[Porphyrin excretion and blood iron under pyridoxal-5-phosphate administration in porphria cutanea tarda]

Urinary excretion of porphyrins in two cases of porphyria cutanea tarda during a period of various treatments

The urinary excretion of porphyrins in two cases of porphyria cutanea tarda (PCT) has been followed during a period in which various treatments have been tried. In one patient pyridoxal-5-phosphate (P-5-P) injections lead to a dramatic increase in porphyrin excretion. In another P-5-P treatment was followed by a significant decrease in porphyrin excretion. p-Aminobenzoic acid (PABA) apparently had no effect on porphyrin excretion, while repeated phlebotomies had the expected effect. In both patients all variations in the total amount of porphyrins excreted were almost exclusively due to the variations in the amounts of heptacarboxylic porphyrin type III and uroporphyrin I. A secondary finding was an increase in hexa- and penta-carboxylic porphyrins type III without a concomitant increase in coproporphyrin III.

[Accident in treatment of porphyria cutanea tarda by chloroquine (Resochin) (author's transl)]

About a 65-year old patient with the typical clinical and biochemical characteristics of porphyria cutanea tarda (Pct) is reported. After treatment with Resochin in an erroneously high dosage (1.250 mg instead of 125 mg) an acute crisis set in with a triple increase of porphyrin excretion, fever, tachycardia, hypertension and joint-discomfort. Despite the rise in excretion of total porphyrines in urine to approximately 18.00 mcg/l there was no change in the amount of the porphyrin precursors (ALA, PBG). The pattern of the porphyrin-metabolites (URO-, HEPTA,- HEXA-, PENTA-, COPRO-porphyrin)-expressed in rel.%-does not change during the excessive rise of porphyrin excretion. The duration Resochin-therapy could obviously not be shortened by an initial too high dosage of chloroquine. The mechanism of action of chloroquine in Pct is not clear. It is discussed that a change in the permeability of the liver mitochondria leads to a continuously increased excretion of porphyrin and to an exhaustion of the hepatic porphyrin pool.