I am feeling confused

The language of haematologists is complex. Knowing the lingo can help you find your way in the strange land of MPDs.

When you first learn you have an myeloproliferative disorder, it can be overwhelming to grapple with a new diagnosis. You might find it difficult to understand what your doctor is telling you, or to grasp what you are reading. Even very educated people can find haematological terms baffling. We’ll try to explain terms and concepts as we go, plus you can also find a list of terms in our glossary. Please email us at info@mpdvoice.org.uk if you discover any more that we need to add!

Answers to basic questions

What is blood, exactly?

Sounds like a silly question, because we all know that blood is that red fluid that travels around the body, but in fact blood is a complex substance. Blood has many functions, including heat regulation, keeping us healthy by fighting infection and supplying every cell in the body with energy. Blood is made from a watery fluid called plasma. Floating in the plasma are several types of blood cells including red blood cells, white blood cells and platelets.

What do blood cells do?

Red blood cells carry oxygen throughout the body
Platelets (the name sounds like “little plates”) are flat cells that stack and stick together to heal cuts or wounds
White blood cells are fighter cells – they work to fight infections in our bodies

Where do blood cells come from?

Our bodies make blood cells inside our bones. The marrow in our bones is like a factory that manufactures blood cells. Special cells called “stem cells” (they’re also called “progenitor cells”) live inside the marrow. These cells grow into the cells that travel through our blood, called red cells, white cells and platelets. When the blood cells are mature, they pass right through our bone and into the bloodstream and start traveling through our blood vessels to do their jobs all around the body.

What are MPDs?

Myeloproliferative disorders (MPDs) are a family of disorders. The most common types of MPDs are essential thombocythaemia (ET), polycythaemia vera (PV) and myelofibrosis (MF). Sometimes people start with one type of MPD and it turns into another type over time. People can also be diagnosed with one MPD but still have some attributes of another MPD.

Do people with MPDs have more risks than other people?

People with MPDs have a higher risk than other people of developing blood clots in places in the body where these clots can cause harm.

Why is it bad to have too many blood cells?

People with essential thrombocythaemia can have too many platelets, and people with polycythaemia vera can have too many red blood cells. Having too many blood cells clogs up our arteries and veins. Sometimes the cells stick together to form a clot inside an artery or vein, and this can lead to problems.

What happens if I don’t have enough blood cells?

People with myelofibrosis (MF) don’t have enough blood cells. This is because the blood cell-making factory in their bone marrow is filled up with fibrous material (in other words, rubbish) and the blood cells don’t have enough space to grow. Blood cells deliver oxygen to your body, fight infections and repair any injuries or damage. Your body has a hard time doing these tasks when you have myelofibrosis.

What is blood “stickiness”?

When you cut your finger, platelets stick together to close the cut – the platelets form a clot to stop the body from continuing to bleed after an injury. Doctors sometimes refer to platelets and to other blood cells as being “sticky” – this is because the job of platelets is to stick to other platelets and form clots. Clots are useful because they stop bleeding but they can be a serious problem if they occur in the wrong places and at the wrong times.

Which kinds of clots can be a problem?

There are two types of blood vessels: arteries that carry blood from the heart to the body, and veins that carry blood from the body back to the heart. Blood clots can occur in either type of blood vessel.

Arterial clots A clot in an artery is called an arterial clot
Venous clots A clot in a vein is called a venous clot

Any clot in a blood vessel can potentially be a problem because the clot is like a road block – blood cells cars whizzing down the road can run straight into the road block and then can’t reach their destinations further down the road. If a clot forms a block in the heart, it can cause a heart attack. If a clot blocks blood flow in the brain, it can result in a mini-stroke (TIA) or a stroke.

What does it mean to be at risk?

Having ET or PV increases your risk of experiencing a blood clot such as a heart attack or stroke. (Myelofibrosis is a little different.) There are several different ways to think about risk:

Risk over time: Your short-term versus long-term risk
Amount of risk: Whether your risks are high, medium or low

Your risk can be low, medium or high depending on how old you are, how healthy you are, and whether you have any other medical problems. If you are young and generally healthy, you might not need to take any medications for your MPD, other than possibly low-dose aspirin. People who are older or have other health issues can have higher risks of developing a clot and they need more medication to control their blood counts. One question to ask your haematologist is whether you are a low-risk, medium-risk or high-risk patient. (You know you can’t diagnose yourself with a website, so please check with your haematologist to get the right advice for you.)

People with MPDs also have risks over time. You might feel concerned about taking medications such as hydroxycarbamide that may (or may not) pose risks when taken over a long period of time. Your haematologist will balance this long-term risk with your short-term risk. Young people with MPDs who are taking medications may face more long-term risk, because they will be taking the medication for a very long time.

Still have questions?

Please have a look at our About MPDs section, or email us at info@mpdvoice.org.uk

Even very educated people can feel baffled by what their doctor says.