Pyroglutamate acidosis 2023. A review of 100 cases.

This review concerns the rare, acquired, usually iatrogenic, high-anion-gap metabolic acidosis, pyroglutamic acidosis. Pyroglutamate is a derivative of the amino acid glutamate, and is an intermediate in the 'glutathione cycle', by which glutathione is continuously synthesized and broken down. The vast majority of pyroglutamic acidosis cases occur in patients on regular, therapeutic doses of paracetamol. In about a third of cases, flucloxacillin is co-prescribed. In addition, the patients are almost always seriously unwell in other ways, typically with under-nourishment of some form. Paracetamol, with underlying disorders, conspires to divert the glutathione cycle, leading to the overproduction of pyroglutamate. Hypokalaemia is seen in about a third of cases. Once the diagnosis is suspected, it is simple to stop the paracetamol and change the antibiotic (if flucloxacillin is present), pending biochemistry. N-acetyl-cysteine can be given, but while the biochemical justification is compelling, the clinical evidence base is anecdotal.

[Flucloxacillin-induced hypokalemia]. / Door flucloxacilline geïnduceerde hypokaliëmie.

Flucloxacillin-induced hypokalaemia can be progressive and life-threatening, despite of potassium supplementation. In this case description, a high dose of intravenous flucloxacillin was started after a 68-year-old patient presented with an infected knee replacement. After two days, hypokalaemia was noted with an inadequate response to potassium supplementation. It was decided to change antibiotics and increase potassium supplementation, with good results. It is advisable to include monitoring of potassium levels in local treatment protocols when flucloxacillin is prescribed.

Incidence and predisposing factors for flucloxacillin-related hepatotoxicity in children.

BACKGROUND: Flucloxacillin-induced hepatotoxicity is well established in adults. However, there are few paediatric studies of flucloxacillin-induced hepatotoxicity despite this drug being among the most commonly prescribed in children. We aimed to determine the incidence of flucloxacillin-induced hepatotoxicity in children receiving IV therapy as well as identify risk factors for this adverse drug reaction. METHODS: We undertook a 2 year retrospective audit of children aged 0-18 years admitted to the Royal Children's Hospital (March 2019 to March 2021) who had liver function tests determined before and after receiving IV flucloxacillin for at least 24 hours duration. Causality was assessed using the Roussel Uclaf Causality Assessment Method and Naranjo criteria. RESULTS: Overall, the incidence of hepatotoxicity was 66/393 (17%). The median age of children with hepatotoxicity was 1.1 years (IQR 0.3-11.9), 43 (65%) received two or more concomitant hepatotoxic medications and 23 (35%) were receiving total parenteral nutrition. The median timing of onset of hepatotoxicity after commencement of flucloxacillin was 4 days (range 2-7). Severe hepatotoxicity (Common Terminology Criteria for Adverse Events grade 3 or above) occurred in 9/66 (14%) for bilirubin, 13/66 (20%) for ALT and 10/66 (15%) for GGT. Predisposing factors for hepatotoxicity were increasing age (OR 1.06 per additional year, 95% CI 1.01-1.10, P = 0.02), with adolescents aged 12-18 years having the highest risk (OR 5.10, 95% CI 2.02-12.85, P = 0.001), and two or more concomitant hepatotoxic medications (OR 2.51, 95% CI 1.02-6.18, P = 0.05). The median time to resolution of hepatotoxicity after cessation of flucloxacillin was 5 days (range 2-10). CONCLUSIONS: In children, older patients and those receiving two or more concomitant hepatotoxic medications are at greater risk of flucloxacillin-induced hepatotoxicity.

Development of mouse models with restricted HLA-B∗57:01 presentation for the study of flucloxacillin-driven T-cell activation and tolerance in liver injury.

BACKGROUND: Flucloxacillin (FLX)-induced liver injury is immune-mediated and highly associated to HLA-B∗57:01 expression. Host factors leading to drug-induced liver injury are not yet well understood. OBJECTIVE: Characterize in vivo immune mechanisms determining the development of CD8+ T cells reactive to FLX in animals expressing the risk human leukocyte antigen (HLA) allotype. METHODS: HLA-B∗57:01 transgenic mice (Tg) or Tg strains with H2-KbDb knockout (Tg/KO) or H2-KbDb/PD-1 double knockout (Tg/DKO) were treated with drug and/or anti-CD4 antibody. Drug-induced liver injury was evaluated on the basis of liver enzyme and histologic changes at day 10 of treatment. FLX-reactive CD8+ T cells were characterized in vitro by release of effector molecules on drug restimulation, gene expression, and flow cytometry analysis, and functionality tested for hepatic cytotoxicity. RESULTS: CD8+ T-cell responses to FLX in Tg were dependent on both HLA and mouse major histocompatibility complex I presentation and in vivo priming. Eliminating H2-KbDb in Tg/KO to allow exclusive presentation of FLX by HLA resulted in a less robust drug-specific CD8+T-cell response unless CD4+ cells, including regulatory T cells, were depleted. Treatment of Tg/KO with anti-CD4 antibody and FLX led to subclinical liver inflammation associated with an increase in PD1+CD8+ T cells in the lymphoid organs and liver. Impaired PD-1 expression in Tg/DKO led to liver histopathologic and transcriptional alterations but without hepatic enzyme elevations. Moreover, effector lymphocytes accumulated in the liver and showed FLX-dependent hepatic cytotoxicity in vitro when tolerogenic liver cells were depleted. CONCLUSIONS: In our in vivo models, FLX primes CD8+ T cells to recognize drug presented by HLA-B∗57:01 and murine major histocompatibility complex I. HLA-B∗57:01-dependent CD8+ T-cell reaction to FLX is limited by the presence of CD4+ cells, presumably regulatory T cells, and PD-1 expression. Tolerogenic hepatic cells limit clinical disease through PD-L1 or additional unexplored mechanisms.

Frequency of drug-induced liver injury in children receiving anti-staphylococcal penicillins.

INTRODUCTION: Anti-staphylococcal penicillins (ASPs) are among the most commonly prescribed antibiotics in children and are associated with a risk of drug-induced liver injury (DILI). Despite the frequent use of ASPs in children, there is no consensus on whether liver function tests (LFTs) should be routinely monitored during treatment. OBJECTIVES: To review the literature on the frequency of ASP-related DILI in children to determine the incidence, risk factors and outcomes of hepatotoxicity. METHODS: PubMed, MEDLINE and Embase were searched in January 2022 for original studies of children who received cloxacillin, dicloxacillin, flucloxacillin, methicillin, nafcillin or oxacillin that included ≥10 children aged up to 18 years, and presented data on the incidence of DILI in children exposed to ASPs. RESULTS: Overall, two studies of oral flucloxacillin, two of intravenous (IV) methicillin, three of IV nafcillin and four of IV oxacillin were included. The mean onset of DILI ranged between 7.0 and 19.0 days following commencement of antibiotic treatment and all episodes resolved between 14.2 and 16.0 days after drug discontinuation, with no specific treatment required. This review found that the incidence of DILI in children was 1 in 50 000 for oral flucloxacillin and ranged from 1 in 3 to 13 for IV oxacillin, methicillin and nafcillin. CONCLUSIONS: This review found that routine LFT monitoring is not required in children receiving low dose oral flucloxacillin in a primary care setting, although pharmacovigilance is critical. For IV preparations, the existing data support routine LFT monitoring in those receiving treatment for at least 7 days.

[A case of pyroglutamic metabolic acidosis after cotreatment by flucloxacillin and paracetamol]. / Un cas d'acidose métabolique pyroglutamique sur comédication par flucloxacilline et paracétamol.

We report on the case of a 73-year-old man, who was referred to our emergency department for confusion and dyspnea. He had been under a treatment of flucloxacillin for six weeks because of a possible methicillin-susceptible Staphylococcus aureus (MSSA) endocarditis that was complicated by an acute late infection of a knee prosthesis. The laboratory work-up revealed a metabolic acidosis with a high anion gap. After exclusion of the other explanations, we retained a pyroglutamic metabolic acidosis due to concomitant intake of paracetamol and flucloxacillin, favoured by several risk factors. This diagnosis was confirmed by an organic acid dosage in the urine. After discontinuation of the drugs and a treatment with N-acetylcysteine, the evolution was favourable with correction of the metabolic acidosis and the confusional state.

Nous rapportons le cas d'un homme de 73 ans, sous traitement de flucloxacilline depuis 6 semaines pour une possible endocardite à Staphylococcus aureus sensible à la méticilline (SASM) compliquée d'une infection aiguë tardive d'une prothèse de genou. Il est adressé à notre service d'urgences pour un état confusionnel et une dyspnée. Le bilan met en évidence une acidose métabolique à trou anionique élevé. Après exclusion des différentes étiologies, nous retenons une acidose métabolique pyroglutamique d'origine médicamenteuse sur prise concomitante de paracétamol et flucloxacilline, favorisée par plusieurs facteurs précipitants. Ce diagnostic est confirmé par un dosage d'acide organique dans les urines. Après arrêt des médicaments incriminés et traitement par N-acétylcystéine, l'évolution est favorable avec correction de l'acidose métabolique et de l'état confusionnel.

5-Oxoproline acidosis caused by acetaminophen and flucloxacillin treatment - a case report.

High anion gap metabolic acidosis (HAGMA) is a common diagnosis in the emergency department, which requires a systematic work-up in order to identify and treat the underlying cause. We present an unusual case of HAGMA due to 5-oxoproline accumulation caused by prolonged treatment with both acetaminophen (paracetamol) and flucloxacillin. This paper describes the diagnostic work-up of HAGMA and emphasizes on the approach and initial treatment in case the underlying etiology is unclear.

Antibiotic regimens for late-onset neonatal sepsis.

BACKGROUND: Neonatal sepsis is a major cause of morbidity and mortality. It is the third leading cause of neonatal mortality globally constituting 13% of overall neonatal mortality. Despite the high burden of neonatal sepsis, high-quality evidence in diagnosis and treatment is scarce. Due to the diagnostic challenges of sepsis and the relative immunosuppression of the newborn, many neonates receive antibiotics for suspected sepsis. Antibiotics have become the most used therapeutics in neonatal intensive care units, and observational studies in high-income countries suggest that 83% to 94% of newborns treated with antibiotics for suspected sepsis have negative blood cultures. The last Cochrane Review was updated in 2005. There is a need for an updated systematic review assessing the effects of different antibiotic regimens for late-onset neonatal sepsis. OBJECTIVES: To assess the beneficial and harmful effects of different antibiotic regimens for late-onset neonatal sepsis. SEARCH METHODS: We searched the following electronic databases: CENTRAL (2021, Issue 3); Ovid MEDLINE; Embase Ovid; CINAHL; LILACS; Science Citation Index EXPANDED and Conference Proceedings Citation Index - Science on 12 March 2021. We also searched clinical trials databases and the reference lists of retrieved articles for randomised controlled trials (RCTs) and quasi-RCTs. SELECTION CRITERIA: We included RCTs comparing different antibiotic regimens for late-onset neonatal sepsis. We included participants older than 72 hours of life at randomisation, suspected or diagnosed with neonatal sepsis, meningitis, osteomyelitis, endocarditis, or necrotising enterocolitis. We excluded trials that assessed treatment of fungal infections. DATA COLLECTION AND ANALYSIS: Three review authors independently assessed studies for inclusion, extracted data, and assessed risk of bias. We used the GRADE approach to assess the certainty of evidence. Our primary outcome was all-cause mortality, and our secondary outcomes were: serious adverse events, respiratory support, circulatory support, nephrotoxicity, neurological developmental impairment, necrotising enterocolitis, and ototoxicity. Our primary time point of interest was at maximum follow-up. MAIN RESULTS: We included five RCTs (580 participants). All trials were at high risk of bias, and had very low-certainty evidence. The five included trials assessed five different comparisons of antibiotics. We did not conduct a meta-analysis due to lack of relevant data. Of the five included trials one trial compared cefazolin plus amikacin with vancomycin plus amikacin; one trial compared ticarcillin plus clavulanic acid with flucloxacillin plus gentamicin; one trial compared cloxacillin plus amikacin with cefotaxime plus gentamicin; one trial compared meropenem with standard care (ampicillin plus gentamicin or cefotaxime plus gentamicin); and one trial compared vancomycin plus gentamicin with vancomycin plus aztreonam. None of the five comparisons found any evidence of a difference when assessing all-cause mortality, serious adverse events, circulatory support, nephrotoxicity, neurological developmental impairment, or necrotising enterocolitis; however, none of the trials were near an information size that could contribute significantly to the evidence of the comparative benefits and risks of any particular antibiotic regimen. None of the trials assessed respiratory support or ototoxicity. The benefits and harms of different antibiotic regimens remain unclear due to the lack of well-powered trials and the high risk of systematic errors. AUTHORS' CONCLUSIONS: Current evidence is insufficient to support any antibiotic regimen being superior to another. RCTs assessing different antibiotic regimens in late-onset neonatal sepsis with low risks of bias are warranted.

ANTECEDENTES: La sepsis neonatal es una causa importante de morbilidad y mortalidad. Es la tercera causa de mortalidad neonatal a nivel mundial y constituye el 13% de la mortalidad neonatal total. A pesar de la elevada carga de la sepsis neonatal, la evidencia de alta calidad en el diagnóstico y el tratamiento es escasa. Debido a las dificultades de diagnóstico de la sepsis y a la relativa inmunosupresión del neonato, muchos reciben antibióticos por sospecha de sepsis. Los antibióticos se han convertido en el tratamiento más utilizado en las unidades de cuidados intensivos neonatales, y los estudios observacionales realizados en países de ingresos altos indican que entre el 83% y el 94% de los neonatos tratados con antibióticos por sospecha de sepsis tienen hemocultivos negativos. La última revisión Cochrane se actualizó en 2005. Se necesita una revisión sistemática actualizada que evalúe los efectos de los diferentes regímenes de antibióticos para la sepsis neonatal de inicio tardío. OBJETIVOS: Evaluar los efectos beneficiosos y perjudiciales de diferentes regímenes antibióticos para la sepsis neonatal de inicio tardío. MÉTODOS DE BÚSQUEDA: Se hicieron búsquedas en las siguientes bases de datos electrónicas: CENTRAL (2021, número 3); Ovid MEDLINE; Embase Ovid; CINAHL; LILACS; Science Citation Index EXPANDED y Conference Proceedings Citation Index ­ Science el 12 de marzo de 2021. También se buscaron ensayos controlados aleatorizados (ECA) y cuasialeatorizados en las bases de datos de ensayos clínicos y en las listas de referencias de artículos identificados. CRITERIOS DE SELECCIÓN: Se incluyeron ECA que compararon diferentes regímenes de antibióticos para la sepsis neonatal de inicio tardío. Se incluyeron participantes mayores de 72 horas de vida en el momento de la asignación al azar, con sospecha o diagnóstico de sepsis neonatal, meningitis, osteomielitis, endocarditis o enterocolitis necrosante. Se excluyeron los ensayos que evaluaron el tratamiento de las infecciones micóticas. OBTENCIÓN Y ANÁLISIS DE LOS DATOS: Dos autores de la revisión, de forma independiente, evaluaron los estudios para inclusión, extrajeron los datos y evaluaron el riesgo de sesgo. Se utilizó el método GRADE para evaluar la certeza de la evidencia. El desenlace principal fue la mortalidad por todas las causas, y los desenlaces secundarios fueron: eventos adversos graves, asistencia respiratoria, apoyo circulatorio, nefrotoxicidad, deterioro del desarrollo neurológico, enterocolitis necrosante y ototoxicidad. El punto temporal principal de interés fue el seguimiento máximo. RESULTADOS PRINCIPALES: Se incluyeron cinco ECA (580 participantes). Todos los ensayos tuvieron alto riesgo de sesgo y evidencia de certeza muy baja. Los cinco ensayos incluidos evaluaron cinco comparaciones diferentes de antibióticos. No se realizó un metanálisis debido a la falta de datos relevantes. De los cinco ensayos incluidos, un ensayo comparó cefazolina más amikacina con vancomicina más amikacina; un ensayo comparó ticarcilina más ácido clavulánico con flucloxacilina más gentamicina; un ensayo comparó cloxacilina más amikacina con cefotaxima más gentamicina; un ensayo comparó meropenem con atención estándar (ampicilina más gentamicina o cefotaxima más gentamicina); y un ensayo comparó vancomicina más gentamicina con vancomicina más aztreonam. Ninguna de las cinco comparaciones encontró evidencia de una diferencia al evaluar la mortalidad por todas las causas, los eventos adversos graves, el apoyo circulatorio, la nefrotoxicidad, el deterioro del desarrollo neurológico o la enterocolitis necrosante; sin embargo, ninguno de los ensayos se acercó a un tamaño de información que pudiera contribuir significativamente a la evidencia de los beneficios y los riesgos comparativos de cualquier régimen antibiótico en particular. Ninguno de los ensayos evaluó la asistencia respiratoria o la ototoxicidad. Los efectos beneficiosos y perjudiciales de los diferentes regímenes de antibióticos aún no están claros debido a la falta de ensayos con un poder estadístico adecuado y al alto riesgo de errores sistemáticos. CONCLUSIONES DE LOS AUTORES: La evidencia actual no es suficiente para apoyar que un régimen de antibióticos sea superior a otro. Se justifica la realización de ECA con bajo riesgo de sesgo que evalúen diferentes regímenes antibióticos en la sepsis neonatal de inicio tardío.

Flucloxacillin-induced liver injury in elderly patient.

Flucloxacillin is a penicillin antibiotic used as first-line treatment for soft tissue infections caused by Staphylococcus aureus It is used frequently in the elderly and is an established cause of cholestatic liver injury. Risk factors for cholestasis include prolonged duration of treatment, female sex and older age. Elderly patients are also more likely to suffer from comorbidities and polypharmacy, which increases the incidence of drug-induced liver injury and hospitalisation, which in turn can lead to irreversible deterioration in functional baseline. Our case report aims to raise awareness of flucloxacillin-induced liver injury in elderly patients and to encourage the use of alternative treatments and/or limited duration. We advocate for further research into individualised treatments and new diagnostic techniques in patients with painless jaundice based on their genotype.

Probability of pharmacological target attainment with flucloxacillin in Staphylococcus aureus bloodstream infection: a prospective cohort study of unbound plasma and individual MICs.

OBJECTIVES: MSSA bloodstream infections (BSIs) are associated with considerable mortality. Data regarding therapeutic drug monitoring (TDM) and pharmacological target attainment of the ß-lactam flucloxacillin are scarce. PATIENTS AND METHODS: We determined the achievement of pharmacokinetic/pharmacodynamic targets and its association with clinical outcome and potential toxicity in a prospective cohort of 50 patients with MSSA-BSI. Strain-specific MICs and unbound plasma flucloxacillin concentrations (at five different timepoints) were determined by broth microdilution and HPLC-MS, respectively. RESULTS: In our study population, 48% were critically ill and the 30 day mortality rate was 16%. The median flucloxacillin MIC was 0.125 mg/L. The median unbound trough concentration was 1.7 (IQR 0.4-9.3), 1.9 (IQR 0.4-6.2) and 1.0 (IQR 0.6-3.4) mg/L on study day 1, 3 and 7, respectively. Optimal (100% fT>MIC) and maximum (100% fT>4×MIC) target attainment was achieved in 45 (90%) and 34 (68%) patients, respectively, throughout the study period. Conversely, when using the EUCAST epidemiological cut-off value instead of strain-specific MICs, target attainment was achieved in only 13 (26%) patients. The mean unbound flucloxacillin trough concentration per patient was associated with neurotoxicity (OR 1.12 per 1 mg/L increase, P = 0.02) and significantly higher in deceased patients (median 14.8 versus 1.7 mg/L, P = 0.01). CONCLUSIONS: Flucloxacillin pharmacological target attainment in MSSA-BSI patients is frequently achieved when unbound flucloxacillin concentrations and strain-specific MICs are considered. However, currently recommended dosing regimens may expose patients to excessive flucloxacillin concentrations, potentially resulting in drug-related organ damage.

Flucloxacillin and paracetamol induced pyroglutamic acidosis.

A 75-year-old woman was admitted to a regional hospital with an acute kidney injury (AKI) and nausea on a background of recent treatment for Staphylococcus aureus bacteraemia secondary to pneumonia. The treatment thereof resulted in a high anion gap metabolic acidosis (HAGMA). The pneumonia was initially treated with intravenous piperacillin and tazobactam and the patient transferred to a tertiary hospital. There, the diagnosis of S. aureus bacteraemia secondary to a pulmonary source was confirmed and treatment was changed to intravenous flucloxacillin and the patient was discharged to hospital in the home (HITH is a service that allows short-term healthcare at home to be provided to people who would otherwise need to be in hospital) to complete the antibiotic course. Five weeks after commencing flucloxacillin, the patient was referred back to hospital with nausea and worsening kidney function with an associated significant HAGMA. The patient has a background of chronic kidney disease and chronic back pain for which she was taking long-term paracetamol. The HAGMA was determined to be due to a pyroglutamic acidosis (PGA), deemed secondary to the combined use of paracetamol and flucloxacillin. This was subsequently confirmed with a plasma pyroglutamic acid concentration level of 7467 µmol/L (reference range 20-50 µmol/L) and a urinary level of 1700 mmol/mol creatinine (<110 mmol/mol creatinine). To our knowledge, this is the highest plasma and urinary levels published to date. Furthermore, considering the common use of paracetamol and penicillins, it is important to recognise HAGMA as a potential complication of co-administration of paracetamol and iso-oxylopenicillin. The HAGMA resolved after cessation of flucloxacillin despite the continuation of paracetamol and without administration of N-acetylcysteine. PGA-related HAGMA appears to be a unique potential side effect of iso-oxylopenicillin rather than other beta-lactams.

Flucloxacillin-Induced Hepatotoxicity - Association with HLA-B*5701.

Drug-induced liver injury (DILI) to flucloxacillin is rare and is classified as idiosyncratic, as it is dependent on individual susceptibility, unpredictable, and dose-independent. The authors present the case of a 74 - year - old man with a history of monoclonal gammopathy under investigation and alcoholic habits of 24 g/day, with asthenia, anorexia, nausea, abdominal discomfort, and fever with three days of evolution. He was treated with two courses of antibiotic therapy with flucloxacillin to erysipelas previously (3 months and 2 weeks before admission). Lab tests showed serum AST levels of 349 U/L, ALT 646 U/L, alkaline phosphatase 302 U/L, GGT 652 U/L, total bilirubin 3.3 mg/dL and direct bilirubin 2.72 mg/dL. Infectious, autoimmune, and metabolic causes were ruled out. Magnetic resonance cholangiopancreatography showed normal results. Liver biopsy showed mild multifocal (predominantly microvesicular) steatosis; marked changes in the centrilobular areas (sinusoidal dilatation, marked congestion, hemorrhage, and multifocal hepatocyte collapse); expansion of the portal areas with the formation of bridges; proliferated bile ducts and inflammatory infiltrate of variable density, predominantly mononuclear type. The HLA-B*5701 screening test was positive. Hepatic biochemical tests remain abnormal with a significative increase in total bilirubin, which reached levels of 24.1 mg/dL, with the development of jaundice, pruritus, and choluria. DILI was assumed, and the patient was treated with ursodeoxycholic acid. There was favorable evolution, without evidence of blood coagulation dysfunction or encephalopathy. The analytic normalization was, however, slow, with evolution to chronicity. The authors present this case to remind the possibility of moderate/severe drug-induced liver injury to flucloxacillin, an antibiotic commonly used in clinical practice and association with the HLA-B * 5701 allele reported in the literature.

Successful liver transplantation for drug-induced vanishing bile duct syndrome.

Drug-induced cholestasis has a wide range of clinical presentations, and in a small number of patients, it can progress to severe ductopenia. A 63-year-old woman was referred to our department with progressive cholestasis and hyperbilirubinaemia following a course of flucloxacillin. Despite the comprehensive laboratory, imaging and genetic investigations, no other cause for the cholestasis was demonstrated. Sequential liver biopsies confirmed the development of vanishing bile duct syndrome. She developed significant cachexia and pruritus that did not respond to medical therapy, and hence she was listed for liver transplantation. She underwent liver transplantation 6 months after the initial drug-induced injury. She has remained well with good graft function at 1-year follow-up. The case highlights an extreme form of drug-induced ductopenia and underscores the need for meticulous hepatology input and consideration of liver transplantation in some patients.

Flucloxacillin-Induced Hepatotoxicity - Association with HLA-B*5701

SUMMARY Drug-induced liver injury (DILI) to flucloxacillin is rare and is classified as idiosyncratic, as it is dependent on individual susceptibility, unpredictable, and dose-independent. The authors present the case of a 74 - year - old man with a history of monoclonal gammopathy under investigation and alcoholic habits of 24 g/day, with asthenia, anorexia, nausea, abdominal discomfort, and fever with three days of evolution. He was treated with two courses of antibiotic therapy with flucloxacillin to erysipelas previously (3 months and 2 weeks before admission). Lab tests showed serum AST levels of 349 U/L, ALT 646 U/L, alkaline phosphatase 302 U/L, GGT 652 U/L, total bilirubin 3.3 mg/dL and direct bilirubin 2.72 mg/dL. Infectious, autoimmune, and metabolic causes were ruled out. Magnetic resonance cholangiopancreatography showed normal results. Liver biopsy showed mild multifocal (predominantly microvesicular) steatosis; marked changes in the centrilobular areas (sinusoidal dilatation, marked congestion, hemorrhage, and multifocal hepatocyte collapse); expansion of the portal areas with the formation of bridges; proliferated bile ducts and inflammatory infiltrate of variable density, predominantly mononuclear type. The HLA-B*5701 screening test was positive. Hepatic biochemical tests remain abnormal with a significative increase in total bilirubin, which reached levels of 24.1 mg/dL, with the development of jaundice, pruritus, and choluria. DILI was assumed, and the patient was treated with ursodeoxycholic acid. There was favorable evolution, without evidence of blood coagulation dysfunction or encephalopathy. The analytic normalization was, however, slow, with evolution to chronicity. The authors present this case to remind the possibility of moderate/severe drug-induced liver injury to flucloxacillin, an antibiotic commonly used in clinical practice and association with the HLA-B * 5701 allele reported in the literature.

RESUMO A hepatotoxicidade à flucloxacilina é rara e classifica-se como idiossincrática, uma vez que é dependente da suscetibilidade individual, não expectável e independente da dose. Apresentamos o caso de um homem, 74 anos, antecedentes de gamapatia monoclonal e hábitos alcoólicos de 24 g/dia, com quadro de astenia, anorexia, náuseas, desconforto abdominal e febrícula com três dias de evolução. Referência a dois ciclos de antibioterapia com flucloxacilina por erisipela (três meses e duas semanas antes da admissão). Analiticamente com AST 349 U/L, ALT 646 U/L, FA 302 U/L, GGT 652 U/L, bilirrubina total 3,3 mg/dL, bilirrubina direta 2,72 mg/dL. Excluídas etiologias infecciosa, autoimune, metabólica, bem como patologia das vias biliares por colangio-RM. Biópsia hepática mostrou esteatose multifocal ligeira (predominantemente microvesicular); alterações acentuadas nas áreas centrolobulares (dilatação sinusoidal, congestão acentuada, hemorragia e colapso multifocal de hepatócitos); expansão das áreas portais com constituição de pontes; ductos biliares proliferados e infiltrado inflamatório de densidade variável, predominantemente de tipo mononucleado. Tipagem de HLA-B*5701 positiva. Agravamento analítico atingindo bilirrubina total 24,1 mg/dL, com desenvolvimento de icterícia, prurido e colúria. Admitida a hepatotoxicidade, iniciou terapêutica com ácido ursodesoxicólico. Verificou-se evolução favorável, sem evidência de coagulopatia ou encefalopatia. A normalização analítica foi, no entanto, lenta, com evolução para cronicidade. Os autores apresentam este caso para alertar para a possibilidade de hepatotoxicidade moderada a grave à flucloxacilina, antibiótico de uso comum na prática clínica e associação com o alelo HLA-B*5701 relatada na literatura.

An Under-Recognised Cause of Iatrogenic, Severe Metabolic Acidosis

Case Pyroglutamic acidosis is an uncommonly diagnosed but important cause of a high anion gap metabolic acidosis. Our case report concerns an elderly male admitted to the Intensive Care Unit (ICU) following the acute onset of coma which developed during treatment of a prosthetic joint infection. A diagnosis of pyroglutamic acidosis was ultimately made and later confirmed with laboratory testing. Blood gas analysis revealed a profound high anion gap metabolic acidosis. Treatment Treatment included withdrawal of the precipitating medications, N-acetylcysteine and sodium bicarbonate. Discussion This case highlights an unusual cause of severe metabolic acidosis caused by commonly used medications and readily reversible if recognised. This is of particular relevance in elderly, frail patients as incorrect alternate diagnoses may result in decisions which incorrectly limit critical care therapies.

Intravenous flucloxacillin treatment is associated with a high incidence of hypokalaemia.

Intravenous flucloxacillin is one of the most frequently used high-dose penicillin therapies in hospitalized patients, forming the cornerstone treatment of invasive Staphylococcus aureus infection. Being a nonreabsorbable anion, flucloxacillin has been suggested to cause hypokalaemia, although the frequency and magnitude of this unwanted effect is unknown. In a retrospective cohort, we investigated the incidence and extent of hypokalaemia after initiation of intravenous flucloxacillin or ceftriaxone therapy. In total, 77 patients receiving flucloxacillin (62% male, mean age 70.5 years) and 84 patients receiving ceftriaxone (46% male, mean age 70.8 years) were included. Hypokalaemia occurred significantly more often in patients receiving flucloxacillin than ceftriaxone (42% vs 14%, p < 10-4 ). Moreover, follow-up potassium levels were significantly lower during flucloxacillin therapy. In general, women were more prone to develop hypokalaemia than men. In conclusion, intravenous flucloxacillin use is associated with a striking incidence of hypokalaemia. Therefore, standardized potassium measurements are necessary.

Flucloxacillin Hypersensitivity: Patient Outcomes in a Multicenter Retrospective Study.

BACKGROUND: Flucloxacillin is a narrow-spectrum, beta-lactamase-resistant penicillin. Type I (IgE-mediated) and type IV (T-cell-mediated) reactions are less frequently reported than with other penicillins. OBJECTIVE: To undertake a detailed clinical characterization of a cohort of patients referred with suspected flucloxacillin hypersensitivity. METHODS: We retrospectively analyzed demographic characteristics, presentation, investigation, and management of 108 patients presenting to 4 UK centers. Patients underwent skin prick and intradermal testing with flucloxacillin, major (benzylpenicilloyl poly-l-lysine) and minor determinants, amoxicillin, and benzylpenicillin with immediate and, where appropriate, delayed reading of the test. In the immediate group, a further 14 patients were tested to ampicillin and 16 to Augmentin (co-amoxiclav-combination of clavulanic acid and amoxicillin). Skin test-negative patients underwent oral drug provocation. A multistep protocol was used, depending on risk assessment. RESULTS: Forty of 108 (37%) patients were diagnosed with hypersensitivity to flucloxacillin, of whom 33 (82.5%) showed immediate and 7 (17.5%) nonimmediate hypersensitivity, respectively. In the immediate group, most reactions were severe: 19 of 33 (58%). Intradermal testing had a higher negative predictive value (86%) in the immediate group than in the nonimmediate group (67%). Only a minority of patients (6 of 17 [35%]) with IgE-mediated allergy were cross-sensitized on intradermal testing with other penicillins, compared with 3 of 4 (75%) in the delayed group. CONCLUSIONS: Immediate hypersensitivity reactions to flucloxacillin are more common than delayed. Cross-sensitization to other penicillins appears higher in delayed reactions than in immediate. The negative predictive value of intradermal testing is higher in the immediate group than in the nonimmediate group. Drug provocation testing remains the diagnostic criterion standard.

Lesson of the month 1: A rare adverse reaction between flucloxacillin and paracetamol.

Flucloxacillin, a beta-lactam antibiotic, is a commonly prescribed antibiotic for the treatment of infections caused by staphylococci and streptococci, most notably Staphylococcus aureus Paracetamol is one of the most dispensed medications by NHS England and is used for the treatment of fever and pain.1 However most doctors are unaware that concurrent use of these drugs can cause a potentially fatal drug interaction due to pyroglutamic acidosis (PGA), also known as 5-oxoprolinaemia. PGA is a rare cause of raised anion gap metabolic acidosis due to disruption of the γ-glutamyl cycle. We report the case of a patient with multiple comorbidities who developed PGA due to coadministration of paracetamol and flucloxacillin.

Efficacy and safety of intravenous ceftriaxone at home versus intravenous flucloxacillin in hospital for children with cellulitis (CHOICE): a single-centre, open-label, randomised, controlled, non-inferiority trial.

BACKGROUND: Outpatient parenteral antimicrobial therapy in children is common despite no evidence of its efficacy or safety from clinical trials. We aimed to compare the efficacy and safety of intravenous antibiotic therapy at home with that of standard treatment in hospital for children with moderate to severe cellulitis. METHODS: The Cellulitis at Home or Inpatient in Children from the Emergency Department (CHOICE) trial was a randomised, controlled, non-inferiority trial in children aged 6 months to 18 years who presented to the emergency department at The Royal Children's Hospital (Melbourne, VIC, Australia) with uncomplicated moderate to severe cellulitis. Participants were randomly assigned to receive either intravenous ceftriaxone (50 mg/kg once daily) at home or intravenous flucloxacillin (50 mg/kg every 6 h) in hospital with web-based randomisation, stratified by age and periorbital cellulitis. The primary outcome was treatment failure, which was defined as no clinical improvement or occurrence of an adverse event, resulting in a change in empiric antibiotics within 48 h of the first dose. Secondary outcomes included adverse events and acquisition of antibiotic-resistant bacteria. Outcomes were assessed in all randomised participants with outcome data (intention-to-treat population) and in all individuals who received treatment as allocated and did not have any major protocol violations (per-protocol population). For home treatment to be non-inferior to hospital treatment, the difference between groups in the proportion of children with treatment failure in the intention-to-treat population had to be less than 15%. This trial is registered with ClinicalTrials.gov, number NCT02334124. FINDINGS: Between Jan 9, 2015, and June 15, 2017, we screened 1135 children for eligibility, of whom 190 were randomly assigned to receive ceftriaxone at home (n=95) or flucloxacillin in hospital (n=95). The intention-to-treat analysis comprised 188 children (93 in the home group and 95 in the hospital group) because two children in the home group were found to be ineligible after randomisation and were excluded. Treatment failure occurred in two (2%) children in the home group and in seven (7%) children in the hospital group (risk difference -5·2%, 95% CI -11·3 to 0·8, p=0·088). In the per-protocol analysis, treatment failure occurred in one (1%) of 89 children in the home group and in seven (8%) of 91 children in the hospital group (-6·5%, -12·4 to -0·7). Fewer children treated at home than in hospital had an adverse event (two [2%] vs ten [11%]; p=0·048). There was no difference between groups in rates of nasal acquisition of meticillin-resistant Staphylococcus aureus or gastrointestinal acquisition of extended-spectrum ß-lactamase-producing bacteria or Clostridium difficile after 3 months. INTERPRETATION: Home treatment with intravenous ceftriaxone is not inferior to treatment in hospital with intravenous flucloxacillin for children with cellulitis. The standard of care for the intravenous treatment of uncomplicated cellulitis in children should be home or outpatient care when feasible. FUNDING: The Royal Children's Hospital Foundation and Murdoch Children's Research Institute.