Acute intermittent porphyria presenting as a diffuse encephalopathy

Porphyric encephalopathy in a 15-year-old girl: A case report

A 15-year-old girl presented with new onset tonic-clonic seizures, encephalopathy, abdominal pain, and hypertension with a history of weight loss and emesis. Brain magnetic resonance imaging scans showed diffuse, bilateral cortical and subcortical gray and white matter signal abnormalities. Electroencephalography showed background slowing and disorganization. Extensive evaluation for infection, toxic metabolic, autoimmune disorders, and vasculitis were negative. She was noted to have dark red-colored urine with no red blood cells. Her urine porphobilinogen level was markedly elevated, consistent with the diagnosis of acute intermittent porphyria. She was treated with intravenous hemin with resolution of her neurologic and gastrointestinal symptoms. A hydroxymethylbilane synthase (porphobilinogen deaminase) pathogenic variant was found in porphyria gene panel confirming the diagnosis of acute intermittent porphyria. This case demonstrates a diagnostic challenge posited by a presentation of new onset seizure and encephalopathy due to acute intermittent porphyria, a rare and often overlooked condition in pediatrics.

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 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.

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.

Analysis of biomarkers and metabolic pathways in patients with unstable angina based on ultra‑high‑performance liquid chromatography‑quadrupole time‑of‑flight mass spectrometry

Unstable angina (UA) is a coronary disease with a high mortality and morbidity worldwide. The present study aimed to use non-invasive techniques to identify urine biomarkers in patients with UA, so as to provide more information for the early diagnosis and treatment of the disease. Based on metabolomics, urine samples from 28 patients with UA and 28 healthy controls (HCs) were analyzed using ultra-high-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF/MS). A total of 16 significant biomarkers that could distinguish between patients with UA and HCs, including D-glucuronic acid, creatinine, succinic acid and N-acetylneuraminic acid, were identified. The major metabolic pathways associated with UA were subsequently analyzed by non-targeted metabolomics. The results demonstrated that amino acid and energy metabolism, fatty acid metabolism, purine metabolism and steroid hormone biosynthetic metabolism may serve important roles in UA. The results of the current study may provide a theoretical basis for the early diagnosis of UA and novel treatment strategies for clinicians. The trial was registered with the Chinese Clinical Trial Registration Center (registration no. ChiCTR-ROC-17013957) at Tianjin University of Traditional Chinese Medicine.

Porphyria-induced posterior reversible encephalopathy syndrome and central nervous system dysfunction

BACKGROUND AND AIM

An association between neuropsychiatric manifestations and neuroimaging suggestive of posterior reversible encephalopathy syndrome (PRES) during porphyric attacks has been described in numerous case reports. We aimed to systematically review clinical-radiological features and likely pathogenic mechanisms of PRES in patients with acute hepatic porphyrias (AHP) and porphyric attacks.

METHODS

PubMed, Scopus, Ovid MEDLINE, and Google Scholar were searched (July 30, 2019). We included articles describing patients with convincing evidence of an AHP, confirmed porphyric attacks, and PRES in neuroimaging.

RESULTS

Forty-three out of 269 articles were included, which reported on 46 patients. Thirty-nine (84.8%) patients were women. The median age was 24 ± 13.8 years. 52.2% had unspecified AHP, 41.3% acute intermittent porphyria, 4.3% hereditary coproporphyria, and 2.2% variegate porphyria. 70.2% had systemic arterial hypertension. Seizures, mental changes, arterial hypertension, and hyponatremia occurred more frequently than expected for porphyric attacks (p < .001). Seizures and hyponatremia were also more frequent than expected for PRES. The most common distributions of brain lesions were occipital (81.4%), parietal (65.1%), frontal (60.5%), subcortical (40%), and cortical (32.5%). Cerebral vasoconstriction was demonstrated in 41.7% of the patients who underwent angiography. 19.6% of the patients had ischemic lesions, and 4.3% developed long-term sequelae (cognitive decline and focal neurological deficits).

CONCLUSIONS

Brain edema, vasoconstriction, and ischemia in the context of PRES likely account for central nervous symptoms in some porphyric attacks.

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.

Reversible MRI findings in a case of acute intermittent porphyria with a novel mutation in the porphobilinogen deaminase gene

Acute intermittent porphyria (AIP) is an autosomal dominant disorder caused by a partial deficiency of porphobilinogen deaminase (PBGD), the third enzyme in the of heme biosynthetic pathway. 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. Establishing accurate diagnoses of the patient and asymptomatic family members with AIP involves identifying the PBGD enzyme mutations directly. In this study, we report a 28-year-old woman with acute intermittent porphyria who presented with radiological manifestations suggestive of posterior reversible encephalopathy syndrome, she had a novel PBGD frame shift mutation, base 875 and 876 have been deleted resulting in glutamine to a stop codon (Gln292fs), in a Chinese family.

Inherited or acquired metabolic disorders

This chapter starts with a description of imaging of inherited metabolic disorders, followed by a discussion on imaging of acquired toxic-metabolic disorders of the adult brain. Neuroimaging is crucial for the diagnosis and management of a number of inherited metabolic disorders. Among these, inherited white-matter disorders commonly affect both the nervous system and endocrine organs. Magnetic resonance imaging (MRI) has enabled new classifications of these disorders that have greatly enhanced both our diagnostic ability and our understanding of these complex disorders. Beyond the classic leukodystrophies, we are increasingly recognizing new hereditary leukoencephalopathies such as the hypomyelinating disorders. Conventional imaging can be unrevealing in some metabolic disorders, but proton magnetic resonance spectroscopy (MRS) may be able to directly visualize the metabolic abnormality in certain disorders. Hence, neuroimaging can enhance our understanding of pathogenesis, even in the absence of a pathologic specimen. This review aims to present pathognomonic brain MRI lesion patterns, the diagnostic capacity of proton MRS, and information from clinical and laboratory testing that can aid diagnosis. We demonstrate that applying an advanced neuroimaging approach enhances current diagnostics and management. Additional information on inherited and metabolic disorders of the brain can be found in Chapter 63 in the second volume of this series.

An intensive care approach to posterior reversible encephalopathy syndrome (PRES): An analysis of 7 cases

OBJECTIVE

The aim of this study was to retrospectively evaluate the intensive care unit treatments applied to obstetrics patients with a diagnosis of posterior reversible encephalopathy syndrome (PRES).

MATERIAL AND METHODS

The cases of 7 pregnant patients who had been diagnosed with PRES between July 2011 and July 2013 were retrospectively reviewed. The patients' clinical data, brain magnetic resonance imaging (MRI) images before and after treatment, and neuropsychological tests were evaluated.

RESULTS

Five out of 7 patients had eclampsia, 1 patient had severe preeclampsia, and 1 patient developed HELLP syndrome secondary to PRES. Calcium channel blockers and β-blockers were used as antihypertensive treatment. All patients were treated with parenteral magnesium sulfate. In addition, sodium thiopental was given to control sedation and convulsions in all patients except 1. The neurological and radiological findings of all cases treated in the intensive care unit improved.

CONCLUSION

Posterior reversible encephalopathy syndrome is a clinical condition with a multifactorial etiology and can result in different clinical findings. Radiological imaging techniques can be used for the diagnosis of PRES. Pregnancy and the postpartum period often lead to this syndrome. In some cases, PRES can cause irreversible neurological deficits or death. For patients with severe radiological findings, early diagnosis and thiopental infusion, in addition to treatment with antihypertensive agents and magnesium sulfate, may lead to quicker and more effective recovery from clinical manifestations. We suggest supplementation of standard treatment with early thiopental infusion.

Differential diagnosis of white matter lesions: Nonvascular causes-Part II

The knowledge of characteristic lesion patterns is important in daily practice imaging, as the radiologist increasingly is required to provide precise differential diagnosis despite unspecific clinical symptoms like cognitive impairment and missed elaborated neurological workup. This part II dealing with nonvascular white matter changes of proven cause and diagnostic significance aimed to assist the evaluation of diseases exhibiting lesions exclusively or predominantly located in the white matter. The etiologies commented on are classified as follows: (a) toxic-metabolic, (b) leukodystrophies and mitochondriopathies, (c) infectious, (d) neoplastic, and (e) immune mediated. The respective mode of lesion formation is characterized, and typical radiological findings are displayed. More or less symmetrical lesion patterns on the one hand as well as focal and multifocal ones on the other are to be analyzed with reference to clinical data and knowledge of predilection sites characterizing major disease categories. Complementing spinal cord imaging may be useful not only in acute and relapsing demyelinating diseases but in certain leukodystrophies as well. In neuromyelitis optica (NMO), the detection of a specific antibody and some recently published observations may lead to a new understanding of certain deep white matter lesions occasionally complicating systemic autoimmune disease.

Acute intermittent porphyria caused by novel mutation in HMBS gene, misdiagnosed as cholecystitis

BACKGROUND

Acute intermittent porphyria (AIP) is an autosomal dominant neurovisceral inherited disorder due to a defect in the heme biosynthesis pathway. Misdiagnosis of the porphyrias is not uncommon.

CASE REPORT

We present a case of a 26-year-old female with suspected acute cholecystitis, mental status changes, and seizures. Biochemical and molecular investigations confirmed the diagnosis of AIP by findings of elevated urinary porphobilinogen, 5-aminolevulinic acid, and total porphyrins. DNA molecular testing showed a novel heterozygous mutation (c. 760delC p.L254X) in the exon11 of the HMBS gene. To the best of our knowledge, this is the first report of a misdiagnosis of AIP presenting with acute cholecystitis.

CONCLUSION

Clinicians are alerted to consider the possibility of AIP in an adult presenting with an acute abdomen, features of cholecystitis, and neuropsychiatric manifestations.

Neurological complications of acute intermittent porphyria

BACKGROUND

Acute intermittent porphyria (AIP) is an inherited disorder of heme biosynthesis, the clinical manifestations of which are incompletely understood. In this report, we describe 12 cases of AIP, focusing on the neurological manifestations.

METHODS

Twelve patients were diagnosed with AIP on the basis of characteristic clinical findings, erythrocyte porphobilinogen deaminase (PBGD) activity, and molecular genetics. Central and peripheral nervous system manifestations were noted, and electrophysiological and radiological studies performed. Potential precipitating factors were recorded.

RESULTS

Eleven PBGD gene mutations were identified in 12 patients. Nine patients experienced neurological symptoms involving the central nervous system (consciousness disturbance, n = 8; convulsion/seizure, n = 4; behavior change, n = 1), while 7 patients experienced peripheral neuropathies (motor paresis, n = 7; impairment of bulbar or respiratory function, n = 4). The electrophysiological and electroencephalographic findings were consistent with the neurological symptoms of AIP. Urinary PBG and δ-aminolevulinic acid levels were elevated in all patients. PBGD enzyme activity levels were below normal in all patients. Eight patients had documented exposure to porphyrogenic agents.

CONCLUSIONS

Our detailed description of a relatively large number of cases of AIP may help clinicians to recognize this often difficult-to-diagnose disorder.

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.

Posterior reversible encephalopathy syndrome in intensive care medicine

BACKGROUND

Posterior reversible encephalopathy syndrome (PRES) is a well-recognized clinico-neuroradiological transient condition. Early recognition is of paramount importance for prompt control of blood pressure or removal of precipitating factors and treatment of epileptic seizures or status epilepticus. Delay in the diagnosis and treatment may in fact results in death or in irreversible neurological sequelae.

DISCUSSION

PRES is characterized by headache, altered mental status, seizures, and visual disturbances and is associated with a number of different causes, most commonly acute hypertension, preeclampsia/eclampsia, and immunosuppressive agents. Clinical symptoms and neuroradiological findings are typically indistinguishable among the cases of PRES, regardless of underlying cause. Magnetic resonance studies typically show edema involving the white matter of cerebral posterior regions, especially parieto-occipital lobes but frontal and temporal lobes, and other encephalic structures may be involved.

CONCLUSIONS

Intensivists and other physicians involved in the evaluation of patients with presumed PRES must be aware of the clinical spectrum of the associated conditions, the diagnostic modalities, and the correct treatment.