Differential Diagnosis for a 13-year-old child with 10-15 RBC in urine, creatinine of 3, abdominal pain, and multiple episodes of vomiting

• Single most likely diagnosis:
  • Acute Kidney Injury (AKI) due to dehydration from vomiting: The elevated creatinine level indicates impaired kidney function, which can be caused by dehydration from multiple episodes of vomiting. The presence of RBCs in the urine could be due to the kidney injury itself or a secondary effect of dehydration.
• Other Likely diagnoses:
  • Urinary Tract Infection (UTI): Although the primary symptoms do not strongly suggest a UTI, the presence of RBCs in the urine could indicate an infection, especially if the child has other symptoms like dysuria or fever.
  • Nephrolithiasis (Kidney Stones): Abdominal pain and vomiting can be associated with kidney stones, and the presence of RBCs in the urine supports this diagnosis, as stones can cause bleeding in the urinary tract.
  • Acute Glomerulonephritis: This condition involves inflammation of the glomeruli and can present with hematuria (RBCs in urine), elevated creatinine, and abdominal pain, although it is less likely given the acute presentation with vomiting.
• Do Not Miss diagnoses:
  • Sepsis: Although less likely given the information, sepsis can cause AKI and should be considered, especially if the child shows signs of infection or severe illness.
  • Obstructive Uropathy: Any condition causing obstruction in the urinary tract (e.g., kidney stones, tumors) can lead to renal failure if not promptly addressed. The symptoms of abdominal pain and vomiting, combined with elevated creatinine, make this a critical diagnosis not to miss.
• Rare diagnoses:
  • Alport Syndrome: A genetic disorder affecting the type IV collagen in the kidneys, ears, and eyes, leading to kidney disease, hearing loss, and eye abnormalities. It could present with hematuria but is less likely given the acute presentation.
  • Vasculitis (e.g., Henoch-Schönlein Purpura): Systemic vasculitis can affect the kidneys and present with abdominal pain, vomiting, and renal impairment. However, it is rare and typically accompanied by other symptoms like purpura.
  • Tumor (e.g., Wilms Tumor): Although rare, a tumor in the kidney could cause abdominal pain, vomiting, and elevated creatinine if it obstructs the urinary tract or invades renal tissue.