Which bacterial toxin that blocks the acetylcholine at neuromuscular junction?

Appeared in: NVS Staff Nurse - 2022

Explanation

Botulinum toxin is a neurotoxin produced by the bacterium Clostridium botulinum.
It specifically targets the presynaptic nerve terminals at the neuromuscular junction.
The toxin works by cleaving SNARE proteins, which are essential for the release of the neurotransmitter acetylcholine (ACh).
By blocking ACh release, the toxin prevents muscle stimulation, leading to a descending flaccid paralysis.

Option B: Clostridium is the genus of the bacterium that produces the toxin, not the toxin itself. The question asks for the specific toxin.
Option C: Staphylococcus is a genus of bacteria that produces various toxins, but they are primarily associated with conditions like food poisoning (enterotoxins) and toxic shock syndrome, not the blockade of acetylcholine at the neuromuscular junction.
Option D: Salmonella is a bacterium that primarily causes gastrointestinal illness (salmonellosis). It does not produce a neurotoxin that acts on the neuromuscular junction.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Mechanism of action of bacterial neurotoxins at the neuromuscular junction as background academic context rather than a clinical decision trigger.
The most critical nursing responsibility in a patient with suspected botulism is vigilant respiratory monitoring. Paralysis of the diaphragm can occur rapidly, leading to respiratory failure.
Nurses must be prepared for immediate intervention, including airway management and mechanical ventilation.
Early recognition of descending weakness, ptosis (drooping eyelids), diplopia (double vision), and dysphagia (difficulty swallowing) is crucial for prompt diagnosis and treatment with antitoxin.

How to Approach the Question

First, identify the key concepts in the question: 'bacterial toxin', 'blocks acetylcholine', and 'neuromuscular junction'.
This is a factual recall question. Access your knowledge about major bacterial toxins and their mechanisms.
Evaluate each option. Notice that 'Clostridium' is a bacterium, while 'Botulinum toxin' is the toxin itself. This distinction is important.
Eliminate options associated with different pathologies. Staphylococcus is linked to skin infections and toxic shock, while Salmonella is linked to gastroenteritis.
Confirm that botulinum toxin matches all the criteria in the question: it's a bacterial toxin that blocks acetylcholine at the neuromuscular junction, causing flaccid paralysis.

Concept Tested & Keywords

Concept Tested: Mechanism of action of bacterial neurotoxins at the neuromuscular junction.
Stem keywords: bacterial toxin, blocks acetylcholine, neuromuscular junction
Lead-in keywords: Which

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E6 Nelson Textbook of Pediatrics(2024) — Volume 1 p. 1821-1823

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E6 Nelson Textbook of Pediatrics(2024) — Volume 2 p. 1673-1675

Practise the full NVS Staff Nurse - 2022

Attempt every question from this paper in a timed mock, then review the full solution for each one.