Rat Poison Effects in Humans

Introduction

Rodenticides, commonly called “rat poisons,” are mixed compounds added to baits (paste or palatable grains intended to encourage consumption) and are used to eradicate rodents. However, it is essential to remember that these rodenticides are one of the most toxic household chemicals. Heavy metals like arsenic were used in rodenticides in earlier times, but in the present century, anticoagulants are the most commonly used.

Rat poison is toxic to humans and can result in organ failure, paralysis, internal bleeding, and coma. Sometimes, the symptoms may develop after hours or days after exposure. When a physician suspects rodenticide poisoning, every effort is made to identify the poison (the packet information and label give the chemical name and other information).

What Are the Symptoms Associated With Poisoning?

The clinical presentation varies depending on the ingested rodenticide type.

Anticoagulant:

Superwarfarin is an anticoagulant (blood thinner) rodenticide similar to Warfarin, but phenyl groups replace terminal methyl groups. Therefore, superwarfarin is a hundredfold stronger than Warfarin. Warfarin inhibits the clotting cascade and is a competitive Vitamin K epoxide complex inhibitor.

The clinical symptoms associated with poisoning are:

• Spitting or coughing blood (hemoptysis).

• Blood in urine (hematuria).

• Flank pain (pain on one side between the abdomen and back).

• Bleeding from the nose (epistaxis).

• Bleeding within the skull (intracranial hemorrhage).

• Easy bruising.

• Vomiting.

• Abdominal pain.

Bromethalin:

Bomethalin only produces toxic effects in humans following significant ingestion. It is a neurotoxin that affects the peripheral and central nervous systems. It can lead to symptoms like delirium (an altered mental state in which one is disoriented and confused) and altered mental status followed by cerebral edema.

Cholecalciferol:

Cholecalciferol rodenticides produce toxicity in humans only by consuming large amounts. It leads to hypercalcemia, as intestinal calcium absorption is increased. The symptoms include

• Excessive urination (polyuria).

• Vomiting.

• Excessive thirst (polydipsia).

• Encephalopathy (abnormal brain function).

• Renal failure.

Zinc and Aluminum Phosphide:

When this compound comes in contact with water, phosphine gas is formed. On ingestion of the poison, phosphine gas gets absorbed into the gastrointestinal tract and the bloodstream. The time for symptom onset is around half an hour.

The symptoms include

• Irregular heartbeat.

• Acute gastritis.

• Respiratory failure.

• Liver toxicity.

• Renal failure.

• Metabolic acidosis.

Strychnine:

Strychnine poisoning results in involuntary muscle spasms in both animals and humans. The signs may appear within fifteen minutes following exposure in humans. Impaired breathing may lead to death.

Thallium:

The compound is an odorless and tasteless powder absorbed through skin exposure and inhalation.

Short-term exposure causes the following symptoms:

• Acute gastroenteritis (inflammation of the stomach, small or large intestine that results in nausea, vomiting, abdominal cramps, pain, and diarrhea).

• Hyperpigmentation.

• Hair loss.

• Seizure.

• Cranial nerve dysfunction.

Long-term exposure can lead to abnormal gait, double vision, tremors, etc.

Which Are the Diagnostic Tests Done?

Most patients presenting with rodenticide poisoning will be children, mostly after oral ingestion. The other patient group is mostly adults who made suicide attempts. The most important part of history-taking involves the identification of the substance that was ingested. If the ingesting substance is unknown, the following evaluation tests are done:

• Complete Blood Count - CBC test helps evaluate anemia associated with zinc phosphide toxicity.

• Blood Glucose Level - Low blood glucose levels are seen in zinc or aluminum phosphide toxicity and increased glucose levels in Pyriminil toxicity.

• Arterial Blood Gas - Arterial blood gas (ABG) is a diagnostic test for assessing the blood's oxygen and carbon dioxide levels and determining the body's acid-base balance. Lactic acidosis seen in fluroacetamide toxicity.

• Chest X-ray - Radiopaque substances include thallium, arsenic, and barium carbonate.

• Evaluation of Coagulation Profile - The coagulation profiles are altered in the case of anticoagulant rodenticides.

• Troponin - Troponin levels indicate cardiotoxicity linked with zinc and aluminum phosphide.

• Hepatic Function Test - Hepatic enzymes are elevated in the case of arsenic, thallium, zinc, and aluminum phosphide.

• Basic Metabolic Panel - Hypokalemia is seen in zinc and aluminum phosphide, and hypocalcemia in the case of white phosphorous.

What Are the Complications?

The complications associated with rodenticide poisoning are

• Type 1 diabetes.

• Liver failure.

• Renal failure.

• Permanent brain damage.

What Is the Prognosis?

The prognosis of poisoning depends on the composition of the rodenticide and the amount ingested. Early initiation of treatment leads to a better prognosis. In case of chronic exposure, the recovery period will be longer. Liver transplantation may be required in cases where standard treatment options fail.

What Are the Differential Diagnosis?

The differential diagnosis varies per the clinical presentation (depending on the rodenticide composition).

The list includes,

• Alcoholic hepatitis.

• Gastroenteritis.

• Hypokalemia.

• Hypocalcemia.

• Organophosphate toxicity.

• Diabetic ketoacidosis.

• Acute viral hepatitis.

• Food borne toxin.

What Are the Management Options?

• Immediate management involves supporting breathing, airway, and circulation.

• After the patient is stabilized, if contamination is visible, the patient's clothes are removed, and skin irritation is done with water.

• Anti-emetic administration and rehydration are done. Gastric lavage and activated charcoal are not suggested.

• Supportive care is provided.

Specific management options include

• Benzodiazepines for managing seizures and muscle spasms.

• Renal replacement therapy in case of heavy metal poisoning.

• In acute arsenic poisoning, British anti-lewisite is used for chelation.

• Mineralocorticoids for managing orthostatic hypotension.

What Are the Preventive Measures?

• The best way to prevent poisoning is to avoid using the product; if use is unavoidable, take proper care.

• Rodenticide should be stored in a dry and cool place that is out of reach of pets and children.

• Use protective equipment while handling rodenticides, dead rodents, or rat nests.

• Properly wash hands after handling the poison.

• Try for alternative options if possible.

These include:

• Natural rodent repellants can be used indoors and outdoors.

• The smell of essential oils like peppermint oil helps keep rodents away. Cotton balls can be wetted with the oil and placed in susceptible areas.

• Diatomaceous earth is an effective powdery substance made of an aquatic organism called diatoms.

• Rat traps.

Conclusion

Rat poisons are toxic to humans, so one should be cautious while handling rat poison. The clinical symptoms following exposure depend on the composition of the rodenticide. Treatment should be started as early as possible following exposure, if possible, even before the appearance of symptoms.