This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Miscellaneous, Subject name: Surgery
[{'content': 'Proteus organisms cause \nSelect and explain. \nA. Struvite stones, B. Calcium oxalate stones, C. Cystine stones, D. Xanthine stones', 'role': 'user'}, {'content': 'Answer: A \nExplanation: (A) Struvite stones # STRUVITE STONE: A phosphate calculus is smooth and dirty white. It tends to grow in alkaline urine, especially when urea splitting Proteus organisms are present. As a result, the calculus may enlarge to fill most of the collecting system, forming a staghorn calculus.# TYPES OF RENAL CALCULUS:> Calcium oxalate calculus: Most common; they have hard, small and jagged surface> Uric acid and urate calculus: these are radiolucent> Cystine stones: uncommon, seen in cystinuria; appear only in acid urine; they are pink to yellow when first removed but they change colour to a greenish hue when exposed to air.> Xanthine calculi: are radiolucent; Most common symptom of renal calculi is Pain.', 'role': 'assistant'}]