| Erytropoëtische Protoporphyrie (EPP) |
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INFORMATIE VOOR MEDICIHet artikel hieronder is nog in het engels, maar wordt binnenkort vertaald. Neem ook een kijkje bij literatuur en artikelen waar enkele links staan naar artikelen over EPP op medische- en tandheelkundig vlakTandartsen kunnen klikken op deze link voor meer informatie NTVT.nl - orale aspecten van porphyrie(tandheelkunde) The following artikel from 1995 has been provided by the author for placement on this site. Case Report Photo(chemo)therapy and General Management of Erythropoietic Protoporphyria Dermatology 1995; 190 : 330 - 331 author Rik Roelandts, MD, PhD Photodermatology Unit, Department of Dermatology University Hospital Kapucijnenvoer 33 B-3000 Leuven Belgium NOTE:
The author states that the information in the artikel is still current,
however, the preferred
choice of treatment today is small band UVB phototherapy rather than PUVA therapy. Abstract Erythropoietic protoporphyria is an autosomal dominant or autosomal recessive photodermatosis characterized by a deficiency of the enzyme ferrochelatase. The diagnosis is based on the very typical complaints of burning and pain on sun exposure and on increased protoporphyrin concentration in the red blood cells, the plasma and the feces. Different treatment modalities have been proposed. The treatment of choice has always been beta-carotene. For severe cases, PUVA treatment (see note above) can be given three times a week until a total UVA dose of 120-200 J/cm2. In younger children, UVB phototherapy can be used if beta-carotene gives unsatisfactory therapeutic results. The irradiations are given four times a week until a total dose of 1-1.5 J/cm2 is reached. The first full description of erythropoietic protoporphyria dates from 1961 [1,2] although some case reports were published previously [3]. Erythropoietic Protoporphyria is an autosomal dominant or autosomal recessive photodermatosis characterized by a deficiency of the enzyme ferrochelatase. The result is an accumulation of protoporphyrins especially in the red blood cells (RBC). The most striking symptoms are the acute episodes of burning or pain when the skin is exposed to sunlight, most often on the face and the hands. Strong wind aggravates this sensation ('windburn'). Sometimes erythema or a persistent edematous swelling is visible, less often petechiae and, but rarely, urticaria. In most cases, however, the clinical changes are subtle and difficult to discern: some superficial scarring on the bridge of the nose, linear scars around the mouth, small circular or linear scars on the cheeks an, perhaps, a slight thickening or puffiness of the backs of the hands. The diagnosis is based on the ery typical complaints of burning and painon sun exposure and on increased protoporphyrin concentration in the RBC, the plasma and the feces. Due to the insolubility of protoporphyrin in water, there is no increased excretion of porphyrin in the urine, except in the case of liver failure. The screening test of choice is fluorescence microscopy of the RBC [4]. About 10-30% of the RBC show an orange-red fluorescence when irradiated with 400 nm. Protoporphyrin absorbs around 400 – 410 nm, which also explains why the patients are photosensitive to visible light. Non-water-soluble protoporphyrins can only be excreted by the bile duct. In some patients, protoporphyrin accumulation in the liver may lead to portal fibrosis, cirrhosis and terminal hepatic failure. They usually die in hepatic coma or as a result of bleeding esophageal varices [5]. Up to 1992, 25 cases of fatal iver disease have been described [6]. Different treatment modalities have been proposed for erythropoietic protoporphyria. The treatment of choice has mostly been Beta-Cartone [7]. Usually an oral dose of 30 – 90 mg/day is given in children and 100 – 180 mg/day in adults. A minimal plasma level of 600 μg/100 ml is necessary. About 6 weeks of therapy are needed before maximal photoprotection is obtained. With Beta-Carotene a clear improvement of photosensitivity is noted [8], although the protoporphyrin level remains elevated. The most obvious side effect is a visible yellowing of the skin, most pronounced in the palmar skin creases. There is no staining of the sclera, which could be important for the differential diagnosis with a beginning icterus. In March 1988, we starte PUVA treatment for our patients who had responded insufficiently to Beta-Carotene. The patients were given 0.6 mg/kg of 8-methoxypsoralen 2 h prior to toal body irradiation with UVA, which was done three times a week on Monday, Wednesday and Friday. The starting dose was 0.5 J/cm² of UVA, whereby the UVA dose was increased by 20% every Monday and Friday. This can be done without any major problems. A total of 26 – 30 UVA irradiations was administered. In June 1988, a case report was published of a man with erythropoietic protoporphyria treated with PUVA twice a week after 30 mg trimethylpsoroalen orally 2 h before UVA irradiation, a total of 25 treatments and a cumulative UVA dose of 410 J/cm² [9]. Since then PUVA therapy has been the treatment of choice for our adult patients, the protection obtained being better than with Beta-cartone. (NOTE: Currently UVB Photo-therapy is the preferred treatment over PUVA therapy). We start treatment between the end of March and the beginning of May, depending on the photosensitivity of the patient. The starting dose now is 1.5 J/cm² of UVA. 8-Methoxypsoralen is always used in a dose of 0.6 mg/kg, and treatment is given three times a week until a total UVA dose of 120-200 J/cm², which corresponds to 21 – 27 irradiations. The end dose varies between 15 and 20 J/cm² of UVA. No Beta-carotene is associates. Treatment is repeated every year, as well as the determination of the bloop porphyrin levels and the liver function tests. Since 1991, some of our patients have been treated with UVB phototherapy using an irradiation box with Philips TL 12 lamps. These patients also start their treatment between the end of March and the beginning of May. The starting dose is 6mJ/cm² of UVB. The irradiations are given four times a week, whereby each time the dose is increased by 10%. A total of 20 – 30 irradiations is given, which amounts to a total cumulative UVB dose between 1 and 1.5 J/cm² of UVB and an end dose between 105 and 165 mJ/cm² of UVB. The therapeutic results are also better than with Beta-Carotene. Our youngest patieny treated with photochemotherapy was 16 years old. For younger children, Beta-Carotene is still the treatment of choice, but UVB phototherapy can be used if Beta-Carotene gives unsatisfactory therapeutic results, PUVA therapy is best avoided in children. Apart from these treatment modalities, the patiens have to be warned about possible hazards of operating theater lights [10,11]. Due to their sensibility to 400 nm wavelengths, care has to be taken to protect such patients from phototoxic injury during prolonged surgery. In addition, possible risk factors for liver disease should be avoided. This means that patients should avoid fasting, alcoholic beverages, barbiturates, sulfonamides, estrogen compounds and birth control pills [12]. References
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