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Background and Aims: Porphyrias are inherited metabolic disorders caused by mutations in genes encoding enzymes involved in the heme biosynthetic pathway, leading to the accumulation of heme precursors. Acute hepatic porphyrias (AHP), including acute intermittent porphyria (AIP), can present with predominant peripheral neurological manifestations, often leading to a misdiagnosis as Guillain-Barré syndrome., Methods: We report a case of AIP initially presenting as a peripheral neuropathy mimicking Parsonage-Turner syndrome (neuralgic amyotrophy, NA). Clinical and electrophysiological evaluations were conducted, including nerve conduction studies and needle electromyography (EMG)., Results: A 41-year-old woman presented with burning pain and electric shock-like sensations in the shoulders and trunk, alongside asymmetrical motor weakness in the upper limbs affecting arm abduction and finger extension. Electrophysiological evaluation revealed involvement of the superior trunk of the brachial plexus and the posterior interosseous nerve. Initially diagnosed with NA, she showed significant improvement in proximal strength over nine months but relapsed at fourteen months with severe finger extension weakness. Concurrent severe abdominal pain with constipation led to the identification of elevated urinary porphobilinogen (PBG) and delta-aminolevulinic acid (ALA) levels, confirming AHP and specifically AIP via genetic and biochemical testing. The patient received hemin and givosiran infusions, resulting in decreased ALA levels, improvement of motor weakness, and no further attacks., Interpretation: This case underscores the need to consider AIP in the differential diagnosis of acute neuropathies like NA, especially when accompanied by abdominal pain and severe constipation. Early recognition and appropriate testing for PBG and ALA can prevent misdiagnosis and enable targeted treatment., (© 2024 The Author(s). Journal of the Peripheral Nervous System published by Wiley Periodicals LLC on behalf of Peripheral Nerve Society.)

One-year data from EXPLORE Part A showed high disease burden and impaired quality of life (QOL) in patients with acute hepatic porphyria (AHP) with recurrent attacks. We report baseline data of patients who enrolled in EXPLORE Part B for up to an additional 3 years of follow-up. EXPLORE B is a long-term, prospective study evaluating disease activity, pain intensity, and QOL in patients with AHP with ≥1 attack in the 12 months before enrollment or receiving hemin or gonadotropin-releasing hormone prophylaxis. Data were evaluated in patients with more (≥3 attacks or on prophylaxis treatment) or fewer (<3 attacks and no prophylaxis treatment) attacks. Patients in the total population (N = 136), and more (n = 110) and fewer (n = 26) attack subgroups, reported a median (range) of 3 (0-52), 4 (0-52), and 1 (0-2) acute attacks, respectively, in the 12 months prior to the baseline visit. Pain, mood/sleep, digestive/bladder, and nervous system symptoms were each experienced by ≥80% of patients; most received hemin during attacks. Almost three-quarters of patients reported chronic symptoms between attacks, including 85% of patients with fewer attacks. Pain intensity was comparable among both attack subgroups; most patients required pain medication. All groups had diminished QOL on the EuroQol visual analog scale and the European Organisation for Research and Treatment of Cancer Quality-of-life Questionnaire Core 30 versus population norms. Patients with AHP with recurrent attacks, even those having fewer attacks, experience a high disease burden, as evidenced by chronic symptoms between attacks and impaired QOL., (© 2022 The Authors. Journal of Inherited Metabolic Disease published by John Wiley & Sons Ltd on behalf of SSIEM.)

Acute intermittent porphyria (AIP) is a rare metabolic disease caused by mutations within the hydroxymethylbilane synthase gene. Previous studies have reported increased levels of plasma total homocysteine (tHcy) in symptomatic AIP patients. In this study, we present long-term data for tHcy and related parameters for an AIP patient cohort (n = 37) in different clinical disease-states. In total, 25 patients (68%) presented with hyperhomocysteinemia (HHcy; tHcy > 15 μmol/L) during the observation period. HHcy was more frequent in AIP patients with recurrent disease receiving heme arginate, than in nonrecurrent (median tHcy: 21.6 μmol/L; range: 10-129 vs median tHcy: 14.5 μmol/L; range 6-77). Long-term serial analyses showed a high within-person tHcy variation, especially among the recurrent patients (coefficient of variation: 16.4%-78.8%). HHcy was frequently associated with low blood concentrations of pyridoxal-5'-phosphate and folate, while cobalamin concentration and the allele distribution of the methylene-tetrahydrofolate-reductase gene were normal. Strikingly, 6 out of the 9 recurrent patients who were later included in a regime of givosiran, a small-interfering RNA that effectively reduced recurrent attacks, showed further increased tHcy (median tHcy in 9 patients: 105 μmol/L; range 16-212). Screening of amino acids in plasma by liquid-chromatography showed co-increased levels of methionine (median 71 μmol/L; range 23-616; normal <40), suggestive of acquired deficiency of cystathionine-β-synthase. The kynunerine/tryptophan ratio in plasma was, however, normal, indicating a regular metabolism of tryptophan by heme-dependent enzymes. In conclusion, even if HHcy was observed in AIP patients receiving heme arginate, givosiran induced an aggravation of the dysregulation, causing a co-increase of tHcy and methionine resembling classic homocystinuria., (© 2021 SSIEM.)

Introduction: A small proportion of patients with acute intermittent porphyria (AIP) suffer from recurrent porphyric attacks, with a severely diminished quality of life. In this retrospective case-control study, the burden of disease is quantified and compared among three AIP patient subgroups: cases with recurrent attacks, cases with one or occasional attacks and asymptomatic carriers., Methods: Data from patient records and questionnaires were collected in patients between 1960 and 2016 at the Erasmus Medical Center, Rotterdam, the Netherlands. We collected symptoms related to porphyria, porphyria related complications, attack frequency, hospitalisation frequency, hospitalisation days related to acute porphyric attacks, frequency of heme infusions and medical healthcare costs based on hospitalisations and heme therapy., Results: In total 11 recurrent AIP cases, 24 symptomatic AIP cases and 53 AIP carriers as controls were included. All recurrent patients reported porphyria related symptoms, such as pain, neurological and/or psychiatric disorders, and nearly all developed complications, such as hypertension and chronic kidney disease. In the recurrent cases group, the median lifelong number of hospitalisation days related to porphyric attacks was 82 days per patient (range 10-374), and they spent a median of 346 days (range 34-945) at a day-care facility for prophylactic heme therapy; total follow-up time was 243 person-years (PYRS). In the symptomatic non-recurrent group the median lifelong number of hospitalisation days related to porphyric attacks was 7 days per patient (range 1-78), total follow-up time was 528 PYRS. The calculated total medical healthcare cost for recurrent cases group was €5.8 million versus €0.3 million for the symptomatic cases group.

A survey was posted to 27 women with acute porphyria about complications and outcome of pregnancy. Fifteen women returned the completed questionnaire and the pregnancies were characterised depending on the timing of diagnosis of porphyria. Four women were diagnosed with porphyria before the first pregnancy, five during a pregnancy and six after pregnancy. Five women were diagnosed with porphyria from family studies and the remaining ten were diagnosed when they presented with acute symptoms. There were a total of 33 pregnancies and 23 live births. Four women reported symptoms associated with porphyria during pregnancy. Two women received treatment with haem arginate during pregnancy with one of them having haem arginate therapy weekly with no adverse effect either to her or the baby. One woman had acute pain and skin symptoms during pregnancy but was not diagnosed until after delivery, and another reported acute symptoms during pregnancy. There were no differences, compared to the general population, between birth weight and miscarriage rate, and there were few obstetric complications with only one patient having pre-eclampsia at 37 weeks gestation. These results show that pregnancy is typically uncomplicated in acute porphyria, and that problems are more likely if the porphyria has not been diagnosed previously. We found that administration of haem arginate during pregnancy is safe and its continuous use during pregnancy has no detrimental effect on the outcome of pregnancy.

Acute intermittent porphyria (AIP) results from a deficiency of the porphobilinogen deaminase enzyme of heme biosynthesis. The disease is exacerbated by a wide variety of drugs. Only steroids and azathioprine (Aza) have so far been considered safe in patients with AIP, and cyclosporine is listed as contraindicated. From the transplantation point of view, it is well known that cyclosporine (CsA) is a superior immunosuppressive agent compared to azathioprine. This case report presents a female patient evaluated for renal transplantation. A test dose of CsA was given, and no symptoms of AIP occurred. Renal transplantation with a cadaveric donor was performed, and the patient was immunosuppressed with CsA, Aza, and prednisolone. Following three acute rejections, Aza was replaced by mycophenolate mofetil. Nevertheless, graft function deteriorated slowly, necessitating return to dialysis 3 years after transplantation. No symptoms of AIP were observed while the patient was on cyclosporine and/or mycophenolate mofetil therapy, and the authors conclude that these drugs can be safely administered to at least some patients with AIP.

Acute intermittent porphyria results from a deficiency of the porphobilinogen deaminase enzyme of heme biosynthesis and is commonly exacerbated by a wide variety of medications. When referred a patient with acute intermittent porphyria for a renal transplant, only steroids and azathioprine were discovered as safe in patients with acute intermittent porphyria. The administration of many newer immunosuppressive medications, including calcineurin inhibitors, has not been documented in acute intermittent porphyria. Actually, cyclosporine is presently considered contraindicated in acute intermittent porphyria. To determine if calcineurin inhibitors would be tolerated in acute intermittent porphyria, cyclosporine and tacrolimus were administered pretransplant and were documented not to exacerbate acute intermittent porphyria. A successful renal transplant was then performed using tacrolimus. This is the first reported patient with documented acute intermittent porphyria to tolerate safely several of the newer immunosuppressive medications, including tacrolimus, mycophenolate, and rabbit antithymocytic globulin following renal transplantation. This patient's pretransplant evaluation also suggested that cyclosporine may be safe for some patients with acute intermittent porphyria.

The objective of this study was to assess melatonin production in patients with acute intermittent porphyria (AIP), with and without known epileptic seizures, as a guide to whether melatonin may have anti-convulsive or pro-convulsive effects in AIP. Melatonin concentration in urine, sampled over eight hours on two consecutive nights, was analysed in eight AIP patients with epileptic seizures and in 14 AIP relatives without epilepsy. The AIP patients with epileptic seizures had a significantly lower urinary excretion of melatonin, compared with their AIP relatives without epilepsy, which may indicate that melatonin has a protective effect on seizures.

Acute intermittent porphyria is one of a group of metabolic diseases called the porphyrias that may lead to symptoms of the central nervous system during an acute exacerbation. Certain drugs such as barbiturates are known to precipitate attacks of acute intermittent porphyria, but unfortunately there is little information regarding the safety of many psychotropic drugs in this disorder, especially the newer antidepressants and atypical antipsychotics. We report a case of an elderly patient with acute intermittent porphyria who was treated with a variety of psychotropic agents for a severe depression with psychotic features. Although many of the agents did not improve the psychiatric status of the patient, all the drugs were tolerated without precipitating an episode of acute intermittent porphyria. To our knowledge, this is the first report of the safe use of sertraline, venlafaxine, olanzapine, risperidone, clozapine, buspirone, trazodone, lorazepam, and clonazepam in a patient with documented acute intermittent porphyria. Our report also supports the safety of trifluoperazine. Although response and sensitivity to drugs may vary greatly among patients with this disorder, clinicians may want to consider the possibility of the above drugs to treat psychiatric symptoms in patients with acute intermittent porphyria.