Iran Specialty Board - Urology cheat sheet

Renal blood flow is ~20-25% of cardiac output (~1.1-1.3 L/min); cortex receives ~90% and medulla ~10%, so the medulla is most vulnerable to ischemia.

Glomerular filtration rate = Kf × net filtration pressure; filtration stops when Bowman space pressure equals glomerular capillary pressure, and efferent arteriolar constriction raises GFR.

The ureter has three anatomic constrictions where stones lodge: ureteropelvic junction, crossing of the iliac vessels (pelvic brim), and ureterovesical junction.

Detrusor contraction is mediated by parasympathetic pelvic splanchnic nerves (S2-S4) via M3 muscarinic receptors; sympathetic hypogastric (T10-L2) beta-3 receptors relax the detrusor and alpha-1 receptors contract the bladder neck.

Somatic pudendal nerve (S2-S4) innervates the external urethral sphincter; Onuf nucleus lesions cause sphincter denervation and stress incontinence.

The kidney develops from the metanephros; the ureteric bud induces the metanephric blastema, and failure of induction causes renal agenesis while an ectopic bud position causes a duplicated or ectopic ureter.

Testosterone synthesis requires LH-driven Leydig cells; spermatogenesis requires FSH and high intratesticular testosterone from Sertoli cell action, and the blood-testis barrier is formed by Sertoli cell tight junctions.

Alpha-1 blockers relax prostatic and bladder neck smooth muscle; 5-alpha reductase inhibitors block conversion of testosterone to dihydrotestosterone, lowering prostate volume over 3-6 months.

Urinalysis: dipstick leukocyte esterase and nitrite suggest bacterial cystitis; microscopic hematuria is defined as ≥3 red blood cells per high-power field on two of three specimens.

Serum PSA can be elevated by benign prostatic enlargement, prostatitis, urinary retention, and instrumentation; 5-alpha reductase inhibitors roughly halve PSA after 6-12 months, so double the measured value.

Non-contrast CT of the abdomen and pelvis is the first-line imaging for suspected ureteral colic, with sensitivity above 95% for stones; ultrasound is preferred in pregnancy and children.

Multiphasic CT (non-contrast, corticomedullary, nephrographic, excretory phases) characterizes renal masses; the nephrographic phase best detects renal medullary and small lesions.

Urodynamics: detrusor overactivity is involuntary detrusor contraction during filling; detrusor sphincter dyssynergia is simultaneous detrusor contraction and sphincter EMG activity.

Bladder outlet obstruction on pressure-flow study is suggested by high detrusor pressure with low flow (e.g., detrusor pressure at maximum flow >40 cm H2O with Qmax <12 mL/s).

Retrograde urethrography evaluates the anterior urethra and is performed before catheterization when urethral injury is suspected; voiding cystourethrography evaluates the posterior urethra and reflux.

Renal nuclear scan with MAG3 assesses differential renal function and drainage; a furosemide challenge distinguishes obstructive from non-obstructive hydronephrosis.

Renal cell carcinoma subtypes: clear cell (~70-75%, VHL pathway), papillary (type 1 and 2), and chromophobe; clear cell is the most vascular and most responsive to tyrosine kinase inhibitors and immunotherapy.

Small renal masses ≤4 cm are managed by partial nephrectomy, ablation, or active surveillance; nephron-sparing surgery is preferred when technically feasible to preserve renal function.

Bladder cancer: non-muscle-invasive (Ta, T1, Tis) is treated with transurethral resection with or without intravesical therapy; muscle-invasive (T2 or higher) requires radical cystectomy or trimodal therapy.

Bacillus Calmette-Guérin intravesical therapy is indicated for high-risk non-muscle-invasive bladder cancer and carcinoma in situ; maintenance therapy reduces recurrence and progression.

Prostate cancer risk stratification uses PSA, Gleason/Grade Group, and clinical stage; Grade Group 1 is Gleason 3+3=6 and Grade Group 5 is Gleason 9-10.

Testicular germ cell tumors: seminoma is radiosensitive and usually presents at stage I; non-seminomatous tumors include embryonal, yolk sac, choriocarcinoma, and teratoma, and teratoma may be chemoresistant.

Penile squamous cell carcinoma is associated with HPV (basaloid/warty) and lichen sclerosus (usual type); inguinal lymph node staging determines survival.

Adrenal incidentalomas >4 cm or with suspicious imaging features warrant adrenalectomy; pheochromocytoma must be excluded by plasma metanephrines before any intervention.

Stone composition: calcium oxalate (~70-80%), calcium phosphate, uric acid (~10%), struvite (infection, magnesium ammonium phosphate), and cystine; uric acid stones are radiolucent on plain radiography but visible on CT.

Struvite stones require complete stone removal plus eradication of urease-producing organisms (Proteus, Klebsiella); untreated staghorn calculi cause renal loss.

Shockwave lithotripsy is best for stones <2 cm in the proximal ureter or kidney with good radiopacity; it is less effective for distal ureteral stones and for hard stones (Hounsfield units >1,000).

Ureteroscopy with laser lithotripsy is first-line for distal ureteral stones and for stones up to 2 cm; percutaneous nephrolithotomy is preferred for stones >2 cm, staghorn calculi, and lower pole stones with unfavorable anatomy.

Medical expulsive therapy with an alpha-1 blocker can be considered for distal ureteral stones 5-10 mm to increase spontaneous passage.

Prevention: increase fluid intake to achieve urine output >2.5 L/day; thiazides for hypercalciuria, allopurinol for hyperuricosuria, and alkalinization for uric acid and cystine stones.

Sepsis with obstructing stone requires urgent decompression by ureteral stent or percutaneous nephrostomy; definitive stone treatment is delayed until infection resolves.

Laparoscopic and robotic approaches are preferred for large or complex renal cysts, ureteropelvic junction obstruction (pyeloplasty), and donor nephrectomy.

Stress urinary incontinence is involuntary leakage with effort or sneezing; urge incontinence is leakage preceded by urgency; mixed incontinence has both components.

Midurethral synthetic sling is the standard surgical treatment for stress incontinence; tension-free vaginal tape and transobturator approaches have similar efficacy with different complication profiles.

Pelvic organ prolapse quantification uses the POP-Q system with points Aa, Ba, C, D, Bp, Ap and the hymen as reference; stage 0 is no prolapse and stage IV is complete eversion.

Overactive bladder is treated first with behavioral therapy and bladder training, then antimuscarinics or beta-3 agonists; intradetrusor onabotulinumtoxinA or sacral neuromodulation is used for refractory cases.

Neurogenic bladder: upper motor neuron lesions cause detrusor overactivity and dyssynergia; lower motor neuron lesions cause areflexia and retention; management aims to protect the upper tracts.

Clean intermittent catheterization is the preferred bladder emptying method for incomplete emptying; a post-void residual >150-200 mL suggests significant retention.

Vesicovaginal fistula presents with continuous urinary leakage after pelvic surgery; diagnosis is by speculum examination with methylene blue dye test or cystoscopy.

Urethral diverticulum presents with post-void dribbling, dyspareunia, and a suburethral mass; MRI is the imaging study of choice.

Erectile dysfunction is classified as vasculogenic, neurogenic, hormonal, psychogenic, or drug-induced; phosphodiesterase-5 inhibitors are first-line and require sexual stimulation to be effective.

PDE5 inhibitors are contraindicated with nitrates because both increase cyclic GMP and cause severe hypotension; tadalafil has a long half-life and is not preferred in severe hepatic impairment.

Testosterone replacement is contraindicated in men with untreated prostate cancer or breast cancer and in men with severe lower urinary tract symptoms or untreated polycythemia.

Hypogonadism is diagnosed by low morning total testosterone on two occasions plus symptoms; LH and FSH distinguish primary (elevated) from secondary (low or normal) hypogonadism.

Male infertility evaluation includes two semen analyses, hormonal testing (FSH, LH, testosterone), and physical examination for varicocele; azoospermia requires distinguishing obstructive from non-obstructive causes.

Varicocele repair may improve semen parameters in men with palpable varicocele and abnormal semen analysis; it is not routinely recommended for subclinical varicocele.

Priapism lasting >4 hours is a urologic emergency; aspiration and irrigation of the corpora cavernosa with or without phenylephrine is first-line for ischemic priapism.

Hypospadias repair is usually performed at 6-18 months of age; circumcision should be avoided before repair because the foreskin may be needed for reconstruction.

Vesicoureteral reflux grading: grade I is ureteral reflux only, grade II reaches the renal pelvis without dilation, grade III shows mild dilation, grade IV shows moderate dilation with blunting, and grade V shows gross dilation and tortuosity.

Febrile urinary tract infection in a child warrants evaluation for reflux; the choice between voiding cystourethrography and radionuclide cystography depends on the need to assess urethral anatomy.

Cryptorchidism: testes that do not descend by 6 months of age should be referred for orchiopexy, ideally performed by 12-18 months to reduce infertility and malignancy risk.

Undescended testes have increased risk of germ cell tumors, especially intra-abdominal testes; orchiopexy does not eliminate the risk but allows surveillance.

Hypospadias severity is classified by meatal location (glanular, coronal, penile, penoscrotal, perineal); proximal hypospadias may require staged repair.

Posterior urethral valves present with bilateral hydronephrosis, thick-walled bladder, and poor stream in a male neonate; vesicourethral reflux and renal dysplasia determine prognosis.

Wilms tumor typically presents as an asymptomatic abdominal mass in a child under 5 years; treatment combines nephrectomy and chemotherapy, and biopsy is avoided when resectable.

Testicular torsion is a surgical emergency; salvage rates are high within 6 hours and decline sharply after 12 hours, and bilateral orchiopexy is performed at the time of exploration.

Crossmatching prevents hyperacute rejection; preformed donor-specific antibodies detected by complement-dependent cytotoxicity or flow cytometry crossmatch contraindicate transplantation.

Hyperacute rejection occurs within minutes to hours and is due to preformed antibodies; acute cellular rejection occurs days to weeks and is treated with corticosteroids or anti-thymocyte globulin.

Calcineurin inhibitors (tacrolimus, cyclosporine) are nephrotoxic and require therapeutic drug monitoring; tacrolimus is preferred in most current regimens.

Delayed graft function is defined as the need for dialysis within the first week after transplantation; it is more common with deceased-donor and prolonged cold ischemia.

Renal transplant recipients with a rise in creatinine require evaluation for rejection, drug toxicity, obstruction, and infection; ultrasound is the first imaging study.

Post-transplant lymphoproliferative disorder is associated with Epstein-Barr virus and immunosuppression; treatment includes reduction of immunosuppression.

Living donor nephrectomy is typically laparoscopic or robotic; donor evaluation must assess renal function, anatomy, and medical and psychosocial suitability.

A kidney transplant is generally preferred over dialysis for eligible patients with end-stage renal disease because it improves survival and quality of life.

Urethral injury: anterior injuries are often from straddle trauma and present with blood at the meatus; posterior injuries are associated with pelvic fracture and membranous urethral disruption.

Retrograde urethrography is the initial study for suspected urethral injury; catheterization should not be attempted before imaging when injury is suspected.

Renal trauma is graded by the American Association for the Surgery of Trauma; hemodynamically stable patients with grade I-IV injuries are managed nonoperatively, while grade V or instability may require intervention.

Bladder rupture: extraperitoneal rupture is often managed with catheter drainage; intraperitoneal rupture requires surgical repair.

Urethral stricture disease is most commonly caused by trauma or instrumentation; treatment options include dilation, direct visual internal urethrotomy, and urethroplasty for recurrent strictures.

Urinary diversion: ileal conduit is the most common incontinent diversion; orthotopic neobladder requires a competent urethral sphincter and negative urethral margins.

Testicular trauma with suspected rupture requires scrotal exploration and repair; ultrasound is used when the diagnosis is uncertain.

Penile fracture presents with a snap, detumescence, and a tunical defect; immediate surgical repair reduces long-term erectile dysfunction.

Uncomplicated cystitis in women is treated with nitrofurantoin, trimethoprim-sulfamethoxazole, or fosfomycin; fluoroquinolones are reserved because of collateral damage and resistance.

Complicated urinary tract infection includes pyelonephritis, catheter-associated infection, and infection in men or pregnant women; culture-directed therapy is required.

Acute bacterial prostatitis presents with fever, perineal pain, and dysuria; treatment is with a fluoroquinolone or trimethoprim-sulfamethoxazole for 2-4 weeks.

Abscesses of the prostate or kidney require drainage; a prostatic abscess may need transurethral or transperineal drainage.

Fournier gangrene is necrotizing fasciitis of the perineum; treatment is urgent surgical debridement plus broad-spectrum antibiotics.

Genital herpes is caused by herpes simplex virus and presents with painful vesicles; treatment with acyclovir or valacyclovir reduces duration and transmission.

Human papillomavirus is associated with penile, anal, and cervical cancer; vaccination prevents infection with high-risk types.

Sterile pyuria with negative cultures should prompt evaluation for tuberculosis, especially in endemic areas; urine acid-fast bacillus cultures are required.

Venous thromboembolism prophylaxis should be risk-stratified; extended prophylaxis is recommended after major pelvic cancer surgery for up to 4 weeks.

Antibiotic prophylaxis before urologic procedures is guided by procedure type and patient risk; routine prophylaxis is not recommended for clean procedures without implantation.

Enhanced recovery after surgery protocols include preoperative counseling, limited fasting, multimodal analgesia, and early ambulation to reduce length of stay.

Complications of transurethral resection of the prostate include bleeding, retrograde ejaculation, urethral stricture, and transurethral resection syndrome from hypotonic irrigation absorption.

Robotic and laparoscopic surgery: insufflation-related complications include subcutaneous emphysema, pneumothorax, and gas embolism; capnothorax should be considered with sudden hemodynamic instability.

Patient safety: wrong-site surgery prevention requires preoperative marking and a time-out; surgical counts and specimen labeling are part of the safety checklist.

Acute kidney injury after surgery is monitored by urine output and creatinine; oliguria is urine output <0.5 mL/kg/h for 6 hours.

Radiation safety: fluoroscopy time should be minimized, and lead shielding and dosimetry are required for staff during endourologic procedures.

Informed consent requires disclosure of diagnosis, proposed treatment, alternatives, and material risks; it must be voluntary and documented.

Confidentiality may be breached only when required by law or when there is a serious threat to the patient or others.

Conflict of interest must be disclosed in research, publication, and clinical practice; financial relationships with industry should not influence patient care.

Resource allocation decisions should be based on medical need and evidence, not on patient characteristics unrelated to prognosis.

Shared decision-making is appropriate when multiple reasonable options exist, such as active surveillance versus treatment for low-risk prostate cancer.

Medical errors should be disclosed to patients in accordance with institutional policy and ethical duty; apology and explanation support trust.

Health policy relevant to urology includes screening recommendations, coverage of prostate cancer screening, and access to transplantation; these vary by jurisdiction.

Professional boundaries and appropriate communication with patients, including chaperone use during intimate examinations, are part of ethical practice.