Urology Flashcards
When does differentiation in of the bipotential gonad begin?
6 weeks
What is the SRY gene
Sex-determining Region on the Y chromosome
-on the short arm Y chromosome causes gonads to become testes
What hormone does the Sertoli cells make and what is it’s effect
Antimullerian hormone (AMH)
-Results in ipsilateral regression of mullerian ducts (which would become fallopian tubes, uterus, cervix and upper vaginal in normal F)
What hormone does the Leydig cells make and what is it’s effects
Testosterone
-Ipsilateral development of wolfian ducts (which become vas, epididymis, seminal vesicles)
How does development of male external genitalia occur?
-at 8 weeks there is virilization of the external genitalia due to Testosterone exposure
- Enzyme 5 alpha reductase converts 8% of testosterone to dihydrotestosterone (DHT) (the more potent form of T)
- DHT is critical for normal and complete male virilization
How does the development of female internal and external genitalia occur?
XX –> no SRY –> no testes –> no testosterone & No AMH (female by default)
XX –> no SRY –> Ovaries and mullerian duct development
No testosterone –> Female external genitalia
What are the two most common forms of DSD
- 46 XX CAH
- masculinized female
- most common form of DSD - 45X/45 XY Mixed gonadal dysgenesis
- 2nd most common form of DSD
Describe 46XX CAH
- AR Inborn error of metabolism
- Deficient glucocorticoid synthesis (+/- mineralocorticoid synthesis) by the adrenal gland
- 75% virilized salt water, 25% simple virilizers (no salt waste)
- 95% have 21-hydroxylase deficiency
- metabolic pathway shunted toward adrenal sex steroid production, proximal to the defect
- decrease/no cortisol production –> increase ATCH –> ++ increased testosterone
What is the management of 44XX CAH
gender assignment: usually female
Surgery: feminizing genitoplasty & vaginoplasty
Medical: Hydrocortisone (to restore cortisol & suppress further virilization), Fludrocortisone if salt waster
Which gonads have increased risk for cancer
- Gonads with Y chromosome have increased risk of gonadoblastoma
- If male gender selected, need informed discussion regarding orchiopexy vs orchiectomy and androgen replacement
What are the 3 defects that can be seen in hypospadias
Hypospadias is an arrest during embryologic penile development
- Foreskin is incomplete ventrally
- Urethra meatus not at tip of penis
- Erections curve downwards
-90% of HS cases are isolated penile defects, but may be part of a syndrome
When should prenatal XX CAH treatment start
Should begin before normal virilization of external genitalia occurs (before 8 wks)
- only the female fetus with defect will benefit from prenatal treatment
- AR so only 1/4 of preg affected
- treatment only beneficial for 1/8 of preg
- only for research
- treat with dexamethasone
What is an Intravenous Pyelogram
IVP
- no longer really used now
- used IV contrast taken up by the kidney and excreted during a series of KUB x-rays
- Indications: to diagnosis stones and obstruction
- able to define the collecting system anatomy better than US and provides functional information regarding obstruction
- however it is invasive and needs radiation
What is a Voiding Cystourethrogram
VCUG
-injection of contrast into the bladder via a urethral catheter and fluoroscopy during bladder filling and voiding
indications: assess for VUR and PUV
advantages: provides anatomic detail of refluxing collecting system and urethra (Allows for IRS grading)
risks: invasive (catheter) radiation
What is a Nuclear Cystogram
NC
-injection of radionuclide into bladder via urethral catheter
Imaging of bladder filling and voiding
Indications: Initial assessment for VUR in F only . Follow-up of VUR in both M & F
advantage: less radiation than VCUG
risks: invasive (cath). radation
does not assess for PUV (should not be 1st line for M with hydronephrosis or UTI )
What is a Renal Scan
- IV injection of radionuclide. Gamma camera imaging of kidney uptake +/- excretion
indications: multiple: Different radionucleotide for different indications
advantages: provides functional information
risks: invasive (IV +/- cath) radiation. child must be held still
What does a MAG3, radionuceotide + diuretic and DMSA tell you
MAG3 = split renal function (always adds up to 100%)
Only diuretic can tell you about obstruction
DMSA - can only tell you about renal scarring
What is a Renal/Bladder US
-anatomical assessment using sound waves
indication: anatomical imaging of the urinary tract
advantages: non invasive, no radiation exposure, clarifies cystic vs solid masses
risks: not as sensitive as CT. May miss stones/masses. Normal US does not rule out VUR
What is Urodynamics
-various functional studies done to assess bladder function
Voiding calendar: two day home data collection of time and volume of voids. Provides urinary frequency and functional bladder capacity. Helpful to dx overactive bladder (OAB)
Post Void Residual (PVR): US bladder scanner. Assess bladder emptying
Uroflowmetry: Velocity curve of urinary stream. Assess for urethral obstruction
Cystometry (AKA “invasive “ UDS): Assessment of bladder pressures during bladder filling and voiding. Requires urethral and rectal pressure problems and child must lay still while awake
Pelvic floor electromyography (EMG): Assessment of relaxation/contraction of plevic floor muscles during bladder filling and voiding. Assess for N pelvic floor relaxation w/ voiding (synergistic voiding)
What is the definition of unresolved congenital hydronephrosis (CH)
2009 Canadian Urological Association Guideline
3rd trimester: CH if >/ 9 mm APD
How do you do a postnatal assessment of CH. What is considered to require an urgent US (4)
-recommend RBUS for all newborns with a history of unresolved CH
Urgent US (before discharge from hospital):
- bilat severe CH (> 15 mm APD) or solitary kidney with CH
- oligohydramnios
- urethral obstruction
- concern about patient compliance with postnatal evaluation
Elective US (w/n 30 days) -all others
What can be wrong with doing an U/S too early
US done < 48 hours age may underestimate grade of HN/HUN and warrant repeat
Which grades of CH is associated with significant obstruction?
Significant obstruction only associated with SFU III & IV HN
Severe HN has thinned parenchyma
What are the 4 most common causes of significant CH
- UPJO: uretero-pelvic junction obstruction
- significant hydronephrosis without hydroureter - High grade VUR (vesico-ureteral reflux)
- UVJO (Uretero-vesical junction obstruction)
- due to UVJ stenosis - PUV (posterior urethral valves)
- significant bilat HN in males
- due to bladder outlet obstruction
- bladder anomalies would likely be noted
What is recommended as follow up of CH after postnatal US
Further imaging AFTER initial post-natal US:
SFU I & II: Repeat US in 6 months (no VCUG unless UTI)
SFU: III & IV HN/HUN: Appropriate to refer to urology, VCUG (no age restriction) and diuretic renal scan (age 4 - 6 wks to allow for renal maturity)
What are the symptoms of acquired hydronephrosis
Often UPJO Typically presents with symptoms: -recurrent abdominal pain/flank pain -recurrent pyelonephritis -vomiting (+/- pain) after increased fluid intake
Investigations: RBUS. If Hydropresent, confirm obstruction with diuretic renal scan
List 7 causes of obstructive Uropathies
Obstruction may occur anywhere along the urinary tract and be congenital or acquired
UPJO UVJO/Ureterocele/Ectopic ureter Prolapsing ureterocele (obstructs bladder neck) PUV (obstructs posterior urethra) Urethral stricture Severe meatal stenosis Scarred phimosis
What are suspicious signs antenatally of PUV (5)
- male
- bilateral hydronephrosis
- distended thick walled bladder
- Keyhole sign
- oligohydramnious
How do you manage PUV (7)
- stabilize if resp issues
- urgent postnatal RBUS
- Bladder decompression
- Serial serum creatinine levels
- Confirmatory VCUG
- Consult with nephro (fluid, acid-base, lyte management)
- Consult Urology (surgical management)
What are the highlights of the CPS statement on UTIs in infants and children
-imaging should only be performed when it is likely to alter management
-RBUS after 1st febrile UTI
-VUCG (or NC in females) is reserved for those w/ abnormal RBUS or if have a 2nd febrile UTI)
-No abx prophylaxis for VUR I-III w/ hx of febrile UTI
-Referral/discussion with Uro/nephro for VUR IV - V or significantly abnormal RUBS findings
-Children w/ recurrent UTIs should be managed individually
-bagged urine maybe be used for UA but not Ucx
-contamination is very common from a male when foreskin cannot be retracted
-cystitis in older children - 2 - 4 day course of oral Abx is usually adequate
children with suspected cystitis do not require imaging
What is VUR
Vesico-Ureteric Reflex
- the retrograde flow of urine from bladder to kidneys
- does not cause UTI (except high volume VUR preventing adequate bladder emptying)
- does increase ease of access of bacteria in the bladder to the kidney to cause pyelo
How has VUR management changed?
- more selective about who we screen/treat for VUR
- avoid dx asymptomatic VUR: don’t screen siblings with VUR (30% risk), no longer screen for VUR in those with SFU I & II CH (15% risk)
- don’t txt asymptomatic VUR
- avoid treating low VUR associated with UTI
When is a cystogram warranted? (7)
- Febrile UTI WU: abnormal RBUS, if > 1 febrile UTI
- Work up of SFU III of IV congenital hydro
- WU of late presentation of HUN
- FU of VUR if results will alter management
- Management of neurogenic bladder
- Suspicion of PUV or urethral stricture in male (VCUG)
- Recurrent cystitis in prepubertal male (rule out PUV w/ VCUG)
How do you investigate recurrent cystitis? What are symptoms of bladder and bowel dysfunction (BBD) (5)
Focus on behavioural anomalies rather than anatomic ones
Look for bladder and bowel dysfunction
- Constipation
- Infrequent voiding
- Voiding postponement
- Overactive bladder (OAB)
- Incomplete emptying
How do you manage recurrent cystitis
Manage bladder and bowel dysfunction
- diet/meds for constipation
- timed voiding for infrequent voiding
- avoidance of urine holding
- management of overactive bladder if identified
If symptoms morbid and frequent (3 UTI in 6 mo or 4 in last year) consider offering 3-6 mo continuous abx proph
Highlights of CPS statement on Prophylatic abx for children with recurrent UTIs
- Managing constipation appropriately may be helpful for decreasing UTI recurrences
- if CAP used, should be used for no more than 3 - 6 mon then reevaluate
- choice antimicrobials is TMP/SMX or nitrofurantoin
- switch antimicrobial if urine cx shows resistant organism, even if suspect contamination
- if urine isolate shows resistance to both TMP/SMX & nitrofurantoin, consider stopping CAP rather than using broad spectrum antimicrobials for CAP
What is the most common cause of Daytime Incontenance. List 8 other causes
Most common: Overactive bladder
Other causes:
- Infrequent voiding
- Voiding postponement
- Vaginal voiding
- Giggle incontinence
- Ectopic ureter
- Cystitis
- Bladder outlet obstruction
- Neuropathic
What is overactive bladder? What are signs and symptoms of OAB (7)
uninhibited bladder contractions causing urgency or incontinence
OAB signs/symptoms: -no neurogenic anomalies -frequency (> 8 voids/day on voiding calendar) -Urgency (history) -urge incontinence (history/voiding calendar) -urine holding position -small functional bladder capacity -commonly associated with: constipation nocturnal enuresis recurrent cystitis
What are treatments for OAB
- treat constipation
- observation (if not bothersome)
- timed voiding (every 1.5 - 2 hrs)
- treat UTIs
2nd line:
-anticolinergics (AKA antimuscarinics): reduces intensity and frequency of involuntary contractions
What is the presentation of renal stones (3)
- renal colic (flank pain +/- nausea & vomiting)
- incidental on imaging (RBUS or CT)
- Hematuria
What is the treatment for renal colic
Conservative txt:
-analgesia & alpha blocker (tamsulosin) to hasten passage of small ureteric stones
Interventional txt:
- for large stones to large to pass, unremitting pain, persistent severe obstruction, solitary kidney or infected kidney
How do you prevent stones recurrence?
To prevent recurrence:
- metabolic work up (blood work and 24 hour urine collection)
- passed stone should be retrieved and sent for chemical analysis
-60% are calcium oxalate
- when no metabolic anomaly is identified and stone composition either CaOx or unknown:
- increase fluid intake
- avoid excess salt intake (urinary Ca excreted w/ urine Na)
- normal calcium intake (more effective than Ca restriction)
What are causes of scrotal swelling (8)
- Testicular swelling:
- testicular tumor
- orchitis
- testicular torsion - Peri-testicular swelling
- hydrocele
- varicocele
- large epididymal cyst
- inguinal hernia
- infectious epididymitis - Scrotal wall edema due to inflammation:
- testicular torsion
- torision of the appendix testis
- Epididymo-orchitis or orchitis
What are the 2 different types of Hydrocele
Communicating
- risk is development of indirect hernia
- allow for 18 mon for resolution before referral
Non-Communicating
- may be part of continuum of resolution of communication hydrocele
- may be reactive (infection, trauma, tumor)
- imbalance of scretion > absorption
- refer if large/bothersome
What is the role of US in Hydrocele (4)
Limited role
- to confirm scrotal testis (> 6 mons of age)
- to differentiate from inguinal hernia
- to rule out testis tumor (adolescent age)
- when associated with scrotal pain NYD
What is the DDX of a tender testes?
- Testicular torsion (this unless proven otherwise)
- Torsion of the appendix of the testes or appendix epididymis
- Infectious epididymitis/epididymo-orchitis: rare in prepubertial males, if afebrile screen with urine dip
When should surgical reduction of testicular torsion occur?
Ideally btw 4 - 6 hours of onset
-if suspect don’t do u/s just call surgery
What are the CPS Circumcision Highlights?
- the CPS statement does not recommend the routine circumcision of every newborn male
- Rate of Canadian newborn circumcision 32%
- Age 6 yrs: 50% of foreskins retract
- Age 17 yrs: 95% of foreskins retract
- increased risk of STI transmission and penile cancer does not justify recommendation of routine circumcision
- Topical steroids recommended for hastening retraction of foreskin and release of adhesions
- Meatal stenosis (seen following 2 - 10% of newborn circumcision can be prevented by applying petroleum jelly to the glans for up to 6 mons following circumcision
