Diseases of urinary tract 2 Flashcards
What are the common causes of obstruction at the renal pelvis?
Calculi - renal stone
Tumour
Ureteropelvic stricture
What stones are large, difficult to remove and have to be broken down?
Staghorn
What are the main intrinsic causes of acute obstruction at the level of the ureter?
Calculi
Tumours
Slough (from inflammation)
Clots (usually road traffic accidents)
What type of obstructions are there?
Intrinsic
Extrinsic - from outside the ureter
What are the main extrinsic causes of obstruction at level of ureter?
Pregnancy
Tumours e.g. cervix
Retriponeal fibrosis
What is vesicoureteral reflux?
Usually occurs in young gilder (male, congenital)
Reflux of urine due to dysfunction; ureteral valves)
What is an important cause of obstruction in older males? (>60yrs)
Prostate - hyperplasia, carcinoma, prostatitis - constricts urethra
What happens if there is an obstruction at level of urethra?
Whole system gets dilated (children)
Name a functional cause of renal obstruction?
Neurological conditions e.g. spinal cord injury
What are the main sequelae of renal obstruction and renal stasis?
Stone/calculi formation
Urinary tract infection - cystitis, pyelonephritis
Kidney damage
What can obstruction at the urethral level cause? What it caused by?
Bladder hypertrophy (detrusor hypertrophy)
Due to prostatic hyperplasia
What is the main consequence of obstruction to the kidney? Whats it characterised by?
Hydronephrosis
- Cortical atrophy
- Dilated pelvis and calyces
What can acute complete obstruction cause to the kidney? How is it characterised?
Can reduce GFR and cause acute renal failure
Mild hydronephrosis mild dilatation of pelvis and calyces (not enough time for large dilation)
What can chronic intermitted obstruction cause to the kidney? How is it characterised?
Eventual (slow) cortical atrophy, reduced renal filtration and renal failure
What are the clinic features of complete acute obstruction?
- Acute renal failure
- Anuria
- Pain (VERY)
What are the clinical features of chronic unilateral obstruction?
- asymptomatic
- Eventual cortical atrophy and reduced renal function
What are the features of bilateral partial obstruction?
Polyuria and progressive scarring/reduced function
What is the pathogenesis for renl calculi?
Excess substances in URINE precipitating out e.g. calcium
Change in urine constituents causing substance precipitation e.g. pH
Poor urine output - supersaturation
- reduced citrate
What are the main types of renal stones that can occur?
Calcium (80%)
Struvite (15%) - infections (staghorn)
Urate (5%) - acidic urine
Cystine (1%)
What are the main causes of calcium stones?
- Hypercalcaemia due to bone disease, excessive PTH, sarcoidosis
- Excessive Ca absorption from intestine
- Inability to reabsorb tubular Ca
Idiopathic
Gout - allows Ca to accumulate!
Whats the pathogenesis of struvite stones?
Urease producing bacteria infection -> convert urea to ammonium -> increases urine pH -> precipitates Mg ammonium phosphate salts -> stag horn stones
What are the main cause of urate stones?
Gout -Hyperuricaemia
Idiopathic
What are the main cause of cystine stones?
Rare
Inability of kidneys to reabsorb AAs
What is the gold standard means of investigating for renal calculi?
Non-contrast CT scan
