Patient education: Acute intermittent porphyria (The Basics)

What are porphyrias? — Porphyrias are a group of disorders that affect how the body makes a substance called "heme." Heme is made from iron and is used in blood cells to help them carry oxygen around the body. Heme has other important roles in the body, too, especially in the liver. In people with porphyria, chemicals can build up in the body and cause symptoms.

There are several different kinds of porphyria. "Cutaneous" porphyrias cause skin symptoms. "Acute" porphyrias cause symptoms like belly pain and changes in brain functioning, mood, or thinking.

Acute intermittent porphyria, or "AIP," is the most common type of acute porphyria. It is caused by an abnormal gene that runs in families.

What are the symptoms of AIP? — Many people with AIP never get symptoms. When symptoms do happen, they almost always start in adulthood. Symptoms happen in the form of "attacks" that can last a few days or even weeks. Different things can trigger attacks. These include certain medicines or hormones, smoking, alcohol, infections, not eating enough, or stress. Sometimes the attacks just happen.

Attacks can be different for different people. They can involve:

●Belly pain – This is the most common symptom.

●Vomiting

●Constipation

●Muscle pain, weakness, or numbness – In some cases, muscle weakness can be serious and can even lead to paralysis. Sometimes, the muscles that control breathing are affected.

●Seizures

●Mental symptoms – During an attack, some people feel confused, restless, agitated, or anxious. It's also common to have trouble sleeping.

●A fast heartbeat

●Trouble urinating or red-colored urine

Usually, symptoms go away between attacks. But some people have ongoing symptoms such as pain, weakness, depression, or anxiety.

Will I need tests? — Yes. The first test is usually a urine or blood test to measure the amount of specific chemicals in your body called "PBG" and "porphyrins." This is done while you are having symptoms. If the result is positive, your doctor will begin treatment right away. You will also have samples of your bowel movement tested. This will help your doctor figure out if you have AIP, a different kind of porphyria, or something else.

Genetic testing can confirm that you have the abnormal gene that causes AIP. Some people find out they have this gene when they get tested after a family member is diagnosed with AIP. But many people who have the gene never develop symptoms.

How is AIP treated? — There are a few different treatments for AIP attacks. They include:

●Hemin – The main treatment for attacks is a medicine called hemin (brand name: Panhematin). It is given through a thin tube that goes into a vein, called an "IV," for several days or longer. Hemin stops the body from making the chemicals that cause symptoms. Most people need to stay in the hospital for treatment and monitoring, especially if the attack is severe. Mild attacks can sometimes be treated with a sugar solution given through an IV.

●Symptom control – During an attack, you will also get other medicines to treat your symptoms. These might include medicines to relieve pain, help with nausea and vomiting, treat seizures, or help you sleep. If you have weakness of the muscles that control breathing, you might need a machine to help you breathe.

Treating AIP also involves trying to prevent attacks before they happen. This can include:

●Avoiding things that might trigger an attack – Many medicines can make AIP worse. Your doctor can give you a list of medicines to avoid, as well as other things you can do to help prevent attacks. Some women can lower the chance of attacks by using hormone therapy. Eating a balanced diet, treating any infections right away, and avoiding smoking and alcohol can also help.

●Givosiran – If you have frequent AIP attacks, your doctor might prescribe a medicine called givosiran (brand name: Givlaari). This medicine is given as a shot under the skin once a month. It can help lower the number of attacks you have, although the attacks might not stop completely.

People with chronic or long-term symptoms might need ongoing treatment, too. If you have pain, your doctor or nurse can help you find ways to manage it.

In severe cases, if a person has had repeated attacks and other treatments have not helped, a liver transplant might be an option. This is very rare.

What if I want to have children? — People with AIP can have children. Some women have more frequent attacks while they are pregnant, but most do not. If you do have attacks when you are pregnant, these can be treated with hemin in the usual way.

If you want to have children, talk to your doctor, a genetic counselor, or a porphyria expert. Since AIP is caused by an abnormal gene, there is a 50 percent chance that you could pass the gene on to each of your children.

When you do have children, you will need to decide if you want them to be tested for the abnormal gene. This is a personal decision. If you do choose testing, you might want to do it around the time your child goes through puberty. That's because attacks are rare during childhood, but the risk goes up when the hormones start to change. If it turns out that your child does have the gene, it doesn't mean they will have attacks. But it does mean they can avoid things that might trigger an attack. They can also be better prepared for attacks if they do happen.

What will my life be like? — Many people with AIP never have attacks. Even if you do get attacks, they can be treated and sometimes prevented. But some people do have depression or anxiety related to their AIP. If you are having trouble coping with your condition, talk to your doctor or nurse. It might be helpful to speak to a counselor. There are treatments that can help with depression and anxiety, too.

More on this topic

Patient education: Porphyrias (The Basics)
Patient education: Porphyria cutanea tarda (The Basics)
Patient education: Erythropoietic protoporphyria (The Basics)