Urology T1-16 Flashcards
- What are the three initial embryological components of the human kidney?
Pronephros, Mesonephros, Metanephros.
From where do the three embryological components of the kidney arise?
They arise from the intermediate mesoderm on the dorsal body wall.
Which of the three initial embryological kidneys develops into the adult kidney?
The metanephros develops into the adult kidney.
When does the pronephros arise during pregnancy?
The pronephros arises on day 22 of pregnancy.
What is the pronephros composed of?
The pronephros is composed of a small group of nephrotomes (segmented division of the mesoderm).
What do nephrotomes contribute to in the pronephros?
Nephrotomes are needed for the development of the pronephric duct from the intermediate mesoderm.
When does the pronephric duct reach the cloacal wall, and what is it called at this stage?
The duct reaches the cloacal wall on day 26 and is referred to as the Wolffian (mesonephric) duct.
What arises from the Wolffian (mesonephric) duct?
The mesonephric tubules arise from the Wolffian duct.
What happens to the nephrotomes and pronephric part of the duct later on?
They involute completely later on.
From what does the mesonephros arise?
The mesonephros arises from the mesonephric duct and adjacent mesonephric tubules.
What transformation occurs to form the mesonephric tubules?
The tubules form via a mesenchymal to epithelial transformation.
What structures do the segments of mesonephric tubules later contribute to?
They contribute to the formation of the metanephric glomeruli and proximal and distal tubules.
Does the mesonephros produce urine, and if so, how is it drained?
Yes, the mesonephros produces small amounts of urine, which drains via the Wolffian duct.
What happens to the mesonephros by the end of the first trimester?
Most of the mesonephros has involuted.
What do the remnants of the caudal mesonephric tubules become in males?
They become part of the epididymis, seminal vesicle, and ejaculatory duct.
What are the two cell types that initially compose the metanephros?
Epithelial cells of the ureteric bud and mesenchymal cells of the metanephric mesenchyme.
From where and when does the ureteric bud arise?
The ureteric bud arises from the Wolffian duct around day 28.
What happens to the ureteric bud by day 32?
The bud grows and its tip (ampulla) penetrates the metanephric blastema.
What interactions occur between the ureteric bud and mesenchymal cells of the metanephros?
Epithelial-mesenchymal interactions occur, triggering the ureteric bud to branch and form the ureter, renal pelvis, calyces, and collecting tubules.
What process occurs in the mesenchyme at the same time as the ureteric bud branching?
The mesenchyme undergoes epithelial conversion to form nephrons (nephrogenesis).
What structures make up each nephron?
Each nephron is composed of a glomerulus, proximal convoluted tubule, Loop of Henle, and a distal convoluted tubule.
What forms the capillary meshwork in the glomerular tufts to supply each nephron?
Branches from the internal iliac artery form the capillary meshwork in the glomerular tufts.
During what weeks does the embryonic kidney ascend, and from where?
The kidney ascends from its pelvic position during weeks 6-9.
What happens to the kidney’s vasculature as it reaches its final lumbar position?
The vasculature reorganizes to form a definitive renal artery.
By what week does the fetal kidney start producing urine?
Fetal urine is produced by week 10.
What is the cloaca, and how is it initially closed off?
The cloaca is the common end of the rectal tube and the urogenital tract, closed by the cloacal membrane.
What septum forms around day 28, and what is its function?
The uro-rectal septum forms and divides the cloaca into a primitive urogenital sinus (anterior) and rectum (posterior).
How does the cloacal membrane divide?
The cloacal membrane divides into an anterior urogenital membrane and a posterior anal membrane.
When does the urogenital membrane break, and what does it result in?
The urogenital membrane breaks in week 7, creating an open connection between the developing urinary tract and the amniotic cavity.
What is the vesico-urethral canal, and what does it become?
The vesico-urethral canal is the upper part of the primitive urogenital sinus and will eventually form the bladder.
What happens to the allantois as it remains attached to the apex of the fetal bladder?
The allantois loses its patency and persists as the urachal remnant (median umbilical ligament).
What do the mesonephric ducts fuse to form in the bladder?
The mesonephric ducts fuse to form the trigone of the bladder.
What happens to the ureters as the kidneys ascend?
The ureters rapidly elongate to compensate for the ascent of the kidneys.
What will the distal part of the primitive urogenital sinus form?
It will form the definitive urogenital sinus.
In females, what does the definitive urogenital sinus give rise to?
It gives rise to the entire urethra and the vestibule of the vagina.
In males, what does the definitive urogenital sinus give rise to?
It gives rise to the posterior urethra (the anterior urethra is formed from the closure of the urethral folds).
- Where are the kidneys located in the body?
The kidneys are retroperitoneal organs situated at the back of the abdominal cavity in the lumbar region, extending from the 11th rib to the iliac crest.
Why is the right kidney lower than the left?
The right kidney is lower due to the presence of the liver.
What surrounds the kidneys and helps suspend their position?
The kidneys are surrounded by peri-renal fat, which helps suspend their position.
What glands are located on top of the kidneys?
The adrenal glands are located on top of the kidneys.
What structure enters the hilum of the kidney, and where is it located relative to the renal vein?
The renal artery enters the hilum of the kidney and is located posterior to the renal vein.
Where do the renal lymphatics drain?
The renal lymphatics drain into the right and left lumbar (caval and aortic) lymph nodes.
What type of fibers are found in the renal nerve plexus, and what does it innervate?
The renal nerve plexus contains both sympathetic and parasympathetic fibers and serves to innervate the kidney.
Approximately how many nephrons are in a mature kidney?
A mature kidney has around 1 million nephrons.
What are the components of a nephron?
Each nephron is composed of a glomerulus, proximal tubule, Loop of Henle, and distal tubule.
To what are the nephrons connected in the kidney?
Nephrons are connected to a collecting duct system.
What are the primary functions of the kidneys?
The kidneys regulate the secretion of nitrogenous waste products, maintain homeostasis of water, electrolytes, and acid-base, and produce hormones such as renin.
What is the function of the lower urinary tract?
The lower urinary tract forms a low-pressure area for urinary storage.
- What is the most common examination used for the urinary tract?
Ultrasound (US).
What frequencies are used for urological ultrasound imaging?
3.5 MHz is used for urology, and 5 MHz is used for testes and penile imaging.
Which urological organs can be imaged using ultrasound?
Kidneys, adrenal glands, bladder, prostate, seminal vesicles, scrotal organs, urethra, and penis.
Which urological organ cannot be imaged using ultrasound?
The ureter.
What can be determined about the kidneys using ultrasound?
Ultrasound can determine the size, location, shape, and number of kidneys.
How is prostate imaging performed using ultrasound?
The prostate can be examined via supravesical imaging or with a 5 MHz transrectal probe.
How do we calculate the volume of the prostate using ultrasound?
We measure the dimensions of the prostate and divide by 2.
What is the normal volume of the prostate?
The normal volume of the prostate is between 20-25 cm³.
How is the seminal vesicle visualized in ultrasound?
The seminal vesicles can only be seen transrectally.
What is the best use of transrectal ultrasound of the prostate?
It is best used to accurately guide a biopsy needle.
What probe frequency is used to examine the testes via ultrasound?
A small 5 MHz probe is used to examine the testes.
What are the most frequent testicular disorders seen with ultrasound?
Small tumors, epididymitis, testicular torsion, infarct, or cyst.
What intra-scrotal pathologies can be seen with ultrasound?
Hydrocele, varicocele, hematocele, and intra-scrotal hernia.
What is a hydrocele testis?
An accumulation of serous fluid in the tunica vaginalis of the testis.
What is a hematocele?
An accumulation of blood in the tunica vaginalis of the testis.
What is a varicocele?
An abnormal enlargement of the pampiniform venous plexus of the testis.
What can X-rays be used to visualize in urology?
Calcium-containing stones, foreign bodies, and different bone diseases (such as metastasis).
What can a KUB (Kidney, Ureter, Bladder) or IVP (Intravenous pyelography) with contrast show?
They can show the duration and intensity of urinary excretion.
What does retrograde pyelography reveal, and how is it performed?
Retrograde pyelography can reveal obstructions or ureteric strictures, using a cystoscope with a tube to introduce contrast medium and visualized with fluoroscopy.
How is antegrade pyelography performed?
It is done via a percutaneous nephrostomy where dye is injected directly into the collecting system for visualization.
What is cystography, and when is it indicated?
Cystography is when the bladder is filled with a urinary catheter and X-rays are used for visualization. It is indicated if a bladder perforation is suspected.
What is urethrography used for, and how is it done?
Urethrography introduces radio-contrast into the urethra (usually via catheter) and X-rays are taken to locate and measure the length of a urethral stricture.
What can CT imaging be used to detect in urology?
CT is used to image urological tumors, lymph nodes, stones, kidney abscesses, emergencies, and congenital diseases.
What is MRI particularly good for in urology?
MRI is very good for functional imaging but is typically used as a last resort after other imaging techniques.
When is isotope scintigraphy indicated, and which isotope is used?
Isotope scintigraphy, using MAG3 Tc-99m, is indicated in prostate, bladder, or renal cancers to prove or exclude bone metastases. It is also used to determine the individual function of each kidney.
What should be analyzed in urine samples during lab examination?
Urine volume, color, smell, pH, RBC and WBC count, fungi, trichomonas, crystals, creatinine, carbamide, Na, and K levels should be analyzed.
What are the normal amounts of RBCs and WBCs in urine?
Normal RBCs: 0-1 cells/field. Normal WBCs: 2-4 cells/field.
What additional tests should be done besides urine analysis?
A full blood count, liver function test, and the measurement of creatinine and carbamide concentrations as well as Na and K levels should be performed.
What is the tumor marker for prostate cancer?
The tumor marker for prostate cancer is PSA (Prostate-Specific Antigen).
What are the tumor markers for testicular cancer?
The tumor markers for testicular cancer are Beta-hCG, Alpha-fetoprotein, and NSE (neuron-specific enolase).
- What are simple cysts in the kidney?
Simple cysts can be within the kidney or on its surface, lined with cuboidal epithelium and filled with clear, serous fluid.
How do kidney cysts form?
Kidney cysts form congenitally due to unregulated epidermal growth factor mitogens needed for nephrogenesis.
What percentage of fetuses can have simple kidney cysts?
Simple kidney cysts can occur in 1-50% of fetuses.
How are simple kidney cysts diagnosed and treated?
Diagnosed with ultrasound (US); treatment (if needed) includes unroofing or percutaneous aspiration of the fluid.
What characterizes polycystic kidney disease?
Polycystic kidney disease is an autosomal recessive disease affecting both kidneys, with tubules filled with cysts.
How common is polycystic kidney disease in fetuses, and what is a major complication?
It occurs in 0.01% of fetuses and can lead to oligohydramnios, resulting in pulmonary hypoplasia.
What is the only definite solution for polycystic kidney disease?
The only definite solution is a renal transplantation.
What is multi-cystic kidney disease?
It is a congenital condition affecting one kidney (unilateral) with variably sized and communicating cysts.
What is the most common renal cystic disease and the most common cause of an abdominal mass in infants?
Multi-cystic kidney disease.
What are the symptoms of multi-cystic kidney disease, and how is it diagnosed?
Symptoms include abdominal pain, hematuria, and hypertension. Diagnosis is via ultrasound or IV pyelography with Tc-99m-DMSA for difficult cases.
What is the treatment for severe multi-cystic kidney disease?
Treatment involves a nephrectomy for severe symptoms.
What is medullary sponge kidney?
Medullary sponge kidney is characterized by small medullary cysts and dilated intra-papillary collecting ducts, giving a sponge-like appearance on radiology.
What are the symptoms and occurrence rate of medullary sponge kidney?
Symptoms include renal colic, UTIs, hematuria, or formation of stones. It occurs in 0.02% of pregnancies.
How is medullary sponge kidney diagnosed?
Diagnosed with IV urography, which shows enlarged kidneys with calcifications (mainly in papillae), elongated papillary tubules that fill with contrast, and persistent medullary opacity.
What is the treatment for medullary sponge kidney?
Symptomatic treatment.
What is renal agenesis?
Renal agenesis is the absence of one or both kidneys, which can be unilateral or bilateral.
What causes renal agenesis?
It is caused by the absence of a nephrogenic ridge or failure of the ureteral bud to develop from the Wolffian duct.
How common is renal agenesis in pregnancies?
It occurs in 0.025% of pregnancies.
What is the prognosis for unilateral renal agenesis?
Individuals can have normal lives if the solitary kidney functions correctly, as it undergoes compensatory enlargement.
What happens in cases of bilateral renal agenesis?
Bilateral renal agenesis leads to oligohydramnios, causing pulmonary hypoplasia, and results in death within 2 days of birth.
How can renal agenesis be diagnosed?
It can be diagnosed with any imaging technique.
Is there any treatment for renal agenesis?
No, there are no treatments for renal agenesis.
What is a duplex kidney?
A condition where a patient has two separate pelvicalyceal systems and ureters.
What causes a duplex kidney?
It occurs when two separate ureteric buds develop from a Wolffian duct.
What structures develop in a duplex kidney due to the presence of two ureteric buds?
Two completely separate renal units, collecting systems, ureters, and ureteral orifices develop.
What does the Weigert-Meyer law describe in relation to duplex kidneys?
It describes the relationship of the upper and lower renal moieties in duplex kidneys, where the upper pole ureter drains inferomedial to the normal lower moiety ureter.
Why does the upper pole moiety ureter drain inferomedial in duplex kidneys?
Because the lower pole ureter separates earlier from the Wolffian duct, it migrates superiorly, while maintaining its original embryologic relationship during drainage.
What is a ureterocele and how is it related to duplex kidneys?
A ureterocele is a congenital dilation of the distal ureter, often associated with ectopic insertion, and can obstruct its own collecting system in duplex kidneys.
How is a duplex kidney with ectopic ureter diagnosed and treated?
Primarily diagnosed with IV urography. Treatment can include a heminephrectomy or ureterectomy if the upper moiety is non-functional, or a ureteroneocystostomy if renal function is normal.
What is renal ectopia?
A congenital condition where a kidney is located in an abnormal position, such as pelvic, iliac, abdominal, thoracic, or contralateral (crossed ectopia).
What causes renal ectopia?
It occurs when the nephrogenic tissue migrates abnormally during embryonic elongation, or is prevented from moving properly into the true pelvis.
What are the common characteristics and risks of an ectopic kidney?
The ectopic kidney is usually smaller and abnormally shaped. It may lead to a higher chance of UTIs, calculus formation, or secondary hypertension.
What is the treatment for renal ectopia?
Symptomatic treatment for UTIs, stones, or hypertension. A nephrectomy may be performed if the other kidney functions well.
What is a horse-shoe kidney?
A congenital condition where the two kidneys are fused at their lower poles, forming a U-shaped structure.
How does a horse-shoe kidney develop?
It occurs when the two metanephric masses are too close, allowing cells to migrate between them and form an isthmus connecting the lower poles.
What are the symptoms and complications of a horse-shoe kidney?
Symptoms include hydronephrosis, infections, or calculus formation due to ureteropelvic obstruction. However, 30% of cases are asymptomatic.
How is a horse-shoe kidney diagnosed and treated?
Diagnosed with ultrasound (US), but CT or retrograde pyelography is more definitive. Treatment is symptomatic.
What is an ectopic ureter?
An ectopic ureter is when the ureter has its orifice in an abnormal position, not in its usual location on the bladder. This occurs when the ureteral orifice remains on the caudal Wolffian duct and is not absorbed into the bladder.
Where can the ureteral orifice of an ectopic ureter be located?
The ureteral orifice may be in the bladder neck, proximal urethra, or outside of the urinary sphincter area.
In males, it can drain into the bladder neck, prostatic urethra, or Wolffian duct structures such as the seminal vesicles, vas deferens, or epididymis, while still being upstream of the external sphincter.
Why is an ectopic ureter a common cause of urinary incontinence in females?
In females, the ectopic ureter often drains outside the control area of the urinary sphincter, leading to urinary incontinence.
What are the complications associated with an ectopic ureter?
Complications of an ectopic ureter include a higher chance of urinary tract infections (UTIs) and, in females, urinary incontinence.
What are the treatment options for an ectopic ureter?
Treatment for an ectopic ureter includes ureteral re-implantation or ureteropyelostomy, which creates a new communication between the ureter and the renal pelvis.
What is a ureterocele?
A ureterocele is a cystic dilation of the terminal ureter, caused by incomplete dissolution of the membrane dividing the ureteric bud from the urogenital sinus or abnormal muscular development.
What complications can a ureterocele cause?
A large ureterocele can obstruct the bladder neck or contralateral ureteral orifice, leading to hydronephrosis, increased UTI risk, and potential incontinence due to interference with normal sphincter function.
How is a ureterocele diagnosed?
A ureterocele is diagnosed via ultrasound (US) or intravenous pyelography (IVP).
What are the treatment options for a ureterocele?
Treatment for a ureterocele involves preserving renal function and eliminating infection, obstruction, or reflux. Surgical options include resecting the ureterocele or performing a partial ureterectomy.
What is uretero-pelvic junction (UPJ) obstruction?
UPJ obstruction is a stricture at the uretero-pelvic junction, which can be caused by defective development of circular musculature or mechanical obstruction from an aberrant vessel near the junction.
How is uretero-pelvic junction obstruction diagnosed?
UPJ obstruction is diagnosed with ultrasound (US).
What symptoms can uretero-pelvic junction obstruction present?
UPJ obstruction is usually asymptomatic but can present with urinary tract infections (UTIs), pain, and hematuria.
What is the treatment for uretero-pelvic junction obstruction?
Treatment for UPJ obstruction is the Anderson-Hynes pyeloplasty, a surgical procedure to correct the obstruction by reshaping the UPJ.
What is hydronephrotic pyelum, and how is it treated?
Hydronephrotic pyelum involves a dilated renal pelvis due to obstruction. The treatment includes resecting the hydronephrotic pyelum and the stenotic part of the ureter, then stitching the remaining parts back together.
What is vesico-ureteral reflux?
Vesico-ureteral reflux is the retrograde flow of urine from the bladder back into the upper urinary tract. It occurs due to a deficiency in the longitudinal muscle of the ureter, leading to an inadequate valvular mechanism.
What are the symptoms of vesico-ureteral reflux?
Symptoms of vesico-ureteral reflux can include urinary tract infections (UTIs), abdominal pain, hydronephrosis, and calculus formations. It is usually asymptomatic.
What are the grades of vesico-ureteral reflux and their characteristics?
Grade 1: Flow remains in the ureter; the ureter is not dilated.
Grade 2: Urine refluxes into the pelvis and calyces without dilation.
Grade 3: Mild dilation of the ureter, pelvis, and calyces.
Grade 4: Moderate ureteral tortuosity and dilation of the pelvis and calyces.
Grade 5: Massive dilation of the ureter, pelvis, and calyces with papillae losing shape and significant ureter tortuosity.
How is vesico-ureteral reflux treated?
Low-grade vesico-ureteral reflux may resolve spontaneously. High-grade reflux usually requires ureteral re-implantation surgery.
What is megaureter?
Megaureter is a condition characterized by a dilated or large ureter. It can be due to primary obstructive causes, such as an aperistaltic ureteral juxtavesical segment, or secondary obstructive causes like infra-vesical obstructions.
What are the types of megaureter and their causes?
Primary obstructive megaureter: Due to abnormal musculature development in the ureter.
Secondary obstructive megaureter: Due to infra-vesical obstructions, such as a posterior urethral valve.
Non-obstructive, non-refluxing megaureter: Resulting from inflammation and toxins inhibiting normal ureteral peristalsis.
How is megaureter diagnosed and treated?
Megaureter is diagnosed using urography. Treatment involves surgical remodeling of the ureter and re-implantation into the bladder.
- Where does the ureter normally traverse before opening into the bladder?
The ureter normally traverses through the base of the bladder, traveling through the ureteral hiatus. It courses between the detrusor muscle and the bladder mucosa before opening into the bladder.
What is the usual developmental sequence of the bladder and surrounding structures?
Normally, the bladder separates from the rectum, and the anterior abdominal muscles develop before the cloacal membrane regresses.
This results in the bladder and hindgut being distinct structures in the abdomen before the regression of the cloacal membrane.
What does the distal end of the Wolffian duct become?
The distal end of the Wolffian duct becomes the ejaculatory duct.
What is a peri-ureteral diverticulum?
A peri-ureteral diverticulum occurs when the ureteral hiatus is large enough that the distal ureter and surrounding bladder mucosa herniate through the detrusor muscle during micturition.
What is bladder exstrophy?
Bladder exstrophy occurs when the cloacal membrane ruptures before the mesoderm has separated the anterior bladder from the abdominal wall, resulting in the bladder being exposed on the abdominal surface.
What is cloacal exstrophy?
Cloacal exstrophy occurs before the bladder is separated from the hindgut by the uro-rectal septum, leading to a complex exposure of both the bladder and hindgut.
