Acute hepatic porphyria (AHP) refers to a family of rare genetic diseases that affect the production of heme, a component of red blood cells. It can cause life threatening complications.

AHP can cause a range of symptoms, from severe abdominal pain to neurological complications, significantly impacting the quality of life. Understanding AHP is essential for early diagnosis and effective management.

This article explains what acute hepatic porphyria is, its causes, symptoms, treatment, and outlook. It will also answer some frequently asked questions.

A combination of tests may be necessary to diagnose acute hepatic porphyria.Share on Pinterest
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Acute hepatic porphyria (AHP) is a group of genetic diseases that directly affect certain liver functions, which potentially lead to neurological complications. It is rare, with the most common type affecting approximately 5 to 10 per 100,000 individuals worldwide.

In AHP, symptoms can occur suddenly. It most directly affects the liver, leading to episodic attacks of severe symptoms. These attacks particularly occur in women ages 15 to 50 years old.

Types

There are four main types of AHP:

  • Acute intermittent porphyria (AIP): This is the most common form, accounting for 80% of all cases. AIP occurs due to a deficiency of the enzyme hydroxymethylbilane synthase.
  • Hereditary coproporphyria (HCP): This type results from a deficiency in the enzyme coproporphyrinogen oxidase.
  • Variegate porphyria (VP): This type is due to a deficiency of the enzyme protoporphyrinogen oxidase. VP can affect the skin and cause neurological symptoms.
  • ALA-Dehydratase deficiency porphyria (ADP): This is an extremely rare type. It can occur due to a deficiency in the ALA-dehydratase enzyme.

While AHP can involve sudden symptoms, the chronic form of the condition tends to involve continuous symptoms. Chronic types of hepatic porphyria include porphyria cutanea tarda (PCT) and hepatoerythropoietic porphyria.

AHP occurs due to genetic mutations that cause a problem with heme production. Heme is vital for carrying oxygen to cells in the body.

When the process of producing heme is disrupted, the chemicals that would otherwise be used to make heme, known as porphyrins or porphyrin precursors, build up in the liver. This is hepatic porphyria. These substances are toxic. Some porphyrins are particularly toxic to the skin, while others are especially damaging to the nervous system.

Individuals inherit AHP, meaning that if one or both parents carry the defective gene, they can pass it on. It is not contagious and cannot develop in any other way. Certain medications affecting liver enzymes can trigger acute attacks in people with these conditions.

Additional triggers include:

Approximately 90% of symptomatic patients are female, and attacks typically begin two to four days before menstruation. They are rare after menopause.

Symptoms of AHP can be mild or severe, lasting days or weeks. They vary widely, but symptoms may include:

Some may not experience any symptoms, even though they carry the defective gene associated with AHP.

Diagnosis can be difficult because AHP is a rare disease, and the wide range of symptoms can be similar to other illnesses.

To identify AHP, a doctor may carry out a combination of tests, including:

  • Urine tests: To measure the levels of porphyrin precursors, such as porphobilinogen (PBG) and aminolevulinic acid (ALA), which can be significantly higher in individuals with AHP.
  • Genetic testing: This involves sending blood or saliva samples to the lab to identify genetic mutations associated with AHP. Genetic testing can confirm the diagnosis and help identify at-risk family members.
  • Blood and stool tests: Doctors might also check blood and stool for levels of substances, such as ALA, PBG, and porphyrins to confirm the diagnosis.
  • Erythrocyte porphobilinogen deaminase (PBGD): A blood test can show reduced activity of this enzyme in about 90% of people, even those without symptoms.
  • Other tests: Doctors may check basic metabolic panels for problems, such as low sodium levels (hyponatremia), which can occur as AHP can affect the nervous system or kidneys.

The best time to diagnose AHP is if a doctor carries out these tests when an individual is having an attack or shortly after one. An early diagnosis is essential for managing symptoms and avoiding further complications.

Management of AHP focuses on:

Acute attack management

There is no cure for AHP, but doctors may recommend ways to manage symptoms. Attacks often require hospitalization.

To manage acute attacks, treatment may include:

  • Intravenous heme therapy (IHT): Administering heme can reduce the synthesis of porphyrin precursors and alleviate symptoms.
  • Pain management: Pain relievers can help with severe pain.
  • Intravenous glucose: Glucose can suppress the production of porphyrin precursors.

Long-term management

Managing AHP long term may include:

  • Avoiding triggers: People with AHP should avoid known triggers such as specific drugs, alcohol, and fasting.
  • Regular monitoring: Regular follow-up with healthcare professionals to monitor liver function and porphyrin levels are essential.
  • Liver transplant: In severe cases, a doctor may recommend a liver transplant if a person has repeated, life threatening attacks or if other treatments have not been successful.

The outlook for individuals with AHP varies depending on how often they experience symptoms and how severe they are. With prompt diagnosis and treatment, many individuals can live a full life.

That said, recurrent attacks can sometimes lead to chronic complications. This is why early diagnosis and prompt treatment are crucial to improving outcomes.

In this section, we answer some frequently asked questions about AHP.

What are the symptoms of hepatic porphyrias?

Symptoms can vary widely but commonly include:

  • severe abdominal pain
  • neurological disturbances, such as seizures and neuropathy
  • gastrointestinal issues, such as nausea and constipation
  • dark-colored urine

What happens when you have porphyria?

Some people with porphyria have no symptoms.

However, during an acute attack, a toxic buildup of porphyrins can lead to severe pain, neurological symptoms, and autonomic dysfunction. In the long term, it can cause chronic pain, chronic kidney disease, and neurological damage.

What is the survival rate for porphyria?

Survival rates depend on the specific type of porphyria and the severity a person has. For most, the life expectancy is similar to people without porphyria.

In people with AHP, especially those with chronic overproduction of ALA and PBG, there is a higher risk of developing systemic hypertension, chronic kidney disease, and liver cell cancer. These conditions can affect survival rates.

Generally, with early diagnosis and treatment, individuals with AHP may lead healthy lives.

AHP is a rare but serious group of genetic disorders that affects heme production in the liver. Heme is a vital component of blood. It can cause acute attacks with symptoms such as severe abdominal pain or constipation.

Triggers of AHP include stress, medications, or hormonal changes. Diagnosis often involves urine and genetic tests, while treatment includes managing and preventing acute attacks.

Early detection and comprehensive care are essential for improving the quality of life and outlook for individuals with AHP.