Study guide
Genitourinary System: High-Yield PANCE Review
The Genitourinary System comprises roughly 5% of the PANCE blueprint and centers on high-frequency topics: UTIs, nephrolithiasis, BPH/prostatitis, acute and chronic kidney disease, glomerular disease, and GU malignancies. Master first-line antibiotics, imaging choices, and the nephritic-vs-nephrotic distinction, as these generate the most exam questions.
UTI, Pyelonephritis & Asymptomatic Bacteriuria
- ◆E. coli is the #1 pathogen. Lower UTI (cystitis) = dysuria, frequency, urgency, suprapubic pain WITHOUT fever; upper UTI (pyelonephritis) adds fever, flank/CVA tenderness, and N/V.
- ◆Uncomplicated cystitis first-line (IDSA): nitrofurantoin 100 mg BID x5d, TMP-SMX DS BID x3d (only if local resistance <20% and no use in the prior 3 months), or fosfomycin 3 g single dose. Avoid nitrofurantoin if CrCl <30 or in pyelonephritis (inadequate tissue/renal levels).
- ◆Acute pyelonephritis outpatient: fluoroquinolone (ciprofloxacin 500 mg BID x7d) or a one-time IV/IM ceftriaxone dose then an oral agent; admit if septic, pregnant, vomiting, or immunocompromised.
- ◆Screen and TREAT asymptomatic bacteriuria ONLY in pregnancy and before urologic procedures — use nitrofurantoin, cephalexin, or amoxicillin; avoid fluoroquinolones and avoid TMP-SMX in the 1st and 3rd trimesters.
- ◆Do not treat asymptomatic bacteriuria in the elderly or chronically catheterized (drives resistance).
Nephrolithiasis
- ◆Calcium oxalate stones are most common (~75-85%). Non-contrast helical CT is the diagnostic gold standard; renal ultrasound is preferred in pregnancy and children.
- ◆Classic presentation: sudden colicky flank pain radiating to the groin, gross/microscopic hematuria, and a patient writhing/unable to sit still.
- ◆Stones <5 mm usually pass spontaneously; medical expulsive therapy with an alpha-blocker (tamsulosin) x~30 days is offered for stones ≤10 mm (strongest benefit in distal ureteral stones). Stones >10 mm, proximal, or refractory need urology (ureteroscopy or shockwave lithotripsy).
- ◆Obstructing stone PLUS infection (fever, pyuria) is a urologic emergency requiring urgent decompression (ureteral stent or percutaneous nephrostomy) — antibiotics alone are insufficient.
- ◆Uric acid stones are radiolucent (low urine pH, gout) → treat/prevent with potassium citrate alkalinization; struvite (staghorn) stones arise from urease-producing organisms (Proteus).
- ◆Prevention: high fluid intake, low sodium, thiazides for hypercalciuria, and potassium citrate for hypocitraturia.
BPH & Prostatitis
- ◆BPH causes obstructive/irritative LUTS (hesitancy, weak stream, nocturia, incomplete emptying). Alpha-blockers (tamsulosin) give rapid relief; 5-alpha-reductase inhibitors (finasteride) shrink large glands over months and lower PSA by ~50%.
- ◆Avoid anticholinergics, antihistamines, and decongestants in BPH — they can precipitate acute urinary retention.
- ◆Acute bacterial prostatitis: fever, dysuria, perineal pain, and an exquisitely tender/boggy prostate — avoid vigorous prostate massage (bacteremia risk). Treat with fluoroquinolone or TMP-SMX.
- ◆In men <35 or with STI risk, cover N. gonorrhoeae/chlamydia with ceftriaxone 500 mg IM single dose (1 g if ≥150 kg) plus doxycycline 100 mg BID x7d.
- ◆Chronic bacterial prostatitis requires prolonged therapy (fluoroquinolone or TMP-SMX for 4-6 weeks).
Acute Kidney Injury & Chronic Kidney Disease
- ◆AKI types: prerenal (BUN/Cr >20:1, FeNa <1%), intrinsic ATN (muddy-brown granular casts, FeNa >2%), postrenal (obstruction — check bladder scan/renal US).
- ◆CKD is staged by GFR and albuminuria; diabetes and hypertension are the leading causes. ACE inhibitors/ARBs slow progression in proteinuric and diabetic CKD, and SGLT2 inhibitors add cardiorenal protection.
- ◆CKD complications: anemia (low erythropoietin), hyperphosphatemia, secondary hyperparathyroidism, metabolic acidosis, and hyperkalemia.
- ◆Emergent dialysis indications (AEIOU): Acidosis (refractory), Electrolytes (severe hyperkalemia), Intoxications, Overload (refractory pulmonary edema), Uremia (pericarditis, encephalopathy).
- ◆Peaked T waves, widened QRS, and sine-wave patterns indicate hyperkalemia — give IV calcium first for membrane stabilization.
Glomerular Disease: Nephritic vs Nephrotic
- ◆Nephritic = hematuria with RBC casts, hypertension, oliguria, and mild proteinuria. Post-streptococcal GN follows infection by 1-3 weeks with LOW C3; IgA nephropathy causes synpharyngitic gross hematuria; anti-GBM (Goodpasture) pairs hematuria with hemoptysis.
- ◆Nephrotic = proteinuria >3.5 g/day, hypoalbuminemia, edema, and hyperlipidemia. FSGS is most common in adults (HIV, obesity); minimal change disease predominates in children and is steroid-responsive.
- ◆Membranous nephropathy (anti-PLA2R antibody) associates with solid-organ malignancy; diabetic nephropathy is the most common overall cause of nephrotic-range proteinuria.
- ◆Nephrotic syndrome carries a hypercoagulable risk (loss of antithrombin III) — watch for renal vein thrombosis.
- ◆Workup: urinalysis with microscopy, spot protein/creatinine ratio, complement levels, and renal biopsy for definitive diagnosis.
GU Malignancies & Urinary Incontinence
- ◆Bladder cancer (urothelial): painless gross hematuria is the hallmark; smoking is the #1 risk factor and cystoscopy is diagnostic.
- ◆Renal cell carcinoma: classic triad of hematuria, flank pain, and palpable mass; may cause paraneoplastic syndromes (erythrocytosis from EPO, hypercalcemia from PTHrP).
- ◆Prostate cancer: peripheral-zone adenocarcinoma; USPSTF recommends shared decision-making for PSA screening in men 55-69 and recommends against routine screening at age ≥70; Gleason score grades aggressiveness.
- ◆Stress incontinence (leak with cough/exertion) → pelvic floor exercises; urge/overactive bladder (detrusor overactivity) → antimuscarinics or mirabegron; overflow incontinence (retention from BPH/neurogenic bladder) → relieve obstruction/catheter.