The exception to this may be latent post-puberty genetic carriers of hereditary coproporphyria.As most porphyrias are rare conditions, general hospital labs typically do not have the expertise, technology, or staff time to perform porphyria testing. In general, testing involves sending samples of blood, stool, and urine to a reference laboratory. All samples to detect porphyrins must be handled properly. Samples should be taken during an acute attack; otherwise a false negative result may occur. Samples must be protected from light and either refrigerated or preserved.If all the porphyrin studies are negative, one must consider pseudoporphyria. A careful medication review often will find the cause of pseudoporphyria. Additional tests
Further diagnostic tests of affected organs may be required, such as nerve conduction studies for neuropathy or an ultrasound of the liver. Basic biochemical tests may assist in identifying liver disease, hepatocellular carcinoma, and other organ problems. Management
Acute porphyria
Carbohydrate administration
Often, empirical treatment is required if the diagnostic suspicion of a porphyria is high since acute attacks can be fatal. A high-carbohydrate diet is typically recommended; in severe attacks, a dextrose 10% infusion is commenced, which may aid in recovery by suppressing heme synthesis, which in turn reduces the rate of porphyrin accumulation. However, this can worsen cases of low blood sodium levels (hyponatraemia) and should be done with extreme caution as it can prove fatal. Heme analogs
Hematin (trade name Panhematin) and heme arginate (trade name NormoSang) are the drugs of choice in acute porphyria, in the United States and the United Kingdom, respectively.
Triggers
Acute porphyria can be triggered by a number of drugs, most of which are believed to trigger it by interacting with enzymes in the liver which are made with heme. Such drugs include:
Sulfonamides, including sulfadiazine, sulfasalazine and trimethoprim/sulfamethoxazole. Sulfonylureas like glibenclamide, gliclazide and glimepiride, although glipizide is thought to be safe. Barbiturates including thiopental, phenobarbital, primidone, etc. Systemic treatment with antifungals including fluconazole, griseofulvin, ketoconazole and voriconazole. (Topical use of these agents is thought to be safe due to minimal systemic absorption.) Certain antibiotics like rifapentine, rifampicin, rifabutine, isoniazid, nitrofurantoin and, possibly, metronidazole. Ergot derivatives including dihydroergotamine, ergometrine, ergotamine, methysergide, etc. Certain antiretroviral medications (e.g. indinavir, nevirapine, ritonavir, saquinavir, etc.) Progestogens
Some anticonvulsants including: carbamazepine, ethosuximide, phenytoin, topiramate, valproate. Some painkillers like dextropropoxyphene, ketorolac, metamizole, pentazocine
Some cancer treatments like bexarotene, busulfan, chlorambucil, estramustine, etoposide, flutamide, idarubicin, ifosfamide, irinotecan, ixabepilone, letrozole, lomustine, megestrol, mitomycin, mitoxantrone, paclitaxel, procarbazine, tamoxifen, topotecan
Some antidepressants like imipramine, phenelzine, trazodone
Some antipsychotics like risperidone, ziprasidone
Some retinoids used for skin conditions like acitretin and isotretinoin
Miscellaneous others including: cocaine, methyldopa, fenfluramine, disulfiram, orphenadrine, pentoxifylline, and sodium aurothiomalate. Pathogenesis
In humans, porphyrins are the main precursors of heme, an essential constituent of hemoglobin, myoglobin, catalase, peroxidase, and P450 liver cytochromes.The body requires porphyrins to produce heme, which is used to carry oxygen in the blood among other things, but in the porphyrias there is a deficiency (inherited or acquired) of the enzymes that transform the various porphyrins into others, leading to abnormally high levels of one or more of these substances.