Acute gastrointestinal paraquat poisoning: diagnosis and resuscitation treatment

2021-07-27 11:36 PM

Paraquat poisoning death is very high, in the first hours, pain in the mouth, throat, along the sternum and epigastrium, inflammation, ulcers, slips of the mouth, throat, esophagus appear after many hours.

Paraquat poisoning has a very high mortality, generally, up to 70-90%, the role and opportunity to apply current treatment measures are limited because the poison is distributed and attached quickly to the lungs (within a short period of time). In the first 6 hours, lethal concentrations can be reached), causing lung damage, progressive pulmonary fibrosis. Breathing oxygen accelerates the progression of pulmonary fibrosis.

The general treatment attitude that seems to be most effective today is to urgently take advantage of the first hours after drinking with the simultaneous application of detoxification measures, fluid infusion, active diuretics, dialysis, and then the results. combination of immunosuppressive and symptomatic therapy.

Diagnosis and evaluation

The patient drank herbicides, the vomit was green, the blue solution was contained in a plastic bottle. Assert if the active ingredient name is paraquat.

In the first hours, pain in the mouth, throat, posterior sternum and epigastrium. Inflammation, ulcers, erosions of the mouth, throat, esophagus appear after many hours.

Respiratory failure: acute progression within the first few days (lung injury, pneumothorax, pneumomediastinum) or onset after weeks and then worsening (pulmonary fibrosis). Assess by SpO 2 , arterial blood gas, chest X-ray, lung computed tomography, pulmonary function test.

There may be hypotension, acute heart failure (fulminant) or renal failure (early day one), hepatitis after a few days. (Test). Complete blood count, urea, creatinine, bilirubin, electrolytes, AST, ALT, arterial blood gas, urinalysis.

Qualitative paraquat test (rapid test), helping to confirm the diagnosis: gastric juice, chemical sample, or urine (maybe negative after taking 24 hours if kidney failure is not); + 10ml of suspected toxic sample is alkalized with NaHC03 to reach pH 8 - 9, then add sodium dithionite powder, urine, if there is paraquat, will turn blue (blue, blue), can be seen Paraquaturia is positive if urine is collected within 24 hours of ingestion with normal renal function. If kidney failure is present, the test may be positive up to several days later.

Quantification of paraquat in the blood (if possible); blood collection within 24 hours of oral administration, predicting survival.

Differential diagnosis

Drinking other corrosive substances: for example, other acids, alkalis, pesticides containing glyphosate, diquat (chemical samples without the above identification, mucosal lesions but no pulmonary fibrosis).

Treatment

Measures to detoxify and increase detoxification must be carried out at the same time as soon as possible, so as not to affect the other measures.

Limit absorption of toxins

Induce vomiting: within the first 1 hour.

Gastric lavage: within the first 6 hours, wash until the water is no longer blue.

Absorb poison (in the first 6 hours), take one of the following 3 drugs (priority in order):

+ Activated charcoal: 1 g/kg/time, used 3 times, 2 hours/time and sorbitol double dose.

+ Fuller's earth: adults 100-150g, children 2g/kg, mix the ratio of 1 part medicine + 2 parts water by weight.

+ Clay, clay or normal soil (if far from the hospital): mix drinking water immediately.

Increases elimination of toxins

Positive diuresis, ensuring 200ml/hour: do it in the first 24 hours, continue if the paraquaturia is still positive.

Dialysis (if possible): performed within the first 24 hours, consider if after 24 hours the urine is still positive:

+ Adsorbent hemodialysis (activated charcoal column) repeated every 12-24 hours until paraquaturia is negative.

- If only HD, can be done in the first 4 hours after poisoning.

Immunosuppressive therapy

Methylprednisolone: ​​15mg/kg/day (mixed with 200ml glucose 5%, intravenous infusion 2 hours), for 3 days.

Cyclophosphamide: 15mg/kg/day (mixed with 200ml glucose 5%, intravenous infusion 2 hours), for 2 days.

Then: dexamethasone 8 mg/time x 3 times/day, for 14 days, intravenously, then gradually reduce the dose and stop.

If PaO 2 < 60 mmHg: immediately restart methylprednisolone as above, repeat cyclophosphamide dose as above in 1 day (repeat this drug only if the previous dose is more than 14 days apart and white blood cell > 3G/L).

Antioxidants (optional, if available)

Intravenous N-acetylcysteine: 150mg/kg, mixed with 500ml glucose 5%, IV infusion for 3 hours after the first dialysis, then 300mg/kg, 500ml glucose 5%, infusion 21ml/hour for 3 weeks.

Vitamin E: 300mg x 2 times/day, orally.

Deferoxamine (Desferan, used after the first hemodialysis): 100mg/kg, mixed with 500ml of 5% glucose, 21ml/hour intravenously, used for 1 day.

Supportive treatment

Add oxygen only if PaO 2 < 40 mmHg or SpO 2 < 80%.

Gastrointestinal mucosa.

Decreased gastric secretion: intravenous administration.

Good pain relief can use opiate preparations.

Parenteral nutrition should include lipid solutions.

Explain to the patient's family: explain to cooperate when there is an opportunity to treat and understand the prognosis of poisoning.

Follow-up and prognosis

Note: for the first few days the patient may be fine, with respiratory failure often later.

Daily chest X-ray, lung CT scan once a week.

Daily blood gas, liver, and kidney function tests.

Test respiratory function when stable and every 1-2 weeks.

See you periodically.

Prevention

It is best not to use paraquat as a herbicide.

When still using this chemical: only use less than 5% solution, do not circulate higher concentration in the community.