Final answer:
The nurse should initially ask the mother if the child had a recent sore throat, as this could indicate a previous streptococcal pharyngitis infection, which if untreated, could lead to rheumatic fever and cause damage to the heart valves.
Step-by-step explanation:
The nurse initially asking the mother of a child with a diagnosis of rheumatic fever about signs of a recent sore throat would be a critical first step. Rheumatic fever is often a sequela of an inadequately treated streptococcal infection, such as pharyngitis. In cases where the streptococcal pharyngitis is not properly treated with antibiotics, the immune response to this infection can lead to the inflammatory condition known as rheumatic fever, which can cause harm to the heart valves—a condition described as rheumatic heart disease. Understanding the child's recent medical history of throat infections is essential, as it could provide information about the potential cause of the rheumatic fever and guide further treatment decisions.
Given that rheumatic fever can occur 2-3 weeks after an untreated or inadequately treated episode of strep throat, the nurse's inquiry would address whether the child had a sore throat or streptococcal infection prior to the onset of symptoms associated with rheumatic fever. This information is vital for assessing the risk of recurrent attacks and planning preventive measures to protect the heart valves from further damage. It is also congruent with the guidelines, which emphasize the importance of treating acute streptococcal pharyngitis to prevent rheumatic fever.