Lethal diquat poisoning manifests as acute central nervous system injury and circulatory failure: A retrospective cohort study of 50 cases

Abstract

Background: The mortality rate of patients with diquat (DQ) poisoning is extremely high due to insufficient understanding of DQ-induced injury. This study aimed to summarize the characteristics of DQ poisoning as well as analyse the correlation between plasma DQ concentration and patient outcomes, thus providing a new strategy for diagnosis and treatment.

Methods: This single-centre retrospective cohort study was conducted at the Emergency Department of the First Affiliated Hospital, Zhejiang University School of Medicine, China, between Oct 9, 2019 and March 10, 2022. 50 patients, whose plasma or urine samples tested positive for diquat and negative for paraquat by high performance liquid chromatography-tandem mass spectrometry, were included in the study.

Findings: The mortality rate of acute DQ poisoning was 25 (50%) of 50. Compared with the survival group, the death group presented significantly higher initial plasma DQ concentration (Cp₁), aspartate aminotransferase, alanine aminotransferase, serum creatinine, and creatine kinase-MB (P < 0.05). We found that six (24.0%) patients died of central nervous system injury, six (24.0%) patients died of refractory circulatory failure, and 13 (52.0%) patients died of central nervous system injury combined with circulatory failure. Receiver operator characteristic curve analysis showed that the area under the curve of Cp₁ was 0.967 (95% CI: 0.911, 1.000), and the cut-off value was 3516.885 ng/mL (sensitivity, 90.9%; specificity, 96.0%).

Interpretation: Lethal DQ poisoning is primarily associated with serious brain and vascular injury, as well as a high rate of mortality. Further research into the mechanisms of refractory circulatory failure and central nerve system damage could help reduce mortality.

Funding: There are no funding sources to declare.

Keywords: Central nervous system injury; Circulatory failure; Diquat poisoning, plasma diquat concentration; High-performance liquid chromatography-mass spectrometry; Neuroimaging.

Figure 1

The prognosis of acute diquat (DQ) poisoning is related to the initial plasma DQ concentration (Cp₁). (A) Based on the prognosis, the gray bar symbolises patients in the death group, and the white bar symbolises patients in the survival group. Then it was sorted according to the initial plasma and urinary concentration of DQ; (B) Correlational analysis between Cp₁ and test time; (C) We calculated the clearance rate of plasma DQ concentration according to the following formula: R = 100 × (Cp₂ - Cp₁)/Cp₁ (%). The correlational analysis between the clearance rate of plasma DQ concentration and Cp₁.

Figure 2

Clinical characteristics of acute DQ poisoning. Dynamic laboratory indexes between survival and death groups from day 1 to day 5 of DQ poisoning, includes ALT, TBil, CK-MB, APTT, PT, TT, SCr, WBC, Neu, PO₂, PCO₂, and Lac. (compared with survival group, *P < 0.05, **P < 0.01, ***P < 0.001). DQ: diquat; ALT: alaninetransaminase; TBil: total bilirubin; CK-MB: creatine kinase-MB; APTT: activated partial thromboplastin time; PT: prothrombin time; TT: thrombin time; SCr: serum creatinine; WBC: white blood cell; Neu: neutrophils; PO₂: artial pressure of oxygen; PCO₂: artial pressure of carbon dioxide; Lac: actic acid.

Figure 3

Abnormal head CT imaging. Head CT appearance of the medulla oblongata (A), the midbrain (B), the basal ganglia (C), and the thalamus (D) was the low-density image, as well as the brain tissue was diffuse swelling.

Figure 4

Statistical analysis chart of patients with lethal DQ poisoning. Histogram of frequency distribution based on fatal complication; (B) Receiver operating characteristic curves for predicting all-cause mortality based on initial plasma DQ concentration (Cp₁) and initial urinary DQ concentration (Cu₁); (C) Survival analysis was performed based on the occurrence of fatal complications; Patients in Group A had no central nervous injury and no refractory circulatory failure; patients in Group B had central nervous injury; patients in Group C had refractory circulatory failure; and patients in Group D had both central nervous injury and refractory circulatory failure.