Myeloma Nurse Learning Programme Module 3 – Diagnosis of myeloma Renal impairment

Renal impairment

Kidney damage is a common and potentially serious complication of myeloma which can result in kidney failure.

At diagnosis, up to 20% of patients present with acute renal failure (eGFR < 15(%) renal function). Of these, around 10% of patients require dialysis. Renal impairment can also evolve over time with an estimated further 40% developing renal failure during the course of their myeloma.

The signs and symptoms of kidney damage include:

Reduced urine output or frothy urine
Fatigue
Swollen ankles/feet
Shortness of breath
Headache, thirst or nausea

The most common cause of kidney damage is myeloma kidney disease or cast nephropathy. This occurs when excessive free light chains deposit in the distal tubules, blocking affected tubules and obstructing the flow of urine. The free light chains are also directly toxic to the proximal renal tubules, causing interstitial inflammation and fibrosis and further adding to renal impairment.

Other factors that may also contribute to renal damage include:

Dehydration
Hypercalcaemia
Urinary tract infection and sepsis
Exposure to nephrotoxic drugs e.g. non-steroidal anti-inflammatory drugs (NSAIDS), antibiotics and contrast media
Co-morbidities including diabetes, hypertension, congestive heart failure
Plasma cell infiltration, amyloid or light chain deposition disease

Watch the following animation that explains what the causes of kidney damage are in myeloma patients and how they affect kidney function.

Myeloma patients can become dehydrated for a variety of reasons, including: anorexia, nausea, vomiting, analgesic use or if they are hypercalcaemic. Renal impairment itself also reduces the ability of the kidneys to reabsorb water, thus contributing to dehydration.

Patients with newly diagnosed myeloma who have myeloma-induced acute kidney disease usually receive immediate treatment with a dexamethasone and bortezomib based regimen. Further damage can be minimised by ensuring patients keep well hydrated (drinking two to three litres of water/fluid per day is usually recommended). If treatment is started early, is effective against the myeloma, and reduces light chain production, then kidney function can often be restored. The recommended daily fluid intake may be different if the patient already has kidney damage.

There are also other ways in which excessive light chains can damage the kidneys. One of these is known as light chain deposition disease (LCDD) caused by light chains being deposited in the kidney glomeruli. This condition is typically treated in the same way as myeloma kidney disease i.e. with bortezomib and dexamethasone.

Nurses have an important role in educating patients and families about the importance of drinking at least two to three litres of fluid daily to maintain renal health and to explore the type of fluids that individuals feel comfortable taking. Instructions should also include showing what a litre of fluid is, using examples.

If the patient is admitted to an inpatient ward, it is important that fluid balance charts are correctly updated to allow any early signs of dehydration to be identified and treated accordingly. This is often done by support staff under the guidance of the nursing and medical team.

Renal impairment

Further reading