Six little-known warning signs of multiple myeloma after death of Max Payne actor James McCaffery

James McCaffrey, an American actor best known for voicing video game character Max Payne, has died after battling blood cancer.

The 65-year-old star was reportedly diagnosed with multiple myeloma, a type that develops from plasma cells in the bone marrow – the 'spongy' substance that lurks in the bones.

According to charities, there are around 6,000 new cases of myeloma in Britain every year, while in the US more than 35,000 cases are diagnosed each year.

Here we discuss the warning signs of multiple myeloma.

Bone pain

Like other types of cancer, multiple myeloma may not cause symptoms in the earliest stages of the disease.

In fact, doctors sometimes only suspect a patient has the disease after an abnormal blood or urine test, the NHS says.

But eventually the cancer can cause a wide range of problems, including persistent bone pain.

Dull pain is usually felt in the back, ribs or hips.

The pain is caused by a large number of plasma cells collecting in one area, which can damage bones and even cause fractures, says Cancer Research UK.

In some cases affecting the spine, it can cause tingling and numbness.

Fatigue

Although it sounds like a cold, being extremely tired, weak, and out of breath is another potential warning sign of myeloma.

Fatigue is caused by a shortage of red blood cells.

As with bone pain, this is caused by the exceptional accumulation of plasma cells in the bone marrow, which effectively crowds out 'normal' red blood cells.

Extreme thirst

Constantly feeling thirsty can also be a sign of the disease.

In addition to crowding out 'normal' blood cells, the buildup of abnormal plasma cells can directly damage bones.

When bones become damaged, they release calcium into the blood – medically known as hypercalcemia.

Symptoms of this include feeling thirsty, sick, tired, stomach ache and frequent urination, according to the NHS.

Additionally, it can cause constipation and confusion and, if left untreated, lead to extreme drowsiness.

Blurry sight

In addition to all of the above, endless headaches, dizziness, and blurred vision can all be subtle signs of multiple myeloma.

The NHS says this trifecta is due to the cancer cells producing excess proteins that cause the blood to thicken, known as hyperviscosity.

When the blood becomes too thick, it cannot flow freely through the body's blood vessels, which can block the very thin channels in the brain and cause the symptoms.

Bruising and unusual bleeding

Warning signs of myeloma can also include strange bruising and unusual bleeding, such as nosebleeds, bleeding gums and even heavy periods.

Abnormal bruising and excessive bleeding can occur due to the buildup of plasma cells in the bone marrow.

Similar to the way they crowd out red blood cells, the overproduction of plasma can stop platelet production, according to Cancer Research UK.

Platelets work by clumping together to form a clot to stop bleeding. If there are fewer of them, the chance of bruising and bleeding is greater.

But CRUK says this symptom is 'quite rare' for myeloma.

Repeated infections

Suffering from frequent viral or bacterial infections can be another warning sign.

That's because the cancer causes an overproduction of cancerous plasma cells and abnormal antibodies, which cannot work in the normal way to prevent infections.

Plasma cells are an essential part of the body's immune system.

Normal, healthy plasma cells produce antibodies that fight viruses and bacteria.

In addition, the excess plasma cells overcrowd the bone marrow, leaving not enough room for the production of normal white blood cells, which are also part of the body's defense system against insects.