Clinical course of a fatal ingestion of diquat

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

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.

Acute diquat poisoning causes rhabdomyolysis

We studied the case of a 36-year-old female patient who self-administered about 30 ml of diquat solution (200 g/L) during a suicide attempt. She developed nausea, vomiting, dizziness, and weakness in her limbs and was admitted to the emergency department of our hospital 4 h later. The patient developed progressive swelling and pain in both calves 12 h after admission. Based on symptoms, lower limb color Doppler ultrasound, and elevated levels of myoglobin and creatine kinase, the patient was diagnosed with rhabdomyolysis caused by diquat poisoning. The patient recovered and was discharged after treatment with hemoperfusion, continuous venovenous hemodialysis, acid suppression, liver protection, low-dose glucocorticoids, etc. Rhabdomyolysis caused by diquat poisoning has not been previously reported. We attempted to analyze the mechanism of this symptom through a literature review. We recommend the routine monitoring of creatine phosphokinase (CK) and myoglobin (MYO) in patients with diquat poisoning to avoid missed diagnosis. Further, the mechanism of this poisoning symptom was discussed through the literature review.

Lethal diquat poisoning manifesting as central pontine myelinolysis and acute kidney injury: A case report and literature review

Diquat is a nonselective herbicide that is used as a contact and preharvest desiccant to control terrestrial and aquatic vegetation. Increasing numbers of cases of diquat poisoning have recently been reported. Organs commonly affected by diquat poisoning include the kidney, liver, and lung. Neurological involvement of diquat poisoning is relatively rare. A 21-year-old man ingested 100 mL of diquat (20 g/100 mL) 5 hours before admission. Fifteen minutes after ingestion, he developed nausea and vomiting. The patient was sent to the emergency intensive care unit, and gastric lavage was performed. Continuous renal replacement therapy and continuous venovenous hemodiafiltration with hemoperfusion were performed, and methylprednisolone was administered. Five days after admission, the patient developed disturbance of consciousness and positive bilateral Babinski signs. Head computed tomography demonstrated hypodensity in the pons. At 11 days after admission, brain magnetic resonance imaging showed acute pontine demyelination. At 15 days after admission, the patient died of multiple organ dysfunction syndrome. We encountered a case of diquat poisoning with central pontine myelinolysis and acute kidney injury. This case highlights the clinical value of neuroimaging examination for early diagnosis of central pontine myelinolysis.

Diquat causes caspase-independent cell death in SH-SY5Y cells by production of ROS independently of mitochondria

Evidence indicates that Parkinson's disease (PD), in addition to having a genetic aetiology, has an environmental component that contributes to disease onset and progression. The exact nature of any environmental agent contributing to PD is unknown in most cases. Given its similarity to paraquat, an agrochemical removed from registration in the EU for its suspected potential to cause PD, we have investigated the in vitro capacity of the related herbicide Diquat to cause PD-like cell death. Diquat showed greater toxicity towards SH-SY5Y neuroblastoma cells and human midbrain neural cells than paraquat and also MPTP, which was independent of dopamine transporter-mediated uptake. Diquat caused cell death independently of caspase activation, potentially via RIP1 kinase, with only a minor contribution from apoptosis, which was accompanied by enhanced reactive oxygen species production in the absence of major inhibition of complex I of the mitochondrial respiratory chain. No changes in α-synuclein expression were observed following 24-h or 4-week exposure. Diquat may, therefore, kill neural tissue by programmed necrosis rather than apoptosis, reflecting the pathological changes seen following high-level exposure, although its ability to promote PD is unclear.

Fatal diquat intoxication

Background. Since the introduction of diquat in agriculture practice in 1960's, about 40 cases of poisoning have been described in detail in medical literature. Case report. We presented two cases. A case one, a 35-year-old, previously healthy, woman ingested 14% diquat solution. The poisoning had fulminant course, consisted of severe stomachache, vomiting, cardiocirculatory shock, respiratory failure and cardiac arrest 20 hours post-ingestion. Autopsy revealed myocardial infarction, bronchopneumonia and incipient renal damage. A case two, a 64-year-old man developed severe gastroenteritis, corrosive lesions of mucosal surfaces, acute renal injury, arrhythmias, brain stem infarction and bronchopneumonia. The diagnosis of diquat poisoning was made retrospectively upon the clinical picture and identification of pesticides he had been exposed to. The patient died 18 days post-exposure. The most prominent findings on autopsy were pontine hemorrhage and infarction, bronchopneumonia, left ventricle papillary muscle infarction and renal tubular damage. Conclusion. Cardiocirculatory disturbances led to fatal complications, the heart and brain infarction. We pointed out the heart as one of the most severely affected organs in diquat poisoning.

Potential developmental neurotoxicity of pesticides used in Europe

Pesticides used in agriculture are designed to protect crops against unwanted species, such as weeds, insects, and fungus. Many compounds target the nervous system of insect pests. Because of the similarity in brain biochemistry, such pesticides may also be neurotoxic to humans. Concerns have been raised that the developing brain may be particularly vulnerable to adverse effects of neurotoxic pesticides. Current requirements for safety testing do not include developmental neurotoxicity. We therefore undertook a systematic evaluation of published evidence on neurotoxicity of pesticides in current use, with specific emphasis on risks during early development. Epidemiologic studies show associations with neurodevelopmental deficits, but mainly deal with mixed exposures to pesticides. Laboratory experimental studies using model compounds suggest that many pesticides currently used in Europe--including organophosphates, carbamates, pyrethroids, ethylenebisdithiocarbamates, and chlorophenoxy herbicides--can cause neurodevelopmental toxicity. Adverse effects on brain development can be severe and irreversible. Prevention should therefore be a public health priority. The occurrence of residues in food and other types of human exposures should be prevented with regard to the pesticide groups that are known to be neurotoxic. For other substances, given their widespread use and the unique vulnerability of the developing brain, the general lack of data on developmental neurotoxicity calls for investment in targeted research. While awaiting more definite evidence, existing uncertainties should be considered in light of the need for precautionary action to protect brain development.

Mechanisms of toxicity, clinical features, and management of diquat poisoning: a review

USES: Diquat (1,1'-ethylene-2,2'-bipyridilium) is a nonselective bipyridyl herbicide, related structurally to paraquat, which is used both as a contact herbicide and a preharvest desiccant. In comparison to paraquat, diquat is used much less widely in agriculture.

MECHANISMS OF TOXICITY

Diquat is a potent redox cycler and is readily converted to a free radical which, in reaction with molecular oxygen, generates superoxide anions and subsequently other redox products. These products can induce lipid peroxidation in cell membranes, and potentially cause cell death.

FEATURES

Over the period 1968-1999, only 30 cases of diquat poisoning were reported in detail in the literature, of which 13 (43%) were fatal. Local and systemic effects have been reported following diquat exposure, with systemic features being invariably associated with ingestion. In severe and usually fatal cases, gastrointestinal mucosal ulceration, paralytic ileus, hypovolemic shock, acute renal failure, and coma have been reported.

MANAGEMENT

After rapid confirmation of the diagnosis using a qualitative urine test, gut decontamination may be considered in patients who present within 1 hour of a life-threatening ingestion (>6 g). Supportive measures including fluid and electrolyte replacement should then be employed. Although hemofiltration and hemodialysis are of proven value if renal failure supervenes, there is no clinical evidence that hemodialysis or hemoperfusion removes toxicologically significant amounts of diquat, thereby reducing the risk of organ failure and preventing a fatal outcome in severe cases.