Post-renal causes of kidney damage Flashcards Preview

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How is post-renal kidney damage caused?

By the obstruction of urinary flow anywhere along the route of urine


What route does urine take?

Collecting duct -> ureter -> bladder -> urethra


What happens once the passage of urine is obstructed?

Increased pressure behind the obstruction backing into the kidney causes hydronephrosis


What are the two types of obstruction that leads to post-renal kidney disease?

Unilateral obstruction - only one kidney is obstructed

Bilateral obstruction - both kidneys are obstructed


Why are unilateral obstructions normally asymptomatic?

Normal kidney replaces the function of the abnormal kidney

Overall kidney function might not obviously be impaired

Can cause significant injury if the other kidney is damaged or missing


What are causes of upper tract obstruction?

Obstructing stones - kidney stones, not all lead to kidney injury

Lesions on the urotherial wall - tumour

Extrinsic compression - more common

Developmental abnormalities - born


What are examples of extrinsic compression that leads to post-renal kidney injury?

Compressing lymph nodes - pelvic malignancy

Locally spreading cancer

Inflammatory masses

Post surgical or radiation fibrosis (inflammatory)


What is the most common cause of post-renal kidney injury in women?

Gynecological tumours


What are the most common causes of post-renal kidney injury in men?

Happen lower down in the urinary tract compared to women

Prostatic hyperplasia - ploriferation of cellular elements of the prostate


What are the symptoms of post-renal kidney injury?

Urinary retention

Renal insufficiency

Recurrent UTIs


How do you relieve obstruction of post-renal kidney injury?



Bladder catheter


How does a stent relieve post-renal kidney injury?

This is a flexible stent

Passed down the ureter through the bladder all the way up into the kidney

Allows urine to flow down


How does a nephrostomy relieve post-renal kidney injury?

Stent is directly placed into the kidney

Catheter perforates the skin and passes through the body wall and renal parenchyma

Catheter maintains passageway

Terminates in renal pelvis and passes into the collecting duct


How does a bladder catheter relieve post-renal kidney injury?

Tube is passed into the bladder

Urine passes through the flexible tube and collects in an urine bag

Balloon is inflated to prevent it from moving

Definitive procedures can then be pursued to remove obstruction