What is usually considered the number of white cells necessary on microscopy to make the diagnosis of a definite UTI?

Correct Answer: B

Rationale: 10,000 WBC/mm³ (10 WBC/µL unspun) is the threshold for definite UTI significant pyuria confirms infection (e.g., >10/hpf spun). 1,000 is too low normal range. 50,000-100,000 exceed typical severe cases. 10,000 distinguishes it, critical for microscopic diagnosis, unlike subthreshold or excessive counts.

Correct Answer: A

Rationale: Bladder ruptures are usually extraperitoneal (~60-85%) pelvic fracture association, not intraperitoneal (~15-25%), incorrect. Pelvic fracture link true, common cause. Symptoms (anuria, hematuria, meatal blood) accurate. Retrograde cystogram gold standard, correct. Extraperitoneal predominance distinguishes the error, key to bladder trauma patterns, unlike association, signs, or imaging truths.

Correct Answer: C

Rationale: Schistosomiasis is the top global hematuria cause parasitic bladder infestation (e.g., S. haematobium) in endemic areas outpaces neoplasia (older adults), infection (UTIs), and BPH (men). Schistosomiasis's prevalence distinguishes it, critical for worldwide epidemiology, unlike age or gender-specific causes.

Correct Answer: C

Rationale: Renal colic can present without hematuria ~10% lack it (e.g., early/no abrasion), correct. Males predominate (2:1) not females. ~90% are radio-opaque calcium dominant. Recurrence is ~50% by 5 years higher risk. Hematuria's absence distinguishes it, key to variable presentation, unlike gender, imaging, or recurrence errors.

Correct Answer: B

Rationale: Hyperkalemia is the most likely cause in dialysis arrest missed sessions spike potassium (e.g., >6.5 mmol/L), triggering arrhythmias. Pericardial effusion (uremic) is slower less acute. Hypocalcemia and hypertension occur less fatal acutely. Potassium's lethality distinguishes it, key to dialysis emergencies, unlike effusion or chronic issues.