In the early stages, multiple myeloma may not cause any symptoms or complications, and may only be diagnosed after a routine blood or urine test.
However, it will eventually cause a wide range of problems, some of which are outlined below.
Multiple myeloma can cause pain in affected bones, most often the back, ribs or hips. The pain is frequently a persistent dull ache, which may be made worse by movement.
Bone fractures and spinal cord compression
Multiple myeloma can weaken the bones and make them more likely to break (fracture). The spine and ribs are most often affected.
Fractures of the spine can cause the sections of the spine to collapse, leading to pain and occasionally compression of the spinal cord (the main column of nerves running down the back).
Compression of the spinal cord can cause pins and needles, numbness and weakness in the legs and feet, and sometimes problems controlling your bladder and bowels.
Multiple myeloma can affect the production of blood cells in our bone marrow, which can lead to a lack of red blood cells (anaemia). This can also occur as a side effect of myeloma treatment.
If you have anaemia, you may feel very tired, weak and breathless.
People with multiple myeloma are particularly vulnerable to infection because the condition interferes with the immune system (the body's natural defence against infection and illness).
You may find you get infections frequently and that they last for a long time.
Raised calcium levels in the blood
A high level of calcium in the blood (hypercalcaemia) can develop in people with multiple myeloma because too much calcium is released from affected bones into the bloodstream.
Symptoms of hypercalcaemia can include extreme thirst, feeling sick, needing to urinate frequently, constipation, confusion and drowsiness.
Bruising and unusual bleeding (haemorrhage) – such as frequent nosebleeds, bleeding gums and heavy periods – sometimes occurs in multiple myeloma because the cancer cells in your bone marrow can stop blood clotting cells called platelets being made.
In some people, multiple myeloma can cause the blood to become thicker than normal. This is known as hyperviscosity, which can cause problems such as blurred vision, headaches, dizziness, bleeding from the gums or nose, and shortness of breath.
Kidney damage can occur in people with multiple myeloma for several reasons. Abnormal proteins produced by the cancer cells can damage the kidneys, as can other complications, such as hypercalcaemia. Some medications used to treat multiple myeloma can also cause kidney damage.
Eventually, the kidneys may stop working properly. This is known as kidney or renal impairment, or kidney or renal failure. Signs of kidney failure can include:
- weight loss and poor appetite
- swollen ankles, feet or hands
- tiredness and a lack of energy
- shortness of breath
- itchy skin
- feeling sick
When to seek medical advice
You should see your GP if you have symptoms of multiple myeloma. While they're unlikely to be caused by cancer, it's best to be sure by getting a proper diagnosis.
You should seek immediate medical help if you have symptoms of spinal cord compression, hypercalcaemia or kidney failure, as these are medical emergencies that need to be investigated and treated as soon as possible.
Read more about diagnosing multiple myeloma and treating multiple myeloma.