This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Kidney, Subject name: Pediatrics
All of the following are true about xanthogranulomatous pyelonephritis except - 
Select and explain. 
A. Proteus is most common organism, B. Seen only in infancy, C. It is a form of chronic pyelonephritis, D. Focal form is common in children
B: Seen only in infancy
Answer: B: Seen only in infancy 
Explanation: Ans. is 'b' i.e., Seen only in infancy Xanthogranulomatous pyelonephritiso Xanthogranulomatous pyelonephritis is a form of chronic pyelonephritis characterised by destruction of renal parenchyma and the presence of granulomas, abscesses and collection of lipid laden foamy macrophages (foam cells).o Age of presentation ranges from infancy to 16 yearso Focal form being more common in children- Appear healthyo Those who affected diffusely, present with non-specific symptoms of chronic infection.i) Weight lossii) Feveriii) Lethargyiv) Failure to thriveo Proteus is the most common causative organism.