When monitoring patients on antitubercular drug therapy, the nurse knows that which drug may cause a decrease in visual acuity?

Correct Answer: C

Rationale: The correct answer is C: ethambutol (Myambutol). Ethambutol is known to cause optic neuritis, leading to a decrease in visual acuity. This adverse effect is dose-dependent and more likely to occur with prolonged use. Rifampin (A), isoniazid (B), and streptomycin (D) do not typically cause visual disturbances. Rifampin may cause a harmless orange discoloration of bodily fluids. Isoniazid is known for hepatotoxicity and peripheral neuropathy. Streptomycin can lead to ototoxicity and nephrotoxicity. Therefore, ethambutol is the correct choice due to its association with visual acuity changes.

Correct Answer: B

Rationale: The correct answer is B: Blocking pain sensation without loss of consciousness. Local anesthetics work by blocking nerve impulses in a specific area, leading to loss of sensation without affecting consciousness. This is achieved by blocking sodium channels in the nerves. Option A is incorrect as local anesthetics do not cause amnesia or loss of consciousness. Option C is incorrect as it refers to the effects of sedatives, not local anesthetics. Option D is incorrect as a stupor or somnolent state indicates a decreased level of consciousness, which local anesthetics do not cause.

Correct Answer: B

Rationale: The correct answer is B because dryness of mouth, hyperpyrexia (high fever), and hallucination are not typical symptoms of mushroom poisoning. Salivation, lacrimation, nausea, vomiting (choice A), headache, abdominal colic (choice C), bradycardia, hypotension, and shock (choice D) are common symptoms seen in mushroom poisoning cases. Dry mouth, high fever, and hallucinations are more likely to be associated with other conditions or toxicities.

Correct Answer: C

Rationale: The correct answer is C because infants and children are more sensitive to atropine's effects, including the potential for causing a rise in body temperature. Atropine inhibits sweat gland function, leading to decreased ability to regulate body temperature, especially in pediatric populations. Choice A is incorrect because atropine fever can occur in adults as well. Choice B is incorrect because pregnancy status does not directly affect the likelihood of atropine-induced fever. Choice D is incorrect because not all adults experience atropine fever, while infants and children are more susceptible.

Correct Answer: C

Rationale: The correct answer is C: Pupillary dilator muscle. Beta adrenoreceptor subtypes are found in bronchial muscles, heart, and fat cells, but not in pupillary dilator muscles. These receptors are involved in various functions such as bronchodilation, cardiac stimulation, and lipolysis. Pupillary dilator muscles are predominantly innervated by alpha adrenergic receptors, not beta adrenergic receptors, which regulate pupil constriction. Thus, the absence of beta adrenoreceptor subtypes in pupillary dilator muscles makes choice C the correct answer.