Porphyrias: A clinically based approach

Obstacles to Early Diagnosis of Acute Hepatic Porphyria: Current Perspectives on Improving Early Diagnosis and Clinical Management

Porphyrias are, for the most part, inherited disorders of the heme biosynthetic pathway which lead to accumulation of specific intermediates responsible for most of the symptoms and signs of biochemically active disease. Acute hepatic porphyrias usually come to clinical attention primarily in women in their reproductive years who present with episodic, severe, generalized abdominal pain. Such acute attacks may also be associated with tachycardia, systemic arterial hypertension, hyponatremia, recent history of dark reddish to brownish urine, and anxiety, delirium, and sensory or motor neuropathies. Diagnosing AHPs is often challenging, requiring a high index of suspicion and the appropriate testing showing elevated ALA and/or PBG in a random urine specimen. Obstacles to diagnosis include inappropriate testing for porphyrins only, inadequate sample handling, and ordering genetic testing as the initial diagnostic test. While some of these pitfalls in diagnosis are surmountable with current knowledge, others are in need of more research.

The diagnosis of acute intermittent porphyria combined with seizures: Case report

RATIONALE

Acute intermittent porphyria (AIP) is a rare metabolic disorder affecting heme production due to enzyme porphobilinogen deaminase deficiency. Diagnosing acute intermittent porphyria is difficult because its symptoms interrelate with those of other common diseases. When AIP is combined with seizures, the diagnosis process is more complicated. This case report shows all tests and criteria used to arrive at the final stage of diagnosis.

PATIENT CONCERNS

The patient complained of severe abdominal pain, nausea, vomiting, and intermittent convulsions. Her medical history shows she had abdominal pain, mainly dull pain in the left upper abdomen.

DIAGNOSES

Different symptomatic tests were done, and the cause of her symptoms was uncertain. A urine sun drying test was then done and confirmed the presence of porphyrin used to diagnose AIP. A genetic test was done after the patient was discharged, and AIP diagnosis was confirmed.

INTERVENTIONS

Acute intermittent porphyria treatment was administered.

OUTCOMES

The patent recovered fully.

LESSONS

It is essential to consider acute intermittent porphyria diagnosis in patients having unexplained severe abdominal pain associated with neurological and psychiatric symptoms. Since AIP is a rare disease with a high mortality rate when not treated early, Clinical practices should include AIP as one of the tests done on patients showing these symptoms at an early stage. The fastest way to identify this is to conduct a urine test. The change of color from brown to reddish color is a diagnostic indicator of AIP. This strategy helps reduce misdiagnoses and delayed treatment of the right disease.

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.

Development and validation of diagnostic algorithms for the laboratory diagnosis of porphyrias

Porphyrias are rare metabolic disorders of the haem synthesis. They can present with acute neurovisceral attacks, cutaneous symptoms, or a combination of both. As they present with a wide variety of clinical symptoms, diagnosis is often delayed and correct interpretation of porphyria-related tests remains a challenge for many physicians. We developed and validated two algorithms for the laboratory diagnosis of porphyrias based on presenting symptoms. Based on a literature search and clinical/laboratory expertise, we developed algorithms for acute and cutaneous porphyrias. We validated these algorithms using all porphyria related laboratory test requests between January 1st 2000 and September 30th 2020 in UZ Leuven. In addition, we also evaluated our algorithm using samples from the European porphyria network (EPNET) external quality assessment scheme (2010-2021). Sensitivity of the algorithm for acute porphyria was 100.0% [74.9%-100.0%] (13 acute intermittent porphyria (AIP) and 1 variegate porphyria [VP]) with a specificity of 98.5% [91.0%-100.0%] (65 patients). Sensitivity of the algorithm for cutaneous porphyria was 100% [95.1%-100.0%] (7 VP, 59 porphyria cutanea tarda (PCT), 23 erythropoietic protoporphyria (EPP), 2 X-linked erythropoietic protoporphyria [XLEPP]) with a specificity of 93.9% [82.9%-98.5%]. There were no diagnostic samples of other types of porphyria. The algorithms correctly identified 18 of the 19 EPNET porphyria cases. One of the two hereditary coproporphyria cases was missed. The algorithms for acute and cutaneous porphyria showed high sensitivity and specificity and can be used to aid the clinician in correctly interpreting the laboratory findings of porphyria-related tests.

Diagnosis and treatment of icteric hepatitis caused by erythropoietic protoporphyria: A case report

Erythropoietic protoporphyria (EPP) is a rare inherited disease caused by partial deficiency activity of the enzyme ferrochelatase (FECH), resulting in excessive accumulation of protoporphyrin IX in erythrocyte and tissues. Here, we report a patient with photosensitive dermatitis and acute icteric hepatitis caused by EPP, whose clinical and biochemical results successfully improved following 2-month treatment with glucose load, ursodeoxycholic acid capsules, and cholestyramine powder. This case provides a reference for a combination therapy strategy for patients with liver and skin injury caused by EPP.

Assessment of Clinical and Laboratory Use of the Cutaneous Direct Immunofluorescence Assay

Importance

Dermatologists submit direct immunofluorescence (DIF) biopsies on a daily basis, using an assay detecting immunoreactant deposition with a panel that has traditionally comprised immunoglobulin (Ig) G, IgA, IgM, C3, and fibrin, with or without albumin antibodies.

Objectives

To evaluate and compare the frequency of immunoreactants in DIF biopsies submitted over an 8-year period and assess use by dermatologists based on clinical impression.

Design, Setting, and Participants

A quality improvement study was conducted in a community outreach reference laboratory associated with a large academic medical center. Results of 2050 consecutive DIF skin biopsies submitted to the laboratory between April 1, 2012, and June 12, 2020, were analyzed by final pathologic diagnosis and antibody subtype positivity, in comparison with clinical impression. Biopsies in which the submitting physician had not performed the biopsy were excluded.

Main Outcomes and Measures

Histopathologic findings and the results of DIF biopsies using the standard 6-antibody panel were evaluated in correlation with the submitted clinical diagnosis to assess immunoreactivity of the assay.

Results

Of 2050 DIF biopsies submitted, 367 (17.9%) were positive; IgG, IgA, and C3 alone identified all primary immunobullous disease cases (pemphigoid, pemphigus, linear IgA, and dermatitis herpetiformis), and IgA, C3, and fibrin antibodies alone identified all vasculitis cases. A panel of IgG, IgA, IgM, and fibrin identified all cases of lupus erythematosus. DIF results were positive in less than half of cases of hematoxylin and eosin biopsy-confirmed lupus erythematosus (23 of 47 [49%]). A total of 247 biopsies were submitted for clinical diagnoses not optimally supported on DIF: lichen planus, porphyria, and connective tissue disease.

Conclusions and Relevance

The findings of this study suggest that there is a knowledge gap among dermatologists relating to the opportunity for high-value, cost-conscious use of DIF. The practice of reflexive antibody testing using a 6-antibody panel for all DIF biopsies is likely unnecessary. DIF protocols tailored to the clinical diagnosis may enhance cost-effectiveness without loss of test sensitivity or specificity.

Acute non-traumatic tetraparesis - Differential diagnosis

INTRODUCTION

Potentially life-threatening disorders may present in the emergency department with acute tetraparesis, and their recognition is crucial for an appropriate management and timely treatment. Our review aims to systematize the differential diagnosis of acute non-traumatic tetraparesis.

RESULTS

Causes of tetraparesis can be classified based on the site of defect: upper motor neuron (UMN), peripheral nerve, neuromuscular junction or muscle. History of present illness should include the distribution of weakness (symmetric/asymmetric or distal/proximal/diffuse) and associated clinical features (pain, sensory findings, dysautonomia, and cranial nerve abnormalities such as diplopia and dysphagia). Neurological examination, particularly tendon reflexes, helps further in the localization of nerve lesions and distinction between UMN and lower motor neuron. Ancillary studies include blood and cerebral spinal fluid analysis, neuroaxis imaging, electromyography, muscle magnetic resonance and muscle biopsy.

CONCLUSIONS

Acute tetraparesis is still a debilitating and potentially serious neurological condition. Despite all the supplementary ancillary tests, the neurological examination is the key to achieve a correct diagnosis. The identification of life-threatening neurologic disorders is pivotal, since failing to identify patients at risk of complications, such as acute respiratory failure, may have catastrophic results.

Healthcare Utilization and Cost Burden of Porphyria in Commercially Insured Adults in the United States

OBJECTIVES

The healthcare burden associated with porphyria remains unevaluated despite the associated increased risks of morbidity and mortality. We aimed to assess the healthcare utilization and cost burdens of porphyria in the United States (US) using real-world claims data.

METHODS

We performed a case-control analysis of adults in the Truven Health MarketScan^® Commercial Claims database (2010-2015). Using propensity scores, 2788 porphyria cases were matched 1:1 to porphyria-free controls with chronic liver disease. Total and service-specific parameters were quantified for the 12 months before porphyria diagnosis versus the 12 months after diagnosis and over the 12 months following a randomly selected date for controls. Wilcoxon signed rank tests and McNemar tests were used to examine incremental differences in burden between cases and controls. Adjusted multivariable generalized linear regression models were used to compare healthcare burdens for cases versus controls.

RESULTS

Relative to the 12 months before porphyria diagnosis, the following 12 months had more claims per patient (35.94 vs 39.67; p < 0.0001) and increased per-patient healthcare costs (US$21,308 vs US$27,270; p < 0.0001). Porphyria cases incurred US$7839 more in total unadjusted costs compared with controls in the 12 months after index date. Compared with controls, cases also had more claims (39.67 vs 34.81), primarily due to inpatient admissions (1.80 vs 0.78) and outpatient visits (21.41 vs 17.98). Cases also had higher healthcare costs for inpatient admissions (US$8882 vs US$4674) and outpatient visits (US$12,378 vs US$9801).

CONCLUSION

Porphyria is associated with significant healthcare costs and utilization burdens driven by increased inpatient admissions, outpatient visits, and pharmaceutical claims.

Therapeutic strategies for acute intermittent porphyria

Acute intermittent porphyria (AIP) is an autosomal dominant disease caused by mutations in porphobilinogen deaminase (PBGD), the third enzyme of the heme synthesis pathway. Symptoms of AIP usually manifest as intermittent acute attacks with occasional neuropsychiatric crises. The management of AIP includes treatment of acute attacks, prevention of attacks, long-term monitoring and treatment of chronic complications. Intravenous injection of heme is the most effective method of treating acute attacks. Carbohydrate loading is used when heme is unavailable or in the event of mild attacks. Symptomatic treatment is also needed during attacks. Prevention of attacks includes eliminating precipitating factors, heme prophylaxis and liver transplantation. New treatment options include givosiran (siRNA) to down-regulate ALA synthase-1 (ALAS1) and the messenger RNA of PBGD (PBGD mRNA) delivered to the liver cells of patients with AIP. Long-term monitoring of chronic complications includes regular liver-kidney function and hepatocellular carcinoma (HCC) screening.

Systemic lupus erythematosus and hydroxychloroquine-related acute intermittent porphyria

Porphyrias, particularly acute intermittent porphyria (AIP), are rare disorders which could be associated with systemic lupus erythematosus (SLE). Although the association with AIP has been known since 1952, only 11 cases have been published to date. It is widely known that precipitating causes such as infections, hormonal changes, sunlight exposure, stress and drugs could provoke an AIP crisis. Hydroxychloroquine (HCQ) is usually used in lupus patients, but rarely appears to trigger AIP crises even in SLE patients. The case of a 51-year-old man in whom AIP onset was probably due to hydroxychloroquine use during SLE management is presented. SLE onset was accompanied by fever, pleural, lung and joint involvement with a characteristic SLE autoantibody panel. Although prednisone was given, the joint symptoms did not subside. HCQ was then started; however, some days later the patient suffered anxiety, vomiting and severe abdominal pain refractory to pain-relief drugs and liver function had worsened. No cutaneous lesions were observed. The patient suffered similar episodes accompanied by paralytic ileus and dark-coloured urine, the sediment of which showed no abnormalities. In addition, no myoglobinuria was found. This finding raised the suspicion of AIP and urine tests revealed elevated values of delta-aminolevulinic acid and porphobilinogen. Hydroxychloroquine was preventively suspended and the patient improved notably within a few days. In the following months, the patient suffered no relapse and the prednisone dose could be lowered. Finally, a review of the literature on this topic highlighted the exceptional nature of an API/ SLE association particularly in men. Interestingly, porphyria may present first followed by SLE, or vice versa. The latency period between drug administration and disease onset varies from days to 2 years. Both chloroquine and HCQ may induce PAI in SLE patients. Clinicians should be alerted to a possible association with AIP when a patient with SLE recently put on HCQ presents acute onset of abdominal and/or neurological symptoms and dark urine. Appropriate tests and prompt HCQ cessation are mandatory.