Acute hepatic porphyria (AHP) is a group of rare genetic conditions that can cause severe, sudden (acute) symptoms. These symptoms can happen in various parts of the body and often require a hospital visit. There are four types of AHP which include:
- acute intermittent porphyria,
- variegate porphyria,
- hereditary coproporphyria, and
- ALAD-deficient porphyria.
It is estimated that 5 in every 100,000 persons have AHP. Most people with AHP start to develop symptoms when they are adults. While AHP can affect anyone, it is more common in women and Caucasians. People with AHP have a defective gene that leads to problems making heme, which is an important part of hemoglobin. Hemoglobin is a protein in red blood cells that carries oxygen throughout the body. This defect leads to the buildup of toxic chemicals in the body that can damage nerve cells and cause severe symptoms. Sometimes the AHP attacks can be life-threatening.
Most Common Symptoms of Acute Hepatic Porphyria
People with AHP can experience gastrointestinal, neurologic, psychiatric, cardiovascular, or skin symptoms. The most common symptom is abdominal pain which can be severe and last several hours.
Those with AHP can also experience chronic symptoms. These are symptoms that last a long time and may include:
- fatigue- feeling overly tired or having low energy
- nausea- feeling of sickness in the abdomen, stomach, chest, or head with feeling an urge to vomit
- pain– physical discomfort and/or suffering in the body
Gastrointestinal Symptoms of AHP
AHP often affects the GI tract and can cause:
- Pain and/or discomfort in the belly area (stomach and intestines)
Neurological Symptoms of AHP
AHP also commonly leads to neurologic and psychiatric symptoms. The symptoms are related to the nervous system, including the brain, spinal cord, and nerves of the body. Symptoms that impact the nervous system include:
- Pain in arms, legs, chest, back, neck, or head
- Muscle weakness
- Mental symptoms like agitation, confusion, depression, and/or hallucinations
Patients can also experience fast heart rate, high blood pressure, dark or reddish urine, and skin blisters on areas exposed to the sun, among others.
Diagnosing Acute Hepatic Porphyria
The type of test that should be done depends on whether the person is having symptoms at the time. When a person is having symptoms from AHP, a spot urine test for porphobilinogen (PBG), a porphyrin, may be used. This test simply involves urinating in a specimen container, often a small cup. The sample is then tested in the lab for PBG levels. If PBG levels are high, a healthcare provider can tell that a person has AHP.
Other tests that may be done include a urine test for aminolevulinic acid (ALA) as well as testing for total porphyrins in the urine, blood, or stool. If someone has severe kidney disease, a blood test for PBG may also be done. This is due to the kidney being unable to properly filter urine. As AHP is caused by a gene defect, genetic testing can also be used to diagnose the condition. Unlike the urine tests mentioned above, the genetic test can be done when a patient is not experiencing symptoms. Genetic testing is also helpful for diagnosing the condition in family members of those with known AHP. The genetic test looks for problems in 4 different genes and can diagnose the specific type of AHP that one may have (acute intermittent porphyria, variegate porphyria, hereditary coproporphyria, and ALAD-deficient porphyria).
Treating Acute Hepatic Porphyria
When someone with AHP is experiencing an acute attack, treatment with intravenous (IV) hemin in the hospital can help with symptoms. At that time, it is also important to try to identify what may have caused the attack (e.g., infection, medicine, diet changes) so that they can be avoided in the future.
A drug called Givosiran (Givalaari®) was approved by the U.S. Food and Drug Administration in 2019 for the treatment of adults with AHP. It is a medicine that is injected under the skin once a month. In clinical trials, patients on givosiran had fewer acute attacks from AHP when compared to those given a placebo. A placebo is a pill or treatment with no active ingredients. While taking givosiran, patients should have their liver and kidney tests monitored by their healthcare team. For patients with AHP who suffer from repeated severe attacks, do not respond to IV hemin or givosiran, or have a very poor quality of life, liver transplantation can be considered as a last resort.
A full list of safe and unsafe medicines for AHP can be found at the American Porphyria Foundation Drug Database
Adapted from IFFGD’s publication #581 Understanding Acute Hepatic Porphyria by Christopher V. Almario, MD, MSHPM; Cedars-Sinai Medical Center, Karsh Division of Gastroenterology and Hepatology