5: Obstruction & Urolithiasis/ Disorders of the Prostate Flashcards
what are the 3 classes of prostatitis
acute
chronic
chronic non-bacterial
what are the main causative pathogens of acute prostatitis
E.coli
proteus and staph species
STI pathogens: C.trachomatis and N.gonorrhoea
- inflammation can be focal or diffuse
how does a patient with acute prostatitis present
general symptoms: malaise, rigor, fever
local symptoms: difficulty passing urine, dysuria and perineal tenderness
what does a rectal examination of acute prostatitis reveal
soft, tender, enlarged prostate
how does chronic prostatitis arise
- inadequately treated infection
- can occur because some antibodies cannot penetrate prostate effectively
- often a history of recurrent prostatic and urinary tract infections
- same causative organisms as acute
how is diagnosis of chronic prostatitis confirmed
- Histological examination showing neutrophils, plasma cells and lymphocytes
- A positive culture from a sample of prostatic secretion
what is the most common type of prostatitis
chronic non-bacterial
- results in enlargement of the prostate
what is the usual causative organism of chronic non-bacterial prostatitis
C. trachomatis
- typically sexually active men
what does histological examination of chronic non-bacterial prostatitis
fibrosis as result of chronic inflammation
describe BPH
- detectable in nearly all men over the age of 60
- non-neoplastic enlargement of the prostate gland can eventually lead to bladder outflow obstruction
- cause is unknwon but may be related to levels of male sex hormones (testosterone)
why do symptoms develop in BPH
enlarging prostate gland compresses on the prostatic urethra
what symptoms do pt w BPH exhibit
obstructive lower urinary tract symptoms
- difficulty or hesitancy in starting to urinate
- a poor stream
- dribbling postmicturition
- frequency and nocturia
what would DRE of pt w BPH show
firm, smooth and rubbery prostate
what can untreated BPH present with
- acute urinary retention which is accompanied by distended and tender bladder and desparate urge to pass urine
- alternatively the pt may have progressive bladder distention –> chronic painless retention
- can lead to bilateral upper tract obstruction and renal impairment, w the pt presenting w CKD
describe the medical and surgical treatment of BPH
medical
- a-blockers: relax smooth muscle at bladder neck and within prostate
- finasteride (5a reductase inhibitor): presents the conversion of testosterone to the more potent androgen dihydrotestosterone
surgical
- transurethral resection of the prostate (TURP)
describe urinary tract obstructions
- can occur at any level
- can be unilateral or bilateral, complete or incomplete and of gradual or acute onset
what do urinary tract obstructions increase the risk of
UTI, reflux and stone formation
what are causes of urinary retention
- calculi
- pregnancy: high levels of progesterone relax muscle fibres in renal pelvis and ureters = dysfunctional obstruction
- BPH
- recent surgery
- drugs
- urethral strictures
- pelviureteric junction obstruction
- pelvic masses
- constipation
- inflammation
- tumour
- neurogenic disorders
what do neurogenic disorders result from (3)
- congenital abnormalities affecting spinal cord
- external pressure on the cord or lumbar nerve roots
- trauma to the spinal cord e.g. cauda equina syndrome
differentiate between acute and chronic urinary retention
acute
- painful inability to void
- Residual volume 300 -1500ml
- hot, sweaty
- pain relieved by drainage
- no upper tract insult (hydronephrosis)
chronic
- Painless
- May still be voiding
- Residual volume 300 –4000ml
- larger clothes
- may have obstructive uropathy
what is involved in the management of acute urinary retention
- catheterise and record any residual volume
- history taking e.g. last void, complete sensation of void or some left, pain, fluid intake, stream (splitting, dribbling, symptoms of urge incontinence)
- exam (abdo - may be able to palpate bladder if distended, external genitalia, DRE)
- urine dip
- U&Es
- treat any obvious causes e.g. constipation
- BPH: alpha blocker, may trial w/out catheter after 1-2 weeks
describe the management of chronic urinary retention
- Catheterise and record residual volume
- History
- Exam
- Urine dip, U&Es
- plan for long term catheterisation or intermittent self-catheterisation - would not attemp TWOC
distinguish high vs low pressure chronic urinary retention
High pressure:
* Abnormal U&Es due to kidney dysfunction, unable to clear K+, hydronephrosis
* Repeat episodes can cause permeant renal scaring and CKD
Low pressure:
- Normal renal function
- No hydronephrosis
what is post obstructive diuresis and what can it lead to
- following resolution of urinary retention kidney can over-diurese and large amounts of water are lost from the body
- gradient is lost to concentrate urine due to urine previously backing up into the kidney and ureter so can’t reabsorb as much water (massive loss of electrolytes)
- can lead to worsening AKI (pre renal)
what is the management plan of post-obstructive diuresis
- urine output should be monitored for 24hrs post catheterisation
- pt w high urine volumes should be supported w IV
- monitor Cr, eGFR
- check lying standing BP, daily weight
- do not give back residual volume
what is hydronephrosis
dilation of the renal pelvis and calyces due to obstruction at any point along the urinary tract causing increased pressure and blockage
- post renal cause of AKI
what are the 2 forms of hydronephrosis
- Unilateral – caused by an upper urinary tract obstruction
- Bilateral – caused by obstruction in the lower urinary tract e.g. englarged prostate
what happens in hydronephrosis
- reflux of urine back up into kidney
- progressive atrophy of the kidney develops, back pressure from obstruction is transmitted to the distal parts of the nephron
- GFR declines and if the obstruction is bilateral, pt goes into renal failure
why does GFR decline in hydronephrosis
so much fluid in bowmans capsule so pressure is larger than pressure in capillaries - filter doesnt filter out
what are the different levels at which hydronephrosis can occur
- Obstruction at the pelviureteric junction = hydronephrosis
- Obstruction at the ureter = hydroureter, eventually developing hydronephrosis
- Obstruction of the bladder neck/urethra = bladder distension with hypertrophy, eventually leading to hydroureter and thus hydronephrosis
what type of pain can acute ureteric obstruction result in
renal colic (pain radiating from site of obstruction loin to groin pain)
what is acute ureteric obstruction usually caused by
calculus but can be due to blood clots or sloughed papilla
- usually but not always a unilateral problem
what does acute ureteric obstruction lead to if bilateral
acute renal failure
- presents as anuria or oliguria
what can develop as a result of acute ureteric obstruction
pyonephrosis - infected, obstructed system
what is pyonephrosis
- infected, obstructed kidney
- urological emergency!!
- pus in renal pyramids
what can failure of decompression in pyonephritis result in
death from sepsis and permanent loss of renal function
how can an upper urinary tract obstruction be diagnosed
- CT or USS to show structure not function
- diuretic renograpgy (MAG3) is a functional test
- give radioactive tracer, give furosemide at around 20 mins to eliminate tracer from body
how can the upper urinary tract be drained
-
nephrostomy: thin tube inserted into renal pelvis which drains urine into bag (prevents hydronephrosis)
- in interventional radiology under LA by radiologist -
JJ stent: coiled at both ends, passed up urethra
- done in theatre under GA by urologist
what is urolithiasis
urinary calculi
where are the most common sites for urinary calculi (3)
pelviureteric junction
pelvic brim
vesicoureteric junction
what is a predisposing factor of urolithiasis
dehydration as it inc conc of urine
- high recurrence rate
who does urolithasis affect
10% of the population
- more common in men and Caucasian
what is the gold standard for diagnosing urolithiasis
CT of kidneys, ureters and bladder (non contrast)
what are the 5 types of urinary calculi
- Calcium oxalate stones (75%) –most common. Associated with hypercalcemia and primary hyperparathyroidism and hyperoxaluria
- Mixed calcium phosphate and calcium oxalate stones –associated with alkaline urine
- Magnesium ammonium phosphate stones –associated with urea splitting bacteria
- Uric acid stones –associated with gout and myeloproliferative disorders
- Cystine stones –patients with inherited cystinuria
- Indinavir stones - HIV, invisible on CT
what does the clinical presentation of urolithiasis depend on
the site of the stone
what kind of pain would a pt w a renal stone present with
continuous dull ache in the loin
how would a pt with ureteric stones present
- classic renal colic due to inc in peristalsis in the ureters in response to passage of small stone
- typically radiates from loin to groin
- pt appears sweaty, pale and restless w nausea and vomiting
what can bladder stones cause
strangury - urge to pass something that will not pass
what 3 things can most urinary calculi cause
- recurrent and unstable UTIs
- hematuria
- renal failure
(may be asymptomatic)
what does management of urolithiasis involve
- Management involves adequate analgesia and a high fluid intake
- Urine should be sieved for analysis
- Stones of 4-5mm or less usually pass spontaneously
- Larger stones might require surgical intervention
- Prevention of further stone formation is achieved with a high fluid intake and correction of any underlying metabolic abnormality
- thiazide: blocks transporter in DCT, favours reabsorption of Ca2+
what interventional treatment is available for urolithiasis
- Consider intervention for larger stones (>7mm) or those causing obstruction, intractable pain, or infection
- Extracorporeal Shock Wave Lithotripsy (ESWL)
- Ureteroscopy
- Percutaneous Nephrolithotomy (PCNL)
describe Extracorporeal Shock Wave Lithotripsy (ESWL)
- suitable for smaller stones, typically less than 2cm in size
- a non-invasive procedure that employs shock waves to break down stones into smaller fragments, making them easier to pass or manage
describe ureteroscopy
- suitable for stones within the ureter or smaller stones in the kidney
- involves the use of a thin, flexible instrument to visualize and access stones, making it possible to remove or fragment them.
describe Percutaneous Nephrolithotomy (PCNL)
- reserved for larger stones, typically those larger than 2cm within the kidney
- a more invasive approach, requiring a small incision to access and remove or break down the stones
what is a staghorn calculus
type of kidney stone that can block the renal pelvis and the calcyes
how does renal colic typically present
- sudden, severe flank pain radiating to groin/scrotum
- constant or colicky
- rolling around
- O/E: temp, unremarkable abdo exam
what are ddx for renal colic
- ruptured AAA (pt >60!)
- pancreatitis
- biliary colic
- appendicitis
- gynae pathology in women e.g. ovarian cysts
what investigations are indicated in renal colic
- urine dip + pregnancy test in women
- FBC, U&Es, calcium
- CT KUB
what is the acute management of renal colic
- NSAIDs: often diclofenac PR
- opiates prn e.g. morphine
- monitor pain and watch closely for signs of sepsis/pyrexia
- initial severe pain improves due to reduced urine output from affected kidney and pyelo-venous and pyelo-lymphatic shunting
what is the importance of features of sepsis in a patient with confirmed or suspected renal colic
fever or signs of sepsis + obstructed kidney is a urological emergency
- irreversible loss of renal function
- worsening sepsis
- multi-organ failure and death
what is the management of stone formers
- check serum calcium: if it is high v likely to have hyperparathyroidism so check PTH (may need parathyroidectomy)
- advise 2-3l water/day
- avoid excessive salt/red meat
- citrate beneficial
- maintain normal calcium intake
what are causes of post obstructive diuresis
- fluid overload
- osmotic diuresis
- polyuric phase of ATN
- iatrogenic e.g. unnecessary IV fluids
