Rodenticide (Yellow Phosphorus Poison)-Induced Hepatotoxicity in India: Constraints During Management

Auxiliary Partial Orthotopic Liver Transplantation Is a Safe and Effective Option for Yellow Phosphorus Toxin-induced Acute Liver Failure

BACKGROUND

Ingestion of yellow phosphorus-containing rodenticides (YPR) or firecrackers is an important cause of acute liver failure (ALF) in young adults and children, particularly in South and South-East Asia and South America. Emergency liver transplantation is indicated in cases refractory to intensive supportive therapy, including low-volume plasma exchange. There are no published reports on the feasibility of auxiliary partial orthotopic liver transplantation (APOLT) for YPR-induced ALF.

METHODS

Clinical details of patients undergoing APOLT for YPR-induced ALF in 1 unit are reported. Details of postoperative follow-up, native remnant regeneration, and immunosuppression withdrawal are also reported.

RESULTS

Between January 2021 and December 2023, 3 patients (4 y, 1.5 y, and 26 y) underwent emergency living donor liver transplantation for YPR-induced ALF. All patients were refractory to supportive therapies, including therapeutic plasma exchange, and demonstrated progression of liver injury in the form of severe encephalopathy needing intubation, ventilation, and organ support. APOLT was considered because of their young age and minimal intraoperative inotropic requirement. All explants showed confluent parenchymal necrosis with microvesicular and macrovesicular steatosis. Patients were initially maintained on standard immunosuppression. Good remnant regeneration was noted on follow-up imaging in all cases, enabling gradual withdrawal of immunosuppression. Currently, 1 child has been off immunosuppression for 15 mo and 2 others are on reduced doses of immunosuppression. All patients demonstrated good liver function.

CONCLUSIONS

APOLT procedure can be an appropriate transplant option in YPR-related ALF for children and young adults without severe hemodynamic instability.

Definitions, etiopathogenesis and epidemiology of ALF

Acute liver failure (ALF) is a rare but preventable cause of acute hepatic dysfunction which is associated with significant mortality, unless treated appropriately. There are significant regional variations in the etiologies of ALF globally and this determines the outcomes of the disease as well as the long-term survival in patients receiving liver transplantation for management. Improvements in understanding of disease pathophysiology and critical care medicine have led to better outcomes over the last few decades. Despite this, the burden of indeterminate ALF and the pathogenesis of many etiological agents are yet to be fully known. Improvements in diagnostic and prognostic modalities are expected to decrease the morbidity and mortality associated with ALF. Changes in vaccination programs and stronger legislative practices regarding over-the-counter sale of acetaminophen and non-proprietary drugs are expected to reduce the burden of disease globally.

Acute liver failure

Acute liver failure (ALF) is a life-threatening disorder characterised by rapid deterioration of liver function, coagulopathy, and hepatic encephalopathy in the absence of pre-existing liver disease. The cause of ALF varies across the world. Common causes of ALF in adults include drug toxicity, hepatotropic and non-hepatotropic viruses, herbal and dietary supplements, antituberculosis drugs, and autoimmune hepatitis. The cause of liver failure affects the management and prognosis, and therefore extensive investigation for cause is strongly suggested. Sepsis with multiorgan failure and cerebral oedema remain the leading causes of death in patients with ALF and early identification and appropriate management can alter the course of ALF. Liver transplantation is the best current therapy, although the role of artificial liver support systems, particularly therapeutic plasma exchange, can be useful for patients with ALF, especially in non-transplant centres. In this Seminar, we discuss the cause, prognostic models, and management of ALF.

Assessing the clinical efficacy of low-volume therapeutic plasma exchange in achieving recovery from acute liver failure induced by yellow phosphorous poisoning

BACKGROUND

Acute liver failure (ALF) following yellow phosphorous (YP) ingestion is similar to acetaminophen-induced ALF and it has become a public concern in our region. This study assessed low volume therapeutic plasma exchange (LV-TPE) efficacy in improving the transplant free survival in YP poisoning.

METHODS

Adult patients with toxicology reports of YP and ALF requiring critical care were included in the study. LV-TPE was planned for three consecutive days and three more if required. Performed 1.3 to 1.5 plasma volume replacing with 0.9% normal saline, 5% human albumin solution, and fresh frozen plasma based on ASFA 2019 criteria. MELD score, laboratory parameters, LV-TPE details were captured. The study end point was clinical outcome of the patients.

RESULTS

Among 36 patients, 19 underwent LV-TPE and 17 opted out of LV-TPE and they were included as a control arm. The MELD score was 32.64 ± 8.05 and 37.83 ± 9.37 in both groups. There were 13 survivors in LV-TPE group leading to a 68.42% reduction in mortality. The coagulation and biochemical parameters showed a significant percentage change after LV-TPE. Refractory shock, delay in initiating procedure and acidosis were independent predictors of mortality.

CONCLUSION

A well-timed LV-TPE improves the survival of patients with ALF due to YP poisoning.

Standard-Volume Is As Effective As High-Volume Plasma Exchange for Patients With Acute Liver Failure

Background/Aims

Acute liver failure (ALF) is associated with fatal outcomes without liver transplantation. Two randomized studies reported standard volume (SV) and high volume (HV) plasma exchange (PLEX) as effective therapeutic modalities for patients with ALF. However, no studies have compared the safety and efficacy of SV with HV PLEX, which we aimed to assess.

Methods

This retrospective study included patients with ALF admitted between March 2021 and March 2023 who underwent PLEX. All patients underwent HV PLEX until May 2022, and then thereafter, SV PLEX was performed. The objectives of the study were to compare transplant-free survival (TFS) at 30 days, efficacy in reducing severity scores, biochemical variables, and adverse events between SV (total plasma volume x 1) and HV (total plasma volume x 1.5-2) PLEX.

Results

Forty two ALF patients (median age: 23.5 years; females: 57.1%; MELD Na: 34.67 ± 6.07; SOFA score- 5.24 ± 1.42) underwent PLEX. Of these, 22 patients underwent SV-PLEX, and 20 underwent HV-PLEX. The mean age, sex, etiology distribution, and severity scores were similar between the groups. The median number of PLEX sessions (2) was similar in both groups. On Kaplan-Meier analysis, TFS was 45.5% in SV group and 45% in HV group (P = 0.76). A comparable decline in total bilirubin, PT/INR, ammonia, and MELD Na scores was noted in both groups. The cumulative number of adverse events was similar between the HV group (77.3%) and SV group (54.5%; P = 0.12).

Conclusions

SV PLEX is safe and as effective as HV PLEX in patients with ALF. Further randomized controlled trials with a larger sample size are needed to validate these findings.

Critical care management of acute liver failure

The management of acute liver failure (ALF) in modern hepatology intensive care units (ICU) has improved patient outcomes. Critical care management of hepatic encephalopathy, cerebral edema, fluid and electrolytes; prevention of infections and organ support are central to improved outcomes of ALF. In particular, the pathogenesis of encephalopathy is multifactorial, with ammonia, elevated intra-cranial pressure and systemic inflammation playing a central role. Although ALF remains associated with high mortality, the availability of supportive care, including organ failure support such as plasma exchange, timely mechanical ventilation or continuous renal replacement therapy, either conservatively manages patients with ALF or offers bridging therapy until liver transplantation. Thus, appropriate critical care management has improved the likelihood of patient recovery in ALF. ICU care interventions such as monitoring of cerebral edema, fluid status assessment and interventions for sepsis prevention, nutritional support and management of electrolytes can salvage a substantial proportion of patients. In this review, we discuss the key aspects of critical care management of ALF.

Growing Evidence for Survival Benefit with Plasma Exchange to Treat Liver Failure

Plasma exchange (PLEX) to treat liver failure patients is gaining increasing momentum in recent years. Most reports have used PLEX to treat patients with acute liver failure (ALF) or acute on chronic liver failure (ACLF). Etiology of liver disease has an important bearing on the prognosis of the illness in these patients. The accruing data suggest survival benefit with PLEX compared with standard medical treatment to treat ALF and ACLF patients, in randomised controlled trials done world-over. The American College of Apheresis now recommends high-volume PLEX as first-line treatment for ALF patients. Most matched cohort studies done from India which recruited patients with a specific etiology of ALF or ACLF report survival benefit with PLEX compared to standard medical treatment. The survival benefit with PLEX appears more pronounced in ALF patients rather than in ACLF patients. Systematic analysis of the efficacy of PLEX to treat ALF and ACLF patients is needed. There is also a need to identify dynamic predictive scores to assess which patients with ALF or ACLF will respond to PLEX.

Novel radiological technique to recognize acute liver failure caused by yellow phosphorous containing rodenticides

Yellow phosphorous rodenticide (YPR) poisoning is the commonest cause for acute liver failure (ALF) in southern and western India. Due to medicolegal issues, history of YPR ingestion may not be available. As early recognition of YPR poisoning is important and there are no specific biochemical assays, other early predictors to identify this entity is necessary. We evaluated the diagnostic role of plain computed tomography (CT) in identifying YPR-induced ALF. All patients admitted to the liver unit with a diagnosis of ALF underwent a plain CT scan abdomen. Demographic details, clinical history, laboratory parameters, liver attenuation index (LAI) calculated on CT scan, treatment details, need for liver transplantation and clinical outcome were analyzed. Parameters for YPR-induced ALF (ALF-YPR) and other causes (ALF-OTH) were compared. Ability of LAI to distinguish ALF-YPR and ALF-OTH was analyzed using receiver operating characteristic (ROC) curve analysis. Twenty-four patients (15 female [62.5%]) were included in the study. Thirteen patients (54%) had YPR poisoning, while the rest formed the ALF-OTH group (11,46%). ALF-YPR patients had higher transaminase levels, lower peak serum bilirubin levels. ALF-YPR livers had significantly lower LAI as compared to ALF-OTH (- 30 vs. - 8, p = 0.001). On ROC curve analysis, an LAI greater than - 18 ruled out YPR as the cause for ALF with 91% sensitivity and 85% specificity. On regression analysis, LAI was the only independent factor predicting ALF-YPR (odds ratio - 0.86, [0.76, 0.96] p = 0.008). Our data shows that LAI on plain abdominal CT scan can be used to quickly recognize ALF-YPR in unclear cases so that necessary treatment protocol can be activated, or patient transfer arranged. Our analysis shows that an LAI greater than - 18 can reliably rule out YPR ingestion as the cause for ALF.

Improving Transplant-free Survival With Low-volume Plasma Exchange to Treat Children With Rodenticide Induced Hepatotoxicity

Background

In a prior report, no patient with rodenticidal hepatotoxicity who met Kochi criteria (MELD score ≥36 or baseline INR ≥6 with hepatic encephalopathy) (PMID: 26310868) for urgent liver transplantation survived with medical management alone. Plasma exchange (PLEX) may improve survival in these patients.

Objectives

We describe our experience with low-volume PLEX (PLEX-LV) in treating rodenticide ingestion induced hepatotoxicity in children.

Methods

From prospectively collected database of rodenticidal hepatotoxicity patients managed as in-patient with department of Hepatology from December 2017 to August 2021, we retrospectively studied outcomes in children (≤18 years). Hepatotoxicity was categorized as acute liver injury (ALI, coagulopathy alone) or acute liver failure (ALF, coagulopathy and encephalopathy). Kochi criteria was used to assess need for urgent liver transplantation. The primary study outcome was one-month survival.

Results

Of the 110 rodenticidal hepatotoxicity patients, 32 children (females: 56%; age: 16 [4.7-18] years; median, range) constituted the study patients. The study patients presented 4 (1-8) days after poison consumption (impulsive suicidal intent:31, accidental:1). Twenty children (62%) had ALI [MELD: 18 (8-36)] and 12 (38%) had ALF [MELD: 37 (24-45)].All children received standard medical care, including N-acetyl cysteine; ALF patients also received anti-cerebral edema measures. None of the patient families opted for liver transplantation. Seventeen children (ALI: 6, ALF: 11) were treated with PLEX-LV (3 [1-5] sessions, volume of plasma exchanged per session: 26 [13-38] ml/kg body weight) and peri-procedure low dose prednisolone.At 1 month, 28 of the 32 children (87.5%) were alive (4 ALF patients died). Of 10 children who met Kochi listing criteria for urgent liver transplantation, two children were ineligible for PLEX-LV (due to hemodynamic instability) and of the remaining 8 children treated by PLEX-LV, 6 (75%) survived.

Conclusions

PLEX-LV shows promise as an effective non-liver transplant treatment in children with rodenticidal hepatotoxicity.