Analysis of blood phenylalanine is central to the monitoring of patients with phenylketonuria (PKU) and age‐related phenylalanine target treatment‐ranges (0‐12 years; 120‐360 μmol/L, and >12 years; 120‐600 μmol/L) are recommended in order to prevent adverse neurological outcomes. These target treatment‐ranges are based upon plasma phenylalanine concentrations. However, patients are routinely monitored using dried bloodspot (DBS) specimens due to the convenience of collection. Significant differences exist between phenylalanine concentrations in plasma and DBS, with phenylalanine concentrations in DBS specimens analyzed by flow‐injection analysis tandem mass spectrometry reported to be 18% to 28% lower than paired plasma concentrations analyzed using ion‐exchange chromatography. DBS specimens with phenylalanine concentrations of 360 and 600 μmol/L, at the critical upper‐target treatment‐range thresholds would be plasma equivalents of 461 and 768 μmol/L, respectively, when a reported difference of 28% is taken into account. Furthermore, analytical test imprecision and bias in conjunction with pre‐analytical factors such as volume and quality of blood applied to filter paper collection devices to produce DBS specimens affect the final test results. Reporting of inaccurate patient results when comparing DBS results to target treatment‐ranges based on plasma concentrations, together with inter‐laboratory imprecision could have a significant impact on patient management resulting in inappropriate dietary change and potentially adverse patient outcomes. This review is intended to provide perspective on the issues related to the measurement of phenylalanine in blood specimens and to provide direction for the future needs of PKU patients to ensure reliable monitoring of metabolic control using the target treatment‐ranges.
Severe recurrent acute attacks of porphyria have traditionally been treated with either prophylactic human haemin or gonadorelin analogues (GnA) in females. Evidence on the most effective treatment for this patient subgroup is lacking. This audit surveyed the use of prophylactic GnA in the UK.Twenty female patients (who experienced between 2 and 45 acute attacks of porphyria requiring hospitalisation and treatment with human haemin prior to GnA prophylaxis) were included in the audit. Data was retrospectively collected based on patient history and case review.Twenty three treatment courses were given lasting a median period of 12 months. Monthly subcutaneous Goserelin was most commonly used. In three patients in whom timing with the menstrual cycle was not considered, an acute attack occurred after initiation of the first dose. The majority of patients experienced oestrogen deficiency symptoms during treatment. Fifty percent of the prescribed courses of GnA resulted in a degree of clinical benefit. This successfully treated group experienced between 3 and 20 acute attacks prior to and between 0 and 6 acute attacks during GnA treatment.The audit revealed large variation in practice in the United Kingdom regarding indication, duration of treatment, specific drug used and management of side effects. In view of the limited treatment options available for this cohort and the mixed outcome successes reported, we believe it is reasonable for porphyria specialists to continue offering GnA treatment to women with severe recurrent debilitating acute attacks of porphyria associated with the menstrual cycle, and we propose best practice guidelines to standardise management.
The autosomal dominant acute hepatic porphyrias (AHPs), acute intermittent porphyria, hereditary coproporphyria (HCP) and variegate porphyria (VP), are low penetrance adult onset disorders caused by partial deficiency of enzymes of haem biosynthesis. All are associated with acute neurovisceral attacks, which are a consequence of the increased hepatic demand for haem triggered by hormones, stress, drugs or systemic infections which leads to upregulation of the pathway and overproduction of haem precursors 5-aminolaevulinic acid (ALA) and porphobilinogen (PBG). Acute episodes are characterised by severe abdominal pain, nausea, vomiting, hyponatraemia, hypertension and tachycardia, behavioural disturbance and can progress to include seizures, peripheral motor neuropathy and posterior reversible encephalopathy syndrome if undiagnosed and untreated. VP and HCP may also present with photocutaneous skin lesions either alone or during acute symptoms. Diagnosis involves demonstrating increased excretion of PBG in urine. Treatment focuses on removing or managing triggers, supportive treatment and suppressing the hepatic haem pathway by administering human haemin. Chronic complications include hypertension, chronic kidney disease and hepatocellular carcinoma. A small proportion of symptomatic patients with AHP progress to repeated acute attacks which require preventative therapy. A new RNA interference therapy has recently been licensed and is likely to become the treatment of choice in this situation.
Background: The inappropriate use of tumour markers (TMs) is a common problem. The aim of this audit was to evaluate the impact of local guidelines on the TM requesting patterns of a General Surgery Department. Methods: CA 125, CA 19-9, CA15-3, CEA, AFP and HCG requests from all hospital surgical locations were audited over two periods of eight months before and after the implementation of local requesting guidelines. Results: Postintervention, total TM requests decreased by 32% while patient requests decreased by 9.8%. Single TM requesting increased and requests for panels containing four or more TMs decreased from 279 to 60 requests (78% reduction). Conclusion: Interdepartmental collaboration and the implementation of local guidelines have resulted in a change in requesting behaviour, most notably a reduction in multiple TM panel requests.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.