Porphyria cutanea tarda

Porphyria cutanea tardaPorphyria cutanea tarda is a term that spans a group of diseases in which heme synthesis enzyme activity is uroporfinogena decarboxylase deficiency. Porphyria cutanea tarda include enzyme gene mutations in hereditary and earned may occur in genetically predisposed people after exposure to hepatotoxine or in the context of liver tumors.Clinical expression of hereditary porphyrias earned and usually follows exposure to agents or conditions that affect hepatocytes and lead to hepatosideroza. These agents include ethanol, estrogen, hepatitis and HIV, along with hemochromatosis genes.
Excess iron triggers the formation of toxic oxygen species and oxidative stress increases facilitating porfirinogeneza. Reduction of the heme synthesis enzyme activity to 25% of normal clinical signs cause. Exposure to hydrocarbon compounds, polyhalogenated aromatic compounds in the environment cause disease in many people-toxic porphyrin epidemic porphyria. Liver tumors that produce excess porphyrins are rare cases of porphyria cutanea tarda.
Clinical appears veziculizare and petechiae on the arms, hands and face. As observed hypertrichosis, urine discoloration, pigmentation type facial melasma, alopecia scleredemului scar and related lesions. Avoiding the sun is the primary prevention of photosensitivity. Alcohol should be avoided, estrogen. The practice of therapeutic phlebotomy to reduce iron stores.
Pathogenesis
When missing liver enzyme activity porphyrin synthesis this pathway of synthesis byproducts accumulate in the liver, plasma and other organs. Porphyrins with many carboxyl groups are water soluble and excreted by the kidneys. 8 groups of carboxyl porphyrins are called uroporfirine, those four groups isocoproporfirine coproporfirine and excreted mostly in feces. Photoactive porphyrins are molecules that abseorb energy from visible light spectrum violet. Leather so excited porphyrins mediate oxidative determine the sign of skin lesions.
Fotocutanata most common manifestation of porphyria cutanea tarda is due to increased mechanical fragility of blood vessels in the dermis, the occurrence of erosions, ulcers and painful blisters after sun exposure. They heal with depigmentation and scarring. Other common features of late cutaneous porphyria include hypertrichosis, scleroderma similar boards that may develop dystrophic calcifications and similar colored urine excretion of wine or tea.
Causes and Risk Factors
Common cause of late cutaneous porphyria is to reduce the enzymatic activity of heme cycle. Many risk factors acting simultaneously or separately to inhibit this enzyme. Hepatic viral infections are often associated with porphyria cutanea tarda. Hepatitis C cause 50% risk of developing this disease. The association with HIV virus is also incriminated. There is also a close relationship between porphyria and hemochromatosis genes.