Urology Syllabus

Outline the renin-angiotensin-aldosterone system's effect on sodium and blood pressure.

Renin cleaves angiotensinogen to angiotensin I; ACE converts it to angiotensin II, which vasoconstricts and stimulates aldosterone, increasing $\ce{Na+}$ (and water) reabsorption to raise blood pressure.

What are the normal serum ranges for sodium and potassium?

Sodium $135$–$145\text{ mmol/L}$; potassium $3.5$–$5.0\text{ mmol/L}$.

Which hormone increases renal $\ce{K+}$ secretion, and where does it act?

Aldosterone, acting on the principal cells of the late distal tubule and collecting duct to increase $\ce{Na+}$ reabsorption and $\ce{K+}$ secretion.

State the Cockcroft-Gault equation for estimating creatinine clearance.

$$CrCl = \frac{(140 - \text{age}) \times \text{weight (kg)}}{72 \times S_{Cr}\,(\text{mg/dL})} \times (0.85 \text{ if female})$$

What imaging modality is first-line for suspected renal colic/urolithiasis, and why?

Non-contrast (unenhanced) helical CT of the abdomen and pelvis, because it detects nearly all stone types with high sensitivity and specificity without contrast.

What is a KUB radiograph and one limitation?

A plain X-ray of the Kidneys, Ureters, and Bladder; its limitation is that radiolucent stones (e.g., uric acid) and small stones may not be visualized.

What does a voiding cystourethrogram (VCUG) primarily evaluate?

Bladder and urethral anatomy during voiding, chiefly to detect vesicoureteral reflux and posterior urethral valves.

What urine dipstick findings suggest a urinary tract infection?

Positive leukocyte esterase (indicating pyuria) and positive nitrites (indicating nitrate-reducing bacteria such as $\ce{E.\ coli}$).

What colony count on a clean-catch midstream urine culture defines a significant UTI?

$\geq 10^{5}$ colony-forming units per mL (CFU/mL) of a single uropathogen.

What is the normal serum PSA reference range, and what elevation is concerning?

Normal is typically $< 4\text{ ng/mL}$; values above this raise suspicion for prostate pathology (BPH, prostatitis, or cancer) and warrant further evaluation.

Distinguish cystoscopy from ureteroscopy.

Cystoscopy is endoscopic visualization of the urethra and bladder; ureteroscopy extends the scope up the ureter (and to the kidney) to inspect and treat stones or tumors.

What is percutaneous nephrolithotomy (PCNL) and its main indication?

An endoscopic procedure accessing the kidney through a percutaneous tract in the flank to remove stones; it is the preferred treatment for large ($> 2\text{ cm}$) or staghorn renal calculi.

Differentiate nephritic from nephrotic syndrome by their hallmark features.

Nephritic: hematuria, hypertension, and mild-to-moderate proteinuria with RBC casts. Nephrotic: heavy proteinuria ($> 3.5\text{ g/day}$), hypoalbuminemia, edema, and hyperlipidemia.

How is chronic kidney disease staged, and what defines stage 5 (kidney failure)?

By GFR: stage 5 is GFR $< 15\text{ mL/min}/1.73\text{ m}^{2}$, indicating kidney failure usually requiring dialysis or transplant.

What is the most common type of kidney cancer in adults?

Renal cell carcinoma (clear cell subtype most common), arising from the proximal tubular epithelium.

List the four main types of urinary stones by composition.

Calcium (oxalate/phosphate, ~$80\%$), struvite (magnesium ammonium phosphate), uric acid, and cystine stones.

Which stone type is associated with urease-producing bacteria and alkaline urine?

Struvite ($\ce{MgNH4PO4}$) stones, associated with infections by urease-producing organisms such as Proteus, which raise urine pH.

What is first-line management for a small ($< 5\text{ mm}$) distal ureteric stone?

Conservative management with hydration, analgesia, and medical expulsive therapy (e.g., an alpha-blocker such as tamsulosin), as most pass spontaneously.

What is the most common causative organism of uncomplicated UTIs?

Escherichia coli ($\ce{E.\ coli}$), responsible for roughly $80\%$ of uncomplicated infections.

Differentiate cystitis, pyelonephritis, and urethritis by site.

Cystitis is infection of the bladder, pyelonephritis of the kidney (upper tract), and urethritis of the urethra.

Contrast urge incontinence with stress incontinence.

Urge incontinence is involuntary leakage due to detrusor overactivity (sudden urge); stress incontinence is leakage on increased abdominal pressure (coughing, sneezing) due to sphincter/pelvic floor weakness.

What is neurogenic bladder?

Bladder dysfunction (overactive or underactive) resulting from neurological damage to the nerves controlling micturition, e.g., from spinal cord injury, multiple sclerosis, or diabetes.

What is benign prostatic hyperplasia (BPH) and which zone of the prostate is affected?

Non-malignant enlargement of the prostate arising in the transition zone, causing lower urinary tract obstructive symptoms.

In which prostate zone does most prostate cancer arise, and what is the main histologic type?

The peripheral zone; the main histologic type is adenocarcinoma.

What two drug classes are used medically for BPH, and how do they work?

Alpha-blockers (e.g., tamsulosin) relax prostatic smooth muscle for rapid symptom relief; $5\alpha$-reductase inhibitors (e.g., finasteride) shrink the gland by blocking conversion of testosterone to dihydrotestosterone.

Contrast partial (nephron-sparing) nephrectomy with radical nephrectomy.

Partial nephrectomy removes only the tumor with a margin, preserving renal function; radical nephrectomy removes the entire kidney (often with surrounding fascia and adrenal), used for larger or central tumors.

What is the gold-standard surgical treatment for symptomatic BPH, and what does it entail?

Transurethral resection of the prostate (TURP), in which obstructing prostatic tissue is resected endoscopically through the urethra.

What is a radical prostatectomy and a common complication?

Surgical removal of the entire prostate and seminal vesicles for localized prostate cancer; common complications include erectile dysfunction and urinary incontinence.

Distinguish a continent urinary diversion from an ileal conduit after cystectomy.

An ileal conduit routes ureters to a segment of ileum draining to an external stoma/bag (incontinent); a continent diversion (e.g., neobladder) creates an internal reservoir from bowel that stores urine and can be voided or catheterized.

What is extracorporeal shock wave lithotripsy (ESWL) and its ideal stone target?

A non-invasive technique using focused acoustic shock waves to fragment stones so they pass in the urine; it is ideal for renal or upper-ureteric stones smaller than about $2\text{ cm}$.