Toxicology of AChE Inhibitors

Questions and Answers

What happens to the bond formed between organophosphates and acetylcholinesterase if no antidote is administered within a certain time frame?

The bond may become permanent, known as aging. (correct)

The bond becomes temporary and is easily reversible.

The bond dissipates completely after 24-36 hours.

The bond increases in strength but remains reversible.

What causes the bond between organophosphates and acetylcholinesterase to become irreversible?

The formation of a stable ionic bond.

The displacement of the diethyl group from the phosphate. (correct)

The addition of a hydroxy group to the phosphate.

The activation of the enzyme leading to hyperactivity.

What is the time frame within which an antidote must be administered to prevent the aging process of the OP-AchE bond?

36-48 hours

12-24 hours

48-72 hours

24-36 hours (correct)

Which factor contributes to the aging of the OP-AchE bond?

The time delay in administering the antidote. Signup and view all the answers

Which functional group detachment is responsible for the permanent bond formation in organophosphate toxicity?

Diethyl group Signup and view all the answers

What does an initial ECG showing sinus tachycardia indicate?

Increased heart rate Signup and view all the answers

What is suggested by the presence of pulmonary edema on a chest radiograph?

Fluid accumulation in the lungs Signup and view all the answers

Bronchospasm indicated on a radiograph is most likely associated with which condition?

Asthma or allergic reactions Signup and view all the answers

Which underlying condition could potentially cause both tachycardia and pulmonary edema?

Heart failure Signup and view all the answers

What is a common clinical significance of both tachycardia and bronchospasm?

Increased oxygen demand and airway resistance Signup and view all the answers

Study Notes

Organophosphate (OP) Toxicity

AChE bond may become permanent if antidote is not administered within 24-36 hours, a process known as aging.
Aging occurs when the diethyl group leaves the phosphate, resulting in an irreversible bond.

Clinical Signs and Symptoms

Initial ECG findings include sinus tachycardia and heart block (HB).
Chest radiographs may show pulmonary edema and bronchospasm.
Characteristic garlic-like odor of breath noted in certain toxic exposures.
Physical examination may reveal anxiety, diaphoresis, tachycardia, vomitus, and diarrhea.
Specific symptoms include salivation and gastrointestinal distress.

Mechanism of Phosphine Gas Toxicity

Zinc sulfide phosphine gas acts as a cytochrome C oxidase inhibitor.
Causes cellular toxicity leading to necrosis of the gastrointestinal tract, and injuries to the liver, kidney, and lungs, particularly upon inhalation.

Symptoms of Zinc Phosphide Toxicity

Central nervous system effects include headache, ataxia, seizures, and coma.
Gastrointestinal symptoms may present as nausea and black vomitus with a rotten fish odor.

Description

This quiz delves into the toxic effects of AChE inhibitors and the irreversible binding of these compounds to acetylcholinesterase. Key concepts such as the aging process and the role of the diethyl group in toxicity are explored. Understand the critical timing for antidote administration to mitigate irreversible effects.