Ryali Madhavi E, Whittier William L
Section of Nephrology, Rush University Medical Center, Chicago, Illinois 60607-1878, USA.
Semin Dial. 2010 Jan-Feb;23(1):83-7. doi: 10.1111/j.1525-139X.2009.00672.x.
Porphyria cutanea tarda (PCT) is a vesiculobullous skin disorder characterized by a defect in heme biosynthesis. Reduced activity of the hepatic enzyme uroporphyrinogen decarboxylase (URO-D) results in accumulation of photosensitive porphyrins; this ultimately leads to the skin fragility and blistering that is characteristic of this disease. The majority of cases of PCT are associated with acquired deficiencies of the enzyme URO-D, secondary to hepatic injury precipitated by medications or infections. Less commonly, PCT has been documented in patients with end-stage renal disease. The pathogenesis of PCT in long-term hemodialysis (HD) has been attributed to many factors, but the following mechanisms have been implicated: (i) decreased hepatic URO-D activity due to suppressive effects of iron and other hepatotoxins and (ii) poor porphyrin clearance by renal replacement therapies. We report a case of PCT that developed in a patient on maintenance HD for 4 years. He had a history of hepatitis C and evidence of iron overload. However, as the patient was anemic, therapeutic phlebotomy was problematic and therefore erythrocyte-stimulating agents were maximized to mobilize iron stores and allow phlebotomy. With this treatment, the patient's skin lesions improved in conjunction with decreasing ferritin levels.
迟发性皮肤卟啉症(PCT)是一种以血红素生物合成缺陷为特征的水疱大疱性皮肤病。肝脏酶尿卟啉原脱羧酶(URO-D)活性降低导致光敏性卟啉积聚;这最终导致了该疾病特有的皮肤脆弱和水疱形成。大多数PCT病例与URO-D酶的后天性缺乏有关,继发于药物或感染引起的肝损伤。较少见的是,终末期肾病患者也有PCT的记录。长期血液透析(HD)中PCT的发病机制归因于多种因素,但涉及以下机制:(i)由于铁和其他肝毒素的抑制作用导致肝脏URO-D活性降低,以及(ii)肾脏替代疗法对卟啉的清除不佳。我们报告了一例在维持性血液透析4年的患者中发生的PCT病例。他有丙型肝炎病史和铁过载的证据。然而,由于患者贫血,治疗性放血存在问题,因此最大限度地使用促红细胞生成剂来动员铁储备并允许放血。通过这种治疗,患者的皮肤病变随着铁蛋白水平的降低而改善。