Let’s talk about stomach pain — we all experience it from time to time, but it’s usually not a big deal. Although it’s uncomfortable, abdominal pain is typically not cause for concern. Most stomach discomfort is caused by indigestion, constipation, gas, a stomach virus, food allergy/intolerance, or menstrual cramps.
Of course, sometimes stomach pain comes out of nowhere, and if it persists, it might be time to consult a doctor. If you’ve ever experienced severe abdominal pain along with other seemingly unrelated symptoms (like limb weakness/pain, back or chest pain, confusion, anxiety, nausea or vomiting, seizures, diarrhea, constipation, or dark/reddish urine), it could be a sign of acute hepatic porphyria (AHP).
What Is AHP?
AHP refers to a family of rare, genetic diseases characterized by painful attacks and for some people, chronic and debilitating symptoms that negatively impact their ability to function. There are four types of AHP: acute intermittent porphyria (AIP), variegate porphyria (VP), hereditary coproporphyria (HCP), and ALAD-deficiency porphyria (ADP).
People with AHP may experience a variety of different symptoms, which makes it challenging to diagnose. In fact, the journey to diagnosis for someone with AHP can take up to 15 years and it’s not unusual for patients to be misdiagnosed, since its symptoms often mimic other more common diseases. Common misdiagnoses include ulcerative colitis, irritable bowel syndrome, endometriosis, fibromyalgia, among others. Misdiagnosis of AHP can lead to unnecessary treatments, surgeries and hospital stays.
What Causes AHP?
In people with a genetic defect for AHP, an enzyme deficiency results in the buildup of toxins called aminolevulinic acid (ALA) and porphobilinogen (PBG), which are released throughout the body. ALA and PBG are harmful to nerve cells and have been associated with AHP attacks and symptoms.
According to the National Human Genome Research Institute, “Most of the porphyrias are inherited conditions. The genes for all the enzymes in the heme pathway have been identified. Some forms of porphyria result from inheriting one altered gene from one parent (autosomal dominant). Other forms result from inheriting two altered genes, one from each parent (autosomal recessive). Each type of porphyria carries a different risk that individuals in an affected family will have the disease or transmit it to their children.” However, not everyone who has a genetic mutation for AHP will develop symptoms. AHP affects people of all ages, races, ethnicities, and genders, but it is most common among women between the ages of 15 and 45. In fact, approximately 80% of people with AHP are women.
Symptoms of AHP
According to the U.S. National Library of Medicine, “Episodes of acute porphyria can cause abdominal pain, vomiting, constipation, and diarrhea. During an episode, a person may also experience muscle weakness, seizures, fever, and mental changes such as anxiety and hallucinations. These signs and symptoms can be life-threatening, especially if the muscles that control breathing become paralyzed.”
Because the manifestations of AHP can vary from person to person and change over time, it’s important to educate yourself about the various symptoms of AHP and speak with your doctor if you think you may be experiencing signs of the disease:
1. Severe, Unexplained Abdominal Pain
Severe, unexplained abdominal pain is the most common symptom of AHP. More than 90% of people who have AHP attacks experience severe stomach pain.
2. Mental Changes
Another symptom of AHP is a change in mental state or mental health. Symptoms may include confusion, anxiety, depression, hallucinations and insomnia, tiredness and fatigue.
3. Cardiovascular Issues
Some people with AHP experience a rapid or irregular heart rate or high blood pressure.
4. Gastrointestinal Issues
In addition to abdominal pain, people with AHP may experience other symptoms of the autonomic nervous system, such as nausea, and vomiting. Gastrointestinal problems, including constipation and diarrhea, are also symptoms of AHP.
5. Limb Weakness/Pain
AHP also affects the peripheral nervous system, with symptoms including limb weakness or pain, numbness, muscle weakness, a tingling sensation, and sensory loss.
6. Paralysis
If left untreated, one of the most serious symptoms of AHP is paralysis, including respiratory paralysis.
7. Changes in Urination
Some people with AHP may notice dark/reddish urine.
8. Seizures
In severe cases, AHP can lead to seizures.
9. Other
There are a number of other AHP symptoms, including low blood sodium, back or chest pain, full-body pain, and blisters or skin lesions on sun-exposed skin (symptoms of HCP and VP only).
AHP Attack Triggers
AHP attacks may be triggered by environmental factors. Although not all people with AHP have the same triggers, common ones include:
- Alcohol
- Certain medications
- Hormones
- Extreme fasting/dieting
- Physical or emotional stress
- Smoking
AHP Diagnosis
Although many people with AHP deal with years of misdiagnoses, confirming an AHP diagnosis can be easy, and the two most common techniques used to help inform a diagnosis include a urine test and a genetic test. People who think they might be experiencing symptoms of AHP should ask their healthcare provider about testing for AHP.
AHP Management
While there is no cure for AHP, there are some treatment options, management techniques, and lifestyle changes that can help. People should always discuss management options with their healthcare provider. Another important step when establishing a care plan is to enlist the help of a support team — that may include friends and family, a therapist, a team of doctors, or an AHP support group. The American Porphyria Foundation, NORD and Global Genes, organizations dedicated to supporting the lives of individuals and families impacted by AHP and rare diseases more broadly, can also offer support and assistance. To learn more about AHP, access educational resources and hear stories from people living with the condition, visit www.PinpointAHP.com.
A message from Alnylam Pharmaceuticals, Inc. AS1-USA-00804
