In which condition would a child present with proteinuria and fatigue?

The presentation of proteinuria and fatigue in a child is most indicative of nephrotic syndrome. In nephrotic syndrome, there is significant protein loss in the urine, leading to proteinuria, which typically manifests as an increase in urinary protein levels. This condition is often associated with edema, fatigue, and a range of symptoms due to the loss of proteins that are important for maintaining oncotic pressure in the blood.

While chronic kidney disease (CKD) does lead to fatigue due to the accumulation of waste products and changes in fluid and electrolyte balance, it does not always present with significant proteinuria as a primary symptom. Fatigue can be a late feature in CKD, and other symptoms may precede it.

Glomerulonephritis can also cause proteinuria and fatigue, but the presentation is often acute and accompanied by other symptoms such as hematuria, hypertension, and possibly edema. These distinguishing features make nephrotic syndrome the more likely diagnosis in a child presenting primarily with proteinuria and fatigue.

Liver dysfunction may lead to fatigue but typically does not present with proteinuria. Instead, patients may exhibit symptoms related to altered liver function, such as jaundice or ascites, and lab tests would reflect abnormalities in liver enzyme levels.