Many acute attacks are precipitated by controllable or avoidable factors such as drugs, alcohol, fasting (including dieting) or hormones.
Drugs: People with acute intermittent porphyria must take great care with medication, as many chemical agents are capable of inducing an acute attack. It is important ALWAYS to check the safety of any medicine or remedy. This includes prescription medicines as well as over- the- counter treatments, tonics and herbal remedies, some of which have been known to cause attacks. While over 100 drugs are considered suspect, there are many other drugs available and good alternatives can almost always be found. For a list of safe drugs, click here
Some people with porphyria may occasionally need a drug, perhaps for a serious illness, that carries some risk of provoking an acute attack or which has been introduced so recently that there is little information about its effect on porphyria. In this situation, your doctor, after fully discussing and explaining the risks, may decide to prescribe the drug for you.
Even though acute attacks are very rare before puberty, it is safest for children if they also avoid all drugs that are not known to be safe in porphyria.
The response of people with porphyria to drugs that have been reported to produce acute attacks in others is unpredictable in that a reaction does not invariably follow in every case. When there is a reaction, it always takes the form of an acute attack, which develops within days of taking the provoking drug. Reactions such as dizziness, feeling faint, allergies or short- lived skin rashes, which may occur immediately or very soon after taking the drug are common after drugs and rarely have anything to do with porphyria.
Alcohol: While many doctors experienced in the care of those with acute porphyria strongly recommend absolute avoidance of alcohol, some people may find this recommendation difficult to follow. Experience has shown that people who have experienced an acute attack greatly reduce the risk of further attacks if they become teetotal for life. For those shown by testing to have inherited the gene responsible for one of the acute porphyrias but who have not experienced an acute attack, it is best that they avoid alcohol. However, it this proves impossible a reasonable compromise is to keep intake as low as practicable and, in particular, to avoid heavy red wines, brandy and other liqueurs.
Diet: Low calorie diets, such as those used to reduce weight, and prolonged periods with little food may provoke an acute attack. It is therefore important to keep to a normal diet with regular meals, eating enough to maintain a desirable body weight. People who have had an acute attack should obtain advice from a dietician about how this is best achieved for their particular circumstances. Enough should be eaten to maintain a normal body weight with 55- 60% of the total food energy intake coming from carbohydrate. At least three regular meals should be eaten each day; some people, particularly women with pre-menstrual problems, may find it easier to eat small meals every three hours rather than three normal sized meals.
Patients with severe porphyria, particularly those who have repeated attacks, may need special dietary advice from their doctor and a dietician. If you are overweight, you should consult your doctor about the sort of diet that will allow you to lose weight gradually but safely.
Warning jewelry: It is important to wear a wrist bracelet or neck pendant at all times to warn that you have porphyria. Such warning is particularly helpful in emergencies when you may not have an opportunity to explain that you have porphyria. Details can be obtained from the Medic Alert Foundation , 12 Bridge Wharf, 156 Caledonian Road , London , N1 9UU .
Anesthetics and surgical operations: You must tell your surgeon and anesthetist in advance that you have porphyria. A special anesthetic that is safe in porphyria will be needed.
The dentist: You should tell your dentist that you have an acute porphyria. Dentists often use local unaesthetic agents and the safety of at least one of these has been questioned in the past.
Immunizations: All vaccines licensed for human uses are safe to administer to people who have an acute porphyria.
Particular issues for women.
Women are at least three times more likely than men to experience an acute attack, due mostly to female hormones, particularly progesterone. This hormone is found in the combined oral contraceptive (the pill), as well as in hormone replacement therapy (
In special circumstances, where the risk is low and the benefits high, your doctor may consider, after discussion with you, that the use of progesterone- containing preparations, particularly in replacement doses given through the skin from patches, is justified.
Pre- menstrual symptoms: In some women, attacks are clearly related to the pre- menstrual phase of the menstrual cycle and your doctor may need to consider a number of treatment options such as using special hormones to suppress your periods for 1-2 years. If you do need this sort of treatment, it needs to be done under close supervision by a doctor and will need regular monitoring.
Pregnancy: Though nearly all pregnancies are uneventful, there is a small increased risk of having an acute attack during or after pregnancy. However, the chances and dangers of such an acute attack are much diminished if porphyria has been previously diagnosed. It is therefore very important for the doctors providing care during pregnancy to know that you have acute porphyria. For those who have experienced an acute attack severe enough to require hospital care, pregnancy is best delayed until at least 12 months after recovery from the acute episode.
Treatment of acute attacks.
Importance of early recognition and accurate diagnosis: Early recognition of an acute attack allows early treatment. The early symptoms which herald an acute attack are often easily recognized by those who have previously experienced an attack. When these symptoms are recognized, immediate intake of sugary substances such as lucozade, HyCal or glucose tablets (e.g. Dextrosol) may help to reduce the severity and duration of the acute episode. But you may feel too sick to do this.
Early recognition is more difficult for those people who have inherited an acute porphyria but who have never experienced an acute attack. As a consequence, there is often considerable apprehension about pains that usually turn out to be due to causes other than acute porphyria. It must be noted that people with porphyria commonly experience abdominal discomfort, just like those who do not have the condition, and a doctor will need to consider other medical conditions which may cause abdominal pain. These conditions include a range of bowel disturbances, urinary infection and sometimes other urgent medical problems such as appendicitis. In this situation, the diagnosis of acute porphyria can usually be established or excluded by testing the urine for porphobilinogen, one of the precursors of porphyrins.
Treatment of an acute attack: As soon as an acute attack is diagnosed, you should stop any provoking agents e.g. drugs. For people who require hospital admission, intravenous haem arginate, which helps to overcome the relative deficiency of haem in the liver and which takes away the body's desire to increase the supply of the chemicals needed for haem production, may need to be given. The British National Formulary contains information about how to obtain this compound. If it cannot be obtained soon enough, large quantities of glucose, which has a similar but lesser effect, may be used.
Other treatments are likely to include the use of drugs to relieve pain and nausea and to provide sedation. It is also important to maintain an adequate intake of calories and this may require feeding intravenously or through a naso-gastric tube.
Skin Problems in the acute Porphyrias.
The skin is never affected in acute intermittent porphyria. Skin problems occur in 10-20% of adults who have inherited the gene for variegate porphyria and are often their only symptom. Areas of skin exposed to sunlight, particularly the backs of the hands, face and legs, become fragile, break easily and form blisters. Broken areas may become infected, be slow to heal and leave small scars.
If you have skin problems, you should look after your skin carefully. Avoid direct sunlight as much as possible, even sunlight that passes through window glass in your home or car. Protect your skin from sunlight by wearing light cotton gloves, long sleeves and a hat when you go out. Not everyone will find this necessary or acceptable; adjust your clothing as it suits you. Ordinary sunscreen ointments are not affective. The only ones that may help are the thick, opaque preparations with high protection factors (often containing titanium oxide) that block both UVA and UVB light. Use silicone barrier cream and rubber gloves when working in the kitchen or elsewhere. Keep any broken or blistered skin clean by washing with water and a mild soap; avoid strong antiseptics.
Identical skin problems may occur in hereditary coproporphyria but usually only during an acute attack of porphyria and are rarely persistent.