Week 3 Lectures Flashcards
what germ layer is the nephron derived from
mesoderm of the metanephric diverticulum
what germ layer are the collecting ducts derived from
from the ureteric bud, a diverticulum of the nesonephric duct
what cells secrete renin
JGA/Granular cells
what are the urogenital ridges
after the embryo rolls up at 4-5 weeks, the intermediate mesoderm forms two ridges that lie on either side of the midline
give rise to the urinary system (kidneys and ureters) and the internal genital systems (ovaries, fallopian tubes, uterus//testis, vas deferens)
What are the 3 stages of kidneys development in mammals
pronephrous/pronephric kidney–>mesonephrous/mesonephric kidney–>metanephrous/metanephric kidney
what is the pronephric kidney
develops in the first 6 somites (cervical region)
nonfunctional
induces the formation of the PRONEPHRIC DUCT
what is the pronephric duct
induced to form by the pronephric kidney
it grows down through the thorax and abdominal regions where it is referred to as the mesonephric duct and it induces the formation of the mesonephric kidney and its tubules
what is the mesonephric kidney
functional kidney in the first trimester with approximately 70 tubules each
continues to grow and enters the cloaca
what is the metanephric kidney
the functional kidney in the adult
URETERIC BUDS grow out of the posterior aspect of the mesonephric duct and into the surrounding mesoderm–>inductive effects occur between the bud and the mesoderm –> gives rise to the ureter, collecting duct, and metanephric kidney–> buds grow out and branch to form the collecting duct–>tips od the duct induce formation of cysts–> cysts form tubules –> at the distal end of the tubule, the bowman’s capsule forms–> angiogenic factors then assist in the formation of capillaries and glomeruli –> the proximal end of the tubule fuses with the collecting duct of the ureteric buds –> the first 4 connections atrophy to produce the renal medulla
what is the developmental defect that results in polycystic kidney disease
results if the tubules fail to fuse with the collecting duct of the ureteric buds
how do the kidneys end up in their proper anatomical position
they migrate upwards from the pelvis into the abdominal cavity
they can become hung up during migration–>therefore, one or both kidneys can be located anywhere on the route of migration
blood vessels that supply the kidneys change during migration–some of these vessels can persist causing obstruction of the ureters, leading to drainage problems
describe the partitioning of the cloaca
formation of the rectum, anus, urinary bladder and urethra
cloaca is partitioned by the URORECTAL FOLD–>it migrates across the cloaca, separating it into two compartments and uses with the cloacal membrane
dorsal compartment = rectum
ventral compartment = UROGENITAL SINUS
the distal end of the urinary mesonephric ducts and the ureters are resorbed into the bladders, such that they enter separately—together they form the base of the bladder
what is the urogenital sinus
forms part of the urinary bladder and urethra
what does the mesonephric duct form in males?
mesonephric duct = woffian duct–> form the vas deferens and the testis
what does the mesonephric duct first become, and then form, in females
the mesonephric duct is first replaced by two new ducts, the paramesonephric ducts (Mullerian ducts)
these form the fallopian tubes, which fuse midline to form the uterus and the proximal 2/3 of the vagina
the distal 1.3 of the vagina is formed from the sinovaginal bulb which develops from the base of the UROGENITAL SINUS
what are duplication anomalies?
duplication of one or both ureters, resulting from the initial formation of two ureteric buds instead of one per metanephric kidney
may be associated with a ureterocele–swelling at the distal end of the ureter (two ureters drain into one bladder causing swelling)
what is renal agenesis
absent kidney development
can occur secondary to a defect of the wolffian duct, ureteric bud, or metanephric blastema (metanephric mesenchyme)
in true agenesis, the ureter and the ipsilateral bladder hemitrigone are absent
the contralateral kidney undergoes compensatory hypertrophy, to some degree prenatally but primarily after birth
aprrox 15% of these children have contralateral vesicoureteral reflux, and most males have an ipsilateral absent vas deferens because the wolffian duct is absent
bilateral renal agenesis is incompatible with extra-uterine life
what is a horseshoe kidney
fusion abnormality in which the two metanephric blastema (mesenchyme that forms the kidney) are not separated during development
most common form of fusion anomaly
may be associated with UPJ obstruction
describe the process of testicular descent
testicles begin to form just before second fetal month
by the 4th months, it has migrated down from the kidney and lies next to the internal inguinal ring
at the 7th months, the testicle, accompanied by a small peritoneal tube (the hernia sac) passes thru the inguinal ring, inguinal canal, and external ring to take its normal position in the scrotum
what is cryptorchidism
un-descended testis
associated with sub-fertility and testicular cancer
what is the navicular fossa? what is it formed from?
it is formed from the glans of the penis, which is initially solid but cannulates to give rise to the navicular fossa which joins with the urethra
the navicular fossa is the spongy part of the male urethra located at the glans penis portion–it lies just proximal to the external urethral orifice
what does the genital tubercle form in females? males?
F: clitoris
M: glans of penis
what do the urogenital folds form in females? males?
F: labia minor
M: shaft of penis and penile urethra
what do the labioscrotal swellings form in the female? male?
F: labia major
M: scrotum
at what week does male and female differentiation occur?
at embryonic age week 7 (gestational age week 9)
what controls the development of external genitalia?
the SRY sex determining gene located on the Y chromosome
what does the SRY gene do and how does it do this
determines the development of the gonads testis versus ovary
the ovaries do not produce factors that influence genitalia development
the testis function to produce two important products–androgens (i.e testosterone) which initiate male external organ development, and Mullerian inhibiting factor, which causes regression of female internal organ development
what is adrenal hyperplasia
the most common cause of abnormal genital development
enzymatic effect–>lack of negative feedback by anterior pituitary–>hyperstimulation of adrenal glands –>overproduction of adrenal androgens
excess androgens–> virilization of external genitalia in girls (internal genitalia not affected)
lack of androgens–> undervirilization in boys
what can cause congenital obstruction
narrowing of the UPJ
secondary to abnormal smooth muscle development
vessels around the ureter dont form properly, causing constrictions along the tube
usually these types of obstructions cause hydronephrosis
there may also be a congenital propensity for renal stone development
what can cause vesicoureteral reflux
this reflux = defined as retrograde flow of urine from the bladder to the kidney
may be due to an abnormal ureteric bud, resulting in a short intravesicular ureter
usually associated with pyelonephritis, renal dysplasia or damage
MOST COMMON LUT CONGENITAL ANOMALY
what causes cryptochidism
failure of testicular descent from the abdominal location to the scrotum
basically because the testes form near the kidney in development, and in the 3rd trimester, they are able to descend down into the scrotum
this descent may occur naturally after birth as well
there may be several reasons for lack of descent, including abnormal abdominal scarring and mutations in the SRY gene on the Y chromosome
what can cause intersex disorders
there may be enzymatic defects in the formation of cortisol and aldosterone during development (a “21OH” deficiency)
this means there is no negative feedback for the production of these steroid hormones
more steroid precursors are shunted into pathways that create more adrenal androgens
this would lead to external/male genitalia in girls, while the internal genitalia would not be affected
what is hypospadius
abnormal development of the genital tubercle
specific features:
- urethral meatus opens proximal to the glans
- incomplete foreskin
- ventral penile curve
if left untreated, it will interfere with normal urination, normal sexual function and will have obvious cosmetic issues
describe 3 ways a clinical presentation of hematuria may be divided
- pseudohematuria–> colored urine but negative dipstick for urine–> DDx = food, dyes, meds (i.e rifampin)
- hematuria but no RBCs on microscopy–>myoglobinuria; hemoglobinuria (due to hemolysis)–>these will both register on dipstick as blood
- true hematuria
in what three ways can true hematuria be divided
- nephrological (casts and/or protein)
- urological (no casts or protein; think anatomically–ureter, bladder, urethra, other)
- hematological (coagulopathy, sickle hemoglobinopathies)
how can nephrological true hematuria be further subdivided
- associated with urinary tract infection
- associated with proteinuria (think anatomically–glomerular, tubulointerstitial)
- associated with casts
describe a DDX for hematuria
- renal calculi
- neoplasm (bladder, renal, ureter)
- trauma (exercise induced, penetrating trauma)
- infections (UTI–pyelonephritis, cystitis, prostatitis, urethritis)
- glomerulonephritis (IgA nephropathy, post-strep glomerulonephritis, lupus, HUS)
- Misc (abnormal urethral structure, meds, BPH)
how would hematuria due to upper tract (kidneys and ureters) present
- total hematuria (from beginning to end of stream)
- renal colic = obstruction of ureter (most likely stone)
- chances of stone increased if also present with nausea, vomiting, unable to find comfortable position, previous Hx of stones
how would hematuria present due to bladder
- total hematuria
- terminal hematuria (end of stream)
- voiding symptoms (frequency, urgency, dysuria) are indicative of (a) inflammation of the bladder, (b) bladder stone, (c) carcinoma in situ
- tissue fragments (bladder tumor)
how would hematuria present if due to prostate
- initial or terminal hematuria
- most of volume of voided urine is non-bloody
BPH is painless, may have associated voiding symptoms of nocturia, slow stream, hesitancy etc)
how would hematuria present if due to urethra
- initial or terminal hematuria
2. most of volume of voided urine is non bloody
how do GU-specific hematurias (glomerulonephritis) present?
i.e post-strep IgA, Goodpasture’s
- reddish brown, tea colored urine
- dysmorphic RBCs
- RBC or granular casts
- heavy proteinuria
- Hx or RTI (post strep gomerulonephritis)
- not severe bleeding
- painless but associated with HTN and edema
how does systemic hematuria present
- Clots–indicative of more severe bleeding–>RULE OUT glomerulonephritis
- bruising easily/arthralgia/rashes–>connective tissue disease
- Hx of chronic AFib–> renal embolus
- other pulm symptoms–>miliary TB
- pre-renal coagulopathy–>immune thrombocytopenia purpura, Von Willebrand’s disease, Warfarin/Heparin
how would a renal tumor present clinically?
- gross hematuria (40%)
- flank pain (40%)
- palpable flank mass (25%)
- classic triad (1-3–>10%)
- right sided varicocele (
what are some symptoms of paraneoplastic syndrome?
anemia hepatic dysfunction weight loss malaise hypoalbuminemia hypercalcemia anorexia thrombocytosis night sweats fever HTN erythrocytosis chills
how would bladder cancer present clinically?
- classic = hematuria, usually GROSS and PAINLESS
- frequency, urgency and dysuria (30%)
more advanced local disease: pelvic pain, bladder outlet obstruction, flank pain secondary to obstructed upper tract, feeling of incomplete voiding, intermittent stream, straining
how would renal colic present
- crampy intermittent pain that originates in the flank and radiates toward the groin (testicles in men and labia majora in women)
- nausea and vomiting in 50%
- hematuria in most cases, and gross hematuria in some
- patients often move around a lot trying to find a comfortable position (this differs from peritonitis where patients lie still)
- rebound tenderness, guarding and rigidity
- fever means that patient might have a superimposed infection (UROLOGIC EMERGENCY)
advantages of ultrasound in imaging the urinary tract
- first line choice for investigating HEMATURIA
- good for assessment of renal parenchyma (masses, renal size, atrophy)
- excellent for assessment of hydronephrosis, and RENAL STONES
- AVAILABLE in most community hospitals and is portable
- non invasive
- no radiation exposure or contract agent
- relatively cheap
disadvantages of US for imagining urinary tract
- ureters are not typically seen (so not useful for ureter stones, tumors)
- US waves do not pass thru air
- patients who are obese are more difficult to image due to attenuation from fat
advantages of CT-KUB in imaging urinary tract
- accurate and reproducible (easy to compare images)
- sensitive to STONES!!!, even uric acid stones
- tiny stones easily visible
- can visualize renal outline, collecting system, perirenal edema and inflammation commonly seen in stones
- procedure of choice for RENAL CALCULI
- no contrast given
- can be used to rule out other alternate life threatening diagnoses
disadvantages of CT KUB in imaging the urinary tract
- ionizing radiation exposure
- more expensive than ultrasound or plain radiograph
- no functional information given
advantages of MRI for imaging the urinary tract
- absence of radiation
- excellent soft tissue and vascular details
- contrast media is less nephrotoxic
disadvantages of MRI for imaging the urinary tract
- more time consuming than CT and moderately more expensive
2. less readily available
advantages of IVP for imaging the urinary tract
- assesses both FUNCTION and anatomy of the kidney (though not as well as the other techniques that also do so)
- relatively cheap
- good test for evaluation of stones
- good for determining the presence of absence of obstruction
- good for evaluating congenital variants (i.e UPJ obstruction)
- shows the pelviclyceal system well for assessment of TCC
disadvantages of IVP in imaging the urinary tract
- slow (20-30 min)
- if obstruction present, might take several hours more
- contrast is somewhat nephrotoxic
- allergic reactions might occur
- relatively invasive (compared to plain x-rays)
- less sensitive for RCC
advantages of CT with contrast for evaluation of the urinary tract
- better evaluation of renal parenchyma than the non-contrast CT
- better ID of tumors, infarcts, and renal abcesses
- provides some functional information
disadvantages of CT with contract for imaging the urinary tract
- contrast can OBSCURE STONES
- nephrotoxic contrast
- may have allergic rxns
- radiation dose is higher than CTKUB
advantages of retropyelogram
no issues with allergies to contrast dye
disadvantages to retropyelogram
invasive cystoscopy is required
describe a simple cyst
fluid filled
describe a complex cyst
septation/nodules
what imaging techniques are good for distinguishing renal cysts from solid masses
US, CT, MRI (altho MRI doesnt clearly demonstrate calcifications)
what does an oncocytoma look like on CT
stellate central scar
what does an angiomyolipima look like ok CT
mass contains fat on CT
which calculi are opaque on CT KUB
calcium (75%) and struvite (15%
cystine calculi are less opaque on KUB
uric acid stones are radioluscent on KUB and opaque on CT KUB
what type of stones are radioluscent on CT KUB
indinovir stones
what % of staghorn calculi are struvite calculi
70%
what are staghorn calculi
large stones at renal pelvis
does everyone with hematuria need imaging?
yes
for symptomatic hematuria, describe the order of imaging tests
- US is good first line test
- CT KUB = recommended is renal colic may be present
- if US shows mass–CT the renal mass
- if US shows obstruction (hydronephrosis but no visible stones)–> CT IVP or urologist cystoscopy
- if there is a Hx of trauma–> CT
for asymptomatic (painless) hematuria, describe the order of imaging tests
- do a US to rule out stones, mass or obstruction
- if mass on US–> CT renal mass (MRI)
- is no mass on US–> CT IVP or cystoscopy
when is cystoscopy indicated?
in every form of GROSS HEMATURIA unless the diagnosis is obvious from other techniques
what is a retropyelogram
urologic procedure whereby a physician injects contrast into the ureter in order to visualize the ureter and kidney
if you have symptomatic hematuria (pain) +
- fever, chills?
- irritative voiding symptoms?
- renal colic with nausea and vomiting?
what is the diagnosis?
- UTI
- inflammation of bladder or prostate, bladder stone or carcinoma in situ
- acute obstruction of ureter by stone
what does painless hematuria usually suggest?
urinary malignancy or BPH
stones, trauma or infections are rarely painless