ABU Qualifying Exam key terms

The functional unit of the kidney, consisting of a glomerulus and its tubule, which filters plasma and modifies the filtrate to produce urine. Each human kidney contains roughly one million nephrons.

The volume of plasma filtered into Bowman's space per unit time, normally about 125 mL/min. It is determined by the filtration pressure, surface area, and permeability of the glomerular barrier.

A process in the loop of Henle whereby fluid flowing in opposite directions in descending and ascending limbs generates an osmotic gradient, allowing concentration or dilution of urine under hormonal control.

A peptide released from the posterior pituitary that increases water permeability of collecting duct cells via aquaporin channels, concentrating urine and raising blood volume when osmolality rises.

A structure where the distal tubule contacts the afferent arteriole, sensing sodium delivery and perfusion pressure to regulate renin release and thereby systemic blood pressure.

A hormonal cascade in which renin cleaves angiotensinogen to angiotensin I, converted to angiotensin II, which constricts vessels and stimulates aldosterone release, raising blood pressure and retaining sodium.

Autonomous aldosterone production, usually from an adrenal adenoma or bilateral hyperplasia, causing hypertension with hypokalemia and suppressed renin. It is a common secondary cause of resistant hypertension.

A catecholamine-secreting tumor of adrenal chromaffin cells producing paroxysmal hypertension, headache, palpitations, and sweating. Diagnosis relies on plasma metanephrines, and preoperative alpha blockade is required.

Narrowing of one or both renal arteries, usually from atherosclerosis or fibromuscular dysplasia, that reduces renal perfusion and activates renin release, causing renovascular hypertension and sometimes declining renal function.

Cell-surface proteins encoded by the major histocompatibility complex that present peptides to T cells and determine tissue compatibility. Matching these antigens reduces rejection in kidney transplantation.

The percentage of a reference donor population against which a patient's serum antibodies react, reflecting prior sensitization from transfusion, pregnancy, or previous grafts and predicting crossmatch difficulty.

Immediate graft destruction within minutes to hours caused by preformed donor-specific antibodies activating complement and thrombosing graft vessels. It is prevented by a negative pretransplant crossmatch.

T-cell-mediated immune attack on a transplanted organ occurring days to months after surgery, producing graft dysfunction and interstitial lymphocytic infiltration that responds to corticosteroid pulses and intensified immunosuppression.

A drug such as tacrolimus or cyclosporine that blocks T-cell activation by inhibiting calcineurin-dependent cytokine transcription. Nephrotoxicity and hypertension are common adverse effects requiring level monitoring.

Polyomavirus infection of renal allograft tubular cells causing graft dysfunction and fibrosis, typically in the first two years after transplant. Reducing immunosuppression is the mainstay of treatment.

An enzymatic technique that amplifies a specific DNA segment through repeated cycles of denaturation, primer annealing, and extension, enabling detection of pathogens or mutations from minute samples.

High-throughput parallel sequencing of many DNA fragments simultaneously, allowing detection of mutations, copy changes, or microbial genomes without prior targeted assumptions.

Short DNA fragments released into plasma from dying cells, including tumors and donor organs. Assays of these fragments are used for noninvasive cancer genotyping and graft injury monitoring.

A gene whose protein product restrains cell growth or promotes repair; loss of both alleles removes this brake and predisposes to cancer. Examples include VHL and TP53.

A mutated or overexpressed gene that drives uncontrolled cellular proliferation, often arising from a proto-oncogene. Examples in urologic cancer include activated tyrosine kinases and growth factor receptors.

An autosomal dominant syndrome from VHL gene loss causing bilateral renal cell carcinomas, pheochromocytomas, pancreatic cysts, and cerebellar hemangioblastomas, requiring lifelong surveillance.

A serine protease produced by prostatic epithelium that liquefies semen. Serum levels rise with benign enlargement, prostatitis, and prostate cancer, making it a screening and monitoring marker of limited specificity.

A grading system for prostate adenocarcinoma that sums the two most prevalent architectural patterns, each scored 1 to 5, producing a total that predicts biologic aggressiveness and guides treatment.

Sampling of prostatic tissue, usually by transrectal or transperineal ultrasound-guided cores, to diagnose cancer in men with elevated antigen levels or abnormal examination findings.

A seven-item validated questionnaire quantifying lower urinary tract symptoms from incomplete emptying through nocturia, plus a quality-of-life question, used to grade benign prostatic obstruction severity.

Nonmalignant proliferation of prostatic transition zone glands and stroma that compresses the urethra, producing hesitancy, weak stream, and incomplete emptying in aging men.

Involuntary bladder muscle contractions during filling that cause urgency and urge incontinence, demonstrable on urodynamics. It may be idiopathic or secondary to obstruction or neurologic disease.

Physiologic testing that measures bladder and urethral pressure and flow during filling and voiding, distinguishing obstruction from impaired contractility and identifying overactivity.

The volume of urine remaining in the bladder after voiding, measured by catheter or ultrasound. Elevated values suggest outlet obstruction or detrusor underactivity and risk urinary retention.

Retrograde flow of urine from bladder into the ureter due to a short or incompetent ureterovesical junction, predisposing children to pyelonephritis and renal scarring.

A congenital membranous obstruction in the male posterior urethra causing prenatal hydronephrosis, thick-walled bladder, and possible renal dysplasia; endoscopic ablation is the initial treatment.

Dilatation of the renal pelvis and calyces from obstructed urine flow or reflux, seen on imaging. Severity and renal function determine whether decompression by stent or nephrostomy is urgent.

A catheter placed percutaneously into the renal collecting system to divert urine and relieve obstruction when retrograde access is impossible or the patient is too unstable for definitive surgery.

A flexible tube placed endoscopically between kidney and bladder to maintain urine flow past obstruction or after surgery, often causing flank discomfort, urgency, and hematuria while in place.

A noninvasive treatment that focuses shock waves on a urinary stone to fragment it into pieces small enough to pass, best suited to stones under two centimeters in the kidney or proximal ureter.

Endoscopic passage of a scope through the urethra and bladder into the ureter to visualize, fragment, or extract stones and to biopsy or treat urothelial lesions.

A magnesium ammonium phosphate calculus formed when urease-producing bacteria alkalinize urine, producing large branching stones that require complete removal and infection eradication.

Necrotizing fasciitis of the perineum and genitalia from a polymicrobial infection, presenting with pain out of proportion, crepitus, and systemic toxicity; it demands urgent surgical debridement and antibiotics.

Inflammation of the epididymis, usually from ascending bacterial infection or sexually transmitted organisms, causing scrotal pain, swelling, and tenderness relieved by elevation.

Twisting of the spermatic cord that cuts off blood flow to the testis, producing sudden severe pain and a high-riding testis. It is a surgical emergency requiring detorsion within hours.

Dilatation of the pampiniform plexus, usually left-sided, that raises scrotal temperature and is a common correctable cause of impaired semen quality and male infertility.

Persistent inability to achieve or maintain an erection sufficient for intercourse, often from vascular, neuropathic, or psychogenic causes. It can be an early marker of cardiovascular disease.

A drug class that prevents breakdown of cyclic guanosine monophosphate in cavernosal smooth muscle, enhancing erection when nitric oxide is released. Nitrate coadministration is contraindicated.

A prolonged erection lasting more than four hours without stimulation. The ischemic low-flow type is painful and threatens tissue viability, requiring aspiration or shunt surgery urgently.

An abnormal tract between bladder and vagina, often after pelvic surgery or radiation, causing continuous urine leakage. Diagnosis is by speculum examination and imaging, and repair is usually surgical.

A tract between rectum and urethra, typically complicating prostate surgery, radiation, or trauma, producing urine per rectum and recurrent urinary infection; repair often requires tissue interposition.

Scarring and narrowing of the urethral lumen from trauma, instrumentation, or inflammation, causing weak stream and retention. Treatment ranges from dilation to graft urethroplasty.

A urinary diversion in which ureters are implanted into an isolated segment of ileum brought to the skin as a stoma, draining urine into an external appliance.

A urinary reservoir constructed from bowel and anastomosed to the urethra in place of the removed bladder, allowing voiding per urethra, though catheterization may be needed for incomplete emptying.

A normal-anion-gap acidosis caused by chloride retention or bicarbonate loss, seen after urinary diversion using bowel segments that reabsorb chloride and secrete bicarbonate.

Serum potassium above the normal range, which can cause muscle weakness and lethal cardiac arrhythmias. In urology it commonly accompanies renal failure or obstructive uropathy.

Inability to concentrate urine from deficient antidiuretic hormone secretion or renal unresponsiveness, producing large volumes of dilute urine, thirst, and risk of hypernatremia.

An adrenal mass discovered on imaging obtained for unrelated reasons. Evaluation screens for hormonal excess and assesses imaging features that predict malignancy.