National Acute Porphyria Service (NAPS)

Addenbrooke's services



What is porphyria?

The porphyrias are a group of 8 rare disorders caused by problems making haem, an important component of many chemicals in the body including haemoglobin. Most porphyrias are inherited and caused by faults in one of the genes involved in producing haem. The type of porphyria and the illness depends on which step in the haem synthesis pathway is affected.  Most of the problems are caused by build up of haem precursor chemicals in the body, which can cause severe illness.  Many of these chemicals are a purple-red colour, and the name porphyria comes from the Greek word for purple (porphyra).


What is acute porphyria?

Almost all acute porphyrias fall into one of three types: acute intermittent porphyria, AIP; variegate porphyria, VP; and hereditary coproporphyria, HCP.  They are all very rare and many doctors have never seen a case.  However they are inherited as autosomal dominant conditions, meaning that the defective gene only has to be passed on from one parent. This means that several members of the same family can be affected. 


How can acute porphyria affect you?

There are two possible effects, acute attacks or skin sensitivity to sunlight.


Acute attacks can occur in acute intermittent porphyria, variegate porphyria or hereditary coproporphyria.  The underlying cause of attacks is thought to be nerve damage.  Attacks start with severe pain in the stomach, back and legs.  There are often other problems such as vomiting, constipation, purple/red coloured urine (especially after leaving it to stand), a rapid pulse and high blood pressure, and low sodium (salt) concentration in the blood.  Many people feel agitated and anxious during attacks.  In severe attacks there may be seizures or weakness of the muscles in the arms and legs, or even paralysis.  Attacks are rarely fatal but they can cause a severe illness requiring admission to hospital.  In such cases, treatment with haem arginate (Normosang) infusions may shorten the attack.  Most patients make a complete recovery and lead normal healthy lives.  A few patients have repeated attacks, which may be serious and result in long term ill health.


Women are more likely to have attacks than men particularly in the 20-40 year age group. It is extremely rare for children to be affected before puberty.  Attacks may be triggered in susceptible people by commonly prescribed drugs, including oral contraceptives and some antibiotics.  Other triggers include alcohol, hormone fluctuations (during the menstrual cycle or pregnancy), fasting or dieting, illness, surgery or stress. 


Attacks of porphyria are often misdiagnosed as something else in patients who are not known to have porphyria.  However it is also important that people with known porphyria don’t assume every illness is related to their porphyria, otherwise there is a risk that serious conditions, like appendicitis, could be missed.


Skin problems in acute porphyria only occur in variegate porphyria and hereditary coproporphyria (not in acute intermittent porphyria) and are caused by build up of porphyrins in the skin, which react with light to cause skin damage.  The best treatment is to cover up exposed skin when going out in the sun.


About 9 out of 10 people who inherit porphyria never have any problems from it, even if they have a close relative who is badly affected. It is still important that they keep to the safe drug list, and inform their doctor if they get ill or need an operation, or in women, if they become pregnant.  They can still pass on the faulty gene to their children.




Management of acute attacks

Attacks of porphyria often resolve in a few days with plenty of rest. It may help to increase intake of carbohydrates with starchy or sugary food or with glucose drinks.  Simple painkillers such as paracetamol may be useful. Patients with severe pain and/or vomiting, seizures or paralysis should be admitted to hospital for monitoring and treatment. This may include administration of intravenous haem arginate, a blood product, which can shorten the duration of attacks and reduce the risk of complications. This is supplied in the UK by Orphan Europe. For English patients, haem arginate should only be administered in conjunction with the NAPS clinical team and in accordance with the BIPNET guidelines which can be found on the British and Irish Porphyria Network website.


Normosang - on the safe list

Prevention of attacks

It is important to keep to drugs that are known to be safe in acute porphyria, since many commonly prescribed drugs can trigger attacks.  A list of safe drugs is published by the Welsh Medicines Information Centre in Cardiff, and updated every year. The list can be found in the Clinical Guidance section of the Porphyria Service Cardiff website. You should always check safety of any prescribed medicine or over-the-counter treatments with your doctor. All hormonal forms of contraception (including the oral contraceptive pill and implantable hormone preparations), and Hormone Replacement Therapy (HRT) should be avoided in patients with acute porphyria. Alcohol can also trigger porphyria attacks, and if you do drink alcohol, you should keep your intake low. Diet should be healthy with regular meals, and avoidance of long periods without food. Smoking can make porphyria worse and is best avoided.


Rarely patients with porphyria have such frequent acute attacks that it is necessary to start specific preventative treatment, such as medication to suppress the menstrual cycle in women, or regular haem arginate infusions. This should always be arranged in conjunction with a porphyria specialist.


Management of skin problems

For patients with skin problems, protection from sunlight using suitable clothing and hats is important.  Special sunblock can be used to block out visible light, which is harmful in porphyria. Conventional sunscreens are not effective as they block ultraviolet rather than visible light.Further information about skin problems in porphyria can be found at the British Association of Dermatologists web site and the British Porphyria Association website.




What is NAPS?

The National Acute Porphyria Service (NAPS) started on April 1st 2012.  It has been funded by the Department of Health to help patients with severe acute porphyria.  The service is delivered by three National Acute Porphyria Centres in Cardiff, London (Kings College Hospital) and Cambridge. They work in partnership with Regional Porphyria Centres in Salford and Leeds. Specialist clinics are held at all five centres.


Who is included?

NAPS focuses on the most severely affected patients with acute porphyria.  Patients are eligible either if they have been admitted to hospital with an attack in the last two years, or if they are on treatment to prevent attacks, such as regular haem arginate infusions or drugs suppressing ovulation.  Patients must also be living in England.


How does NAPS work?

When a patient is admitted to hospital with an attack, the hospital doctor should telephone NAPS.  Porphyria specialists will help doctors at the patient’s local hospital to provide the correct treatment.  This may include sending haem arginate by courier, and giving advice about intravenous fluids, safe drugs, and pain control.  When the patient leaves hospital, they will be offered an appointment at one of the National or Regional Centres as well as receiving care from a doctor at their local hospital who will be guided by a porphyria specialist.

All patients on regular haem arginate or other treatments to prevent attacks should be under the care of NAPS. They will continue to receive much of their treatment at their local hospital. However, they will also have the opportunity to see a porphyria specialist at one of the National Centres, as well as experts who can help with related problems, such as pain, kidney damage, or coping with illness.  Patients needing regular haem arginate can usually be offered the possibility of having this treatment at home with nursing support, if preferred.


How will patients benefit?

Because porphyria is so rare, it is difficult for doctors to get the experience needed to give patients the best possible care. NAPS will allow all patients with acute attacks to benefit from expert advice.


What about patients who are not eligible for NAPS?

Many patients with acute porphyria, as well as those with other forms of porphyria, are not included in NAPS, but would still benefit from seeing a specialist. These patients should visit their GP to discuss referral to a specialist centre. Patients living in Scotland, Ireland and Wales can also request GP referral to a porphyria specialist.




How will you help if I am admitted to my local hospital with an attack?

If you are admitted to hospital with an acute attack, we will give advice about treatment to the doctor looking after you, and we will send haem arginate to your hospital if required.


How do I get a clinic appointment?

If your GP or local hospital doctor refers you into the service, you will be contacted by telephone or letter to arrange an appointment date. Clinics are generally held on Thursday afternoons in Clinic 5 in the outpatient department. If you are not eligible for the service,but would still like to be seen in Cambridge for help with your porphyria, it may be possible to see you in our general metabolic clinic on a Wednesday morning.


Who will I see?

Most clinics are carried out by Dr Penny Stein, however there are several specialists involved in the management of porphyria and you could meet any of them.  Cambridge University Hospitals NHS Foundation Trust is a teaching hospital and from time to time there may be junior doctors and other medical staff present at your consultation. Please ask if you wish to speak to the Doctor or nurse in private.


Medical Staff

Professor T M Cox

Professor T M Cox

Dr P B Deegan

Dr P B Deegan

Dr P E Stein

Dr P E Stein



Nursing Staff

Names/photos to follow



Finding Clinic 5 and the hospital

From the Outpatients entrance: go through the Outpatients reception area. Turn left, passing the WRVS coffee shop on your right. Clinic 5 entrance is on the left hand side.

> Finding the hospital


Will I have any tests or investigations?

It is common to have regular blood and urine tests at each visit. If you need to be seen by any other specialists we will arrange this on an individual basis. For those patients receiving regular infusion of haem arginate we have an experienced vascular access department that  can advise onand actively manage long term venous access.



Guidance for Professionals



Urgent enquiries about current NAPS patients

Within office hours (Mon-Fri 9-5) the Cambridge porphyria service can be contacted for clinical advice by calling switchboard on 01223 245151 and asking for the porphyria service.


Out of hours, please phone the Emergency number (the switchboard of the University Hospital of Wales on 02920 747747) and ask for “the out of hours porphyria service”. You will be given the switchboard number of the on call NAPS centre, allowing you to contact the on call NAPS Clinician.


Urgent enquiries about new patients

Clinicians wishing to prescribe haem arginate for a new patient either within or out of hours should phone the Emergency number above to discuss the case. Haem arginate will be supplied without charge for English patients if agreed with a NAPS Clinician prior to prescription.New patients referred urgently by phone will be followed up in clinic at one of the three NAPS centres.  We are happy to give clinical advice regarding non-English patients, however haem arginate for non-English patients is not funded through NAPS and should be purchased directly from Orphan Europe.

> Orphan Europe


Non urgent referrals

Any non urgent referrals should be addressed to one of the porphyria team at the contact address below.  Please ensure the patient’s contact telephone number is included in your referral letter together with the results of any biochemical or genetic porphyria testing that has already been carried out.  We aim to offer new patients a clinic appointment within 5 weeks of receipt of referral.


Urine porphobilinogen analysis

Urine porphobilinogen (PBG) analysis to confirm an acute attack of porphyria or for monitoring known patients can be carried out at Cambridge University Hospitals NHS Foundation Trust. Please collect a random 10ml urine sample in a plain tube, check the tube is labelled with patient details, and protect from light by wrapping in foil or a brown envelope.  Sample request card should state “urine for porphobilinogen quantitation” for a patient with known porphyria, or “urine for porphobilinogen screening test” for a patient without a previous diagnosis of porphyria.  Refrigerate the sample prior to analysis. Send by first class post to Department of Clinical Biochemistry, Box 232 Cambridge University Hospitals NHS Foundation Trust, level 4 Pathology block, Hills Rd, Cambridge, CB2 0QQ.Please discuss with the NAPS Clinician if urgent.





National Acute Porphyria Service

Box 135

Cambridge University Hospitals NHS Foundation Trust

Hills Road




Appointment / administrative enquiries:  01223  348153
General telephone enquiries:  01223  245151 – ask for the porphyria service


The service is open Mon – Fri, 9 – 5 for patients.


Finding clinic 5

From the Outpatients entrance: go through the Outpatients reception area. Turn left, passing the WRVS coffee shop on your right. Clinic 5 entrance is on the left hand side.


> Finding the hospital






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