Impact of COVID-19 on paediatric chronic intestinal failure: A tertiary care children's hospital experience.

OBJECTIVES: Paediatric patients with intestinal failure (IF) are at risk for both gastrointestinal (GI) and systemic complications, thus depending on a functioning network of multidisciplinary care. Data on the clinical impact of coronavirus disease 2019 (COVID-19) or the pandemic-related restrictions are limited. We aimed to analyse the clinical course of COVID-19 in children with IF, and to evaluate the perceived impact of the COVID-19 pandemic on IF patients and their caregivers by analysing quality of life (QoL), health-related QoL (HRQoL) and health care. METHODS: Children with IF presenting at our intestinal rehabilitation centre were enrolled and interviewed about test-proven COVID-19 infection. A standardised questionnaire was offered to all caregivers of IF patients and to two control groups (children with inflammatory bowel disease and gastrointestinal healthy children). RESULTS: Between December 2020 and November 2022, 25 out of 127 patients with IF contracted COVID-19. Forty-eight per cent had GI symptoms, 32% required additional intravenous fluids and 20% were hospitalized. Only 25% of vaccinated children showed signs of GI dysfunction, compared to 52% of unvaccinated children. Analysis of 93 questionnaires showed a negative impact on QoL and HRQoL (>66.7% and >27.8%, respectively). IF patients frequently experienced restrictions in health care, including appointments, services and supply of parenteral nutrition or medications. Caregiver burden increased significantly more often in caregivers of children with IF (p = 0.007). CONCLUSIONS: Paediatric patients with IF contracting COVID-19 have an increased risk for GI dysfunction which may be alleviated by vaccination. Children and their caregivers were highly burdened by pandemic-related restrictions and reductions in health care provision.

Role of high-volume plasmapheresis in the management of paediatric acute liver failure.

OBJECTIVES: Paediatric acute liver failure (PALF) is a life-threatening disease. Management aims to support hepatic regeneration or to bridge to liver transplantation. High-volume plasmapheresis (HVP) removes protein-bound substances, alleviates inflammation, and improves survival in adult acute liver failure. However, experience with HVP in PALF is limited. Aim of this study is to report on feasibility, safety, efficacy and outcomes of HVP in PALF. METHODS: Retrospective observational study in children with PALF. HVP was performed upon identification of negative prognostic indicators, in toxic aetiology or multiorgan failure (MOF). Exchanged volume with fresh-frozen plasma corresponded to 1.5-2.0 times the patient's estimated plasma volume. One daily cycle was performed until the patient met criteria for discontinuation, that is, liver regeneration, liver transplantation, or death. RESULTS: Twenty-two children with PALF (body weight 2.5-106 kg) received 1-7 HVP cycles. No bleeding or procedure-related mortality occurred. Alkalosis, hypothermia and reduction in platelets were observed. Haemolysis led to HVP termination in one infant. Seven children (32%) survived with their native livers, 13 patients (59%) underwent liver transplantation. Two infants died due to MOF. Overall survival was 86%. International normalization ratio (INR), alanine aminotransaminases (ALT), bilirubin and inotropic support were reduced significantly (p < 0.05) after the first HVP-cycle (median): INR 2.85 versus 1.5; ALT 1280 versus 434 U/L; bilirubin 12.7 versus 6.7 mg/dL; norepinephrine dosage 0.083 versus 0.009 µg/kg/min. Median soluble-interleukin-2-receptor dropped significantly following HVP (n = 7): 2407 versus 950 U/mL (p < 0.02). CONCLUSIONS: HVP in PALF is feasible, safe, improves markers of liver failure and inflammation and is associated with lowering inotropic support. Prospective and controlled studies are required to confirm efficacy of HVP in PALF.

Pediatric and Adult Liver Disease in Alpha-1 Antitrypsin Deficiency.

Alpha-1 antitrypsin deficiency (AATD) arises due to inherited variants in SERPINA1, the AAT gene that impairs the production or secretion of this hepatocellular protein and leads to a gain-of-function liver proteotoxicity. Homozygous Pi*Z pathogenic variant (Pi*ZZ genotype) is the leading cause of severe AATD. It manifests in 2 to 10% of carriers as neonatal cholestasis and 20 to 35% of adults as significant liver fibrosis. Both children and adults may develop an end-stage liver disease requiring liver transplantation. Heterozygous Pi*Z pathogenic variant (Pi*MZ genotype) constitutes an established disease modifier. Our review summarizes the natural history and management of subjects with both pediatric and adult AATD-associated liver disease. Current findings from a phase 2 clinical trial indicate that RNA silencing may constitute a viable therapeutic approach for adult AATD. In conclusion, AATD is an increasingly appreciated pediatric and adult liver disorder that is becoming an attractive target for modern pharmacologic strategies.

Etiology and Outcome of Adult and Pediatric Acute Liver Failure in Europe.

Acute liver failure (ALF) is rare but life-threatening. Common causes include intoxications, infections, and metabolic disorders. Indeterminate etiology is still frequent. No systematic data on incidence, causes, and outcome of ALF across Europe are available. Via an online survey we reached out to European Reference Network Centers on rare liver diseases. Numbers and etiology of ALF cases during 2020 were retrieved and diagnostic and treatment availabilities assessed. In total, 455 cases (306 adult, 149 pediatric) were reported from 36 centers from 20 countries. Intoxication was the most common cause in adult and pediatric care. The number of cases with indeterminate etiology is low. Diagnostic tools and specific treatment options are broadly available within this network. This is the first approach to report on etiology and outcome of ALF in the pediatric and adult population in Europe. High diagnostic yield and standard of care reflects the expert status of involved centers.

Balloon angioplasty versus stent placement for the treatment of portal vein stenosis in children: a single center experience.

PURPOSE: To evaluate the safety and efficacy of percutaneous interventional treatment of portal vein stenosis in children. MATERIAL AND METHODS: A retrospective analysis of all interventional treatments for portal vein stenosis in pediatric patients at a single institution from 2010 to 2021 was conducted. Platelet count, spleen size and portal vein flow velocity were assessed during the follow-up period. Primary and primary assisted patency time were determined. RESULTS: A total of ten children (median age 28.5 months, interquartile range (IQR): 2.75-52.5 months) with portal vein stenosis after Mesorex-Shunt (n = 4), liver transplantation (n = 3) and other etiologies (n = 3) underwent 15 interventional procedures. There were five reinterventions and one discontinued intervention. The technical success rate was 93.3% (14/15) and clinical success of treated patients was 100% (14/14). Median follow-up was 18 months (IQR: 13.5-81 months). The median primary patency time for stent placement was 70 months (IQR: 13.5-127.25 months). For balloon angioplasty, the median primary patency time was 9 months (IQR 7.25-11.5 months), while the median assisted primary patency time was 14 months (IQR: 12 to 15 months). Platelet count, spleen size and portal vein flow velocity reliably corresponded to recurrence of portal vein stenosis in asymptomatic patients during follow-up. CONCLUSION: Interventional treatment is a safe and efficient method to treat portal vein stenosis with long patency times, regardless of etiology. Primary stent placement shows a higher primary patency time than balloon angioplasty. Implementation of stent placement as the primary interventional method may improve patency times and reduce the need for repeat reinterventions in pediatric patients.

Efficacy and safety of maralixibat treatment in patients with Alagille syndrome and cholestatic pruritus (ICONIC): a randomised phase 2 study.

BACKGROUND: Alagille syndrome is a rare genetic disease that often presents with severe cholestasis and pruritus. There are no approved drugs for management. Maralixibat, an apical, sodium-dependent, bile acid transport inhibitor, prevents enterohepatic bile acid recirculation. We evaluated the safety and efficacy of maralixibat for children with cholestasis in Alagille syndrome. METHODS: ICONIC was a placebo-controlled, randomised withdrawal period (RWD), phase 2b study with open-label extension in children (aged 1-18 years) with Alagille syndrome (NCT02160782). Eligible participants had more than three times the normal serum bile acid (sBA) levels and intractable pruritus. After 18 weeks of maralixibat 380 µg/kg once per day, participants were randomly assigned (1:1) to continue maralixibat or receive placebo for 4 weeks. Subsequently, all participants received open-label maralixibat until week 48. During the long-term extension (204 weeks reported), doses were increased up to 380 µg/kg twice per day. The primary endpoint was the mean sBA change during the RWD in participants with at least 50% sBA reduction by week 18. Cholestastic pruritus was assessed using observer-rated, patient-rated, and clinician-rated 0-4 scales. The safety population was defined as all participants who had received at least one dose of maralixibat. This trial was registered with ClinicalTrials.gov, NCT02160782, and is closed to recruitment. FINDINGS: Between Oct 28, 2014, and Aug 14, 2015, 31 participants (mean age 5·4 years [SD 4·25]) were enrolled and 28 analysed at week 48. Of the 29 participants who entered the randomised drug withdrawal period, ten (34%) were female and 19 (66%) were male. In the RWD, participants switched to placebo had significant increases in sBA (94 µmol/L, 95% CI 23 to 164) and pruritus (1·7 points, 95% CI 1·2 to 2·2), whereas participants who continued maralixibat maintained treatment effect. This study met the primary endpoint (least square mean difference -117 µmol/L, 95% CI -232 to -2). From baseline to week 48, sBA (-96 µmol/L, -162 to -31) and pruritus (-1·6 pts, -2·1 to -1·1) improved. In participants who continued to week 204 (n=15) all improvements were maintained. Maralixibat was generally safe and well tolerated throughout. The most frequent adverse events were gastrointestinal related. Most adverse events were self-limiting in nature and mild-to-moderate in severity. INTERPRETATION: In children with Alagille syndrome, maralixibat is, to our knowledge, the first agent to show durable and clinically meaningful improvements in cholestasis. Maralixibat might represent a new treatment paradigm for chronic cholestasis in Alagille syndrome. FUNDING: Mirum Pharmaceuticals.

A new variant of Abernethy malformation treated by transhepatic interventional closure: a case report.

BACKGROUND: Congenital portosystemic shunts (CPSS) are rare vascular malformations and can be classified into extrahepatic and intrahepatic shunts. Extrahepatic CPSS, also termed Abernethy malformations are associated with severe long-term complications including portopulmonary hypertension, liver atrophy, hyperammoniemia and hepatic encephalopathy. We report a hitherto undescribed variant of Abernethy malformation requiring an innovative approach for interventional treatment. CASE PRESENTATION: We describe a 31-year-old patient following surgical repair of atrioventricular septal defect at the age of 6 years. In the long-term follow-up he showed persistent pulmonary hypertension which deteriorated despite dual pulmonary vasodilative treatment. When he developed arterial desaturation and symptomatic hyperammoniemia detailed reassessment revealed as underlying cause a hitherto undescribed variant of Abernethy malformation connecting the portal vein with the right lower pulmonary vein. Following interdisciplinary discussions we opted for an interventional approach. Since the malformation was un-accessible to interventional closure via antegrade venous or retrograde arterial access, a transhepatic percutaneous puncture of the portal vein was performed. Temporary balloon occlusion of the malformation revealed only a slight increase in portal venous pressure. Interventional occlusion of the large vascular connection was achieved via this transhepatic approach by successive implantation of two large vascular occluding devices. The postinterventional course was unremarkable and both ammonia levels and arterial saturation normalized at follow-up of 12 months. CONCLUSIONS: Portal vein anomalies should be included in the differential diagnoses of pulmonary hypertension or pulmonary arterio-venous malformations. Based on careful assessment of the anatomy and testing of portal vein hemodynamics interventional therapy of complex Abernethy malformations can be performed successfully in specialized centers.

Whole liver transplantation in children under 10 kg: How to minimize the high risks of a still challenging procedure.

BACKGROUND: Whole liver transplantation in infants <10 kg is a rare procedure with moderate outcomes (67%-79% graft survival at 1 year) and high rates of vascular complications (hepatic artery thrombosis 5-26%). METHODS: Retrospective single-center analysis of whole liver transplantation in infants <10 kg and systematic review of the literature focused on survival rates and surgical complications. RESULTS: Between January 2005 and December 2020, 175 liver transplantations in 173 children were performed at our center. A total of 92 (53%) children weighed less than 10 kg; 19 (21%) of them underwent WLT and constitute the study population. Median age of the recipients was 10 months (21 days-24 months) and median body weight 6.5 (3.1-9.8) kg. Median age of the donors was 5 (1-84) months and median body weight 6.1 (4-21) kg. Median donor-to-recipient body weight ratio was 1.2 (range: 0.6-4.5). Postoperatively, neither hepatic artery nor portal vein thrombosis occurred. A biliary complication occurred in 4 cases: 1 bile leak (early), 3 anastomotic stenoses (1 delayed and 2 late), and 1 non-anastomotic stenosis (late). Patient survival rate at 1, 5, and 10 years was 100%, 92%, and 92%, respectively. Overall, death-censored graft survival after 1, 5, and 10 was 100%. CONCLUSION: Our results are excellent in terms of complications and graft and patient survival. This involves not only high-end surgical performance but also close interdisciplinary perioperative cooperation based on strong standard operating procedures and mainly focused on fluid management, hemostasiology, and strict monitoring of vessel patency.

Severe acute hepatitis and acute liver failure of unknown origin in children: a questionnaire-based study within 34 paediatric liver centres in 22 European countries and Israel, April 2022.

To detect potential concern about severe acute hepatitis in children, we conducted a survey among 50 ERN RARE-LIVER centres. By 26 April 2022, 34 centres, including 25 transplant centres, reported an estimated median of 3-5, 0-2 and 3-5 cases in 2021, 2020 and 2019 and a mean of 2 (range: 0-8) cases between January and April 2022 (mean in 10 large liver transplant centres: 3). Twelve centres reported suspicion of an increase, but no rise.

Multisystem inflammation and susceptibility to viral infections in human ZNFX1 deficiency.

BACKGROUND: Recognition of viral nucleic acids is one of the primary triggers for a type I interferon-mediated antiviral immune response. Inborn errors of type I interferon immunity can be associated with increased inflammation and/or increased susceptibility to viral infections as a result of dysbalanced interferon production. NFX1-type zinc finger-containing 1 (ZNFX1) is an interferon-stimulated double-stranded RNA sensor that restricts the replication of RNA viruses in mice. The role of ZNFX1 in the human immune response is not known. OBJECTIVE: We studied 15 patients from 8 families with an autosomal recessive immunodeficiency characterized by severe infections by both RNA and DNA viruses and virally triggered inflammatory episodes with hemophagocytic lymphohistiocytosis-like disease, early-onset seizures, and renal and lung disease. METHODS: Whole exome sequencing was performed on 13 patients from 8 families. We investigated the transcriptome, posttranscriptional regulation of interferon-stimulated genes (ISGs) and predisposition to viral infections in primary cells from patients and controls stimulated with synthetic double-stranded nucleic acids. RESULTS: Deleterious homozygous and compound heterozygous ZNFX1 variants were identified in all 13 patients. Stimulation of patient-derived primary cells with synthetic double-stranded nucleic acids was associated with a deregulated pattern of expression of ISGs and alterations in the half-life of the mRNA of ISGs and also associated with poorer clearance of viral infections by monocytes. CONCLUSION: ZNFX1 is an important regulator of the response to double-stranded nucleic acids stimuli following viral infections. ZNFX1 deficiency predisposes to severe viral infections and a multisystem inflammatory disease.

Genotype correlates with the natural history of severe bile salt export pump deficiency.

BACKGROUND & AIMS: Mutations in ABCB11 can cause deficiency of the bile salt export pump (BSEP), leading to cholestasis and end-stage liver disease. Owing to the rarity of the disease, the associations between genotype and natural history, or outcomes following surgical biliary diversion (SBD), remain elusive. We aimed to determine these associations by assembling the largest genetically defined cohort of patients with severe BSEP deficiency to date. METHODS: This multicentre, retrospective cohort study included 264 patients with homozygous or compound heterozygous pathological ABCB11 mutations. Patients were categorized according to genotypic severity (BSEP1, BSEP2, BSEP3). The predicted residual BSEP transport function decreased with each category. RESULTS: Genotype severity was strongly associated with native liver survival (NLS, BSEP1 median 20.4 years; BSEP2, 7.0 years; BSEP3, 3.5 years; p <0.001). At 15 years of age, the proportion of patients with hepatocellular carcinoma was 4% in BSEP1, 7% in BSEP2 and 34% in BSEP3 (p = 0.001). SBD was associated with significantly increased NLS (hazard ratio 0.50; 95% CI 0.27-0.94: p = 0.03) in BSEP1 and BSEP2. A serum bile acid concentration below 102 µmol/L or a decrease of at least 75%, each shortly after SBD, reliably predicted NLS of ≥15 years following SBD (each p <0.001). CONCLUSIONS: The genotype of severe BSEP deficiency strongly predicts long-term NLS, the risk of developing hepatocellular carcinoma, and the chance that SBD will increase NLS. Serum bile acid parameters shortly after SBD can predict long-term NLS. LAY SUMMARY: This study presents data from the largest genetically defined cohort of patients with severe bile salt export pump deficiency to date. The genotype of patients with severe bile salt export pump deficiency is associated with clinical outcomes and the success of therapeutic interventions. Therefore, genotypic data should be used to guide personalized clinical care throughout childhood and adulthood in patients with this disease.

Access to care in rare liver diseases: New challenges and new opportunities.

Patients with rare diseases are often disadvantaged, particularly those with rare liver diseases. Reasons for disadvantage include delayed or overlooked diagnosis, lack of local expertise and high-quality care, poor scientific understanding of the disease process and limited therapeutic options. In adult liver disease this can be compounded by prejudices towards patients with liver disease in general, because of a perception (incorrect for all rare liver diseases) that liver disease is lifestyle related and thus "self-inflicted". In paediatric rare liver diseases, such as biliary atresia, optimising outcomes requires a particularly timely diagnosis. Irrespective of patient age, the scientific and medical community must rise to the challenge of advancing our understanding of rare liver disease, searching for more effective and specific therapies, and providing the infrastructure to provide the best care for all patients, infants, children, young and older adults. The European Reference Network for Rare Liver Diseases is an important step in this direction.

Screening Endoscopy Contributes to Relevant Modifications of Therapeutic Regimen in Children With Intestinal Failure.

OBJECTIVE: The role of endoscopy in the diagnostic workup of children with intestinal failure (IF) is not well defined. It is unclear whether endoscopies should be performed as a screening procedure or only upon manifestation of symptoms. The aim of this study is to evaluate, whether performing screening endoscopy contributes to clinical management in children with IF. METHODS: Comparative retrospective case series study in children with IF (mean age 70.4 months ± 58.4 months) presenting for diagnostic workup in a single intestinal rehabilitation center. Endoscopies were performed either as a screening procedure (Group 1, n = 45) or as indicated by symptoms of gastrointestinal dysfunction (Group 2, n = 11). RESULTS: A total of 92 endoscopies (56 esophagogastroduodenoscopies; 12 enteroscopies; 24 colonoscopies) were performed in 56 children. IF etiology included short bowel syndrome (n = 37), motility disorder (n = 16), and mucosal enteropathy (n = 3). Comparing Group 1 with Group 2 abnormal endoscopic findings were detected in 66.7% versus 81.8%. Findings led to adaptation of therapeutic regimes in 64.7% versus 85.7%. We detected a higher rate of erosive and ulcerative gastritis and duodenitis, enteritis, and colitis in Group 1 compared to Group 2. CONCLUSIONS: Endoscopy in children with IF frequently reveals abnormal findings, leading to recommendations for treatment adaptation in the majority of cases, irrespective of whether endoscopy has been performed as a screening procedure or as indicated by symptoms. Using endoscopy as a screening tool may improve both, the detection of gastrointestinal pathology and the clinical management of children with IF.

High Incidence of Proteinuria in Children With Chronic Intestinal Failure Under Long-term Parenteral Nutrition.

Long-term home parenteral nutrition (LTPN) in children with chronic intestinal failure (CIF) is associated with renal complications such as fluid and electrolyte imbalances, nephrocalcinosis, nephrolithiasis, and chronic kidney disease (CKD). The etiology of CIF-associated nephropathy is multifactorial. The aim of this study was to evaluate renal involvement under LTPN. In this study, 50 patients with CIF, median age 4.2 years (1.4-9.3; 23 girls) were included. Kidney involvement was a frequent finding in this study. CKD was present in 30% of patients without correlation with LTPN duration. Glomerular proteinuria was found in the majority of patients (76%), an important long-term risk factor for the progression of CKD. Increased urinary α-1 microglobulin was significantly associated with duration (years) of LTPN and was increased in patients with CKD.

Outcomes of pediatric identical living-donor liver and hematopoietic stem cell transplantation.

Chronic IS is associated with significant morbidity in transplant recipients. Moreover, IS does not prevent chronic graft failure frequently. Allograft immune tolerance in LT can be induced by complete donor chimerism through allogenic HSCT combined with identical LDLT. This approach may exempt patients from chronic lifelong IS. However, it is unclear whether its benefits justify its risks. Here, we present three cases from our institution and analyze seven additional reports of children treated with HSCT/LDLT, all receiving HSCT due to hemato-oncological indications. In eight of 10 cases, donor macrochimerism resulted in allograft tolerance. Nine patients survived. One patient died due to fulminant ADV infection. Further complications were GvHD (n = 3) and bone marrow failure (n = 2). In conclusion, donor-specific allograft tolerance can be achieved by identical-donor HSCT/LDLT. However, at present, this approach should generally be limited to selected indications due to a potentially unfavorable risk-benefit ratio. Novel toxicity-reduced conditioning protocols for HSCT/LDLT in the absence of malignant or non-hepatic disease may prove to be a sufficiently safe approach for inducing graft tolerance in children receiving a LDLT in the future. This concept may reduce the burden of lifelong IS.

Controversies and Variation in Diagnosing and Treating Children With Wilson Disease: Results of an International Survey.

OBJECTIVES: Variation in care is more common in settings in which evidence-based approaches are limited. The aims of the present study were to describe consensus and variability in approaches taken by pediatric hepatologists in the management of Wilson disease (WD) in children. METHOD: International case-centered, Internet-based survey of pediatric hepatologists. Survey cases were developed by consensus of the authors and were intended to identify variation in the care of children with WD. RESULTS: One hundred eleven of 253 clinicians responded (44%). Of these, 84% of North American and 41% of European participants used guidelines published in their respective region. Although consensus existed on the first-line diagnostic tools (serum ceruloplasmin and baseline 24-hour urinary copper excretion), survey participants did not agree on how much liver copper content was required for diagnosis: 57% considered >250 µg/g dry weight to be consistent with WD, whereas 25% considered >50 µg/g to be diagnostic. Overall, 50% of practitioners perform genetic testing in all suspected cases, and 81% perform genetic testing once they know the genotype of an index patient. For initial treatment of fulminant WD, 51% of participants chose chelation and 15% chose immediate transplantation; 47% chose listing for transplantation followed by monitoring using a disease-severity score, and then carrying out transplantation only when the score reached a critical cut-off. To treat mildly affected siblings of index patients, 43% of practitioners chose zinc. Most reported that they use chelation to treat patients with hepatic dysfunction; however, 29% of North American participants chose not to use D-penicillamine as primary therapy. CONCLUSIONS: From an international perspective, pediatric hepatologists vary in the approaches they use in the care for children with WD. Regional preferences and accessibility to treatments may generate variation. Unwarranted variation, however, may also contribute to differences in outcome and should be targeted to improve quality of care.

Interobserver Agreement on Endoscopic Classification of Oesophageal Varices in Children.

OBJECTIVES: Data regarding agreement on endoscopic features of oesophageal varices in children with portal hypertension (PH) are scant. The aim of this study was to evaluate endoscopic visualisation and classification of oesophageal varices in children by several European clinicians, to build a rational basis for future multicentre trials. METHODS: Endoscopic pictures of the distal oesophagus of 100 children with a clinical diagnosis of PH were distributed to 10 endoscopists. Observers were requested to classify variceal size according to a 3-degree scale (small, medium, and large, class A), a 2-degree scale (small and large, class B), and to recognise red wales (presence or absence, class Red). Overall agreement was considered fair if Fleiss and Cohen κ test was ≥0.30, good if ≥0.40, excellent if ≥0.60, and perfect if ≥0.80. RESULTS: Agreement between observers was fair with class A (κ = 0.34) and class B (κ = 0.38), and good with class Red (κ = 0.49). The agreement was good on presence versus absence of varices (class A = 0.53, class B = 0.48). The agreement among the observers was good in class A when endoscopic features of severe PH (medium and large sizes, red marks) were grouped and compared with mild features (absent and small varices) (κ = 0.58). CONCLUSIONS: Experts working in different centres show a fairly good agreement on endoscopic features of PH in children, although a better training of paediatric endoscopists may improve the agreement in grading severity of varices in this setting.

Pediatric acute liver failure: variations in referral timing are associated with disease subtypes.

UNLABELLED: In pediatric acute liver failure (PALF), rapid referral to a transplant center (TC) is advocated. Clinical variability of PALF may influence referral timing. We aimed to analyze early or late timing of referral in relation to clinical characteristics and outcome in PALF. We conducted a retrospective, single-center, comparative analysis of clinical and liver function parameters in two PALF cohorts (n = 23 per cohort): cohort 1 (early referral, duration of in-patient care before referral (DCR) <7 days) vs. cohort 2 (late referral, DCR ≥ 7 days). Compared to late referrals, patients referred early were more frequently non-icteric and encephalopathic at initial presentation (n = 14 vs. 5 and n = 13 vs. 4, each p < 0.05). Early referred PALF patients had lower hepatic encephalopathy (HE) grades and bilirubin (grade 1 vs. 2, p < 0.02; 215 vs. 439 µmol/l, p < 0.001, respectively) but higher alanine aminotransferase (ALAT) levels (4,340 vs. 963 U/l, p < 0.001). Cumulative poor prognostic indicators were lower in early referrals (2 vs. 4, p < 0.001). In multivariate analysis, subacute liver failure (SLF >7 days between disease onset and development of encephalopathy) was independently associated with late referral (relative risk 9.48; 95 % CI 1.37-64.85, p < 0.02). Differences in survival to discharge were not significant. CONCLUSION: In PALF, referral timing variability is associated with distinct clinical and liver function patterns. Early recognition of prognostic indicators and of SLF may help to improve referral timing and thus PALF management.