Approach Considerations
The diagnosis of hereditary coproporphyria is established by demonstrating excess secretion of coproporphyrins in the stool. [11] Levels of stool coproporphyrins, especially coproporphyrin type III, are markedly elevated, usually 10-200 times greater than in controls.
Levels of urine porphyrins vary, but urine coproporphyrin levels usually are also markedly elevated, especially during acute attacks of the disease. Elevated porphobilinogen levels in the presence of appropriate clinical symptoms is diagnostic of porphyria; this is true of both hereditary coproporphyria and acute intermittent porphyria (AIP). [13, 14] After symptom resolution, urinary porphobilinogen levels may return to normal relatively quickly. [14]
Mild elevations of urine coproporphyrins (eg, as high as two times the reference range) are common and nonspecific. Fasting, subtle liver disease, or normal variations are the most common causes of elevated urine coproporphyrins. In such cases, patients may be incorrectly labeled as having porphyria.
Serum sodium levels should be measured in patients experiencing attacks, as hyponatremia is common; this has been attributed to the syndrome of inappropriate secretion of antidiuretic hormone (SIADH), but renal and/or gastrointestinal sodium loss may also be involved. [14] Mild leukocytosis is another nonspecific finding during an attack.
Although coproporphyria is caused by a defective enzyme, there is little use in measuring the activity of coproporphyrinogen oxidase. The vast majority of patients who have the defective enzyme do not have any symptoms of the disease. Furthermore, the only available clinical assay has been withdrawn due to problems with high rates of false-positive results. The diagnosis of a porphyria attack rests on demonstration of excessive excretion of porphyrins and porphyrin precursors.
Imaging studies are not helpful. Abdominal films sometimes demonstrate an ileus. Findings on cranial computed tomography scans are normal. Brain magnetic resonance imaging scans occasionally show signs of increased edema in patients with very severe attacks.
Identification of a heterozygous pathogenic variant in CPOX (encoding the enzyme coproporphyrinogen-III oxidase) confirms the diagnosis and enables family studies. [15]
Tables
Acetazolamide acetylcholine Actinomycin D Acyclovir Adenosine monophosphate Adrenaline Alclofenac Allopurinol Alpha tocopheryl Acetate Amethocaine Amiloride Aminocaproic acid Aminoglycosides Amoxicillin Amphotericin Ampicillin Ascorbic acid Aspirin Atenolol Atropine Azathioprine Beclomethasone Benzhexol HCl Beta-carotene Biguanides [Bromazepam] Bromides Buflomedil HCl Bumetanide Bupivacaine Buprenorphine Buserelin Butacaine SO4 Canthaxanthin Carbimazole [Carpipramine HCl] Chloral hydrate [Chlormethiazole] [Chloroquine] [Chlorothiazide] Chlorpheniramine Chlorpromazine Ciprofloxacin Cisapride Cisplatin Clavulanic acid Clofibrate Clomiphene Cloxacillin Co-codamol Codeine phosphate Colchicine [Corticosteroids] Corticotrophin (adrenocorticotropic hormone [ACTH]) |
Coumarins Cyclizine Cyclopenthiazide Cyclopropane [Cyproterone acetate] Danthron Desferrioxamine Dexamethasone [Dextromoramide] Dextrose Diamorphine Diazoxide Dicyclomine HCl Diflunisal Digoxin Dihydrocodeine Dimercaprol Dimethicone Dinoprost Diphenoxylate HCl Dipyridamole [Disopyramide] Domperidone Doxorubicin HCl Droperidol [Estazolam] Ethacrynic acid Ethambutol [Ethinyl oestradiol] Ethoheptazine citrate Etoposide Famotidine Fenbufen [Fenofibrate] Fenoprofen Fentanyl Flucytosine Flumazenil Fluoxetine HCl Flurbiprofen Fluvoxamine Maleate Folic acid Fructose Fusidic acid Follicle-stimulating hormone Gentamicin Glafenine Glucagon Glucose Glyceryl trinitrate Goserelin Guanethidine Guanfacine HCl Haem arginate [Haloperidol] Heparin Heptaminol HCl Hexamine [Hydrocortisone] Ibuprofen Indomethacin Insulin Iron Josamycin [Ketamine] |
Ketoprofen Ketotifen Labetalol Luteinizing hormone–releasing hormone Liquorice Lithium Salts lofepramine Loperamide [Lorazepam] Magnesium-sulphate [Mebendazole] Mecamylamine Meclofenoxate HCl Meclozine Mefloquine HCl [Melphalan] Meptazinol Mequitazine Metformin Methadone [Methotrimeprazine] Methylphenidate Methyluracil Metipropranolol Metopimazine Metoprolol [Metronidazole] [Midazolam] Minaprine HCl Minaxolone Morphine Nadolol Naftidrofuryl Oxalate [Naproxen sodium] Natamycin Nefopam HCl Neostigmine Netilmicin Niflumic acid Nitrous oxide Norfloxacin Ofloxacin Oxolinic acid Oxybuprocaine [Oxyphenbutazone] Oxytocin [Pancuronium bromide] Paracetamol Paraldehyde Parapenzolate Br Penicillamine Penicillin Pentolinium Pericyazine Pethidine Phenformin Phenoperidine Phentolamine mesylate Pipotiazine |
Palmitate Piracetam Pirbuterol Pirenzepine Pizotifen [Prazosin] [Prednisolone] Primaquine Probucol Procainamide HCl Procaine Prochlorperazine Proguanil HCl Promazine Propantheline Br Propofol Propranolol Propylthiouracil [Proxymetacaine] Pseudoephedrine HCl Pyridoxine [Pyrimethamine] Quinidine Quinine [Ranitidine] Reserpine Resorcinol Salbutamol Senna Sodium bromide Sodium ethylenediaminetetraacetic acid Sodium fusidate Sorbitol Streptomycin Sulbutiamine Sulindac Sulfadoxine Suxamethonium Talampicillin Temazepam Tetracaine [Tetracyclines] Thiouracils Thyroxine Tiaprofenic acid Ticarcillin Tienilic acid Timolol maleate Tolazoline Tranexamic acid Triacetyloleandomycin Triamterene Triazolam [Trichlormethiazide] Trifluoperazine Trimeprazine Tartrate Trimetazidine HCl Tripelennamine Tubocurarine Vancomycin [Vincristine] Vitamins Warfarin sodium Zidovudine Zinc Preparations |
*Bracketed [] drugs are those in which experimental evidence of porphyrin genicity is conflicting. |
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Alcuronium *Alphaxalone Alphadolone Alprazolam Aluminium Preparations Amidopyrine Aminoglutethimide Aminophylline Amiodarone *Amitriptyline [Amphetamines] *Amylobarbitone Antipyrine *Auranofin *Aurothiomalate Azapropazone Baclofen *Barbiturates *Bemegride Bendrofluazide Benoxaprofen Benzbromarone [Benzylthiouracil] [Bepridil] Bromocriptine Busulphan *Butylscopolamine Captopril *Carbamazepine *Carbromal *Carisoprodol [Cefuroxime] [Cephalexin] [Cephalosporins] [Cephradine] [Chlorambucil] *Chloramphenicol *Chlordiazepoxide *Chlormezanone Chloroform *Chlorpropamide Cinnarizine Clemastine [Clobazam] [Clomipramine HCl] [Clonazepam] Clonidine HCl *Clorazepate Cocaine [Colistin] Co-trimoxazole |
Cyclophosphamide Cycloserine Cyclosporin Danazol *Dapsone Dexfenfluramine Dextropropoxyphene Diazepam *Dichloralphenazone *Diclofenac Na Dienoestrol Diethylpropion Dihydralazine *Dihydroergotamine Diltiazem *Dimenhydrinate *Diphenhydramine [Dothiepin HCl] Doxycycline *Dydrogesterone *Econazole NO3 *Enalapril Enflurane *Ergot compounds Ergometrine maleate Ergotamine tartrate *Erythromycin *Estramustine Ethamsylate *Ethanol Ethionamide *Ethosuximide *Ethotoin Etidocaine Etomidate Fenfluramine *Flucloxacillin *Flufenamic acid Flunitrazepam Flupenthixol Flurazepam *Frusemide *Glibenclamide *Glutethimide *Glipizide Gramicidin *Griseofulvin [Haloperidol] *Halothane *Hydantoins *Hydralazine *Hydrochlorothiazide *Hydroxyzine Hyoscine *Imipramine Iproniazid Isometheptene mucate [Isoniazid] Kebuzone Ketoconazole *Levonorgestrel Lignocaine *Lisinopril Loprazolam Loxapine *Lynestrenol Lysuride |
Maleate Maprotiline HCl Mebeverine HCl *Mecillinam *Medroxyprogesterone [Mefenamic acid] Megestrol acetate *Mephenytoin Mepivacaine *Meprobamate Mercaptopurine Mercury compounds Mestranol [Metapramine HCl] Methamphetamine Methohexitone Methotrexate Methoxyflurane Methsuximide *Methyldopa *Methylsulphonal *Methyprylone Methysergide *Metoclopramide Metyrapone Mianserin HCl Miconazole [Mifepristone] Minoxidil *Nandrolone *Nalidixic acid Natamycin *Nandrolone [Nicergoline] *Nifedipine *Nikethamide Nitrazepam *Nitrofurantoin Nordazepam Norethynodrel *Norethisterone [Nortriptyline] Novobiocin *Oral contraceptives *Orphenadrine Oxanamide [Oxazepam] Oxybutynin HCl Oxycodone *Oxymetazoline *Oxyphenbutazone Oxytetracycline Paramethadione Pargyline *Pentazocine Perhexiline Phenacetin Phenelzine *Phenobarbitone Phenoxybenzamine *Phensuximide *Phenylbutazone Phenylhydrazine *Phenytoin Pipebuzone Pipemidic Acid Piritramide *Piroxicam |
*Pivampicillin *Pivmecillinam Prazepam Prenylamine *Prilocaine *Primidone [Probenecid] *Progesterone Progabide Promethazine [Propanidid] *Pyrazinamide Pyrrocaine Quinalbarbitone Rifampicin Simvastatin Sodium aurothiomalate Sodium oxybate [Sodium valproate] *Spironolactone Stanozolol Succinimides *Sulfacetamide *Sulfadiazine *Sulfadimidine *Sulfadoxine *Sulfamethoxazole *Sulfasalazine *Sulfonylureas Sulfinpyrazone Sulpiride Sulthiame Sultopride *Tamoxifen *Terfenadine Tetrazepam *Theophylline *Thiopentone Na Thioridazine Tilidate Tinidazole *Tolazamide *Tolbutamide Tranylcypromine Trazodone HCl Trimethoprim [Trimipramine] Troxidone Valproate Valpromide Veralipride *Verapamil *Vibramycin Viloxazine HCl [Vinblastine] [Vincristine] Zuclopenthixol |
*These drugs have been associated with acute attacks of porphyria. †Bracketed [] drugs are those in which experimental evidence of porphyringenicity is conflicting. |
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