What type of immunity does a person gain when they receive an infusion of antibodies for short-term protection?

Choice A reason: Bradycardia, or slow heart rate, is not typically associated with dehydration. Dehydration reduces blood volume, triggering compensatory tachycardia to maintain cardiac output. Bradycardia may occur in severe cases with electrolyte imbalances, but it is not a primary manifestation, making this choice incorrect for dehydration.

Choice B reason: Eupnea refers to normal breathing. Dehydration does not directly alter respiratory rate unless severe metabolic acidosis occurs, prompting compensatory hyperventilation. The described symptoms suggest hypovolemia, not respiratory changes, so eupnea is not an additional manifestation of dehydration, making this choice incorrect.

Choice C reason: Orthostatic hypotension, a drop in blood pressure upon standing, occurs in dehydration due to reduced blood volume from fluid loss (e.g., diarrhea). This hypovolemia impairs the body’s ability to maintain blood pressure during positional changes, leading to lightheadedness, making this the correct additional manifestation.

Choice D reason: Elevated blood pressure is not associated with dehydration. Hypovolemia from fluid loss causes low blood pressure due to decreased cardiac output. The body’s compensatory mechanisms, like vasoconstriction, aim to maintain pressure but do not elevate it above normal, making this choice incorrect.

Choice A reason: Facial trauma may increase aspiration risk if swallowing is impaired, but a 21-year-old typically has a robust immune system, reducing pneumonia risk. The trauma does not directly compromise lung defenses or immune function significantly, making this individual less likely to develop pneumonia compared to an immunocompromised person.

Choice B reason: Osteoarthritis and chronic knee pain in a 72-year-old may limit mobility, slightly increasing pneumonia risk due to reduced lung expansion. However, this condition does not directly impair immune function or lung clearance mechanisms, making it a lower risk compared to immunodeficiency, which severely predisposes to infections.

Choice C reason: Elevated cholesterol in a 48-year-old increases cardiovascular risk but does not directly affect lung function or immune response to infections. Without respiratory or immune compromise, this individual has a lower risk of pneumonia compared to someone with a primary immunodeficiency disorder, making this choice incorrect.

Choice D reason: A 69-year-old with a primary immunodeficiency disorder has a severely compromised immune system, impairing the ability to fight respiratory infections like pneumonia. Age-related lung changes and reduced immune response increase susceptibility to pathogens, making this individual at the highest risk for developing pneumonia, which is why this is correct.