Urology: Urinary Tract Infections Flashcards
how can you divide sites of obstruction?
lower and upper urinary tract
what does an obstruction in the lower urinary tract cause?
urinary retention
what does an obstruction in the upper urinary tract cause?
hydronephrosis
requirements of bladder filling and urine storage
- accommodation of increasing volumes of urine
- low detrusor pressure
- appropriate sensation
- bladder outlet closed at rest and remains that way at higher intra-abdominal pressures
- absence of involuntary bladder contractions
requirments of bladder emptying and voiding
- coordinated contraction of the bladder
- smooth musculature of adequate magnitude and duration
- concomitant lowering of resistance at the level of the smooth and striated sphincter
- absence of anatomical obstruction
what are anatomical problems which can cause problems at the outflow tract
- prostatic obstruction
- bladder neck contracture
- urethral stricture
- urethral compression, fibrosis
causes of lower urinary tract obstruction in men
- BPH
- urethral strictures
- prostatic CA/abscesses
- stones
- bladder tumours/cloth retention
causes of lower urinary tract obstruction in women
- pelvic prolapse
- pelvic masses
- urethral stricture
- urethral diverticulum
- Fowler’s syndrome
what is Fowler’s Syndrome?
urinary retention associated with dysfunctional electromyographic activity in the absence of neurological problems; associated with polycystic ovary syndrome
cause of lower urinary tract obstruction found in both sexes
functional obstruction - when the sphincter fails to relax
what happens if urinary retention is left untreated?
can lead to kidney damage or urosepsis
characteristics of acute urinary retention
- suprapubic pain
- sudden inability to void
causes of AUR
- bladder neck obstruction
- urethral causes
- gynaecological causes
- neurological causes
- drugs
- psychogenic
- post-operative urinary retention
- anorectal causes
causes of bladder neck obstruction
- BPH, prostate CA, acute prostatitis, prostatic abscess
- bladder tumour, clot obstruction, bladder stones, bladder neck sclerosis
urethral causes of AUR
- urethral stricture
- urethral tumours
- urethral stones
neurological causes of AUR
- spinal cord lesions in acute phase
- metastatic spinal cord compression
- demyelinating spinal cord diseases
- peripheral neuropathies
pharmacological causes of AUR
- a-adrenergics
- B-blockers
- anticholinergic
- antidepressants and neuroleptics
- opioids
anorectal causes of AUR
- fecal impaction
- rectal tumour
- pain from anorectal surgery
- perirectal abscess
gynaecological causes of AUR
- ovarian or uterine tumours
- high-degree pelvic organ prolapses
- post-partum urine retention
what is a AUR of unknown cause called?
spontaneous
triggered (if the underlying cause is identified)
management of AUR
- history and physical examination (incl DRE)
- bladder catheterisation
- check bloods (creatinine and electrolyte) and urine (urinalysis and culture)
- alpha blocker and attempting TWOC after a variable period of bladder rest
when should consider admitting the patient
- gross haematuria
- urosepsis
- acute renal injury
- drained urine volume >1L
- significant post-obstructive polyuria
- unusual symptoms (severe abdominal pain, neurological)
- inability to manage with an indwelling catheter
what is TWOC?
trial without catheter
risk for TWOC failure?
- older than 70yo
- prostate size larger than 50g
- severe LUTS
- drained volume at catheterisation >1L
- spontaneous AUR vs precipitated
signs and symptoms of chronic urinary retention
- painless urinary retention
- voiding LUTS
- suprapubic discomfort
- recurrent UTIs
- rarely pure storage symptoms
- renal failure
- overflow incontinence
2 main types of CUR
high-pressure and low-pressure
what is high-pressure CUR
obstruction with the presence of detrusor muscle activity
what is low-pressure CUR
detrusor failure with low intravesical pressure
signs of high-pressure CUR
- new-onset hydronephrosis
- high creatinine over baseline
what does high pressure in the detrusor mean?
upper urinary tract damage - AKI/CKD
what is post-obstructive diuresis?
polyuric state after the relief of a urinary tract obstruction, despite reaching homeostasis
risk factors for post obstructive diuresis
- bladder outflow obstruction
- bilateral ureteric obstruction
- unilateral ureteric obstruction in a solitary kidney
what happens if POD is left untreated?
- severe dehydration
- hyponatremia
- shock
- central pontine myelosis
- electrolyte imbalances
- death
how can you diagnose POD?
- urine output after catheterisation
- exceeds 200ml/hr for 2 consecutive hours
- > 3L/1 day
what is the difference between physiological and pathological POD?
- physiological: stops after 24hrs
- pathological: last longer than 48hrs; made worse with excessive IV fluid replacement
main causes of upper urinary tract obstruction
- renal causes
- ureteric causes
- lower urinary tract problems
what are the main things that can cause UUTO?
- congenital
- neoplastic
- inflammatory
- metabolic
- miscellaneous
what are the miscellaneous causes of UUTO?
- sloughed papillae
- trauma
- renal artery aneurysm
- retroperitoneal fibrosis
- aortic aneurysm
- radiation therapy
- pregnancy
how can things from the LUT cause UUTO?
these problems put back pressure into the UUT
what two things are involved in the pathophysiology of UUO
ureteric pressure and renal blood flow
what are the phases of unilateral ureter obstruction
Phase 1 (up to 1.5h post obstruction): ↑ureteric pressure, ↑RBF rises (afferent arteriole dilatation). Phase 2 (from 1.5 to 5h post obstruction): ureteric pressure continues ↑, RBF (efferent arteriole vasoconstriction). Phase 3 (beyond 5h): ureteric pressure falls, RBF continues to fall (afferent arteriole vasoconstriction).
what are the phases of bilateral ureter obstruction?
Acute BUO or obst. of solitary kidney Phase 1 (up to 1.5hr): ureteric pressure rises, RBF rises (afferent arteriole dilatation). Phase 2 (from 1.5-5hr): ureteric pressure continues to rise, RBF is significantly lower than that during unilateral ureteric obstruction. Phase 3 (>5h): ureteric pressure remains elevated (in contrast to UUO). By 24 hours RBF has declined to the same level for both unilateral and bilateral ureteric obstruction.
how do electrolyte balances change in UUO
- dec urine flow
- inc Na absorption
- dec Na excretion
- dec water loss from obstructed kidney
how are electrolyte reabsorption/elimination affected by BUO
- marked natriuresis due to the excessive amount of Na retained
- inc K retention
- solute diuresis from the accumulation of urea in extracellular fluid
- all due to inc release of natriuretic peptides
pathological changes in urinary obstruction
- tubulointerstitial fibrosis
- inflammatory cell infiltration
- apoptotic renal tubular cell death
- kidney function loss
clinical pressure of AUR
- flank pain on diuresis
- radiates to the ipsilateral testicle/labia and lower abdomen
clinical presentation on CUR
- painless/asymptomatic
- obstruction of the bladder outlet
- anuria
- new-onset HTN
- renal failure
- recurrent UTIs
how can you diagnose these conditions
- imaging
investigations for urinary obstruction
- urinalysis
- assessment of renal function
- US
- CTKUB
- CTIVP
- DTPA
- MR Urography
- antegrade and retrograde pyelography
what is the Whitaker’s test
an image-guided procedure which measures the pressure in the kidney or bladder to determine whether there is the presence of obstruction
what is hydronephrosis?
- dilatation of renal pelvis and calyces
what can cause a false positive result for hydronephrosis
- extrarenal pelvis
- parapelvic cysts
- vesicoureteric reflux
- high urine flow
what can cause a false negative result for hydronephrosis
- intrarenal collecting system
- dehydration
- dilated calyces mistaken for renal cortical cysts
what are simple kidney cysts?
- clear fluid filled masses
- increasing incidence with age
- can present with dull pain, acute pain due to intra-cyst bleeding, infection, obstruction
what are complex cysts?
- ones that contain blood, pus or are calcified
- have septation, irregular margins
- malignant potential
- appear on US and CT with contrast
how can you classify kidney cysts lesion?
Bosniak classification
what are medullary sponge kidney
- dilatation of distal collecting ducts
- mainly asymptomatic, symptoms of renal colic and pyelonephritis
- normal renal function
what re calycael diverticula?
outpouching from the pelvo-calceal system
- stasis and stone formation in the diverticulum
what is Autosomal dominant polycystic kidney disease?
- autosomal dominant
- multiple expanding renal parenchymal cysts
associated disorders to ADPKD
- circle of willis berry aneurysms
- cysts of liver, pancreas and spleen
- renal adenomas but no risk of malignancy
- cardiac valve abnormalities; aortic aneurysms
- diverticular disease
clinical presentations of ADPKD
- abdominal masses
- flank pain
- macroscopic haematuria
- UTI
- hypertension
- positive family history
- renal failure
what is acquired renal cystic disease?
- cystic degenerative disease of the kidney
- associated with CRF and ESRF
clinical manifestations of ARCD
- pain
- haematuria
which 2 syndromes predispose to malignancy?
- Von Hippel-Lindau syndrome
- Tuberous sclerosis
