Renal dysfunction ie lower creatinine clearance seen in 50% patients at presentation for MM ( anemia is seen in 75%).
Significance in prognosis: critically important prognostic factor is improvement in renal dysfunction with induction treatment and predicts improved survival even before response to systemic therapy is otherwise assessed.
Monoclonal plasma cell disorders are a spectrum of diseases that includes premalignant MGUS, solitary plasmacytoma, Ig-mediated amyloidosis (AL amyloidosis), and both asymptomatic and symptomatic MM
Range of myeloma associated renal dysfunction: Ig-dependent and -independent categories
Three distinct syndromes account for most cases of Ig-mediated kidney disease
1. Amyloidosis ( proteinuria, low Bp, cardiac dysfunction): monoclonal light chains and other proteins together form β-pleated sheets in the glomeruli
2. Cast nephropathy: casts and crystals composed of filtered monoclonal Ig and other urinary proteins obstruct distal renal tubules, often precipitously, and typically incite an accompanying tubulointerstitial nephritis. Hypercalcemia, sepsis, vol depletion worsens this. Subtype of myeloma commonly associated Ig D myeloma
3. Monoclonal Ig G deposition disease ( may present with microscopic hematuria, elevated BP)intact or fragmented light chains, heavy chains, or both deposit along glomerular and/or tubular basement membranes
Pearls: Ig A myeloma has been described with Henoch Schonlein purpura ( HSP) although this is rare.
Ig-independent mechanisms:
- volume depletion
- sepsis
- pyelonephritis
- hypercalcemia, uric acid nephropathy, rhabdomyolysis
- direct renal parenchymal invasion by plasma cells
- Drugs:nonsteroidal anti-inflammatory drugs, and renin-angiotensin system inhibitors , zoledronic acid and pamidronate.
What is the commonest cause of renal injury? ANS:ATN due to light chains
Light chain myeloma ( 20% of all myeloma) 40-60% with renal injury
Ig D -100% develop renal injury
Reference: Blood journal 2010
No comments:
Post a Comment