Paroxysmal nocturnal hemoglobinuria (PNH) gets its long name from one particular symptom — dark urine you might notice during nighttime or early morning bathroom trips. However, a wide variety of symptoms can occur with this rare form of hemolytic, or red blood cell-destroying, anemia.

Red blood cells contain hemoglobin, a protein that carries vital oxygen for your body’s processes. When hemolysis (premature destruction) causes red blood cells to break apart, hemoglobin is lost, and tissues and organs can’t get enough oxygen. The lack of hemoglobin and resulting oxygen shortage lead to PNH symptoms and, sometimes, life-threatening complications.

Here, we’ll describe several of the common but varied symptoms of anemia with PNH.

1. Dark Urine

Hemoglobin is red, and a hemoglobin buildup caused by hemolysis can make urine appear darker or reddish. Although the breakdown of red blood cells is an ongoing process in hemolytic anemia, you may be more likely to notice darker urine in the morning after a long night’s sleep, when urine is most concentrated. Symptoms may also be more obvious when you have an infection or high stress levels.

2. Shortness of Breath

Shortness of breath in PNH can occur for two reasons. First, hemolysis lowers your red blood cell levels, known as anemia. Your lungs try to compensate for the lack of oxygen-carrying red blood cells, making you feel short of breath.

Second, hemolysis can increase the risk of blood clots, especially in the veins. Blood clots affect 15 percent to 30 percent of people with PNH and can lead to different symptoms throughout the body. When blood clots reduce circulation to the lungs, you may feel short of breath or have trouble breathing. These clots can be detected by imaging tests, such as a CT scan of the chest.

On myPNHteam, members discuss how breathing issues affect everyday life. “One of my strange symptoms is that when I sit to read or watch TV, I get bouts of breathlessness and start gasping. But when I go for a morning jog or do my daily exercises and weight training, I do not get breathless,” said one member, adding that taking deep breaths while doing relaxing activities seems to help.

Getting support from others who can relate to what you’re going through can make it easier to identify your own symptoms so that you feel less alone. They can also help you feel better prepared to talk to your doctor about your symptoms and treatment options.

3. Liver Problems

Blood clots associated with hemolytic anemia can also affect circulation to the liver. People with PNH are more prone to a rare disease called Budd-Chiari syndrome, in which the veins of the liver become narrow or blocked. Symptoms include an enlarged liver, pain in the upper right abdomen, a swollen belly, jaundice (yellowish eyes and skin), nausea, vomiting, and an enlarged spleen.

4. Erectile Dysfunction

Men with PNH can experience severe complications ranging from erectile dysfunction to infertility. Hemolysis decreases blood levels of nitric oxide, a compound in the body that plays a key role in erections. If you notice changes during sex or have trouble conceiving a child with your partner, don’t hesitate to tell your doctor. Discussing these concerns can help uncover other underlying issues that could benefit from treatment.

5. Chest Pain

A shortage of oxygen from anemia and PNH can result in chest pain. The pain or tightness may get worse in certain situations, such as when flying or at a higher elevation than usual. If you have a trip coming up, talk to your doctor about getting a red blood cell count before you leave home. Depending on your levels, they may recommend a blood transfusion or growth factors to help avoid problems. Drinking plenty of water and walking around during long flights, if possible, can also help.

PNH may cause other types of pain, including abdominal pain.

6. Unusually Pale Skin

Skin tones vary among people and even on your own body because of various factors, such as if you have a tan. However, skin that turns pale for no known cause may be a sign of anemia. People of all races can develop a paler or dulled skin color. If your skin takes on a different tone, consider asking your doctor if you should be tested for anemia.

7. Fatigue

Lack of hemoglobin leaves your body’s organs starved for oxygen. As a result, anemia causes tiredness that doesn’t resolve even if you’ve slept well. In addition to feeling tired physically, you may have trouble concentrating, making it difficult to work and manage household tasks.

Discussing all your symptoms with your health care provider can help you choose a treatment plan to improve your quality of life with PNH. It may involve PNH treatments and supplements such as folic acid and iron. You can also discuss lifestyle changes to help you feel your best, such as eating more iron-rich foods.

8. Restless Legs Syndrome

Low iron or hemoglobin levels affect the function of the nervous system. One potential side effect is restless legs syndrome — involuntary leg movements during sleep or while falling asleep. This nervous disorder can also cause aching or unpleasant sensations in the calf muscles, thighs, and feet. If the symptoms keep you from sleeping well, restless legs syndrome can contribute to fatigue related to anemia. Treating the underlying anemia may help.

Could Aplastic Anemia Be Involved?

Another type of anemia, known as aplastic anemia, sometimes occurs alongside PNH. Aplastic anemia is a bone marrow disorder that affects the production of all types of blood cells. The symptoms are similar to those of hemolytic anemia, including fatigue.

Both types of anemia can also make you more vulnerable to infections. However, aplastic anemia affects the immune system’s white blood cells and platelet formation in addition to red blood cells. People with aplastic anemia and bone marrow failure tend to bleed and bruise more easily and have trouble with normal blood clotting.

Fortunately, once your doctor determines the underlying cause of anemia, you can start treatment to reduce your symptoms and feel better. Blood tests, like a complete blood count, will show which types of blood cells are low. If red blood cells, white blood cells, and platelets are all abnormal, a bone marrow biopsy (using a needle to remove a sample of bone marrow for examination in a lab) can help confirm whether you have aplastic anemia.

Blood transfusions and growth factors can help ease the symptoms of aplastic anemia and hemolytic anemia. To cure aplastic anemia, you may be eligible to undergo a bone marrow transplant. However, not everyone is a good candidate for this procedure, and it can be difficult to find a suitable donor. When stem cell transplants aren’t an option, your doctor may consider immunosuppressants or other medications.

Always tell your doctor about any new PNH symptoms, and periodically weigh the benefits and risks of different treatment options. If your health condition changes, you may be eligible for new or different therapies.

Talk With Others Who Understand

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

Which symptoms of anemia affect your life the most? Have you found effective treatments? Share your experience in the comments below, or start a conversation by posting on your Activities page.