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Urology: Comprehensive Reference

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1. Anatomy & Physiology of the Genitourinary (GU) System

Kidneys

• Location: Retroperitoneal, T12–L3; right kidney is slightly lower due to the liver.
• Structure: Cortex (glomeruli, proximal/distal tubules), medulla (loops of Henle, collecting ducts), pyramids, calyces → renal pelvis.
• Blood supply: Renal arteries (from aorta at L1–L2); renal veins drain to IVC (left renal vein is longer, crosses aorta).
• Nephron function: Filtration (glomerulus, ~125 mL/min GFR), reabsorption (PCT ~67% Na/H₂O, loop, DCT), secretion, concentration (medullary gradient, ADH).
• Endocrine roles: Erythropoietin (EPO), renin (RAAS), 1α-hydroxylase (Vitamin D activation), prostaglandins.

Ureters

• Course: ~25–30 cm; cross over iliac vessels at L5/S1; pass posterior to gonadal vessels.
• Three natural narrowings (common sites of stone impaction):
  1. Ureteropelvic junction (UPJ)
  2. Pelvic brim (where ureter crosses iliac vessels)
  3. Ureterovesical junction (UVJ)
• Peristalsis propels urine; transitional epithelium (urothelium) lines the lumen.

Urinary Bladder

• Capacity: 400–600 mL; desire to void at ~150–250 mL.
• Detrusor muscle (smooth muscle, parasympathetic M3 receptors) contracts during micturition.
• Trigone: Fixed triangular area between two ureteric orifices and the internal urethral meatus.
• Micturition reflex: Pontine micturition center (PMC) coordinates detrusor contraction + internal sphincter relaxation (sympathetic α); external sphincter is voluntary (pudendal nerve, S2–S4).

Urethra

Male Genital System

• Testes: Exocrine (spermatogenesis, Sertoli cells) + endocrine (testosterone, Leydig cells); descend by week 28–36 gestation.
• Epididymis: Sperm maturation (~12 days).
• Vas deferens: Joins seminal vesicle → ejaculatory duct → opens into prostatic urethra.
• Prostate: ~20 g (normal); surrounds proximal urethra; zones: peripheral (70%, cancer origin), central, transition (BPH origin), fibromuscular stroma.

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2. Symptomatology of Urological Diseases

Lower Urinary Tract Symptoms (LUTS)

• Urgency, frequency (>8 voids/day), nocturia, urge incontinence, dysuria

• Hesitancy, weak stream, straining, intermittency, incomplete emptying, terminal dribbling

• Post-void dribble, sensation of incomplete bladder emptying

Pain

Other Key Symptoms

• Hematuria: Gross (visible) vs. microscopic; painless gross hematuria → must exclude urothelial cancer/renal cell carcinoma.
• Pneumaturia: Air in urine → vesico-colic fistula.
• Pyuria: Pus in urine → infection/TB.
• Urethral discharge: STI (gonorrhea, chlamydia), prostatitis.
• Erectile dysfunction / ejaculatory problems: Neurogenic, vascular, hormonal.

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3. Laboratory, Instrumental & Radiological Examination

Laboratory Tests

Instrumental / Urodynamic Studies

• Uroflowmetry: Measures urine flow rate (normal Q-max >15 mL/s); reduced in BPH/stricture.
• Post-void residual (PVR): US or catheter; >100 mL significant.
• Urodynamic study (cystometry): Invasive; assesses detrusor pressure, compliance, sphincter function; used in neurogenic bladder, incontinence workup.
• Cystoscopy: Direct visualization of bladder/urethra; gold standard for hematuria evaluation, tumor biopsy, ureteric orifice assessment.
• Ureteroscopy (URS): Flexible or rigid; upper tract stones, urothelial lesions.
• Retrograde pyelography (RGP): Contrast injected via ureteric catheter during cystoscopy; upper tract anatomy/obstruction.

Radiological Examination

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4. Congenital Anomalies of the Genitourinary System

Renal Anomalies

Ureteral & Bladder Anomalies

• Ureterocele: Cystic dilatation of intravesical ureter; simple or ectopic; may obstruct bladder outlet.
• Vesicoureteral reflux (VUR): Grades I–V; risk of pyelonephritis → renal scarring; Rx: low-dose prophylactic antibiotics; Grade IV–V may need surgery.
• Posterior urethral valves (PUV): Most common obstructive uropathy in boys; type I most common (folds from verumontanum); presents as neonate with bladder distension, poor urinary stream, bilateral hydronephrosis; Rx: valve ablation endoscopically.
• Bladder exstrophy: Failure of anterior abdominal wall closure; bladder mucosa exposed; epispadias always associated; complex reconstructive surgery.
• Epispadias / Hypospadias:
  • Hypospadias: Urethral meatus on ventral surface (common, 1:250 boys); chordee; do NOT circumcise (tissue needed for repair).
  • Epispadias: Urethral meatus on dorsal surface; rare; associated with exstrophy complex.

Testicular Anomalies

• Cryptorchidism (undescended testis): Most common in premature infants; ↑ risk of infertility and testicular cancer; orchidopexy by age 12–18 months.
• Testicular torsion predisposition: Bell-clapper deformity (high horizontal lie).

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5. Trauma of the Genitourinary System

Renal Trauma

• Mechanism: Blunt (most common, MVA, falls) > penetrating.
• Presentation: Flank pain, hematuria (but correlation with grade is poor — pedicle injury may have no hematuria).
• Diagnosis: CT with IV contrast (gold standard).
• Management:
  • Grade I–III: Conservative (bed rest, monitoring); most resolve.
  • Grade IV–V: Selective angioembolization (for vascular injuries); surgery for hemodynamic instability, expanding hematoma, or renal pedicle avulsion.

Ureteral Trauma

• Most commonly iatrogenic (gynecological surgery, especially hysterectomy).
• Presentation: Urinary leak, urinoma, hydronephrosis.
• Dx: CT urogram, retrograde pyelography.
• Rx: Early repair (primary ureteral anastomosis), ureteral stenting, or nephrostomy + delayed repair.

Bladder Trauma

• Contusion: Incomplete tear; resolves conservatively.
• Extraperitoneal rupture: Most common (80%); associated with pelvic fractures; Rx: Foley catheter drainage for 2–3 weeks.
• Intraperitoneal rupture: Blow to full bladder; urine in peritoneum → surgical repair.
• Diagnosis: Cystogram (CT or conventional); retrograde fill (300 mL contrast).

Urethral Trauma

• Do NOT pass Foley if urethral injury suspected → RGU first.
• Rx: Suprapubic catheter (SPC) for drainage; delayed urethroplasty (3–6 months) for posterior injuries.

Scrotal / Testicular Trauma

• Testicular rupture: Scrotal US (disrupted tunica albuginea, heterogeneous echogenicity); Rx: Surgical exploration and repair within 72 hours → highest salvage rate.

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6. Nonspecific Infections of the Genitourinary System

Urinary Tract Infections (UTI)

• Uncomplicated (healthy, non-pregnant female, no structural abnormality) vs. Complicated (males, pregnancy, catheter, structural/functional abnormality, immunosuppression).
• Lower (cystitis) vs. Upper (pyelonephritis).

• E. coli (80%), Klebsiella, Staphylococcus saprophyticus (young women), Enterococcus, Proteus (stone-former, alkaline urine).

Acute Bacterial Prostatitis

• Fever, chills, perineal/low back pain, LUTS, boggy tender prostate on PR (do NOT massage — risk of bacteremia).
• Organism: E. coli, Gram-negatives.
• Rx: Fluoroquinolone (ciprofloxacin) 4–6 weeks; if septic → IV + hospitalize.

Chronic Prostatitis / Chronic Pelvic Pain Syndrome (CP/CPPS)

• Most common prostatitis syndrome (Type IIIa/b per NIH classification).
• Pelvic/perineal pain >3 months; LUTS; may have sexual dysfunction.
• Rx: Multidisciplinary — α-blockers, antibiotics trial (4–6 weeks), NSAIDs, physiotherapy, psychosocial support.

Epididymo-orchitis

• Age <35: STI (Chlamydia trachomatis, N. gonorrhoeae) → Ceftriaxone + Doxycycline.
• Age >35: Urinary pathogens (E. coli) → Quinolones or Co-amoxiclav 2–4 weeks.
• Distinguish from testicular torsion (urgent scrotal US + surgical exploration if doubt).

Fournier's Gangrene

• Necrotizing fasciitis of perineum/scrotum; polymicrobial (aerobic + anaerobic synergy).
• Rapidly progressive, life-threatening; septic shock.
• Rx: Emergency wide surgical debridement + broad-spectrum IV antibiotics (carbapenems ± metronidazole ± fluconazole) + ICU care.

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7. Urinary Stone Disease (Urolithiasis)

Epidemiology & Composition

Pathophysiology

Clinical Presentation

• Acute renal/ureteral colic: Sudden-onset, excruciating, colicky flank pain radiating to groin/scrotum/labia; nausea/vomiting; hematuria (90%); restlessness (can't lie still — unlike peritonitis).
• CVA tenderness.
• Large stones (staghorn calculi): Often asymptomatic or chronic infection/hematuria.

Diagnosis

• Non-contrast CT KUB: Most sensitive (99%) and specific (98%); shows stone, size, location, density (HU), skin-to-stone distance, hydronephrosis.
• Urine dipstick/microscopy: Hematuria (but absent in 10%).
• Metabolic workup (recurrent stones): 24-hour urine calcium, oxalate, citrate, uric acid, creatinine; serum calcium, PTH, uric acid.

Management

1. Analgesia: NSAIDs (first-line, e.g., diclofenac IM/PR) > opioids; IV access + antiemetics.
2. Check for infection: Fever + obstructed stone = urological emergency → urgent decompression (nephrostomy or ureteral stent) + antibiotics.
3. Medical expulsive therapy (MET): α-blocker (tamsulosin) for distal ureteral stones ≤10 mm → ↑ passage rate.

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8. Hydronephrosis

Definition

Causes by Level

Grading (Society for Fetal Urology — SFU, I–IV)

• Grade I: Mild splitting of renal pelvis
• Grade II: Pelvic dilatation + some calyceal dilatation
• Grade III: Pelvic + calyceal dilatation without cortical thinning
• Grade IV: Cortical thinning present

Diagnosis

• US: First-line; shows collecting system dilatation; assess cortical thickness.
• CT urogram: Identifies cause and level of obstruction.
• MAG3 renogram: Quantifies differential renal function (DRF) and drainage half-time (T½); T½ >20 min = obstructed.

Management

• Treat underlying cause.
• If significant obstruction threatening renal function → nephrostomy tube (urgent relief) or ureteral stent (JJ stent).
• UPJ obstruction: Dismembered pyeloplasty (Anderson-Hynes); laparoscopic/robotic approach now standard; > 90% success.
• Bilateral hydronephrosis + raised creatinine → bilateral stents or nephrostomies urgently.

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9. Tumors of the Genitourinary System

Renal Cell Carcinoma (RCC)

• Incidence: ~3% of adult cancers; M:F = 2:1; peak 6th–7th decade.
• Histology: Clear cell (75–80%, VHL gene deletion 3p25), papillary (15%), chromophobe (5%), collecting duct (<1%).
• Classic triad (only in 10–15%): Hematuria + flank pain + palpable mass.
• Paraneoplastic syndromes: Polycythemia (EPO), hypercalcemia (PTHrP), hypertension (renin), Stauffer syndrome (non-metastatic hepatic dysfunction), fever.
• "Surgeon's tumor": Often presents with metastases (lung, bone, brain, liver, contralateral adrenal).
• Staging: TNM; renal vein and IVC thrombus extension is characteristic.
• Diagnosis: CT with contrast (Bosniak classification for cystic lesions); MRI for IVC involvement.
• Treatment:
  • Localized: Partial nephrectomy (nephron-sparing, preferred for T1); radical nephrectomy.
  • Metastatic: Targeted therapy (sunitinib, pazopanib — VEGFR inhibitors); immunotherapy (nivolumab/ipilimumab, first-line mRCC); cytoreductive nephrectomy selected cases.

Urothelial (Transitional Cell) Carcinoma — Bladder

• Most common urological malignancy; painless gross hematuria = bladder cancer until proven otherwise.
• Risk factors: Smoking (most important, 50–65%), aniline dyes, cyclophosphamide, schistosomiasis (squamous cell type), pelvic radiation.
• Classification:
  • Non-muscle-invasive bladder cancer (NMIBC): Ta (papillary, superficial), T1 (lamina propria), CIS (flat, high-grade, high recurrence/progression risk).
  • Muscle-invasive bladder cancer (MIBC): T2–T4.
• Diagnosis: Cystoscopy + TURBT (transurethral resection of bladder tumor) — diagnostic and therapeutic; urine cytology for high-grade/CIS.
• Management:
  • NMIBC: TURBT; intravesical BCG (high-risk CIS/T1 high grade) or mitomycin C; surveillance cystoscopy every 3 months × 2 years, then annually.
  • MIBC: Radical cystectomy (gold standard) + neoadjuvant cisplatin-based chemotherapy; urinary diversion (ileal conduit, neobladder); trimodality therapy (TURBT + chemo + RT) for poor surgical candidates.

Urothelial Carcinoma of the Upper Tract (Renal Pelvis & Ureter)

• Less common; associated with Lynch syndrome, aristolochic acid.
• Presentation: Hematuria, flank pain.
• Diagnosis: CT urogram, ureteroscopy + biopsy, urine cytology.
• Rx: Radical nephroureterectomy (standard); endoscopic management for low-grade/solitary kidney.

Urothelial Carcinoma of the Urethra

• Rare; M:F = 3:1; associated with urethral stricture, HPV.
• Presentation: Hematuria, urethral discharge, obstructive symptoms, palpable mass.
• Rx: Surgery (urethrectomy ± cystectomy) ± chemoradiotherapy.

Benign Prostatic Hyperplasia (BPH)

• Pathophysiology: Nodular hyperplasia of transition zone; 5α-reductase converts testosterone → DHT (key driver); obstructs bladder outlet → LUTS.
• Epidemiology: Histological BPH in 50% of men >50, 90% by age 90.
• Presentation: LUTS (storage + voiding); IPSS (International Prostate Symptom Score) to quantify.
• Investigations: IPSS, PVR, uroflowmetry (Q-max), PSA, renal function, US prostate.
• Complications: Acute urinary retention (AUR), chronic retention, UTI, bladder stones, hydronephrosis/CKD.
• Management:

Prostate Cancer

• Most common male cancer; 2nd most common cause of male cancer death.
• Risk factors: Age, family history, African ancestry, BRCA2 mutation.
• Grading: Gleason score (primary + secondary pattern, each 1–5); Grade Group 1–5 (GG1: Gleason 3+3=6, low risk; GG5: Gleason 9–10, high risk).
• PSA: Screening controversial; >4 ng/mL warrants biopsy; PSA density, velocity, free:total ratio improve specificity.
• Staging: TNM; bone scan (if PSA >10, high grade) for metastases; multiparametric MRI (mpMRI) prostate (PI-RADS scoring) before biopsy.

Testicular Tumors

• Most common solid tumor in men aged 15–35.
• Classification:
  • Germ cell tumors (95%): Seminoma (50%, most common, radiosensitive, late presentation) vs. Non-seminoma (NSGCT: embryonal, teratoma, choriocarcinoma, yolk sac).
  • Non-germ cell: Leydig cell, Sertoli cell (rare).
• Presentation: Painless testicular mass (most common); gynecomastia (choriocarcinoma via β-hCG).
• Tumor markers: AFP (not in pure seminoma), β-hCG (all trophoblastic elements), LDH (bulk).
• Diagnosis: Scrotal US (never biopsy transcrotally!); CXR + CT thorax/abdomen/pelvis for staging.
• Rx: Radical orchidectomy (via inguinal approach — standard for all) + stage-dependent adjuvant:
  • Seminoma Stage I: Surveillance or carboplatin × 1–2 cycles.
  • Seminoma Stage II–III: BEP chemotherapy (bleomycin, etoposide, cisplatin) or RT.
  • NSGCT Stage I: Surveillance or BEP × 1 cycle.
  • Advanced: BEP × 3–4 cycles; RPLND (retroperitoneal lymph node dissection).

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10. Emergency Urology

Acute Urinary Retention (AUR)

• Painful inability to void despite full bladder; precipitated by BPH, constipation, drugs (anticholinergics, sympathomimetics), anesthesia, infection, clot.
• Rx: Immediate urethral catheterization (size 14–16Fr); if impossible → suprapubic catheter (SPC). Start α-blocker. TWOC after 2–3 days; if fails → definitive BPH treatment. Monitor for post-obstructive diuresis.

Testicular Torsion

• Urological emergency: Torsion of spermatic cord → venous outflow obstruction → arterial ischemia → infarction.
• Bell-clapper deformity predisposes.
• Peak age: Neonatal + peripubertal (12–18 years).
• Presentation: Sudden severe scrotal pain, nausea/vomiting, high-riding transverse testis, absent cremasteric reflex.
• Diagnosis: Clinical; if high suspicion → immediate surgical exploration without delay for imaging. Color Doppler US if diagnosis uncertain and available immediately.
• Management: Surgical detorsion + bilateral orchidopexy (fix both sides — bilateral deformity); 3-stitch fixation.
• Time to salvage: <6 hours → ~100%; 6–12 hours → ~70%; >24 hours → ~10%.

Urosepsis

• Definition: Sepsis arising from a urogenital focus (obstructed infected kidney most dangerous).
• Sepsis-3 criteria: Life-threatening organ dysfunction caused by dysregulated host response to infection.
• Management: Sepsis bundle (Hour-1):
  1. Blood cultures × 2 (before antibiotics)
  2. Empirical broad-spectrum IV antibiotics within 1 hour (e.g., pip-taz or meropenem if risk of resistance)
  3. IV fluid resuscitation (30 mL/kg crystalloid if hypoperfusion)
  4. Lactate measurement
  5. Monitor urine output
  6. Urgent decompression of obstructed upper tract (nephrostomy or ureteral stent — the source control imperative in urosepsis)
• ICU if vasopressors needed.

Acute Scrotal Pain — Differential Diagnosis

Priapism

• Definition: Persistent erection >4 hours unrelated to sexual stimulation.
• Types: Ischemic (low-flow, 95%); Non-ischemic (high-flow, arterial fistula post-trauma).
• Causes: Sickle cell disease (most common in children), phosphodiesterase-5 inhibitors, intracavernosal injections, antipsychotics (chlorpromazine), hematological malignancies.
• Management (ischemic):
  1. Aspiration of cavernous blood (should be dark/venous → confirms ischemia) + irrigation with saline.
  2. Intracavernosal sympathomimetic injection (phenylephrine preferred).
  3. If fails → surgical shunt (Winter, Al-Ghorab procedures).
  4. Warn: ischemia >24–48 hours → permanent ED.

Obstructing Ureteral Stone with Infection

• Infected hydronephrosis = Pyonephrosis → life-threatening if not drained.
• Rx: Emergency nephrostomy (preferred) or JJ stent + broad-spectrum IV antibiotics + ICU if septic; definitive stone treatment deferred until infection controlled.

Gross Hematuria with Clot Retention

• Causes: Bladder tumor, BPH, upper tract bleeding, anticoagulation.
• Rx: Large-bore 3-way catheter (18–22Fr) → continuous bladder irrigation (CBI) to clear clots → cystoscopy once bleeding controlled (to identify and treat source).

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