Epidemiology and clinical characteristics of seizures in patients with acute intermittent porphyria

A case report of acute intermittent porphyria leading to severe disability

Acute intermittent porphyria (AIP) is a rare inherited metabolic disorder resulting from increased production of porphyrins and their precursors, δ-aminolevulinic acid (ALA) and porphobilinogen (PBG), due to deficiencies in the enzymatic activity of the heme synthesis pathway. The disease is typically characterized by a triad of abdominal pain, neurologic impairment symptoms, and psychiatric abnormalities. However, only a small percentage of patients present with this classic triad of symptoms. Our female patient, aged 23, was admitted to the hospital with a 4-year history of abnormal mood episodes and weakness in the limbs for over 1 week. She had a previous medical history of intestinal obstruction. After admission, a cranial MRI revealed reversible posterior leukoencephalopathy imaging manifestations, and the patient exhibited weakness of the extremities, respiratory failure, seizures, and severely reduced serum sodium concentration. The diagnosis of AIP was ultimately confirmed by a positive urine PBG-sunlight test and analysis of HMBS gene variants. The absence of typical triadic signs in acute attacks of AIP can make early recognition of the disease challenging. We present a case with multiple typical clinical manifestations of AIP in the hope of aiding clinicians in fully recognizing acute intermittent porphyria.

Portuguese Consensus on Acute Porphyrias: Diagnosis, Treatment, Monitoring and Patient Referral

Acute porphyrias are a group of rare genetic metabolic disorders, caused by a defect in one of the enzymes involved in the heme biosynthesis, which results in an abnormally high accumulation of toxic intermediates. Acute porphyrias are characterized by potentially life-threatening attacks and, for some patients, by chronic manifestations that negatively impact daily functioning and quality of life. Clinical manifestations include a nonspecific set of gastrointestinal, neuropsychiatric, and/or cutaneous symptoms. Effective diagnostic methods are widely available, but due to their clinical heterogeneity and non-specificity, many years often elapse from symptom onset to diagnosis of acute porphyrias, delaying the treatment and increasing morbidity. Therefore, increased awareness of acute porphyrias among healthcare professionals is paramount to reducing disease burden. Treatment of acute porphyrias is centered on eliminating the potential precipitants, symptomatic treatment, and suppressing the hepatic heme pathway, through the administration of hemin or givosiran. Moreover, properly monitoring patients with acute porphyrias and their relatives is fundamental to preventing acute attacks, hospitalization, and long-term complications. Considering this, a multidisciplinary panel elaborated a consensus paper, aiming to provide guidance for an efficient and timely diagnosis of acute porphyrias, and evidence-based recommendations for treating and monitoring patients and their families in Portugal. To this end, all authors exhaustively reviewed and discussed the current scientific evidence on acute porphyrias available in the literature, between November 2022 and May 2023.

Neurology of the acute hepatic porphyrias

Porphyrias are a set of rare inherited metabolic disorders, each of them representing a defect in one of the eight enzymes in the haem biosynthetic pathway resulting in the accumulation of organic compounds called porphyrins. Acute hepatic porphyrias (AHP) are those in which the enzyme deficiency occurs in the liver, of which acute intermittent porphyria is by far the most common subtype. Neurology of the AHP is still challenging in practice, and patients rarely receive the correct diagnosis early in the disease course. For AHP, which primarily affects the central and peripheral nervous system, the cause of symptoms seems to be the increased production of neurotoxic precursors, in particular delta-aminolaevulinic acid and porphobilinogen. Neurological complications usually result from severe episodes of acute attacks. The neurologic hallmark of porphyrias is an acute predominantly motor axonal neuropathy resembling a Guillain-Barré syndrome that generally occurs after the onset of other clinical features such as abdominal pain and central nervous system manifestations. Neuropsychiatric syndromes, seizures, encephalopathy, and cerebrovascular disorders are among the possible central nervous system presentations. Therapeutic approach to AHP is divided into management and prophylaxis of an acute attack, including long standing options such as intravenous hematin and new therapeutic agents such as givosiran.

Porphyria attacks in prepubertal children and adolescents

CONTEXT

The clinical and laboratory features of dominant acute hepatic porphyrias (AHPs) in prepubertal children and adolescents have not been well established.

OBJECTIVE

To evaluate clinical and laboratory features of AHPs in prepubertal children and adolescents compared to adults.

DATA SOURCES

OVID (Embase Classic+Embase and MEDLINE), Scopus, and Google Scholar.

STUDY SELECTION

Studies describing symptomatic children or adolescents (<18 years old) with increased urinary porphobilinogen were included.

DATA EXTRACTION

Two reviewers independently extracted the data, with a third reviewer arbitrating discrepancies.

RESULTS

100 studies were included describing 112 patients (26 prepubertal children and 86 adolescents). Differences were found between prepubertal children and adolescents regarding sex distribution (female-to-male ratio: 1:2 vs. 4:1), clinical manifestations, and concomitant clinical manifestations.

LIMITATIONS

There was variation in the methods used to diagnose porphyria attacks across studies, and some elements of the quality of individual studies were unclear.

CONCLUSIONS

Prepubertal children with AHPs and porphyria attacks presented with distinct demographic and clinical characteristics from adolescents and adults. Nearly two-thirds of the affected children were males, and about half had a concomitant medical condition that can constitutively upregulate hepatic δ-aminolevulinic acid synthase-1. Adolescents were comparable to adults in almost all respects.

Acute intermittent porphyria presenting with posterior reversible encephalopathy syndrome (PRES) and abdominal pain

Acute intermittent porphyria is a rare genetic condition in which disrupted haem synthesis causes overproduction of porphyrin precursors. Occasionally, it is associated with posterior reversible encephalopathy syndrome (PRES), presenting with headache, confusion, seizures and visual disturbance. We describe a patient with acute intermittent porphyria who presented with seizures and PRES, and who had previous unexplained severe abdominal pain. Acute intermittent porphyria should be considered as a possible cause of PRES, especially in those with unexplained abdominal pain, since delays in its diagnosis can result in permanent complications.

Acute intermittent porphyria: focus on possible mechanisms of acute and chronic manifestations

Porphyrias are a group of inherited metabolic diseases that include eight types, each of which is caused by a mutation that affects an enzyme of the heme biosynthetic pathway. When an enzyme defect has physiological significance, it leads to overproduction of pathway precursors prior to the defective step. The partial absence of the third enzyme in the heme biosynthetic pathway, porphobilinogen deaminase (PBGD) also known as hydroxymethylbilane synthase (HMBS), results in acute intermittent porphyria (AIP), which affects mainly women. Subjects who had AIP symptoms were deemed to have manifest AIP (MAIP). Clinical manifestations are usually diverse and non-specific. Acute AIP episodes may present with abdominal pain, nausea, and vomiting, and repeated episodes may result in a series of chronic injuries. Therefore, studying the mechanisms of acute and chronic manifestations of AIP is of great significance. This review aims to summarize the possible mechanisms of acute and chronic manifestations in patients with AIP.

Nonconvulsive status epilepticus secondary to acute porphyria crisis

Both variegate and acute intermittent porphyria can manifest with various neurological symptoms. Although acute symptomatic seizures have been previously described, they are typically tonic–clonic and focal impaired awareness seizures. Convulsive status epilepticus and epilepsia partialis continua are rare and have been described on a case report basis. To our knowledge, there are no previously reported cases describing non-convulsive status epilepticus (NCSE) with electroencephalogram (EEG) documentation in the setting of acute porphyria crisis. We report a unique presentation of NCSE, which resolved after administering levetiracetam in a patient with variegate porphyria, without a known seizure disorder.

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Seizures among acute intermittent porphyria (AIP) patients are not uncommon with prevalence being as high as 10%–20%.

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Non-convulsive status epilepticus (NCSE) in variegate porphyria (VP) patients should be considered in patients with altered mental status and acute porphyric crisis.

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Recognition and avoidance of prophyrogenic anti-seizure medications is important in the treatment of these patients.

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Levetiracetam and hemin are potential treatment combinations for nonconvulsive status epilepticus in acute porphyria crisis patients.

Acute intermittent porphyria presenting with seizures and posterior reversible encephalopathy syndrome: Two case reports and a literature review

INTRODUCTION

Acute intermittent porphyria (AIP) is a rare and challenging hereditary neurovisceral disease with no specific symptoms. Posterior reversible encephalopathy syndrome (PRES) is a clinicoradiological syndrome with bilateral reversible posterior gyriform lesions that can be associated with many different conditions, including AIP. Usually, peripheral neuropathy is considered the most common neurological manifestation of AIP. However, AIP should also be considered when seizures and PRES are associated with unexplained abdominal pain.

CASE PRESENTATION

Both the patients were presented with seizures and PRES on brain magnetic resonance imaging (MRI). Unexplained abdominal pain occurred before the onset of seizures. The AIP diagnosis was made after repeated Watson-Schwartz tests. Hematin was not available for these 2 patients. However, supportive treatment including adequate nutrition and fluid therapy as well as specific antiepileptic drugs aided the patient's recovery and no acute attacks had occurred by the 3-year follow-up.

CONCLUSION

In contrast to other causes of PRES patients, seizure is the most common symptom in AIP patients with PRES. This is a strong diagnostic clue for AIP when ambiguous abdominal pain patients presented with seizures and PRES on brain MRI. A positive prognosis can be achieved with the combination of early recognition, supportive and intravenous hematin therapy, and withdrawal of precipitating factors, including some antiepileptic drugs.

Porphyria: often discussed but too often missed

The diagnosis of acute intermittent porphyria (AIP) is often overlooked. We describe a patient with this condition who had all the 'bells and whistles', in whom the diagnosis was only made after considerable delay. Far from an esoteric condition haunting examination candidates, AIP is an important cause of a broad spectrum of neurological symptoms. Its early recognition allows the astute clinician to prevent potentially devastating sequelae. We provide practical guidance on the investigation and management of this complex disorder. With a 'back to basics' approach to the underlying genetics and biochemistry, we hope to dispel some of the confusion that may obstruct a timely diagnosis.

Antiepileptic Drugs and Liver Disease

Acute, symptomatic seizures or epilepsy may complicate the course of hepatic disease. Choosing the most appropriate antiepileptic drug in this setting represents a difficult challenge, as most medications are metabolized by the liver. This article focuses on the acute and chronic treatment of seizures in patients with advanced liver disease and reviews the hepatotoxic potential of specific antiepileptic drugs. Newer antiepileptic drugs without, or with minimal, hepatic metabolism, such as levetiracetam, lacosamide, topiramate, gabapentin, and pregabalin should be used as first-line therapy. Medications undergoing extensive hepatic metabolism, such as valproic acid, phenytoin, and felbamate should be used as drugs of last resort. In special circumstances, as in patients affected by acute intermittent porphyria, exposure to most antiepileptic drugs could precipitate attacks. In this clinical scenario, bromides, levetiracetam, gabapentin, and vigabatrin constitute safe choices. For the treatment of status epilepticus, levetiracetam and lacosamide, available in intravenous preparations, are good second-line therapies after benzodiazepines fail to control seizures. Hepatotoxicity is also a rare and unexpected side effect of some antiepileptic drugs. Drugs such as valproic acid, phenytoin, and felbamate, have a well-recognized association with liver toxicity. Other antiepileptic drugs, including phenobarbital, benzodiazepines, ethosuximide, and the newer generations of antiepileptic drugs, have only rarely been linked to hepatotoxicity. Thus physicians should be mindful of the pharmacokinetic profile and the hepatotoxic potential of the different antiepileptic drugs available to treat patients affected by liver disease.

Clinical, Biochemical Characteristics and Hospital Outcome of Acute Intermittent Porphyria Patients: A Descriptive Study from North India

INTRODUCTION

Acute intermittent porphyria (AIP) is an inherited metabolic disease characterized by disordered heme biosynthesis. There is no recent study reported from India.

MATERIALS AND METHODS

It was a retrospective, observational study. Clinical records of patients of AIP with acute porphyric attacks admitted from April 2008 to December 2016 were analyzed.

RESULTS

Fifteen AIP patients constituted of eight females and seven males were analyzed. Mean age at presentation was 34.33 ± 15.86 years. Thirteen patients (86.67%) had acute flaccid paralysis (AFP). All of them had peripheral neuropathy. These patients concomitantly had abdominal pain, seizure, encephalopathy, autonomic hyperactivity, history of passage of dark urine, and electrolyte abnormality (hyponatremia) in various combinations. Abdominal pain was the presenting symptom in 11 (73.33%) patients. Seven (46.67%) patients had seizure episodes. Five patients (33.33%) had hyponatremia at presentation. Significantly higher percentage of them had seizure at presentation or during hospital stay (P = 0.007). These patients also had evidence of autonomic hyperactivity in the form of higher pulse rate, systolic and diastolic blood pressure at presentation. They had prolonged duration of hospital stay as well (P = 0.016). Eleven patients had partial recovery and rest four patients (26.67%) had in-hospital mortality.

CONCLUSION

Patients had severe neurological involvement manifesting mainly as AFP and seizure episodes. We recommend screening for AIP in patients presenting with features of AFP along with any combination of clinical/laboratory manifestations such as abdominal pain, seizure, encephalopathy, autonomic hyperactivity, passage of dark urine, and hyponatremia. Electrolyte abnormality in the form of hyponatremia was an important severity marker.

Acute Intermittent Porphyria in children: A case report and review of the literature

Acute Intermittent Porphyria (AIP), an autosomal dominant inborn error of heme metabolism, typically presents in adulthood, most often in women in the reproductive age group. There are limited reports on the clinical presentation in children, and in contrast to the adults, most of the reported pediatric cases are male. While acute abdominal pain is the most common presenting symptom in children, seizures are commonly seen and may precede the diagnosis of AIP. As an example, we report a 9year old developmentally normal pre-pubertal boy who presented with acute abdominal pain, vomiting and constipation followed by hyponatremia, seizures, weakness and neuropathy. After a diagnostic odyssey, his urine porphobilinogen was found to be significantly elevated and genetic testing showed a previously unreported consensus splice-site mutation IVS4-1G>A in the HMBS gene confirming the diagnosis of AIP. Here, we discuss the clinical presentation in this case, and 15 reported pediatric cases since the last review 30years ago and discuss the differential diagnosis and challenges in making the diagnosis in children. We review the childhood-onset cases reported in the Longitudinal Study of the Porphyrias Consortium. Of these, genetically and biochemically confirmed patients, 11 of 204 (5%) reported onset of attacks in childhood. Most of these patients (91%) reported recurrent attacks following the initial presentation. Thus, AIP should be considered in the differential diagnosis of children presenting with unexplained abdominal pain, seizures, weakness and neuropathy.

Electroencephalography of encephalopathy in patients with endocrine and metabolic disorders

Patients with acute alteration in mental status from encephalopathy because of underlying metabolic-toxic or endocrine abnormalities are frequently seen in the acute hospital setting. A rapid diagnosis and correction of the underlying cause is essential as a prolonged state of encephalopathy portends a poor outcome. Correct diagnosis and management remain challenging because several encephalopathies may present similarly, and further laboratory, imaging, or other testing may not always reveal the underlying cause. EEG provides rapid additional information on the encephalopathic patient. It may help establish the diagnosis and is indispensable for identifying nonconvulsive status epilepticus, an important possible complication in this context. The EEG may assist the clinician in gauging the severity of brain dysfunction and may aid in predicting outcome. This review summarizes the current knowledge on EEG findings in selected metabolic and endocrine causes of encephalopathy and highlights distinct EEG features associated with particular etiologies.

Acute porphyria presenting as epilepsia partialis continua

Purpose

The porphyrias are a defect in the biosynthesis of heme which can be associated with different neurological symptoms during acute attacks such as peripheral neuropathy, mental disturbance and seizures. So far, there have only been a few case reports of status epilepticus, none of which were of epilepsia partialis continua (EPC). We present here two cases of hereditary coproporphyria (HCP) manifesting EPC as part of the clinical presentation.

Method

The patients’ medical charts, EEG and imaging studies were carefully reviewed.

Results

Case 1 is a 49-year-old male who first presented a tonic-clonic seizure. Case 2 is a 30-year-old male who came to the emergency room for a convulsive status epilepticus. Both evolved to EPC over the next days. EPC persisted despite several antiepileptic drug trials. Diagnosis of HCP was confirmed by a high level of urine, fecal and serum porphyrins in both cases and by genetic testing in one. Over the last 3 years, the first patient has continued to present non-disabling EPC and has had four tonic-clonic seizures associated with alcohol consumption. The second patient died from brain edema one month and half after admission.

Conclusion

Acute porphyrias should be included in the differential diagnosis of new onset status epilepticus, including EPC. Their recognition is important as it modifies significantly patient management, since many anticonvulsants are porphyrogenic.

Porphyric neuropathy

Porphyric neuropathy often poses a diagnostic dilemma; it is typically associated with the hepatic porphyrias, characterized by acute life-threatening attacks of neurovisceral symptoms that mimic a range of acute medical and psychiatric conditions. The development of acute neurovisceral attacks is responsive to environmental factors, including drugs, hormones, and diet. This chapter reviews the clinical manifestations, genetics, pathophysiology, and mechanisms of neurotoxicity of the acute hepatic porphyrias. While the etiology of the neurological manifestations in the acute porphyrias remains undefined, the main hypotheses include toxicity of porphyrin precursors and deficiency of heme synthesis. These hypotheses will be discussed with reference to novel experimental models of porphyric neuropathy.

Purple pigments: the pathophysiology of acute porphyric neuropathy

The porphyrias are inherited metabolic disorders arising from disturbance in the haem biosynthesis pathway. The neuropathy associated with acute intermittent porphyria (AIP) occurs due to mutation involving the enzyme porphobilinogen deaminase (PBGD) and is characterised by motor-predominant features. Definitive diagnosis often encompasses a combination of biochemical, enzyme analysis and genetic testing, with clinical neurophysiological findings of a predominantly motor axonal neuropathy. Symptomatic and supportive treatment are the mainstays during an acute attack. If administered early, intravenous haemin may prevent progression of neuropathy. While the pathophysiology of AIP neuropathy remains unclear, axonal dysfunction appears intrinsically linked to the effects of neural energy deficits acquired through haem deficiency coupled to the neurotoxic effects of porphyrin precursors. The present review will provide an overview of AIP neuropathy, including discussion of recent advances in understanding developed through neurophysiological approaches that have further delineated the pathophysiology of axonal degeneration.

Diagnosing Epilepsy in the Elderly

Elderly individuals represent the fastest-growing segment of the US population. Seizures are common among elderly persons, and the etiology, clinical presentation, and prognosis of seizure disorders can often differ between elderly patients and younger individuals. However, published information regarding the diagnosis and management of epilepsy in elderly patients is scarce. Because a number of conditions that are common in elderly patients may resemble epilepsy, diagnosis can be challenging. Cardiovascular conditions, migraines, drug effects, infections, metabolic disturbances, sleep disorders, and psychiatric disorders are all associated with signs and symptoms that may often mimic epilepsy. New paradigms must be put into practice to establish an accurate diagnosis in the elderly patient; besides an initial evaluation, the patient history and an electroencephalogram should be obtained. Proper diagnosis is essential for proper treatment in the elderly patient.

Acute intermittent porphyria, Rasmussen encephalitis, or both?

A case of a young woman who suffers from refractory epilepsy in the form of Rasmussen encephalitis and acute intermittent porphyria is presented. The patient developed refractory partial seizures with progressive hemispheric atrophy in the first decade. Both her serum and cerebrospinal fluid contained significantly elevated levels of anti-GluR3B antibodies. Her serum also contained anti-NR2A antibodies (directed against the N-methyl-D-aspartate receptor). Seven years later, acute intermittent porphyria was diagnosed as she developed an acute episode of abdominal pain, dark urine, and hyponatremia. For several years, all attempts to discontinue porphyrinogenic antiepileptic drugs such as phenobarbital and valproate resulted in seizure worsening. During a major acute intermittent porphyria crisis, brain edema and coma developed, allowing the discontinuation of phenobarbital. On recovery, atrophy of the right hemisphere ensued. Several etiologic hypotheses are presented. Double insults, porphyria, and an autoimmune process are suggested for the development of Rasmussen encephalitis in this patient. The authors recommend testing for porphyria in cases of Rasmussen encephalitis and other intractable seizures.

An analysis of six cases of acute intermittent porphyria (AIP)

This analysis describes the diagnosis and psychiatric treatment modalities of 6 patients (5 women, 1 man; mean age 28.5 years) of acute intermittent porphyria (AIP), who presented to the Psychiatry OPD over a period of one year. The mean number of episodes was 2.83. Premorbid personality traits, clinical presentation, urine colour and urinary porphobilinogen titre were recorded. Among the 6 patients, 4 had abdominal pain, 5 had autonomic instability, all 6 had mental symptoms, 3 had depression, 2 came in delirium, and 3 had an episode of seizure.

Neuropsychiatric porphyria in patients with refractory epilepsy: report of three cases

OBJECTIVES

Although epileptic seizures are an infrequent feature of acute attacks of the neuropsychiatric porphyrias, there are no significant reports of porphyria in chronic epilepsy. This paper attempts to redress the balance.

METHODS

Three case reports, including detailed laboratory and molecular diagnostics.

RESULTS

Two patients with variegate porphyria and one with acute intermittent porphyria, referred within 1 year to a specialist porphyria service, with a long history of chronic refractory epileptic seizures, are described.

CONCLUSIONS

Porphyria may be an aetiological factor in some cases of chronic refractory partial or generalised epilepsy. Porphyria should also be considered if addition of a new anti-epileptic medication causes a major deterioration in the epilepsy.

Acute intermittent porphyria presenting as a diffuse encephalopathy

Although acute intermittent porphyria presents with dramatic neurological findings, the diagnosis is difficult. An 18-year-old woman had a clinical picture of porphyric encephalopathy. Magnetic resonance (MR) imaging demonstrated multiple large contrast-enhancing subcortical white matter lesions, which regressed with glucose and hematin infusions. Diffusion-weighted MR imaging was normal, and MR spectroscopy excluded acute demyelination or tissue necrosis. MR findings of acute intermittent porphyria can differ from those in posterior reversible encephalopathy syndrome by virtue of intense contrast enhancement. Because diffusion-weighted MR imaging and spectroscopy were normal, the lesions are likely caused by reversible vasogenic edema and transient breakdown of the blood-brain barrier.

An analysis of 112 acute porphyric attacks in Cape Town, South Africa: Evidence that acute intermittent porphyria and variegate porphyria differ in susceptibility and severity

Four forms of porphyria may present clinically with the acute attack, an episodic, severe, and potentially life-threatening manifestation characterized by abdominal and neurologic symptoms. We describe our experience with 112 consecutive attacks observed and treated in 25 patients with the 2 most common forms of acute porphyria in Cape Town, South Africa; 25 attacks in 10 patients with variegate porphyria and 87 attacks in 14 patients with acute intermittent porphyria. The remaining patient experienced more than 100 sequential, severe, and poorly remitting attacks, which are not included in our analysis. In our population, the relative risk of an acute attack in acute intermittent porphyria compared with that in variegate porphyria was 14.3 (confidence intervals, 6.3-32.7). Patients with variegate porphyria were significantly older (median age at first attack, 30 yr) than those with acute intermittent porphyria (median age at first attack, 23.5 yr; p < 0.0001), and demonstrated an equal sex ratio, whereas the male:female ratio in acute intermittent porphyria was 2:12 (p < 0.0001). There was a significant difference in the incidence of factors precipitating the acute attack. Drug exposure was a frequent precipitant of the acute attack in variegate porphyria, whereas hormonal factors were more important in acute intermittent porphyria (p < 0.00001). Patients with acute intermittent porphyria also showed a trend to earlier and more frequent recurrent acute attacks following the initial admission. Mean urine precursor levels, blood pressure, pulse rate, and heme arginate requirement were all significantly higher in patients with acute intermittent porphyria. No significant difference in the frequency of serious complications or in outcome could be shown. We describe our experience with treatment with heme arginate, and provide evidence that heme arginate results in a prompt and statistically significant improvement in symptoms. The incidence of serious complications and mortality in this series was low, confirming a trend to an increasingly good prognosis for patients with acute porphyria who receive expert treatment.

Refractory status epilepticus due to acute hepatic porphyria in a pregnant woman: induced abortion as the sole therapeutic option?

A 22-years old, 55 kg female patient in the twelfth week of pregnancy developed neuropsychiatric syndromes and in the following status epilepticus. Raised porphyrines and porphyrine precursors were found in the patient's urine. Despite intravenous glucose infusions and appropriate medication no reduction in seizure-frequency and neuropsychiatric syndromes was observed. An abortion was induced. After the interruption and starting of haem arginate therapy, seizure activity stopped and porphyrine precursors returned to normal levels, and after 6 weeks the patient was discharged in excellent clinical condition. This report describes a status epilepticus caused by acute hepatic porphyria, triggered by pregnancy, in a 22-years old woman. To our knowledge this is the first report of induced abortion as successful treatment in acute hepatic porphyria induced status epilepticus.

Epilepsy and porphyria: new perspectives

Porphyria is a group of disorders caused by alterations in the enzymatic pathway involved in haem biosynthesis. The clinical picture consists of extraneurological and neurological manifestations, seizures being an important feature. The pathogenesis of seizures is probably related to metabolic imbalance such as hyponatremia and to the intrinsic epileptogenic role of some porphyrins. Many studies report that neural damage can follow a porphyric attack, suggesting that these lesions can be epileptogenic. Several reports also pointed out that porphyria can be precipitated by some antiepileptic drugs (AEDs). More recent AEDs appeared and need assessment in relation to porphyria. An educational program including a registry of patients with porphyria, an intensive study of family history and the genetic background may be useful to obtain better epidemiological data and a clearer understanding of pathogenesis. Application of neuroimaging may detect epileptogenic foci, helping to define the specific risk of seizures for each patient.

Porphyria and dementia: a case report

The porphyrias are a group of rare hereditary metabolic disorders where there is an excess formation and excretion of porphyrins or their precursors. Type IIA, acute intermittent porphyria (AIP), has an estimated prevalence of one to eight per 100,000 in the general population but is thought to have a higher prevalence in psychiatric patients. AIP can present with a variety of psychiatric symptoms, often misdiagnosed. Associated neuropathological changes including focal cerebral ischaemic lesions have been found. However, to our knowledge, no case of dementia and AIP has been described. We present the case of a 56 year old man with a five-year history of progressive cognitive decline, diagnosed with AIP at an advanced stage of dementia. Whether AIP contributed to the dementia or is a coincidental finding is unknown. However treatment of AIP in this case resulted in some improvement in the patient's cognitive state.

Human hereditary hepatic porphyrias

The human hereditary hepatic porphyrias are diseases due to marked deficiencies of enzymes in the heme biosynthetic pathway. Porphyrias can be classified as either hepatic or erythroid, depending on the major production site of porphyrins or their precursors. The pathogenesis of inherited hepatic porphyrias has now been defined at the molecular level. Some gene carriers are vulnerable to a range of exogenous and endogenous factors, which may trigger neuropsychiatric and/or cutaneous symptoms. Early diagnosis is of prime importance since it makes way for counselling. In this article we present an overview of recent advances on hepatic porphyrias: 5-aminolevulinic acid dehydratase deficiency porphyria, acute intermittent porphyria (AIP), porphyria cutanea tarda (PCT), hereditary coproporphyria (HC), and variegate porphyria (VP).

Acute intermittent porphyria, seizures, and antiepileptic drugs: a report on a 3-year-old Nigerian boy

A 3-year-old Nigerian boy was treated with phenobarbitone after having a nonfebrile seizure. Two weeks later his urine was found to contain porphobilinogen, indicating that latent acute intermittent porphyria had been unmasked by phenobarbitone. The drug was discontinued and carbamazepine was substituted. The urine became free of porphobilinogen and the patient remained well. In developing countries phenobarbitone is the most widely used anticonvulsant; it must be avoided in acute intermittent porphyria, and carbamazepine may be tolerated.

Intrastriatal administration of 5-aminolevulinic acid induces convulsions and body asymmetry through glutamatergic mechanisms

The involvement of glutamatergic and GABAergic mechanisms in the behavioral effects induced by the intrastriatal injection of 5-aminolevulinic acid (ALA) (1-8 mgr;mol/2 mgr;l), a metabolite that accumulates in porphyrias, was evaluated. ALA administration to adult female rats increased locomotor activity, induced clonic convulsions and elicited dose-dependent body asymmetry assessed by the elevated body swing test. ALA-induced convulsions were prevented by intrastriatal preadministration of the glutamate antagonists, 6, 7-dinitroquinoxaline-2,3-dione (8 nmol/0.5 microl) or dizocilpine (2. 5 nmol/0.5 microl), but not by the GABA agonist, muscimol (46 pmol/0. 5 microl). Body asymmetry was prevented only by 6, 7-dinitroquinoxaline-2,3-dione pretreatment. A higher dose of muscimol (92 pmol/0.5 microl) prevented both ALA-induced convulsions and body asymmetry. However, this dose of muscimol induced motor biases, which make difficult to ascertain the involvement of GABA(A) receptors in ALA-induced behavioral effects. This study suggests that glutamatergic mechanisms underlie the ALA-induced convulsions and body asymmetry. The present results may be of value in understanding the physiopathology of the neurological dysfunction occurring in acute porphyrias.

The acute porphyrias

The various types of acute porphyria are discussed, as well as their mode of inheritance and the enzyme deficiencies responsible for the symptoms. The symptoms and signs of an acute attack are then described, especially those due to neuropathies and to disturbances of behaviour. Agents which can precipitate attacks are listed. These are most frequently drugs, and as they include those used for anti-epileptic treatment problems soon arise as seizures often occur in this condition. The main complications are hypertension and renal failure, and examples of hyponatraemia and folate deficiency are illustrated. The urgency to diagnose this disorder lies in the need to avoid precipitating factors. Screening tests are discussed, and those needed to confirm the diagnosis. The prognosis has improved over the years, due to increased awareness of the disorder, and better management. During an acute attack the treatment of pain and vomiting will be of particular importance, and then haematin or chelating agents can be tried. With better management most of those who have inherited acute porphyria should be able to lead a normal life.

Treatment of seizures in acute intermittent porphyria: safety and efficacy of gabapentin

Treatment of seizures in acute intermittent porphyria represents a therapeutic dilemma. Patients needing chronic therapy often experience acute porphyric attacks due to increased hepatic metabolism induced by the antiepileptic drugs themselves. Gabapentin is a new antiepileptic drug not appreciably metabolized by the liver in humans, and it appears to be safe and effective in the maintenance therapy of epilepsy in these patients. We report a patient affected by partial and generalized seizures in the course of acute intermittent porphyria, who was safely and successfully treated with gabapentin.

Medical causes of seizures

Seizures are commonly encountered in patients who do not have epilepsy. Factors that may provoke such seizures include organ failure, electrolyte imbalance, medication and medication withdrawal, and hypersensitive encephalopathy. There is usually one underlying cause, which may be reversible in some patients. A full assessment should be done to rule out primary neurological disease. Treatment of seizures in medically ill patients is aimed at correction of the underlying cause with appropriate short-term anticonvulsant medication. Phenytoin is ineffective in the management of seizures secondary to alcohol withdrawal, and in those due to theophylline or isoniazid toxicity. Control of blood pressure is important in patients with renal failure and seizures. Non-convulsive status epilepticus should be considered in any patient with confusion or coma of unclear cause, and electroencephalography should be done at the earliest opportunity. Most ill patients with secondary seizures do not have epilepsy, and this should be explained to patients and their families. Only those patients with recurrent seizures and uncorrectable predisposing factors need long-term treatment with anticonvulsant medication.

[Acute intermittent porphyria associated with epilepsy in a child: diagnostic and therapeutic difficulties]

BACKGROUND

Acute intermittent porphyria is an autosomal dominant inborn error of heme biosynthesis. The diagnosis of acute porphyria is rare before puberty. Its association with epilepsy induces difficulties in diagnosis and seizure treatment.

CASE REPORT

A case of acute intermittent porphyria in a 9-year old boy with epilepsy is reported. The diagnosis was made only after the third hospitalisation, with the measurement of enzyme activity and identification of family members with latent disease. Adjustment of antiepileptic treatment was necessary 7 months later.

CONCLUSION

Most antiepileptic drugs are unsafe because they have demonstrated porphyrinogenicity. Low doses of clonazepam can be used in this situation.

The little imitator--porphyria: a neuropsychiatric disorder

Three common subtypes of porphyria give rise to neuropsychiatric disorders; acute intermittent porphyria, variegate porphyria, and coproporphyria. The second two also give rise to cutaneous symptoms. Neurological or psychiatric symptoms occur in most acute attacks, and may mimic many other disorders. The diagnosis may be missed because it is not even considered or because of technical problems, such as sample collection and storage, and interpretation of results. A negative screening test does not exclude the diagnosis. Porphyria may be overrepresented in psychiatric populations, but the lack of control groups makes this uncertain. The management of patients with porphyria and psychiatric symptoms causes considerable problems. Three cases are described to illustrate some of these issues. Advances in molecular biology permit identification of patients and latent carriers in the family. Care to avoid relapses and improved treatments have reduced the mortality.