Has your doctor mentioned bone marrow failure during appointments for your paroxysmal nocturnal hemoglobinuria (PNH)? They may be referring to a disorder known as aplastic anemia. Acquired aplastic anemia is a type of bone marrow failure closely related to PNH. Keep reading to learn six facts about acquired aplastic anemia and PNH.

1. Your Bone Marrow Can’t Make Enough Blood Cells

Acquired aplastic anemia is one of two bone marrow failure syndromes that can happen along with PNH. Bone marrow is a tissue in the middle of your bones that makes all types of blood cells: red blood cells, white blood cells, and platelets.

Immature cells in the bone marrow are simple cells that can turn into any type of blood cell the body needs. These special cells are nearly or completely missing in people with aplastic anemia. Without these cells, your body has low blood counts for all blood cell types, a condition doctors call “pancytopenia.”

Scientists think that aplastic anemia is an autoimmune disorder. In autoimmune disorders, your immune system mistakenly attacks your cells or tissues. There are many different types of autoimmune disorders. If you have aplastic anemia, white blood cells called lymphocytes attack immature blood cells in your bone marrow. Nobody knows why your immune system starts to act out of control.

More frequently, aplastic anemia can develop due to a lack of important nutrients, certain drugs, and viral infections. In rare cases, aplastic anemia can be caused by a genetic disorder like Fanconi anemia, an uncommon condition that prevents your bone marrow from making enough new blood cells for your body to work normally.

2. You May Bleed Easily or Feel Weak or Dizzy

People with mild cases of aplastic anemia might not have any symptoms. When symptoms do occur, they come from having low levels of blood cells. You might feel tired, dizzy, or weak and suffer from headaches due to anemia (low red blood cells).

If you have too few white blood cells, your immune system is weakened, and you’re at a higher risk of infection. Let your doctor know if you’re having frequent or repeated illnesses. It may be a sign of low white blood cell counts.

If you get a cut or have your period, you might bleed a lot more than normal. You also may have spontaneous bleeds from your nose or gums or bruise easily. These symptoms are caused by low levels of platelets, the blood cell fragments that help your blood clot.

The symptoms of aplastic anemia vary based on which blood cells are low. On the other hand, PNH typically has three main symptoms: the breakdown of red blood cells, a drop in all types of blood cells, and a higher risk of getting blood clots.

3. Aplastic Anemia and PNH Are Closely Related

Aplastic anemia and PNH are closely related and have a lot of similarities. Both conditions are considered autoimmune disorders. They both result in low blood cell counts. With PNH, red blood cells are attacked and destroyed by part of the immune system called the complement system in a process known as hemolysis. With aplastic anemia, low levels of all blood cells result from autoimmune attacks on bone marrow cells.

Scientists are still trying to understand the relationship between the two conditions. But one thing seems clear: Aplastic anemia can lead to PNH. The Aplastic Anemia and MDS International Foundation reports that more than 10 percent of people with aplastic anemia will develop PNH. In fact, the only known risk factor for developing PNH is having aplastic anemia. People with aplastic anemia who have a mutation (change) in the PIGA gene of their bone marrow cells are likely to develop PNH.

The opposite also seems true: PNH can lead to aplastic anemia. Some hematology research shows that about half of people diagnosed with aplastic anemia already have PNH at the time of diagnosis. Many people with PNH may not realize they have it because they experience no symptoms.

Both aplastic anemia and PNH can also lead to another type of bone marrow failure called myelodysplastic syndrome (MDS). As scientists learn more about how these disorders are connected, we’ll be able to understand the risk factors better.

4. Diagnosis Requires a Bone Marrow Biopsy

Your doctor might suspect you have aplastic anemia after a regular blood test if all three blood cell types are low. Although it’s common in PNH for red cells to be low, pancytopenia may be a sign of bone marrow failure.

To diagnose aplastic anemia, your doctor may need to take a small piece of bone marrow from your hip bone, called a bone marrow biopsy. They’ll then be able to look at the tissue under a microscope and count the cells.

Very low amounts of bone marrow cells point to bone marrow failure. Your doctors will also want to rule out similar diseases like leukemia, MDS, and Fanconi’s anemia.

Many symptoms of aplastic anemia overlap with those of PNH, such as fatigue, headaches, and dizziness. This can make it hard to tell if you’ve developed a new disorder. Stay in touch with your doctor about new or worsening symptoms, and attend all recommended follow-up appointments.

Abnormal blood test results can be the first clue that bone marrow isn’t working properly. To diagnose PNH, doctors use a special test called flow cytometry. This test checks for certain proteins that are missing from the surface of blood cells, a key sign of PNH.

5. Aplastic Anemia Can Be Life-Threatening Unless Treated

Aplastic anemia can be life-threatening without treatment. You’ll be at a higher risk of serious infections, bleeding, and heart failure. Aplastic anemia can also lead to leukemia.

The discovery of a new type of medication has dramatically improved the life expectancy of people with PNH. Complement inhibitors like eculizumab (Soliris) and iptacopan (Fabhalta) may prevent or reduce hemolysis by interfering with complement proteins. Now, people with PNH who receive treatment can expect to live just as long as those without PNH. Unfortunately, complement inhibitors don’t improve bone marrow failure in aplastic anemia.

Despite the risks, the outlook for people with both PNH and aplastic anemia has improved with the advances in treatment in recent years. Most people with PNH and aplastic anemia who receive treatment can live a long time, and clinical trials are underway to improve treatment options.

6. Bone Marrow Transplant May Be Recommended

If you have severe aplastic anemia, your doctor will likely recommend an allogeneic bone marrow transplant. This is a procedure in which healthy marrow from a donor is put into your body, allowing it to begin creating new blood cells. Before the transplant, your faulty bone marrow cells will be destroyed with chemotherapy.

You’ll need a bone marrow donor, ideally a sibling or close family member. If no match is available in your family, a bone marrow registry can help identify someone else who has similar blood characteristics to yours. People with PNH who undergo bone marrow transplants have a good chance of living a long time after the procedure.

Not everyone is eligible for a bone marrow transplant. If you’re over the age of 70 or have lung, heart, kidney, or liver disease, your doctor might not recommend a transplant. It may also be difficult to find a suitable donor.

In these cases, aplastic anemia can be treated with medications that reduce the immune system’s attacks on the bone marrow. These drugs are called immunosuppressants. The most common types are anti-thymocyte globulin and cyclosporine. Immunosuppressants can help people recover, but aplastic anemia can return, and it may lead to PNH even if you didn’t have it before.

Complement inhibitors are not effective at treating bone marrow failure. However, people with aplastic anemia and PNH can take complement inhibitors to treat hemolysis. Still, the best option for treating aplastic anemia is often a bone marrow transplant, for those who are eligible and for whom a suitable donor is available.

If you’ve been diagnosed with aplastic anemia or PNH, understanding the link between these two conditions is crucial. Knowing about aplastic anemia can guide you in making informed health decisions, especially if your doctor talks about bone marrow failure or PNH. As researchers learn more, the connection between these conditions becomes clearer, improving the options for treatment. Spotting symptoms early and discussing them with your doctor can help speed up your diagnosis and lead to better results from treatment.

Talk With Others Who Understand

On myPNHteam, the social network for people with paroxysmal nocturnal hemoglobinuria and their loved ones, members come together to ask questions, give advice, and share their stories with others who understand life with PNH.

Have you been diagnosed with acquired aplastic anemia as well as PNH? Do you have advice for those who have been recently diagnosed with both? Share your experience in the comments below, or start a conversation by posting on your Activities page.