Porphyria

Porphyria is the name given to a group of very rare metabolic disorders that occur when your body is unable to produce enough of a substance called haem.

Haem is required for many bodily functions. It is a component of haemoglobin, a vital protein which helps transport oxygen around your body and the pigment that gives red blood cells their colour. Haem also helps to form many other important proteins and is found in all body tissues, but mostly in red blood cells, bone marrow and the liver.


To produce haem, your body needs to convert two simple substances, aminolaevulinate acid (ALA) and porphobilinogen (PBG), known as porphyrin
precursors, into more complicated substances called porphyrins. These are then converted from one type of porphyrin into another to form, haem.

The genes people inherit play an important role
in causing porphyria. Genes are responsible for
managing the production of proteins that control
the cells in your body. In porphyria, the gene that
provides the instructions for making the enzymes
needed to produce haem has an abnormality,
known as a ‘mutation’. This mutation reduces the
amount of haem your body can produce.
People inherit two copies of genes, one from
each parent. In most types of porphyria, people
need to inherit only one copy of a mutated gene,
this is called ‘autosomal dominant’ porphyria. In
rarer porphyrias, including ADP and CEP, people
need to inherit two copies of a mutated gene for
the disease.

What are the symptoms?

Acute porphyrias are characterised by attacks of pain and other signs of neurological distress. Incutaneous porphyrias, the build-up of porphyrins and porphyrin precursors interacts with ultraviolet light from sun exposure to cause your skin to become very sensitive to light.

Symptoms do not usually appear until well after puberty and are seen more in women than in men (and more likely to occur during menstruation). The majority of people who inherit the disorder do not have attacks. Where symptoms do occur, they are sudden and can last for days or weeks.

  • anxiety, restlessness and insomnia
  • severe abdominal pain
  • pain in your arms, legs or back
  • vomiting and constipation
  • high blood pressure (hypertension)
  • muscle pain, tingling, numbness, weakness or paralysis
  • confusion, hallucinations and seizures
  • breathing difficulties (respiratory paralysis), possibly requiring ventilation
  • reddish coloured urine.

Acute attacks happen when the levels of porphyrins in your body become very elevated (increased).

They range in severity and usually require having to go to hospital. In the worst case they may require emergency procedures to prevent death.

Whatever the severity of your attacks, it is essential that medical staff act quickly to ensure you receive the appropriate medical treatment.

There is considered to be a slightly increased risk of having an acute attack during or following pregnancy. This risk is reduced if the porphyria you have is already diagnosed and most pregnancies don’t result in problems.

The symptoms of cutaneous porphyrias and neurocutaneous porphyrias usually appear quickly following exposure to the sun. They usually take the following forms:

  • itching (pruritus)
  • painful skin redness
  • skin swelling
  • blistering (though not associated with EPP)
  • abnormal hair growth on the face can sometimes occur
  • reddish coloured urine.

Skin exposed to sunlight is likely to become very fragile, where even slight contact may cause injury to your skin. Areas most at risk are those more commonly exposed, such as your face, neck, hands and feet. In some cases this can lead to permanent skin damage.

A combination of porphyria cutaneous tarda and chronic liver damage may place a person at much higher risk of developing liver cancer, known as hepatocellular carcinoma (HCC).

Treatment

There is no cure for porphyria. Treatment is aimed at getting rid of or managing your symptoms.

Only drugs known to be safe in porphyria can be prescribed for treatment, as many medications, including common sleeping pills and antibiotics can trigger acute attacks. This underlines the importance of making others aware that you have the condition, and the specific form.

  • stopping medications known or suspected to have triggered your symptoms
  • medication to control pain. If pain is severe, opiate-based drugs such as pethidine or morphine are safe to be given. A sedative, chlorpromazine (thorazine) may be used to relax you and help you sleep. Similarly, rapid heart beat and hypertension can be helped with propranolol to slow your heart rate. Anti-epileptic drugs may be given to control convulsion or seizures
  • oral and intravenous glucose (sugar) to help you maintain a high energy intake
  • haem arginate, a medication that is a form of haem, given to reduce the need for your body to produce its own. Combined with glucose, this lowers porphyrin levels by reducing the formation of aminolaevulinic acid. It is used mainly for severe attacks and is likely to be given to you intravenously over several days. Haem arginate has a rapid effect and an improvement may be expected within one week.

 

Treatment of cutaneous porphyrias is aimed at reducing the amount of porphyrins in your body to help eliminate your symptoms. This may include:

  • phlebotomy, also called venesection, a procedure similar to that used for blood donation in which a quantity of blood (usually up to 500 millilitres) is drawn into a blood donation bag via a needle placed in a vein in your arm. It is carried out to reduce the amount of iron in your body. Phlebotomy is most commonly used for PCT.
  • blood transfusion, the opposite treatment to phlebotomy. This is used for CEP in order to treat anaemia, in which you lack enough red blood cells.
  • a low dose of chloroquine, a drug given in tablet form twice a week.
  • beta carotene, given daily for EEP. Made from the orangey-yellow pigment that gives many fruits and vegetable their colour, beta carotene is converted by the body into vitamin A, to promote healthy skin and eyes and to increase your skin’s tolerance to sunlight. It may also colour your own skin a slight orangey shade.
  • a bone marrow transplant may be required for people with CEP, where the abnormal gene involved may also affect the formation of bone marrow.

Download publication

Download: Porphyria PPH/02/08.pdf

Reviewed by:Dr Adrian Bomford, Reader in Medicine and Honorary Consultant Physician, Institute of Liver Studies, King’s College Hospital, London.

Further Information

Following diagnosis, most people with porphyria are able to lead relatively normal lives by following simple measures to prevent symptoms occurring.

With careful management, some patients are able to experience long periods of time without symptoms or enter remission.

To prevent acute attacks, it is sensible to avoid:

  • taking or accepting medication without first checking that it is safe for you. A list of drugs that are considered safe in the treatment of porphyrias can be obtained from the organisations listed below
  • illegal psychoactive drugs such as cannabis, ecstasy, cocaine, amphetamines and barbiturates
  • smoking and drinking alcohol
  • fasting or following diets that leave you low in energy.

Extra monitoring should be made during pregnancy, when oestrogen levels are elevated.

Wearing some form of medical identification such as a medic alert disc will alert staff to your condition in the event of any emergency treatment.

People with cutaneous porphyrias should stay out of the sun as much as possible. Even exposure to bright light through the windows of a building or car should be avoided. When outside it is advisable to wear sun-protective clothing and heavy sun block containing zinc or titanium.

PCT, the most common skin porphyria, is linked with iron-overload and may cause serious liver damage if not regulated. You may be asked to avoid food rich in iron, vitamin C supplements and high dose oestrogen via contraception.

As is the case in anyone who has a liver condition, alcohol should be avoided.

There is no specific diet recommended for porphyria disorders other than eating healthily and making sure meals are taken regularly. This is more important for people who have acute porphyria as they are more sensitive to the effects of certain foods and beverages. This means keeping up a steady intake of calories by eating plenty of carbohydrates.

People who have acute porphyrias commonly suffer fatigue. This may be due to symptoms affecting muscles and joints (such as pain, numbness and weakness) and the sleep disturbance this may cause. In some cases the effects of medication used to control symptoms may contribute to bouts of tiredness.

It is important that your muscles do not get out of condition or reduce in size (atrophy). For this reason it is likely doctors will encourage you to follow a daily exercise routine or to take part in moderate physical activity a few days a week to keep your muscles in shape and to help you sleep better.

You can obtain more detailed advice about diet and exercise from the organisations listed 

Please visit the support section of our website for information on Support groups in your area or visit our Useful Links section for other organisations who may be able to offer information and support. Other organisations that may be able to offer further information are:

British Porphyria Association (BPA)
Tel: 0300 30 200 30
Email: helpline@porphyria.org.uk
Web: www.porphyria.org.uk

The Drug Database for Acute Porphyria
Web: www.drugs-porphyria.org

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Please visit the support section of our website for information on Support groups in your area.