32 - Renal system 2 Flashcards
Causes of urinary tract obstruction - pelvis
Calculi
Tumours
Ureteropelvic stricture
Causes of urinary tract obstruction - ureter-intrinsic
Calculi Tumours Clots Sloughed papilae Inflammation
Causes of urinary tract obstruction - ureter-extrinsic
Pregnancy
Tumours
Retroperitoneal fibrosis
Causes of urinary tract obstruction - prostate
Hyperplasia
Carcinoma
Prostatitis
Functional obstruction of urinary tract
Neurological conditions
Severe reflux
Sequelae
Infection - cystitis, ascending pyelonephritis
Stone/calculi formation
Kidney damage - acute or chronic
Consequences of urinary tract obstruction dependent on…
Site
Degree of obstruction
Duration
Urinary tract obstruction - clinical presentation
Acute bilateral obstruction -> pain, acute renal failure & anuria
Chronic unilateral obstruction -> asymptomatic, but will go to cause corticol atrophy and reduced renal function
Bilateral partial obstruction -> initially polyuric with progressive renal scarring and impairment
Renal calculi/urolithiasis- epidemiology
7-10% of population + increasing
Male
Peak onset 20-30
Renal calculi/urolithiasis - pathogenesis
Either due to excess of precipitating substances e.g. Ca
Or change in urine constituents (pH)
Poor urine output - supersaturation
Decreased citrate levels
Renal calculi/urolithiasis - classification of stones
Calcium (70%) - calcium oxalate Struvite stones (15%) - magnesium ammonium phosphate Urate stones (5%) - uric acid Cystine stones (1%)
Calcium stones - cause
Hypercalciuria due to: hypercalcaemia, excessive absorption of intestinal Ca2+, inability to reabsorb tubular Ca2+, idiopathic
Other risk factors = gout, hyperoxaluria
Causes of hypercalcaemia
Bone disease
PTH excess
Sarcoidosis
Process of struvite stone formation
- Urease producing bacterial infection
- Urease converts urea to ammonia
- Causes a rise in urine pH
- Precipitation of MgNH4 phosphate salts
- Large ‘staghorn’ calculi
THERE IS A PICTURE OF A STAG
Urate stones
Hyperuricaemia
Gout
Or patients with a high cell turnover e.g. leukaemia
Idiopathic
Cystine stones
Rare
Occur in the presence of an inability of kidneys to reabsorb amino acids
Renal calculi - investigations
Non-contrast CT scanning (gold standard) 95% sensitive
US in pregnancy or where CT not possible (30-67% sensitive)
IV urography (70% sensitive) for stones
Sequelae definition
Secondary condition so caused by another
Sequelae for renal
Obstruction
Haematuria
Infection
Squamous metaplasia +/- squamous cell carcinoma
Renal cell carcinoma
3% of cancers
Vast majority of renal carcinomas are clear cell
In older people M>F
Risk factors for renal disease
Tobacco Obesity Hypertension Oestrogens Acquired cystic kidney disease Asbestos exposure
Von Hippel-Lindau Syndrome - features
Most common of severe cancer syndromes
VHL gene required for breakdown of hypoxia inducible factor-1 (HIF-1) oncogene
Loss of gene function causes cell growth and increased cell survival
Tumours in kidneys, blood vessels and pancreas
Von Hippel-Lindau Syndrome - clinical presentation
Local symptoms - haematuria, palpable abdo mass, costovertebral pain
Incidental
Late presentation: systemic symptoms or mets
Paraneoplastic syndromes
Paraneoplastic syndrome - what is it?
Clinical syndrome caused by tumours
Not related to the tissue that the tumours arose from
Not related to invasion by the tumour of itself or mets
