During a well-baby clinic visit, a mother tells the practical nurse (PN) that her 12-month-old infant is not yet eating solid foods and drinks whole milk from a bottle. Based on these assessment findings, this infant is at the greatest risk for developing which condition?

A. Hematuria is the classic clinical hallmark of acute glomerulonephritis that typically prompts parents to seek medical consultation. The presence of red blood cells in the urine often results in a "cola-colored" or smoky appearance due to the leakage of erythrocytes through the inflamed glomerular basement membrane. This visual change is sudden and alarming to caregivers, serving as a primary reason for acute healthcare visits.

B. Weight loss is an unlikely finding in the initial presentation of acute glomerulonephritis. Instead, these children typically experience rapid weight gain and edema due to sodium and water retention caused by a decreased glomerular filtration rate. The clinical manifestation of fluid overload, including periorbital edema and hypertension, is much more characteristic of the acute inflammatory phase than any nutritional or fluid deficit.

C. Polydipsia, or excessive thirst, is not a typical symptom of acute glomerulonephritis and is more commonly associated with diabetes mellitus or diabetes insipidus. In glomerulonephritis, the renal system is struggling to filter and excrete fluid, often leading to oliguria rather than the polyuria that drives thirst. Consequently, parents would be more likely to report a decrease in urinary frequency and volume rather than increased intake.

D. A sore throat is a precursor to post-streptococcal glomerulonephritis but is usually no longer present by the time the renal symptoms manifest. The typical latency period between a Group A beta-hemolytic streptococcal infection and the onset of kidney inflammation is approximately 1 to 3 weeks. While the history of a sore throat is diagnostically significant, the active renal symptoms like hematuria are what usually motivate the immediate visit.

Respiratory syncytial virus (RSV) is a highly contagious virus that can cause severe respiratory infections, especially in infants and young children. RSV is easily spread through contact with respiratory secretions from infected individuals, and can survive on surfaces for several hours. Therefore, it is important to avoid exposing other children to RSV, especially those who are under 6 months old or have a weakened immune system. The practical nurse (PN) should advise the mother not to take her infant to the birthday party to prevent the spread of RSV to other children. The PN can provide education on how to prevent the spread of RSV, such as washing hands frequently, avoiding close contact with sick individuals, and covering the mouth and nose when coughing or sneezing.