**Question:** Stone seen in urinary tract infection is -

A. Calcium oxalate
B. Uric acid
C. Cystine
D. Phosphate

**Correct Answer:** A. Calcium oxalate

**Core Concept:**
Urinary tract infection (UTI) is a common infection that affects different segments of the urinary system (bladder, ureters, kidneys, and urethra). Infection can lead to the formation of mineral crystals that aggregate and form stones. These stones can be classified based on their composition.

**Why the Correct Answer is Right:**
Calcium oxalate is the most common type of stone found in UTIs. It is formed when calcium ions (Ca2+) bind with oxalate ions (C2O4^2-) to create calcium oxalate crystals. Uric acid stones (option B) are more common in patients with gout or hyperuricemia, not typically associated with UTIs. Cystine stones (option C) are more common in patients with cystinuria, a genetic disorder causing excessive cystine excretion in urine. Phosphate stones (option D) are associated with hypercalciuria, which is not a common feature of UTIs.

**Why Each Wrong Option is Incorrect:**

Option B: Uric acid stones are more commonly associated with hyperuricemia and gout, not UTIs.
Option C: Cystine stones are associated with cystinuria, a genetic disorder, not UTIs.
Option D: Phosphate stones are linked with hypercalciuria, a condition distinct from UTIs.

**Clinical Pearl:**
Understanding the types of urinary stones is essential for appropriate diagnosis and management of patients. In the case of UTIs, the formation of calcium oxalate stones is more common due to elevated calcium concentration and the presence of oxalate. Diagnosis and management of different stone types involve specific interventions like hydration, dietary modifications, and pharmacological interventions.