We all experience aches and pains every now and then — but for people living with paroxysmal nocturnal hemoglobinuria (PNH), certain types of pain may be more frequent or severe.

Keep reading to learn more about the different types of pain that PNH may cause, and how. We’ll also cover when it’s a good idea to talk to your doctor and when your pain is a sign to seek treatment.

What Is PNH?

To better understand what types of pain PNH causes and why, it helps to first understand what causes this disease. Your red blood cells (RBCs) use the protein hemoglobin to carry oxygen throughout your body. They have a specific gene known as the PIGA gene, which helps protect your RBCs from being destroyed by your immune system.

PNH is a rare disease in which mutations in the PIGA gene change the protective protein so that it no longer works. As a result, the complement system (a part of your immune system) begins attacking your RBCs. This complement activation destroys or breaks down your blood cells — a process known as hemolysis.

The broken-down blood cells can no longer carry oxygen. They also release hemoglobin into your bloodstream, which your body filters out in your urine at nighttime and early in the morning. Too much hemolysis leads to hemolytic anemia (low RBC count), which is responsible for causing most PNH symptoms.

Your bone marrow (the spongy tissue that fills your bones) is responsible for making new RBCs, white blood cells (WBCs), and platelets. As PNH progresses in some people, they develop bone marrow failure. This means that your bone marrow works hard trying to make more blood cells — but unfortunately it can’t keep up.

PNH and Blood Clots

PNH also puts you at increased risk of blood clots, especially in the veins or blood vessels that carry oxygen from your organs back to your heart. A blood clot in a vein is known as venous thrombosis. This condition can become life-threatening if a blood clot blocks blood flow to vital organs like the brain or lungs.

Here are six types of pain caused by PNH, blood clots, and other related conditions.

1. Headaches

Anemia (low RBC count) is responsible for many common PNH symptoms, which may include headaches. These can occur when a person doesn’t have enough oxygen in their bloodstream to supply their brain. Headaches caused by anemia can sometimes be accompanied by dizziness, light-headedness, or fatigue.

Blood clots can also block blood flow to the brain. They can get stuck in the cerebral veins that move blood from the brain to the heart, causing severe headaches. In some cases, this can also cause an ischemic stroke, a serious condition in which oxygen to the brain is cut off and brain cells begin dying.

An ischemic stroke is a medical emergency — if you notice the sudden appearance of a severe headache or any of the following symptoms, seek medical attention immediately:

• Weakness or numbness along one side of your body or face
• Vision problems in one or both eyes
• Slurring of speech
• Confusion or trouble understanding others
• Loss of coordination or balance, or trouble walking

2. Muscle Spasms in the Esophagus

Broken-down RBCs release hemoglobin into your bloodstream. Normally, the body has systems in place to help clear out the extra protein. When you’re living with PNH, these systems can’t keep up and become overwhelmed. Free hemoglobin builds up in your bloodstream and attaches to nitric oxide, a chemical that helps your muscles relax.

When there’s less nitric oxide in your bloodstream, your muscles can contract or tighten uncontrollably and cause spasms. Many people with PNH report muscle spasms in their esophagus (the tube that connects the mouth and stomach). Esophageal spasms can cause intense, squeezing chest pain that feels like a heart attack. They also make it hard to swallow food, so you feel like there’s something stuck in your throat.

3. Abdominal Pain

Have you noticed any new abdominal or stomach pain lately? Your PNH may be to blame. In fact, around one-third of people with PNH report they have abdominal pain when they’re diagnosed. Muscle spasms can also affect your stomach and intestines — you may feel cramping or pain along the front and sides of your abdomen.

Blood clots can become stuck in blood vessels throughout your body, including the abdomen. They block blood flow to the stomach and liver, leading to abdominal pain. If you have a blood clot affecting your stomach, you may have sharp pain or feel bloated. Blood clots in the liver can also cause abdominal pain and jaundice (yellowing of your skin and eyes).

Some people with PNH develop Budd-Chiari syndrome, a condition in which blood clots block veins in the liver. Symptoms of Budd-Chiari syndrome include:

• Enlarged liver and/or spleen
• Upper abdominal pain on the right side
• Nausea and vomiting

4. Chest Pain

Chest pain can be alarming. While most people associate this symptom with a heart attack, it may also be a symptom of PNH. Without enough oxygen in your bloodstream, it’s easy to become short of breath and experience chest pain.

Blood clots can become stuck in the arteries that carry blood from your heart to your lungs — this is known as a pulmonary embolism. These blood clots may form in your legs and travel up to your lungs.

Symptoms of a pulmonary embolism include:

• Sharp chest pain that comes on suddenly
• Dyspnea (shortness of breath) that worsens with movement
• Dizziness
• Breathing problems
• Palpitations (racing heartbeat)
• Pain or swelling in your legs

Left untreated, blood clots in the lungs can lead to serious complications, including fluid buildup in your lungs or a heart attack. Call your doctor or seek medical attention immediately if you start to experience chest pain and any other symptoms of a pulmonary embolism.

5. Joint Pain

In rare cases of PNH, inflammation produced by your immune system can damage your joints and other organs and tissues. Your immune system normally uses inflammation to help activate immune cells and kill bacteria and viruses. When there isn’t an infection in your body, inflammation can do more harm than good.

Certain types of PNH can cause joint pain. You may notice your joints are swollen or stiff or that they make grinding or clicking noises when you move. Talk to your doctor about any new joint pain — it may be related to your PNH, or it could be due to an injury or another condition like arthritis.

6. Back or Flank Pain

In some cases, PNH can also affect your kidneys. Blood clots may become stuck in your kidneys’ blood vessels, leading to chronic kidney disease. Your kidneys are responsible for filtering out extra water and waste from your body. When they can’t function properly, it can lead to symptoms like:

• Shortness of breath
• Chest pain
• Flank pain (pain along your abdomen and into your back)
• Muscle cramps

You should talk to your doctor if you notice that you’re also making significantly more or less urine, you have swelling in your feet or legs, or if you’re feeling more nauseous than usual. They may run some tests to check your kidney function.

When To Seek Treatment for Your PNH Pain

If you’re experiencing new or worsening pain, talk to your doctor. They can help you find new or better ways to manage your pain or change your PNH treatment plan. In studies, complement inhibitors like the antibody drug eculizumab (Soliris) have been shown to treat PNH symptoms and reduce the risk of blood clots. A blood transfusion (receiving blood from a healthy donor) may help ease some of your symptoms and improve your quality of life. A health care provider may also prescribe anticoagulation drugs (blood thinners).

If you’re experiencing chest pain or any other signs of blood clots, seek medical attention immediately. Studies show that blood clots are the most common cause of death in people with PNH.

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.

What types of pain have you experienced living with PNH? Do you have tips for how to manage it? Share your experience in the comments below, or start a conversation by posting on your Activities page.