Week 4: Obstruction of the Urinary Tract Flashcards
Normal urinary function
- bladder filling and voiding both occurs under low pressure
- parasympathetic increases bladder contraction and sympathetic decreases (open sphincter)
- this is disturbed when there is obstruction
Division of upper and lower urinary tract.
Bladder and below is Lower
Ureter to kidney is upper
Most common causes of obstruction organized by sites.
- Calyces
- infection TB, trauma, stones, tumors - ureteropelvic junction
- congenital, stones, trauma, extrinsic compression - Ureter
- stones, strictures, trauma, tumor, extrinsic compression - Bladder neck/proximal urethra
- prostatic enlargement!!!
- trauma, bladder neck contractures, prior surgery - Urethra
- most common: strictures
- trauma, prior instrumentation, posterior urethral valves (children-due to embryonic remnant that never dissolves)
Clinical presentation of upper urinary tract obstruction
ACUTE
-renal colic: waves of intense pain, from abdomen, flank, can be in groin
CHRONIC
-recurrent UTIs: stasis of urine–>growth of bacteria
-dull pain, ache, pressure
Clinical presentation of lower urinary tract obstruction
CHRONIC bladder outlet obstruction -bladder hypertrophy -detrusor dysfunction-SM in wall of bladder IRRITATIVE symptoms -urgency -frequency -dysuria -urge incontinence -nocturia OBSTRUCTIVE symptoms -decreased force of stream -dribbling -hesitancy -intermittency -incomplete emptying MAY see renal insufficient in acute or chronic obstruction
Renal changes from obstruction
PHYSIOLOGIC
-altered renal blood flow, changes in GFR, loss of concentrating ability within collecting duct
PHYSICAL/MICRO
-dilation of renal tubules, initial CD then extending proximally
-fibrosis
-apoptosis
-macrophage infiltrate
-hemorrhage, necrosis
-glomeruli is last thing to be affected, only affected with long standing obstruction
Changes that can be detected radiographically from obstruction.
- bladder trabeculation-obstruction below bladder causes hypertrophy that causes scalloped look
- diverticuli (outpouching)
- calculi -due to stasis
- J hooking of ureter: from enlarged prostate pushing upwards
- hydronephrosis
- thinned parenchyma
Describe changes that take place with hydronephrosis
- dilation of renal pelvis and calyces due to outflow tract obstruction
- gross: enlargement of kidneys with blunting of apices of pyramids. Thinning of medulla and cortex
- micro: early dilation of tubules, then tubular compression and atrophy, interstitial fibrosis, glomeruli relatively spared initially
Summarize effects of obstruction of urethra, grossly.
- bladder dilation and hypertrophy
- hydroureter -dilated ureter
- hydronephrosis -dilated renal pelvis and calyces
- bilateral since below bladder
Diagnostic tools for upper urinary tract obstruction.
- based on symptoms and imaging
- renal ultrasound
- CT scan/MRI
- IVP: contrast given and series of x rays at various stages of excretion of the contrast
- diuretic renogram: radioactive isotope given, monitors radioactivity to see how long it takes to leave the urinary tract
- renal resistive index: doppler and blood flow, used mainly in transplants
- whitaker test: old school, using nephrostomy and bladder catheter, infuse saline and measure pressure difference
Benign prostatic hyperplasia (BPH): definition and pathophysiology
- hyperplasia of stroma and epithelium. most common cause of urinary tract obstruction in men.
- beings in 5-6th decade
- little known of pathophysiology
Pathology of BPH
- diffusely nodular surface
- tends to affect medial lobe
- leads to compression of urethra
- associated with tubuloalveolar glands that are either dilated or with infolding of epithelium (serrated edges)
- normally, the glands have 2 layers of cells
Signs and symptoms of BPH
- symptoms: obstructive and irritative symptoms
- signs: bladder hypertrophy, trabeculation of smooth muscle
Describe prostatitis.
ACUTE -primary cause: infection -periglandular-intraglandular infiltrate -predominantly PMNs CHRONIC -largely interstitial infiltrate -mononuclear leukocytes -most cases independent of chronic infection
Complications of benign prostatic hyperplasia
- retention
- infection
- bladder decompensation (areflexic-can’t contract anymore)
- calculi
- hematuria
- hydronephrosis
- renal failure
