Post-Renal Disease Flashcards
Post-Renal Disease:
- disease distal to the nephron
- intrarenal collecting system
- ureter
- bladder
- prostate
- urethra
- includes infection but for the
purposes of this lecture main cause
is obstruction - obstruction causes
hydronephrosis/hydroureter
(dilatation of collecting system or
ureter)
Pathophysiology of Acute Ureteric Obstruction: Overall:
- 3 phases
Pathophysiology of Acute Ureteric Obstruction: Phase 1:
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upto 90mins of obstruction
bowmans capsule pressure increases counteracting glomerular hydrostatic pressure reducing GFR
GFR increases due to counteraction
prostaglandins cause dilatation of the afferent arteriole
Pathophysiology of Acute Ureteric Obstruction: Phase 2:
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90mins-4hrs after obstruction
GFR decreased***
no further dilatation of the afferent arteriole
Pathophysiology of Acute Ureteric Obstruction: Phase 3:
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4hrs-18hrs after obstruction
GFR decreased
Glomeruli shut down
Pathophysiology of Chronic Obstruction: Effect:
after acute
- distal tubular function shuts down:
- reduced excretion of H+
(accumulation in circulation leading
to acidosis)
- reduced excretion of K+ leading to
hyperkalaemia
- difficulty concentrating urine
Pathophysiology of Chronic Ureteric Obstruction: events:
- dilatation of tubules results in
- interstitial fibrosis
- glomeruli relatively preserved
- damage to collecting ducts and
DCTs in medulla - obstructive atrophy
- nephron loss after 4-7 days
- little recoverable renal function after
1 month - urinary tract obstruction is an
emergency
Urinary Tract Obstruction Symptoms:
- colic, loin to groin
- flank pain
- UTI
- pain after drinking
- storage: frequency, urgency, noturia
- ***voiding: hesitancy, poor flow,
dribbling - visible haematuria: exclude cancer
- exercise induced haematuria
- chance finding
Post-Renal Disease: Investigations:
- FBC: anaemia
- renal function tests: U&E, creatinine,
generally normal because one
kidney will compensate - PSA
- urinalysis: blood, protein (more
renal), nitrites (infection)(empiric
antibiotics), glucose (diabetes) - urine culture
- ABG: acidosis, lactate
- USS, CT (KUB)
Contrast CT disadvantage
stones can be missed
Dynamic Renography:
- radioactive tag of MAG3***
- filtered and partly secreted
- area under curve calculated divided
by function - rate of washout identifies
obstruction
Emergency treatment of post renal acute obstruction
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Classification of post renal disease: obstruction:
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Urinary Tract Stones:
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Ureter Colic Pain/symptoms:
- severe pain
- intermittent colicky waves
- loin to groin
- blood in urine
- frequency
- nausea and vomiting
- restless
Urinary Tract Stone Treatment:
- extracorporla shockwave lithotripsy
(ESLW) - Staghorn Calculus: triple phosphate
- cystolithopalxy
- holmium laser stone fragmentation
Pelviureteric Junction Obstruction: Pathology:
- failure of peristalsis through PUJ
- chronic obstruction
- congenital vs acquired
Pelviureteric Junction Obstruction: Diagnosis:
- pain with high fluid intake or alcohol
- USS
- CT urogram
- MAG3 renogram
Pelviureteric Junction Obstruction: Treatment:
laparoscopic or robotic pyeloplasty
Transitional Cell Carcinoma of the Bladder
- obstructive or non-obstructive
- upper tract tumour
- tumour at the ureteric orifice in
bladder can cause obstruction
treatment: cystocopy and transurethral resection
Urinary Retention:
- BPH
-complications of bladder outflow
obstruction
Urinary Retention: Treatment:
- alpha blockers
- 5 Alpha Reductase Inhibitor
Prostate Carcinoma
- peripheral zone of prostate gland
- haematuria, LUTS, bone pain
Prostate Carcinoma Diagnosis:
- elevated serum prostate specific
antigen - DRE: asymmetry, nodule
- biopsy
Uretheral Strictures:
- scarring within the urethra
- rarely causes obstructive
nephropathy - Causes: congenital, post infection
Treatment: urethral dilatation, optical
urethrotomy, urethroplast
