Renal damage associated with multiple myeloma

Renal damage is a common and potentially serious complication of myeloma:

• around 20-25% of patients with multiple myeloma presents with renal impairment while 50% of patients will have it sometime during their illness
• reversal of renal impairment can be achieved in around 50% of the patients but the remaining patients will have some degree of renal insufficiency out of which 2-12% will require renal replacement therapy (1)

The principle mechanism for the renal damage associated with multiple myeloma is the damage caused to renal tubules by free light chains (cast nephropathy, or “myeloma kidney”)

• the risk of renal damage is directly proportionate to the level of urinary free light chain excretion
• it is not associated with light chain class or the presence or absence of whole M-proteins
• around 2% of patients without urinary free light chain have renal insufficiency while this figure increases to 50% with higher levels of urinary free light chain excretion (1)

Other possible pathogenic mechanisms include:

• haemodynamic factors may cause ischaemic renal damage especially in the elderly
• hypercalcaemia
• hyperuricaemia
• amyloidosis
• ureteric obstruction

Reference:

• (1) Bird JM et al. Guidelines for the diagnosis and management of multiple myeloma 2011. Br J Haematol. 2011;154(1):32-75.