MR imaging of acute intermittent porphyria mimicking reversible posterior leukoencephalopathy syndrome

Pathogenesis of acute encephalopathy in acute hepatic porphyria

Acute encephalopathy (AE) can be a manifestation of an acute porphyric attack. Clinical data were studied in 32 patients during AE with or without polyneuropathy (PNP) together with 12 subjects with PNP but no AE, and 17 with dysautonomia solely. Brain neuroimaging was done in 20 attacks during AE, and PEPT2 polymorphisms were studied in 56 subjects, 24 with AE. AE manifested as a triad of seizures, confusion and/or blurred vision. Symptoms lasting 1-5 days manifested 3-19 days from the onset of an attack. 55% of these patients had acute PNP independent of AE. Posterior reversible encephalopathy syndrome (PRES) was detected in 42% of the attacks. These patients were severely affected and hyponatremic (88%). Reversible segmental vasoconstriction was rare. There was no statistical difference in hypertension or urinary excretion of porphyrin precursors among the patients with or without AE. In 94% of the attacks with AE, liver transaminases were elevated significantly (1.5 to fivefold, P = 0.034) compared to a normal level in 87% of the attacks with dysautonomia, or in 25% of patients with PNP solely. PEPT2*2/2 haplotype was less common among patients with AE than without (8.3% vs. 25.8%, P = 0.159) and in patients with PNP than without (9.5% vs. 22.9%, P = 0.207), suggesting a minor role, if any, in acute neurotoxicity. In contrast, PEPT2*2/2 haplotype was commoner among patients with chronic kidney disease (P = 0.192). Acute endothelial dysfunction in porphyric encephalopathy could be explained by a combination of abrupt hypertension, SIADH, and acute metabolic and inflammatory factors of hepatic origin.

Acute Hepatic Porphyrias: "Purple Flags"-Clinical Features That Should Prompt Specific Diagnostic Testing

BACKGROUND

Porphyrias are a group of rare diseases leading to dysregulation in heme biosynthesis and the accumulation of heme precursors, including porphyrinogens, which in their oxidized states [porphyrins] are reddish or purple. Acute hepatic porphyrias (AHP) comprise four diseases that cause acute debilitating neurovisceral attacks. Despite diagnostic advances, AHP is often undiagnosed or misdiagnosed due to a lack of disease awareness, low clinical suspicion, variable presentation, and nonspecific symptoms that mimic more common diseases. Delays in diagnosis and treatment increase the risk of serious acute and chronic complications.

METHODS

In order to assess whether symptoms alone or in combination might be utilized as important indicators or "purple flags" that, when present, should alert clinicians to suspect AHP and pursue specific diagnostic testing, we conducted a comprehensive review of the literature on AHP, including cohort studies and case reports over two epochs, from 1980 to 2006 and from 2012 to 2018.

RESULTS

We found that severe abdominal pain, with or without acute central nervous system manifestations and peripheral neuropathy, continues to be the most frequent symptom. Hyponatremia, change in urine color, and certain chronic symptoms were also identified as features that should raise suspicion of AHP. To improve diagnosis of AHP, clinicians need to take a broad perspective, including demographic data and medical history, into consideration.

CONCLUSIONS

The clinical features of AHP continue to be severe pain, especially pain in the abdomen. Other features that should raise suspicion are autonomic, peripheral, or central neuropathies, hyponatremia, and red-purple urine color.

Acute porphyrias - A neurological perspective

Acute hepatic porphyrias (AHP) can cause severe neurological symptoms involving the central, autonomic, and peripheral nervous system. Due to their relative rarity and their chameleon-like presentation, delayed diagnosis and misdiagnosis are common. AHPs are genetically inherited disorders that result from heme biosynthesis enzyme deficiencies and comprise four forms: acute intermittent porphyria (AIP), variegate porphyria (VP), hereditary coproporphyria (HCP), and ALA-dehydratase porphyria (ALADP). Depending on the clinical presentation, the main differential diagnoses are Guillain-Barré syndrome and autoimmune encephalitis. Red flags that could raise the suspicion of acute porphyria are neurological symptoms starting after severe (abdominal) pain, in association with reddish urine, hyponatremia or photodermatitis, and the presence of encephalopathy and/or axonal neuropathy. We highlight the diagnostic difficulties by presenting three cases from our neurological intensive care unit and give a comprehensive overview about the diagnostic findings in imaging, electrophysiology, and neuropathology.

Reversible splenial lesion syndrome (RESLES) due to acute intermittent porphyria with a novel mutation in the hydroxymethylbilane synthase gene

Background

Reversible splenial lesion syndrome (RESLES) is a clinico-radiological syndrome characterized by the presence of reversible lesions specifically involving the splenium of the corpus callosum (SCC). The cause of RESLES is unknown. However, infectious-related mild encephalitis/encephalopathy (MERS) with a reversible splenial lesion remains the most common cause of reversible splenial lesions. Acute intermittent porphyria (AIP) is an autosomal dominant disorder caused by a partial deficiency of porphobilinogen deaminase (PBGD), the third enzyme in the heme biosynthetic pathway. It can affect the autonomic, peripheral, and central nervous system.

Result

In this study, we report a 20-year-old woman with AIP who presented with MRI manifestations suggestive of RESLES, she had a novel HMBS nonsense mutation, a G to A mutation in base 594, which changed tryptophan to a stop codon (W198*). Conclusion: To the best of our knowledge, this is only one published case of RELES associated with AIP.

Porphyria: An Uncommon Cause of Posterior Reversible Encephalopathy Syndrome

Acute intermittent porphyria (AIP) is rare and the diagnosis is often delayed. It usually presents with abdominal symptoms, behavioural changes, seizures, tachycardia, and hypertension. MRI findings are usually normal or few contrast enhancing lesions may be present. Rarely , reversible vasogenic edema is seen on MRI as T2 weighted and FLAIR hyper intensity without diffusion restriction suggestive of posterior reversible encephalopathy syndrome (PRES). Review of literature suggests that there are only few case reports of AIP associated with PRES. Because diffusion-weighted MRI is normal, the lesions are likely caused by reversible vasogenic edema and transient breakdown of the blood-brain barrier. Treatment of porphyria consists of a high carbohydrate diet supplemented with the use of intravenous glucose and haematin infusions during acute attacks. Management of seizures with commonly used anti-epileptics including phenytoin, valproic acid, carbamazepine and barbiturates can worsen symptoms or precipitate acute attacks because of their enzyme inducing activity. Levetiracetam is the preferred choice these cases. Porphyria is an important differential diagnosis in patients with unexplained abdominal pain along with neuro-psychiatric manifestations. This case report adds to a handful of cases worldwide associating AIP with radiological findings of PRES.

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.

Acute Intermittent Porphyria Presenting with Posterior Reversible Encephalopathy Syndrome, Accompanied by Prolonged Vasoconstriction

A 20-year-old Japanese woman had an attack of acute intermittent porphyria (AIP). Magnetic resonance imaging (MRI) revealed symmetrical lesions in the cerebrum and cerebellar hemisphere, corresponding to posterior reversible encephalopathy syndrome (PRES). Our administration of heme arginate gradually improved the clinical condition associated with AIP and the level of metabolite of nitric oxide (NO), which is a vascular dilator. Repeated MRI and magnetic resonance angiography revealed exacerbated PRES, part of which showed a small infarction, accompanied by progressive vasoconstriction. These findings suggest that the recovery of NO by heme replacement alone is insufficient for preventing brain damage during an AIP attack.

Posterior reversible encephalopathy in the intensive care unit

Posterior reversible encephalopathy syndrome (PRES) is increasingly diagnosed in the emergency department, and medical and surgical intensive care units. PRES is characterized by acute onset of neurologic symptoms in the setting of blood pressure fluctuations, eclampsia, autoimmune disease, transplantation, renal failure, or exposure to immunosuppressive or cytotoxic drugs, triggers known to admit patients to the intensive care unit (ICU). Although the exact pathophysiology remains unknown, there is growing consensus that PRES results from endothelial dysfunction. Because of the heterogeneous nature of the disorder, it is probable that different mechanisms of endothelial injury are etiologically important in different clinical situations. The presence of bilateral vasogenic edema on brain imaging, particularly in parieto-occipital regions, is of great diagnostic utility but PRES remains a clinical diagnosis. Although largely reversible, PRES can result in irreversible neurologic injury and even death. The range of clinical and radiographic manifestations of the syndrome is probably broader than previously thought, and it is imperative that clinicians become familiar with the full spectrum of the disorder, as prompt recognition and elimination of an inciting factor improve outcome. PRES may be the most frequent toxic-metabolic encephalopathy seen in the ICU.

Mitochondrial energetic defects in muscle and brain of a Hmbs-/- mouse model of acute intermittent porphyria

Acute intermittent porphyria (AIP), an autosomal dominant metabolic disease (MIM #176000), is due to a deficiency of hydroxymethylbilane synthase (HMBS), which catalyzes the third step of the heme biosynthetic pathway. The clinical expression of the disease is mainly neurological, involving the autonomous, central and peripheral nervous systems. We explored mitochondrial oxidative phosphorylation (OXPHOS) in the brain and skeletal muscle of the Hmbs(-/-) mouse model first in the basal state (BS), and then after induction of the disease with phenobarbital and treatment with heme arginate (HA). The modification of the respiratory parameters, determined in mice in the BS, reflected a spontaneous metabolic energetic adaptation to HMBS deficiency. Phenobarbital induced a sharp alteration of the oxidative metabolism with a significant decrease of ATP production in skeletal muscle that was restored by treatment with HA. This OXPHOS defect was due to deficiencies in complexes I and II in the skeletal muscle whereas all four respiratory chain complexes were affected in the brain. To date, the pathogenesis of AIP has been mainly attributed to the neurotoxicity of aminolevulinic acid and heme deficiency. Our results show that mitochondrial energetic failure also plays an important role in the expression of the disease.

Severe neurologic manifestations in acute intermittent porphyria developed after spine surgery under general anesthesia: a case report

Porphyrias are inherited metabolic disorders resulting from a specific enzyme defect in the heme biosynthetic pathway. Porphyrias are induced by various precipitants. Clinical features include abdominal pain, neurologic manifestations, autonomic neuropathy, and mental disturbance. Diagnosis may be delayed because of variable symptoms that mimic other diseases and because of the rarity of of porphyrias. Although most patients with known porphyria can complete anesthesia and surgery safely, undiagnosed porphyric patients are in danger of porphyric crisis due to inadvertent exposure to precipitating drugs and environment. We report a case of a patient who experienced delayed emergence with neurological disturbance after general anesthesia, ultimately diagnosed as acute intermittent porphyria.

Posterior reversible encephalopathy syndrome in acute intermittent porphyria

BACKGROUND

Acute intermittent porphyria is an inherited disease that is rarely diagnosed in prepubertal children. It can affect the autonomic, peripheral, and central nervous system. Posterior reversible encephalopathy syndrome is a clinicoradiological entity characterized by headache, seizures, altered consciousness, and visual disorder associated with potentially reversible neuroradiological abnormalities predominantly in the parieto-occipital lobes. We report a child with acute intermittent porphyria who presented with radiological manifestations suggestive of posterior reversible encephalopathy syndrome.

PATIENT

A 9-year-old girl underwent an appendectomy after developing abdominal pain. She subsequently developed bilateral visual disturbance, confusion, seizures, hypertension, tachycardia, nausea, vomiting, constipation, dark tea-colored urine, and recurrent abdominal pain.

RESULTS

Initial brain magnetic resonance imaging revealed hyperintense gyriform lesions on T2-weighted images and hypointense to isointense lesions on T1-weighted images in both parieto-occipital lobes with mild enhancement. The diagnosis of acute intermittent porphyria was confirmed by increased urinary excretion of porphyrin precursors. Her clinical signs gradually improved after intravenous high-dose glucose treatment and symptomatic therapies. A repeat magnetic resonance imaging confirmed complete resolution of the parieto-occipital lesions, suggesting with posterior reversible encephalopathy syndrome.

CONCLUSIONS

The association of abdominal pain, mental status changes, and autonomic dysfunction should arouse the suspicion of acute intermittent porphyria. Acute intermittent porphyria can be associated with posterior reversible encephalopathy syndrome.

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.

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.

Reversible MRI findings of porphyric encephalopathy. A report of two cases

We describe the magnetic resonance imaging (MRI) findings in two patients admitted to our institution with neuropsychiatric symptoms and severe abdominal pain diagnosed as acute intermittent porphyria (AIP). MRI revealed multiple lesions which regressed following treatment. We suggest reversible cerebral vasospasm underlies the MRI abnormalities and the cerebral symptoms in porphyria.

Postoperativ aufgetretene reversible posteriore Enzephalopathie bei einem Patientin mit Morbus Crohn

Posterior encephalopathy (PE) is a rare condition with different origins and unknown pathogenesis. We report on a case of a 16-year-old boy with Crohn's disease who developed PE after peridural anesthesia with ropivacain. A possible connection between PE, ropivacain and Crohn's disease is discussed on the basis of the current literature.

Tumor lysis syndrome as a contributory factor to the development of reversible posterior leukoencephalopathy

INTRODUCTION

Reversible posterior leukoencephalopathy syndrome (RPLS) is a recently described clinical and radiological entity comprising headache, seizures, altered level of consciousness and visual disturbances in association with transient posterior cerebral white-matter abnormalities.

METHOD

We report a young woman with Burkitt's lymphoma who developed RPLS after combined chemotherapy administered during the tumor lysis syndrome.

RESULTS

The symptoms in this patient fitted well with those of RPLS; they included abrupt alterations in mental status, seizures, headache, visual changes and characteristic neuroradiological findings. She was given further combination chemotherapy without any neurological complications, at which time she had already recovered from both RPLS and tumor lysis syndrome.

CONCLUSION

Although many etiological factors have been reported in the development of RPLS, the underlying mechanism is not yet well understood. With prompt and appropriate management, RPLS is usually reversible, and chemotherapy can be continued after complete recovery from RPLS. We suggest that tumor lysis syndrome should be considered as a contributory factor to the development of RPLS in patients for whom treatment with combined chemotherapy for hematological malignancies is planned.

Diffusion-Weighted Imaging in Acute Stroke

Diffusion MR imaging has improved evaluation of acute ischemic stroke vastly. It is highly sensitive and specific in the detection of infarction at early time points when CT and conventional MR sequences are unreliable. The initial DWI lesion is believed to represent infarction core and usually progresses to infarction unless there is early reperfusion. The initial DWI lesion volume and ADC ratios correlate highly with final infarction volume and with acute and chronic neurologic assessment tests. ADC values may be useful in differentiating tissue destined to infarct from that potentially salvageable with reperfusion therapy. ADC values also may be useful for determining tissue at risk of HT after reperfusion therapy. DTI can quantify differences in the responses of gray versus white matter to ischemia. FA may be important in determining stroke onset time, and tractography provides early detection of wallerian degeneration that may be important in determining prognosis. Finally, DWI can determine which patients who have TIA are at risk for subsequent large vessel infarction and can differentiate stroke from stroke mimics. With improvements in MR software and hardware, diffusion MR undoubtedly will continue to improve the management of patients who have acute stroke.

Imaging of acute neurological conditions in pregnancy and the puerperium

Eclampsia is one of the most common acute neurological events occurring during pregnancy. However, there are many other conditions that can present during pregnancy and the puerperium and that may either mimic eclampsia or produce other acute neurological manifestations. Frequently the symptoms and signs are non-specific, and it can be difficult to differentiate between these conditions on clinical grounds alone. Neuroradiological studies can provide valuable diagnostic information, and interventional radiological procedures may play a part in the subsequent management of these conditions. This review focuses on the imaging of acute neurological conditions which may be associated with, or present during, pregnancy and the puerperium.

Kortikale Amaurosis und Status epilepticus bei akuter Porphyrie

The most common neurologic manifestations of acute intermittent porphyria (AIP) are autonomic visceral neuropathy, peripheral motor neuropathy, and CNS dysfunctions including seizures and neuropsychiatric disturbances. In rare instances, however, AIP patients have presented with acute cortical blindness. We present a 20-year-old woman who suffered her first attack of AIP. Following 1 week of abdominal pain, she was transferred from a surgical department because of sudden visual loss and deterioration of consciousness. On admission, she developed several generalized seizures. Magnetic resonance imaging showed bilateral DWI lesions occipitally and in the left anterior circulation. Cerebrospinal fluid, MR angiography, and duplex ultrasound were normal. On the following day, sedation and intubation became necessary because of a generalized status epilepticus. Analysis of porphyrinogens in blood, urine and stool showed significantly elevated values. Intravenous therapy with häm-arginate was initiated and antiepileptic therapy was changed to gagabentine. Under this therapeutical regime she remained stable and extubation was possible 48 h later.

Diffusion-Weighted Imaging in Acute Stroke

In magnetic resonance diffusion-weighted imaging (DWI), regions of the brain are depicted not only on the basis of physical properties, such as T2 relaxation and spin density, which influence image contrast in conventional MR imaging, but also by local characteristics of water molecule diffusion. The diffusion of water molecules is altered in a variety of disease processes, including ischemic stroke. The changes that occur in acute infarction enable DWI to detect very early ischemia. Also, because predictable progression of diffusion findings occurs during the evolution of ischemia, DWI enables more precise estimation of the time of stroke onset than does conventional imaging.

The role of tumor lysis in reversible posterior leukoencephalopathy syndrome

We report on a child with B-cell lymphoma who developed hypertension and reversible posterior leukoencephalopathy syndrome (RPLS) after chemotherapy conducted during recovery from tumor lysis syndrome. After recovery from RPLS, the patient received further combination chemotherapy without recurrence of the neurological signs or symptoms suggestive of RPLS. Many etiological factors have been reported in the development of RPLS; however, little attention has been paid to tumor lysis syndrome as a contributory factor for RPLS. Tumor lysis syndrome can precipitate the development of RPLS in patients with hematological malignancies who are undergoing chemotherapy. Knowledge and awareness would help facilitate immediate management such as normalization of blood pressure and temporary cessation of chemotherapy, helping to avoid irreversible brain damage.

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.

Reversible Leukoencephalopathy Syndrome Associated to Leukopenia in a Chronic Hemodialysis Patient

Reversible leukoencephalopathy syndrome (RLS) is a rare brain disorder, characterized by diffuse attenuation of cerebral white matter, which has been most commonly observed in transplant patients receiving calcineurin inhibitors or in patients with severe hypertension. We report an episode of RLS in a 22-year-old male patient on chronic hemodialysis with well-controlled moderate hypertension who presented with de novo headache and generalized seizures. Cranial magnetic resonance image (MRI) revealed multiple areas of increased signal intensity in the white matter on T2-weighed images which resolved spontaneously at subsequent MRIs. White blood cell count showed leucopenia with normal CD4 count at flow cytometry. A viral etiology could not be demonstrated. Reversible leukoencephaolopathy syndrome symptoms remitted within 72 h but leukopenia persisted over 10 months. The patient received a kidney transplant 15 months after RLS onset and has received cyclosporine since the second post-transplant day. No recurrence of RLS symptoms has been observed. The etiology of the MRI changes in the present case seemed not to be either vasogenic or cytotoxic.

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.

Reversible encephalopathy syndrome: report of 12 cases with follow-up

We report the clinical and neuroradiological features of reversible encephalopathy syndrome and follow-up results in 12 patients. This syndrome seems to be the result of an acute encephalopathy showing with brain edema mainly in the white matter (vasogenic edema). Diffusion-weighted magnetic resonance images are useful to distinguish this entity from acute ischemia. Early recognition and treatment often lead to complete neurological recovery. If unrecognized, the patient's condition can progress to central nervous system failure.

Reversible posterior leukoencephalopathy syndrome complicating cytotoxic chemotherapy for hematologic malignancies

Reversible posterior leukoencephalopathy syndrome (RPLS) is an uncommon but distinctive clinicoradiological entity comprising of headache, seizures, visual disturbance, and altered mental function, in association with posterior cerebral white matter edema. With appropriate management, RPLS is reversible in the majority of cases. Previous reported associations of RPLS include hypertension, eclampsia, renal failure, and use of immunosuppressive drugs; reports in the adult hematology setting are rare. We report two cases of adults undergoing treatment for hematological malignancies who developed RPLS, and we emphasize the importance of early recognition and institution of appropriate management in reducing the risk of development of permanent neurological disability.

Recurrent posterior reversible encephalopathy syndrome (PRES)

Posterior reversible encephalopathy syndrome is a proposed cliniconeuroradiological entity characterized by headache, altered mental status, cortical blindness, seizures, and other focal neurological signs, and a diagnostic magnetic resonance imaging picture. A variety of different etiologies have been reported like hypertension, pre-eclampsia/eclampsia, cyclosporin A or tacrolimus neurotoxicity, uraemia and porphyria. With early diagnosis and prompt treatment, the syndrome is usually fully reversible. We report a case of recurrent PRES of unknown aetiology following intensive care unit treatment and only moderately elevated blood pressure. Clinicians as well as radiologists must be familiar with this clinically frightening, underdiagnosed condition to assure timely diagnosis and treatment to prevent persistent deficits.

Dialysis disequilibrium: another reversible posterior leukoencephalopathy syndrome?

Dialysis disequilibrium syndrome is a disorder of the central nervous system in patients on dialysis. The underlying etiology is thought to be primarily due to cerebral edema; however, neuroradiologic findings have not been described previously. We describe a patient who presented with new onset headaches and status epilepticus after beginning hemodialysis. Her neuroimaging studies revealed white matter changes in the posterior parietal and occipital lobes similar to those seen in patients with reversible posterior leukoencephalopathy syndrome (RPLS). This case suggests that dialysis disequilibrium syndrome and RPLS may represent a spectrum of disorders in which the underlying mechanism is vasogenic edema.

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).