The recommended children's dosage of Keflex is 25 to 50 mg/kg/day in divided doses. The maximum daily safe dosage for a child weighing 42 lb is: Round to the nearest tenth.

(Number Only, do not enter mg, kg, or day with your answer)

The correct answer is choice B. Cardiac valve damage.

Choice A rationale:

Pulmonary hypertension is not a common complication of rheumatic fever. Rheumatic fever primarily affects the heart, joints, skin, and brain, and pulmonary hypertension is not a typical manifestation of this condition.

Choice B rationale:

Cardiac valve damage is a common and serious complication of rheumatic fever. Rheumatic fever is caused by an autoimmune reaction to untreated streptococcal infections, particularly Streptococcus pyogenes. The immune response targets not only the streptococcal bacteria but also the body's own tissues, especially heart valves. This can lead to inflammation of the heart valves, a condition known as rheumatic heart disease. Over time, repeated bouts of rheumatic fever can result in significant damage to the heart valves, leading to valve insufficiency or stenosis. This can ultimately cause heart failure and other cardiovascular complications.

Choice C rationale:

Seizures are not a common complication of rheumatic fever. Rheumatic fever primarily affects the heart and other body systems, but it does not typically lead to seizures.

Choice D rationale:

Cardiac arrhythmias are possible complications of rheumatic fever, but they are not as common or significant as cardiac valve damage. The inflammation and scarring caused by rheumatic fever can disrupt the electrical pathways of the heart, potentially leading to arrhythmias. However, the more prevalent and severe consequence of rheumatic fever is the damage to the heart valves.

The correct answer is choice C. Explain in simple terms how it works.

Choice A rationale:

Asking the girl why she wants to know might be appropriate in some contexts, but children are naturally curious and seeking information is a common behavior. Explaining how the blood pressure apparatus works would likely be more beneficial than questioning her motivation.

Choice B rationale:

Determining why she is anxious assumes that the girl is anxious, which might not be the case. Additionally, the question she asked does not necessarily indicate anxiety, but rather a curiosity about the medical equipment.

Choice C rationale:

Explaining in simple terms how the blood pressure apparatus works is the most appropriate nursing action. This approach respects the child's curiosity and provides her with age-appropriate information, fostering a positive and educational interaction.

Choice D rationale:

Telling her that she will see how it works as it is used might not fully satisfy her curiosity or address her immediate question. Children often benefit from clear and concise explanations, especially when it comes to medical equipment.