- •Hematuria II: causes and investigation
- •Hematospermia
- •Lower urinary tract symptoms (LUTS)
- •Nocturia and nocturnal polyuria
- •Flank pain
- •Urinary incontinence in adults
- •Genital symptoms
- •Abdominal examination in urological disease
- •Digital rectal examination (DRE)
- •Lumps in the groin
- •Lumps in the scrotum
- •2 Urological investigations
- •Urine examination
- •Urine cytology
- •Radiological imaging of the urinary tract
- •Uses of plain abdominal radiography (KUB X-ray—kidneys, ureters, bladder)
- •Intravenous pyelography (IVP)
- •Other urological contrast studies
- •Computed tomography (CT) and magnetic resonance imaging (MRI)
- •Radioisotope imaging
- •Post-void residual urine volume measurement
- •3 Bladder outlet obstruction
- •Regulation of prostate growth and development of benign prostatic hyperplasia (BPH)
- •Pathophysiology and causes of bladder outlet obstruction (BOO) and BPH
- •Benign prostatic obstruction (BPO): symptoms and signs
- •Diagnostic tests in men with LUTS thought to be due to BPH
- •Why do men seek treatment for their symptoms?
- •Watchful waiting for uncomplicated BPH
- •Medical management of BPH: combination therapy
- •Medical management of BPH: alternative drug therapy
- •Minimally invasive management of BPH: surgical alternatives to TURP
- •Invasive surgical alternatives to TURP
- •TURP and open prostatectomy
- •Indications for and technique of urethral catheterization
- •Indications for and technique of suprapubic catheterization
- •Management of nocturia and nocturnal polyuria
- •High-pressure chronic retention (HPCR)
- •Bladder outlet obstruction and retention in women
- •Urethral stricture disease
- •4 Incontinence
- •Causes and pathophysiology
- •Evaluation
- •Treatment of sphincter weakness incontinence: injection therapy
- •Treatment of sphincter weakness incontinence: retropubic suspension
- •Treatment of sphincter weakness incontinence: pubovaginal slings
- •Overactive bladder: conventional treatment
- •Overactive bladder: options for failed conventional therapy
- •“Mixed” incontinence
- •Post-prostatectomy incontinence
- •Incontinence in the elderly patient
- •Urinary tract infection: microbiology
- •Lower urinary tract infection
- •Recurrent urinary tract infection
- •Urinary tract infection: treatment
- •Acute pyelonephritis
- •Pyonephrosis and perinephric abscess
- •Other forms of pyelonephritis
- •Chronic pyelonephritis
- •Septicemia and urosepsis
- •Fournier gangrene
- •Epididymitis and orchitis
- •Periurethral abscess
- •Prostatitis: presentation, evaluation, and treatment
- •Other prostate infections
- •Interstitial cystitis
- •Tuberculosis
- •Parasitic infections
- •HIV in urological surgery
- •6 Urological neoplasia
- •Pathology and molecular biology
- •Prostate cancer: epidemiology and etiology
- •Prostate cancer: incidence, prevalence, and mortality
- •Prostate cancer pathology: premalignant lesions
- •Counseling before prostate cancer screening
- •Prostate cancer: clinical presentation
- •PSA and prostate cancer
- •PSA derivatives: free-to-total ratio, density, and velocity
- •Prostate cancer: transrectal ultrasonography and biopsies
- •Prostate cancer staging
- •Prostate cancer grading
- •General principles of management of localized prostate cancer
- •Management of localized prostate cancer: watchful waiting and active surveillance
- •Management of localized prostate cancer: radical prostatectomy
- •Postoperative course after radical prostatectomy
- •Prostate cancer control with radical prostatectomy
- •Management of localized prostate cancer: radical external beam radiotherapy (EBRT)
- •Management of localized prostate cancer: brachytherapy (BT)
- •Management of localized and radiorecurrent prostate cancer: cryotherapy and HIFU
- •Management of locally advanced nonmetastatic prostate cancer (T3–4 N0M0)
- •Management of advanced prostate cancer: hormone therapy I
- •Management of advanced prostate cancer: hormone therapy II
- •Management of advanced prostate cancer: hormone therapy III
- •Management of advanced prostate cancer: androgen-independent/ castration-resistant disease
- •Palliative management of prostate cancer
- •Prostate cancer: prevention; complementary and alternative therapies
- •Bladder cancer: epidemiology and etiology
- •Bladder cancer: pathology and staging
- •Bladder cancer: presentation
- •Bladder cancer: diagnosis and staging
- •Muscle-invasive bladder cancer: surgical management of localized (pT2/3a) disease
- •Muscle-invasive bladder cancer: radical and palliative radiotherapy
- •Muscle-invasive bladder cancer: management of locally advanced and metastatic disease
- •Bladder cancer: urinary diversion after cystectomy
- •Transitional cell carcinoma (UC) of the renal pelvis and ureter
- •Radiological assessment of renal masses
- •Benign renal masses
- •Renal cell carcinoma: epidemiology and etiology
- •Renal cell carcinoma: pathology, staging, and prognosis
- •Renal cell carcinoma: presentation and investigations
- •Renal cell carcinoma: active surveillance
- •Renal cell carcinoma: surgical treatment I
- •Renal cell carcinoma: surgical treatment II
- •Renal cell carcinoma: management of metastatic disease
- •Testicular cancer: epidemiology and etiology
- •Testicular cancer: clinical presentation
- •Testicular cancer: serum markers
- •Testicular cancer: pathology and staging
- •Testicular cancer: prognostic staging system for metastatic germ cell cancer
- •Testicular cancer: management of non-seminomatous germ cell tumors (NSGCT)
- •Testicular cancer: management of seminoma, IGCN, and lymphoma
- •Penile neoplasia: benign, viral-related, and premalignant lesions
- •Penile cancer: epidemiology, risk factors, and pathology
- •Squamous cell carcinoma of the penis: clinical management
- •Carcinoma of the scrotum
- •Tumors of the testicular adnexa
- •Urethral cancer
- •Wilms tumor and neuroblastoma
- •7 Miscellaneous urological diseases of the kidney
- •Cystic renal disease: simple cysts
- •Cystic renal disease: calyceal diverticulum
- •Cystic renal disease: medullary sponge kidney (MSK)
- •Acquired renal cystic disease (ARCD)
- •Autosomal dominant (adult) polycystic kidney disease (ADPKD)
- •Ureteropelvic junction (UPJ) obstruction in adults
- •Anomalies of renal ascent and fusion: horseshoe kidney, pelvic kidney, malrotation
- •Renal duplications
- •8 Stone disease
- •Kidney stones: epidemiology
- •Kidney stones: types and predisposing factors
- •Kidney stones: mechanisms of formation
- •Evaluation of the stone former
- •Kidney stones: presentation and diagnosis
- •Kidney stone treatment options: watchful waiting
- •Stone fragmentation techniques: extracorporeal lithotripsy (ESWL)
- •Intracorporeal techniques of stone fragmentation (fragmentation within the body)
- •Kidney stone treatment: percutaneous nephrolithotomy (PCNL)
- •Kidney stones: open stone surgery
- •Kidney stones: medical therapy (dissolution therapy)
- •Ureteric stones: presentation
- •Ureteric stones: diagnostic radiological imaging
- •Ureteric stones: acute management
- •Ureteric stones: indications for intervention to relieve obstruction and/or remove the stone
- •Ureteric stone treatment
- •Treatment options for ureteric stones
- •Prevention of calcium oxalate stone formation
- •Bladder stones
- •Management of ureteric stones in pregnancy
- •Hydronephrosis
- •Management of ureteric strictures (other than UPJ obstruction)
- •Pathophysiology of urinary tract obstruction
- •Ureter innervation
- •10 Trauma to the urinary tract and other urological emergencies
- •Renal trauma: clinical and radiological assessment
- •Renal trauma: treatment
- •Ureteral injuries: mechanisms and diagnosis
- •Ureteral injuries: management
- •Bladder and urethral injuries associated with pelvic fractures
- •Bladder injuries
- •Posterior urethral injuries in males and urethral injuries in females
- •Anterior urethral injuries
- •Testicular injuries
- •Penile injuries
- •Torsion of the testis and testicular appendages
- •Paraphimosis
- •Malignant ureteral obstruction
- •Spinal cord and cauda equina compression
- •11 Infertility
- •Male reproductive physiology
- •Etiology and evaluation of male infertility
- •Lab investigation of male infertility
- •Oligospermia and azoospermia
- •Varicocele
- •Treatment options for male factor infertility
- •12 Disorders of erectile function, ejaculation, and seminal vesicles
- •Physiology of erection and ejaculation
- •Impotence: evaluation
- •Impotence: treatment
- •Retrograde ejaculation
- •Peyronie’s disease
- •Priapism
- •13 Neuropathic bladder
- •Innervation of the lower urinary tract (LUT)
- •Physiology of urine storage and micturition
- •Bladder and sphincter behavior in the patient with neurological disease
- •The neuropathic lower urinary tract: clinical consequences of storage and emptying problems
- •Bladder management techniques for the neuropathic patient
- •Catheters and sheaths and the neuropathic patient
- •Management of incontinence in the neuropathic patient
- •Management of recurrent urinary tract infections (UTIs) in the neuropathic patient
- •Management of hydronephrosis in the neuropathic patient
- •Bladder dysfunction in multiple sclerosis, in Parkinson disease, after stroke, and in other neurological disease
- •Neuromodulation in lower urinary tract dysfunction
- •14 Urological problems in pregnancy
- •Physiological and anatomical changes in the urinary tract
- •Urinary tract infection (UTI)
- •Hydronephrosis
- •15 Pediatric urology
- •Embryology: urinary tract
- •Undescended testes
- •Urinary tract infection (UTI)
- •Ectopic ureter
- •Ureterocele
- •Ureteropelvic junction (UPJ) obstruction
- •Hypospadias
- •Normal sexual differentiation
- •Abnormal sexual differentiation
- •Cystic kidney disease
- •Exstrophy
- •Epispadias
- •Posterior urethral valves
- •Non-neurogenic voiding dysfunction
- •Nocturnal enuresis
- •16 Urological surgery and equipment
- •Preparation of the patient for urological surgery
- •Antibiotic prophylaxis in urological surgery
- •Complications of surgery in general: DVT and PE
- •Fluid balance and management of shock in the surgical patient
- •Patient safety in the operating room
- •Transurethral resection (TUR) syndrome
- •Catheters and drains in urological surgery
- •Guide wires
- •JJ stents
- •Lasers in urological surgery
- •Diathermy
- •Sterilization of urological equipment
- •Telescopes and light sources in urological endoscopy
- •Consent: general principles
- •Cystoscopy
- •Transurethral resection of the prostate (TURP)
- •Transurethral resection of bladder tumor (TURBT)
- •Optical urethrotomy
- •Circumcision
- •Hydrocele and epididymal cyst removal
- •Nesbit procedure
- •Vasectomy and vasovasostomy
- •Orchiectomy
- •Urological incisions
- •JJ stent insertion
- •Nephrectomy and nephroureterectomy
- •Radical prostatectomy
- •Radical cystectomy
- •Ileal conduit
- •Percutaneous nephrolithotomy (PCNL)
- •Ureteroscopes and ureteroscopy
- •Pyeloplasty
- •Laparoscopic surgery
- •Endoscopic cystolitholapaxy and (open) cystolithotomy
- •Scrotal exploration for torsion and orchiopexy
- •17 Basic science of relevance to urological practice
- •Physiology of bladder and urethra
- •Renal anatomy: renal blood flow and renal function
- •Renal physiology: regulation of water balance
- •Renal physiology: regulation of sodium and potassium excretion
- •Renal physiology: acid–base balance
- •18 Urological eponyms
- •Index
Chapter 17 |
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Basic science of relevance to urological practice
Physiology of bladder and urethra 660
Renal anatomy: renal blood flow and renal function 661 Renal physiology: regulation of water balance 664 Renal physiology: regulation of sodium and potassium
excretion 665
Renal physiology: acid–base balance 666
660 CHAPTER 17 Basic science in urological practice
Physiology of bladder and urethra
Bladder
The bladder consists of an endothelial lining (urothelium) on a connective tissue base (lamina propria), surrounded by smooth muscle (the detrusor), with an outer connective tissue, adventitia.
The urothelium consists of a multilayered transitional epithelium. It has numerous tight junctions that render it impermeable to water and solutes. The detrusor muscle is a homogeneous mass of smooth muscle bundles.
The bladder base is known as the trigone—a triangular area with the two ureteric orifices and the internal urinary meatus forming the corners. Intravesical pressure during filling is low. The main excitatory input to the bladder is via parasympathetic innervation (S2–4; cholinergic postganglionic fibers that when activated cause contraction; see p. 500).
Urethra
The bladder neck is normally closed during filling. It is composed of a circular smooth muscle (sympathetic innervation). High pressure is generated at the midpoint of the urethra in women, and at the level of the membranous urethra in men, where the urethral wall is composed of a longitudinal and circular smooth muscle coat, surrounded by striated muscle (external sphincter).
The striated part of the sphincter receives motor innervation from the somatic pudendal nerve (S3,4) and has voluntary control (ACh, or acetylcholinesterase mediates contraction).
The smooth muscle component of the sphincter has myogenic tone and receives excitatory and inhibitory innervation from the autonomic nervous system. Contraction is enhanced by sympathetic input (noradrenaline) and ACh. Inhibitory innervation is nitrergic (nitric oxide).
Micturition
Voiding is mediated by the pontine micturition center in the brain. During urine storage, bladder neck and sphincter smooth muscle are constricted, and ganglia in the bladder wall are inhibited by sympathetic input, while somatic innervation causes contraction of the striated sphincter muscle. As the bladder fills, sensory nerves respond to stretch and send information about bladder filling to the CNS.
At a socially acceptable time, the voiding reflex is activated. Stimulation of detrusor smooth muscle by parasympathetic anticholinergic nerves causes the bladder to contract. Simultaneous activation of nitrergic nerves reduces the intraurethral pressure, inhibition of somatic input relaxes the striated sphincter muscle, and sympathetic inhibition causes coordinated bladder neck and sphincter smooth muscle relaxation, resulting in bladder emptying.
RENAL ANATOMY: RENAL BLOOD FLOW AND RENAL FUNCTION 661
Renal anatomy: renal blood flow and renal function
The kidneys and ureters lie within the retroperitoneum (literally behind the peritoneal cavity). The hila of the kidneys lie on the transpyloric plane (vertebral level—L1).
Each kidney is composed of a cortex, surrounding the medulla, which forms projections—papillae, which drain into cup-shaped epithelial-lined pouches called calyces (the calyx draining each papilla is known as a minor calyx, and several minor calyces coalesce to form a major calyx, several of which drain into the central renal pelvis).
The renal artery, which arises from the aorta at vertebral level L1/2, branches to form interlobar arteries, which in turn form arcuate arteries, and then cortical radial arteries from which the afferent arterioles are derived. Venous drainage occurs into the renal vein.
There are two capillary networks in each kidney—a glomerular capillary network (lying within Bowman’s capsule) that drains into a peritubular capillary network, surrounding the tubules (proximal tubule, loop of Henle, distal tubule, and collecting ducts).
The anterior relations of the right kidney are, from top to bottom, the suprarenal gland, the liver, and the hepatic flexure of the colon. Medially, anterior to the right renal pelvis is the second part of the duodenum.
The anterior relations of the left kidney are, from top to bottom, the suprarenal gland, the stomach, the spleen, and the splenic flexure of the colon. Medially lies the tail of the pancreas.
The posterior relations of both kidneys are, superiorly, the diaphragm and lower ribs and, inferiorly (from lateral to medial), transversus abdominis, quadratus lumborum, and psoas major.
Renal blood flow (RBF)
The kidneys represent <0.5% of body weight, but they receive 25% of cardiac output (~1300 mL/min through both kidneys; 650 mL/min per kidney). Combined blood flow in the two renal veins is about 1299 mL/min, and the difference in flow rates represents the urine production rate (i.e., ~1 mL/min).
Autoregulation of RBF
RBF is defined as the pressure difference between the renal artery and renal vein divided by the renal vascular resistance. The glomerular arterioles are the major determinants of vascular resistance.
RBF remains essentially constant over a range of perfusion pressures (~80–180 mmHg) (i.e., RBF is autoregulated).
Autoregulation requires no innervation and probably occurs via the following:
•A myogenic mechanism (increased pressure in the afferent arterioles causes them to contract, thereby preventing a change in RBF)
•Tubuloglomerular feedback—the flow rate of tubular fluid is sensed at the macula densa of the juxtaglomerular apparatus (JGA), and in some way this controls flow through the glomerulus to which the JGA is opposed.
662 CHAPTER 17 Basic science in urological practice
Other factors that influence RBF
•Sympathetic nerves innervate the glomerular arterioles. A reduction in circulating volume (such as blood loss) can stimulate sympathetic
nerves, causing the release of NA (which acts on 1-adrenoceptors on the afferent arteriole) to cause vasoconstriction. This results in reduced RBF and GFR (glomerular filtration rate).
•Angiotensin II constricts efferent arterioles and afferent arterioles and reduces RBF.
•Antidiuretic hormone (ADH), ATP, and endothelin all cause vasoconstriction and reduce RBF and GFR.
•Nitric oxide causes vasorelaxation and increases RBF.
•Atrial natriuretic peptide (ANP) causes afferent arteriole dilatation and increases RBF and GFR.
Renal function
Each kidney has 1 million functional units, or nephrons (Fig. 17.1), the functional unit of the kidney consisting of a glomerular capillary network, surrounded by podocytes (epithelial cells) of Bowman’s capsule, which drains into a tubular system (proximal convoluted tubule, loop of Henle, distal convoluted tubule, collecting tube, and collecting duct) (Fig. 17.1).
Blood is delivered to the glomerular capillaries by an afferent arteriole and drained by an efferent arteriole. An ultrafiltrate of plasma is formed within the lumen of Bowman’s capsule, driven by Starling forces across the glomerular capillaries. Reabsorption of salt and water occurs in the proximal tubule, loop of Henle, distal tubule, and collecting ducts.
Clearance is the volume of plasma that is completely cleared of solute by the kidney per minute.
Glomerular filtration rate (GFR) is the clearance for any substance that is freely filtered and is neither reabsorbed, secreted, nor metabolized by the kidney.
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Figure 17.1 The nephron.
RENAL ANATOMY: RENAL BLOOD FLOW AND RENAL FUNCTION 663
For a substance that is freely filtered at the glomerulus, is neither secreted nor reabsorbed by the renal tubules, and is not metabolized (catabolized), clearance is equivalent to GFR. When a substance is both filtered at the glomerulus and secreted by the renal tubules, its clearance will be greater than GFR. When a substance is filtered at the glomerulus, but reabsorbed by the renal tubules, its clearance will be less than GFR.
GFR is directly related to RBF.
Experimentally, GFR can be accurately measured by measuring the clearance of inulin (a substance that is freely filtered by the glomerulus and is neither secreted nor reabsorbed by the kidneys). Thus, the volume of plasma from which in 1 minute the kidneys remove all inulin is equivalent to GFR. Normally about one-fifth (120 mL/min) of the plasma that flows through the glomerular capillaries (600 mL/min) is filtered.
Clinically, GFR is estimated using serum and urine creatinine, and is ~80–125 mL/min in an adult male and 75–115 mL/min in an adult female.
Clearance of a substance from the plasma can be expressed mathematically as
Clearance = U xV / P
where U is the concentration of a given substance in urine, P is its concentration in plasma, and V is the urine flow.
Clinically, a serum and 24-hour urine can be obtained to measure creatine clearance by the formula:
(Urine creatinine × total urine volume)
Clearance =
(plasma creatinine × time)
where time = 1440 minutes for a 24-hour urine collection
Alternatively, the eGFR (estimated GFR) is based on serum creatinine combined with other factors such as age, sex, and race is used more commonly than the 24-hour urine collection. Various on-line calculators are available for this eGFR calculation, such as http://www.nkdep.nih.gov/professionals/gfr_calculators/idms_con.htm.
The Modification of Diet in Renal Disease (MDRD) eGFR equation does not require weight as results are normalized to 1.732 body surface area (BSA), an accepted “average” adult BSA.1 The National Kidney Disease Education Program, sponsored by the NIH, recommends reporting estimated GFR values greater than or equal to 60 mL/min/1.73 m2 simply as “t60 mL/min/1.73 m2,” not an exact number.
eGFR (mL/min/1.73 m2) = 186 x (Scr)-1.154 x (Age)-0.203
x (0.742 if female) x (1.212 if African American) (conventional units)
1 Levey AS, Bosch JP, Lewis JB, et al. (1999). A more accurate method to estimate glomerular filtration rate from serum creatinine: a new prediction equation. Modification of Diet in Renal Disease Study Group. Ann Intern Med 130(6):461–470.