Bone health in multiple myeloma
Dr Garrick Laudin explains the effects of multiple myeloma on bone health and the treatments needed to preserve the bones.
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What is multiple myeloma?
Multiple myeloma is a cancer of the plasma cell. The plasma cell is the fundamental soldier cell in the immune system, which under normal circumstances produces immunoglobulins (protein molecules) that fight a variety of infections. In myeloma, this soldier cell is no longer under orderly control of the immune system and it undergoes disordered proliferation (growth).
What are the symptoms of multiple myeloma?
The fundamental symptoms are bone pain with brittle bones that are easily broken under minimal stress. In certain cases, the vertebra (bones of the spine) may break (fracture), resulting in compression of the spinal cord producing paraplegia and paresthesias (weakness and altered sensation in the legs). The collapse of the vertebrae, which can be seen as the building blocks of the spine, may cause the spine to adopt an abnormal curvature (kyphosis) or result in the eventual loss of height.
What investigations are undertaken to examine for bone disease?
Basic investigations like plain X-rays of the spine together with more specialised scans like CT and MRI scans are undertaken. These specialised scans are able to detect the smallest of breaks in the bone, with the MRI able to detect fractures that are half the size of a cm (5mm).
How is multiple myeloma treated?
Treatment options are two-fold and include supportive and specific measures. The specific measures involve chemotherapy or immunotherapy (tablets and/or injections) that target and kill the cancerous myeloma cells.
In certain healthy and physically fit patients, a stem cell transplant may also be an option.
The supportive measures are important adjuncts to definitive therapy and include medications (bisphosphonates), radiation, surgery and input from various allied healthcare practitioners (physical and occupational therapists, biokineticists and dietitians).
This group of drugs is vital in maintaining bone health in multiple myeloma as they prevent osteolysis (breakdown of bone) by the osteoclasts (specialised bone remodelling cells) that reside within the bones. The mechanism of action of the osteoclasts and how they interact with the myeloma cancer cells, may be likened to the classic computer game Pac-Man.
The myeloma cancer cells cause the osteoclasts (Pac-Man) to breakdown the bones of the skeleton thereby releasing calcium, an essential building block of bone. The bisphosphonates prevent and slow down the breakdown of bone by the osteoclasts thereby reducing pain, normalising the high calcium levels in the blood and decreasing the chances of fractured bones in the future.
It’s best to consult a dentist prior to starting bisphosphonates as this group of drugs may have some adverse effects on the bones of the jaw.
Radiation is another useful way to manage the skeletal complications of myeloma. It directs high-energy waves to a specific part of the bone resulting in damage to the plasma cells, preventing their replication and further damage of your bone.
Radiation may also be used in emergency cases to relieve pressure on the spinal cord when a plasmacytoma (mass of plasma cells) or vertebral fracture compresses on the spinal cord. When spinal cord compression causes paralysis (severe muscle weakness) or paraesthesia (numbness), emergency surgery may be needed to stabilise the bones of the spinal column.
Fundamental to the management of bone pain is adequate pain medication (analgesia). The management of pain is different for each patient and will be tailored to the level of pain you experience. Some over-the-counter pain medications (non-steroidal anti-inflammatory drugs) may cause or even worsen renal dysfunction (kidney failure) and are best avoided.
Your allied medical team of physical therapists and biokineticists will assist you in the prescription of a tailored exercise plan. Certain exercises like Tai chi and yoga will improve your balance while other non-weight bearing exercises (swimming) will aid in improving muscle strength.
Physical and occupational therapists (OT) may provide you with orthopaedic devices (crutches, walking frames, wheelchairs) to assist in your mobility. OTs will also assist in the assessment of your home and work environment to address and modify hazards that may contribute to falls.
Preserving bone health in myeloma may also be achieved by maintaining a healthy diet, limiting alcohol consumption and the cessation of cigarette smoking.
MEET THE EXPERT – Dr Garrick Laudin
Dr Garrick Laudin is a specialist physician and clinical haematologist affiliated with the University of the Witwatersrand, who currently practices at Chris Hani Baragwanath Academic Hospital. His special interests are the hyperinflammatory syndromes associated with haematological malignancies, the haemolytic anaemias and bone marrow failure syndromes.
This article is sponsored by Adcock Ingram in the interest of education, awareness and support. The content and opinions expressed are entirely the doctor’s own work and not influenced by Adcock Ingram in any way.
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