Drugs: Cyclosporine, salicylates, HCTZ
- Lose weight
- Change diet - increase protein
- lower alcohol
- Remove diuretic, change to losartan
- Start ASAP
- Treat with NSAIDs:
- eg Naproxen 500 mg bid or indeomethacin 50 mg tid.
- Duration: until 1-2 days after symptoms resolve (usually 5-7 days).
- Avoid ASA - will make it worse.
- If contra-indicated, treat with colchicine 1.5 mg q8H x3, then taper until resolution. Colchicine is initiated in acute attacks only.
- Only start this if symptoms are less than 48 hours
- Don't use IV colchicine.
- If contra-indicated, treat with oral, intra-articular, or IV glucocorticoids.
- Use only steroids for CKD and ESRD.
- Intra-articular injection for those with 1-2 affected joints who can't take above medications.
- Prednisone 30-50 mg daily over 7-10 days.
- Intravenous - if all the above is contra-indicated; 20 mg methylprednisone IV.
- Prophylaxis with urate lowering therapy in these people.
- 2 or more attacks/year
- Kidney stones
- Radiographic changes
- Urinary uric acid greater than 1100 mg/day
- Which agent, how much?
- Don't start during acute attack
- Even when stable, start with overlap with NSAID/colchicine. Preferably Colchicine - continue for 6 months after normal urate is achieved.
- Titrate to urate level less than 357 umol
- Renal dose adjustment
- Start with allopurinol; if intolerant, move on to febuxostat
- Don't use these two agents when the patient is also on azathioprine
- In this case, use probenacid instead (causes stones - make sure to hydrate)
- If very severe, treat with IV pegloticase Q2 weeks