Pneumomediastinum predicts early mortality in acute paraquat poisoning

Utility of Clinical Variables for Deciding Palliative Care in Paraquat Poisoning: A Retrospective Study

Background

Patients with paraquat poisoning (PP) have a mortality rate comparable to that of advanced malignancies, yet palliative care is seldom considered in these patients. This audit aimed to identify triggers for early palliative care referral in critically ill patients with PP.

Methods

Medical records of patients with PP were audited. Predictors of mortality within 48 hours of hospitalization and 24 hours of intensive care unit (ICU) admission were considered as triggers for palliative care referral.

Results

Among 108 patients, 84 complete records were analyzed, and 53 out of 84 (63.1%) expired. Within 48 hours after hospitalization, the lowest oxygen partial pressure in arterial blood to a fraction of inspired oxygen [the ratio of partial pressure of oxygen in arterial blood (PaO2) to the fraction of inspiratory oxygen concentration (FiO2) (PaO2/FiO2)] was the independent predictor of mortality, cut-off ≤ 197; the area under the curve (AUC), 0.924; sensitivity, 97%; specificity, 78%; p <0.001; and 95% confidence interval (CI): 0.878-0.978. Kaplan-Meier survival plot showed that the mean survival time of patients with the lowest PaO2/FiO2, ≤197, was 4.64 days vs 17.20 days with PaO2/FiO2 >197 (log-rank p < 0.001). Sequential organ failure assessment (SOFA) score within 24 hours of ICU admission had a cut-off ≥9; AUC, 0.980; p < 0.001; 95% CI: 0.955-1.000; 91% sensitivity; and 90% specificity for mortality prediction. Out of the total of 84 patients with PP analyzed, there were 11 patients admitted to the high dependency units (13.1%) and 73 patients admitted to the ICU (86.9%). Out of the total of 84 patients of PP in whom data was analyzed, 53 (63.1%) patients required ventilator support. All the 53 patients who required ventilator support due to worsening hypoxemia, eventually expired.

Conclusion

The lowest PaO2/FiO2 ≤ 197 within 48 hours of hospitalization, SOFA score ≥9 within 24 hours of ICU admission or need for mechanical ventilation are predictors of mortality in PP patients, who might benefit from early palliative care.

How to cite this article

Rao S, Maddani SS, Chaudhuri S, Bhatt MT, Karanth S, Damani A, et al. Utility of Clinical Variables for Deciding Palliative Care in Paraquat Poisoning: A Retrospective Study. Indian J Crit Care Med 2024;28(5):453-460.

Occult paraquat poisoning causing pneumomediastinum and organizing pneumonia

Pneumomediastinum is not an uncommon manifestation of lung toxicity in acute paraquat ingestion. The condition is almost invariably seen with other lung parenchymal abnormalities such as consolidations, ground-glass opacities and interlobular septal thickening. The diagnosis may be challenging in cases with no history of toxin exposure, presentation with a subacute illness and/or absence of typical local or systemic features of paraquat toxicity.

Paraquat Poisoning Associated With Daisley Barton Syndrome: A Case Report

Pesticides include insecticides, herbicides, and rodenticides. Pesticide poisoning can be intentional, accidental, or occupational. Around 385 million cases of unintentional acute pesticide poisoning occur annually worldwide, with approximately 11,000 fatalities. Herbicides are used to kill weeds and can include chlorophenoxy compounds, bipyridyls, urea-substituted herbicides, organophosphates, and glyphosate. Paraquat is a bipyridyl nonselective contact herbicide with high mortality rates upon exposure in humans. Paraquat poisoning causes acute lung injury, rarely leading to pneumothorax and pneumomediastinum, referred to as Daisley Barton Syndrome. We report a case of a 22-year-old female from Uttarakhand, India, who accidentally ingested paraquat. She was initially asymptomatic, but later developed lung, liver, and kidney injuries as well as pneumomediastinum and pneumothorax.

Association between liberal oxygen therapy and mortality in patients with paraquat poisoning: A multi-center retrospective cohort study

Paraquat (N, N'-dimethyl-4, 4'-bipyridinium dichloride, PQ) intoxication is a common cause of lethal poisoning. This study aimed to identify the risk of using liberal oxygen therapy in patients with PQ poisoning. This was a multi-center retrospective cohort study involving four medical institutions in Taiwan. Data were extracted from the Chang Gung Research Database (CGRD) from January 2004 to December 2016. Patients confirmed to have PQ intoxication with a urine PQ concentration ≥ 5 ppm were analyzed. Patients who received oxygen therapy before marked hypoxia (SpO2 ≥ 90%) were defined as receiving liberal oxygen therapy. The association between mortality and patient demographics, blood paraquat concentration (ppm), and liberal oxygen therapy were analyzed. A total of 416 patients were enrolled. The mortality rate was higher in the liberal oxygen therapy group (87.8% vs. 73.7%, P = 0.007), especially in 28-day mortality (adjusted odds ratio [aOR]: 4.71, 95% confidence interval [CI]: 1.533–14.471) and overall mortality (aOR: 5.97, 95% CI: 1.692–21.049) groups. Mortality in patients with PQ poisoning was also associated with age (aOR: 1.04, 95% CI: 1.015–1.073), blood creatinine level (aOR: 1.49, 95% CI: 1.124–1.978), and blood paraquat concentration (ppm) (aOR, 1.51; 95% CI: 1.298–1.766). Unless the evidence of hypoxia (SpO2 < 90%) is clear, oxygen therapy should be avoided because it is associated with increased mortality.

A Case of Paraquat Poisoning Presenting With Spontaneous Pneumothorax and Pneumomediastinum

Paraquat (1,1’-dimethyl-4,4’-dipyridylium) is a liquid herbicide associated with accidental and suicidal ingestion, leading to fatal toxicity. It can lead to multiple organ dysfunction, including metabolic acidosis, acute kidney and liver injury, pulmonary fibrosis, and acute respiratory distress syndrome (ARDS). Very rarely, this can present with spontaneous pneumothorax or pneumomediastinum or both, which are poor prognostic markers with a mortality rate of almost 100%. Here, we present a young male presenting with paraquat poisoning followed by the development of both pneumothorax and pneumomediastinum and death from respiratory failure. Paraquat poisoning should always be considered in the differential diagnosis in patients presenting with spontaneous pneumothorax or pneumomediastinum in places with high paraquat poisoning prevalence.

Pneumoperitoneum from pneumomediastinum in paraquat poisoning

Pneumomediastinum is not uncommon in paraquat poisoning and usually results from oesophageal perforation or alveolar rupture in fibrotic lung disease. However, the combined presentation of pneumomediastinum and pneumoperitoneum is a rarity. We recently managed a young patient with paraquat ingestion who developed spontaneous pneumomediastinum. His chest radiograph also showed free air under the right hemidiaphragm. This pneumoperitoneum caused no clinical symptom and resolved spontaneously within a few days without any surgical intervention.

Serum anion gap at admission as a predictor of the survival of patients with paraquat poisoning: A retrospective analysis

Paraquat (PQ) poisoning is associated with high mortality rate. Therefore, an accurate method for predicting the survival of patients with PQ poisoning is required. This study evaluated the value of serum anion gap (AG) at admission in predicting the survival of such patients.Cases of patients with PQ poisoning admitted to Cangzhou Central Hospital between May 2012 and March 2019 were retrospectively analyzed. The patients were classified into survival and nonsurvival groups on the basis of their 90-day prognosis. Correlation analysis, Cox regression analysis, and receiver operating characteristic and Kaplan-Meier curve analyses were performed to assess the value of AG in predicting the 90-day survival of patients with PQ poisoning.Only 44 of the 108 patients with PQ poisoning survived; thus, the 90-day survival was 40.74%. AG levels at admission were significantly higher in nonsurvivors (26.53 ± 4.93 mmol/L) than in survivors (20.88 ± 2.74 mmol/L) (P < .001) and negatively correlated with 90-day survival (r = -0.557; P < .001). Cox regression analysis revealed that AG at admission is an independent prognostic marker of the 90-day survival of patients with PQ poisoning. AG level at admission had an area under the receiver operating characteristic curve of 0.836 (95% confidence interval: 0.763-0.909) and an optimal cut-off value of 25.5 mmol/L (59.4% sensitivity and 95.5% specificity).AG level at admission may serve as a candidate marker for predicting the survival of patients with PQ poisoning.

Metabolitic profiling of amino acids in paraquat-induced acute kidney injury

BACKGROUND

The herbicide paraquat (1, 1'-dimethyl-4, 4'-bipyridylium dichloride; PQ) is a poison well-known to cause delayed mortality due to acute kidney injuries (AKI). This study examines the changes in serum amino acids (AAs) metabolite profiles as surrogate markers of renal cell metabolism and function after paraquat poisoning.

METHODS

To identify the metabolic profiling of free serum AAs and its metabolites, serum from 40 paraquat-poisoned patients with or without AKI is collected. LC-MS/GC-MS is performed to analyze AA molecules. A Cox proportional hazard model was used to assess for incidence of AKI. Receiver operating characteristic (ROC) curve is applied to evaluate AKI occurrence and prognosis.

RESULTS

A total of 102 serum AAs and its metabolites were identified. Compared with non-AKI patients, 37 varied significantly in AKI patients. The univariate Cox proportional hazard model analysis revealed that the estimated PQ amount, plasma PQ concentration, urine PQ concentration, APACHE, SOFA scores and 16 amino acids correlated with the incidence of AKI. Further analyses revealed that 3-methylglutarylcarnitine, 1-methylimidazoleacetate, and urea showed higher cumulative hazard ratios for the occurrence of AKI during follow-up (P < 0.05). The area under the curve (AUC) of 3-methylglutarylcarnitine, 1-methylimidazoleacetate and urea were 0.917, 0.857, 0.872, respectively.

CONCLUSION

3-methylglutarylcarnitine, 1-methylimidazoleacetate and urea were associated with AKI in patients with paraquat intoxication.

Pneumomediastinum caused by occult paraquat poisoning: Case report

RATIONALE

Paraquat is a widely applied contact herbicide that is highly poisonous. About 20% of patients with paraquat poisoning develop pneumomediastinum as a complication with a mortality rate of almost 100%.

PATIENT CONCERNS

A 15-year-old boy presented with a 1-month history of retrosternal chest pain with no obvious cause. High-resolution computed tomography showed pneumomediastinum.

DIAGNOSES

After all likely causes of pneumomediastinum were eliminated, the diagnosis of occult paraquat poisoning was made when serum paraquat concentration was revealed at 467.40 ng/mL, despite the patient's denial of ingestion or contact.

INTERVENTIONS

Hemoperfusion, intravenous glucocorticoid, and ulinastatin was administered for 3 days with other routine treatment against paraquat poisoning. The serum paraquat concentration decreased to zero.

OUTCOMES

Despite the general high mortality and poor prognosis of paraquat poisoning, the patient recovered and was completely asymptomatic at his 3-month follow-up.

LESSONS

Paraquat poisoning should be suspected as a differential diagnosis when patients present with pneumomediastinum without recognizable cause.

Metabolic Profiling of Amino Acids Associated with Mortality in Patients with Acute Paraquat Poisoning

Background

Paraquat is a major cause of fatal poisoning after ingestion in many parts of Asia and the Pacific nations. However, optimal prognostic indicators to evaluate patient mortality have not been unequivocally established. Following acute paraquat poisoning, a number of amino acids (AA), are abnormally expressed in metabolic pathways. However, the alterations in AA metabolite levels after paraquat poisoning remain unknown in humans.

Material/Methods

In the present study, 40 patients were enrolled, of whom 16 survived and 24 died. A metabolomics approach was used to assess changes in AA metabolites in plasma and its potential prognostic value following paraquat poisoning. Mass spectrometry (MS) based on metabolite identification was conducted.

Results

Twenty-five AA levels in plasma were abnormally expressed in non-survivor patients. Among them, creatinine, indolelactate, and 3-(4-hydroxyphenyl)lactate were found to be highly correlated with paraquat death prediction. It was noted that the intensity levels of these 3 AA metabolites in the non-survivor group were substantially higher than in the survivor group. Furthermore, we examined receiver operating characteristic (ROC) curves for clinical validation. ROC results showed that 3-(4-hydroxyphenyl)lactate had the highest AUC of 0.84, while indolelactate and creatinine had AUCs of 0.75 and 0.83, respectively, suggesting that they can be used to predict the clinical outcome (although this methodology is expensive to implement).

Conclusions

Metabolic profiling of AA levels could be a reliable tool to identify effective indicators for the early high precision prognosis of paraquat poisoning.

Point-of-care testing in the early diagnosis of acute pesticide intoxication: The example of paraquat

Acute pesticide intoxication is a common method of suicide globally. This article reviews current diagnostic methods and makes suggestions for future development. In the case of paraquat intoxication, it is characterized by multi-organ failure, causing substantial mortality and morbidity. Early diagnosis may save the life of a paraquat intoxication patient. Conventional paraquat intoxication diagnostic methods, such as symptom review and urine sodium dithionite assay, are time-consuming and impractical in resource-scarce areas where most intoxication cases occur. Several experimental and clinical studies have shown the potential of portable Surface Enhanced Raman Scattering (SERS), paper-based devices, and machine learning for paraquat intoxication diagnosis. Portable SERS and new SERS substrates maintain the sensitivity of SERS while being less costly and more convenient than conventional SERS. Paper-based devices provide the advantages of price and portability. Machine learning algorithms can be implemented as a mobile phone application and facilitate diagnosis in resource-limited areas. Although these methods have not yet met all features of an ideal diagnostic method, the combination and development of these methods offer much promise.

Predictors of acute kidney injury after paraquat intoxication

Paraquat intoxication is characterized by multi-organ failure, causing substantial mortality and morbidity. Many paraquat patients experience acute kidney injury (AKI), sometimes requiring hemodialysis. We observed 222 paraquat-intoxicated patients between 2000 and 2012, and divided them into AKI (n = 103) and non-AKI (n = 119) groups. The mortality rate was higher for AKI than non-AKI patients (70.1% vs. 40.0%, P < 0.001). Patients with AKI had a longer time to hospital arrival (P = 0.003), lower PaO₂ (P = 0.006) and higher alveolar-arterial O₂ difference (P < 0.001) 48 h after admission, higher sequential organ failure assessment 48-h score (P < 0.001), higher severity index of paraquat poisoning (SIPP) score (P = 0.016), lower PaCO₂ at admission (P = 0.031), higher PaO₂ at admission (P = 0.015), lower nadir PaCO₂ (P = 0.001) and lower nadir HCO₃ (P = 0.004) than non-AKI patients. Multivariate logistic regression indicated that acute hepatitis (P < 0.001), a longer time to hospital arrival (P < 0.001), higher SIPP score (P = 0.026) and higher PaO₂ at admission (P = 0.014) were predictors of AKI. The area under the receiver operating characteristic curve confirmed that an Acute Kidney Injury Network 48-hour score ≥ 2 predicted AKI necessitating hemodialysis with a sensitivity of 0.6 and specificity of 0.832. AKI is common (46.4%) following paraquat ingestion, and acute hepatitis, the time to hospital arrival, SIPP score and PaO₂ at admission were powerful predictors of AKI. Larger studies with longer follow-up durations are warranted.

Hyperamylasemia as an Early Predictor of Mortality in Patients with Acute Paraquat Poisoning

Background

Paraquat (PQ) is a non-selective and fast-acting contact herbicide which has been widely used in developing countries. Hyperamylasemia was reported in patients with PQ poisoning. This study investigated the predictive value and clinical characteristics of hyperamylasemia in patients with PQ poisoning.

Material/Methods

This study included 87 patients with acute PQ poisoning admitted from July 2012 to May 2015. Data were collected from medical records. Receiver operating characteristic (ROC) analysis was conducted to analyze the discriminatory potential of serum amylase with respect to 90-day mortality.

Results

Of 87 patients, 29 patients had elevated serum amylase. We found that serum amylase was significantly higher among patients with AKI than those with non-AKI (p<0.001), and was an independent predictor of mortality (hazard ratio [HR]=3.644; 95% [CI], 1.684–7.881; p=0.001). The area under the ROC curve for the serum amylase (area under curve [AUC]=0.796; 95% [CI], 0.690–0.903) had a better discriminatory potential than plasma PQ concentration (0.698;0.570–0.825) or urinary PQ concentration (0.647;0.514–0.781) in predicting 90-day mortality.

Conclusions

Hyperamylasemia is a valuable early predictor of 90-day mortality in PQ poisoning.