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
Paraneoplastic syndromes associated with renal cell carcinoma
Cushing’s (ACTH)
Hypercalcaemia (PTH related peptide)
Polycythaemia (EPO)
Renal Cell Carcinoma - morphology
Clear cell: well defined yellow tumours often with haemorrhagic areas. May extend into perinephric fat or into renal vein
Papillary - more cystic more likely to multiple
Renal Cell Carcinoma - microscopy of clear cell
Clear cell has clear cells - duh.
Delicate vasculature
Small bland nuclei
Renal Cell Carcinoma - microscopy of non-clear cell
Papilarry tumours
Cuboidal, foamy cells
Surrounding fibrovascular cores often containing foamy macrophages or calcium
Urothelial cell carcinoma - features
95% of bladder tumours
Arising from specialised multilayers epithelium
Most common in bladder but may rise from renal pelvis to urethra
Urothelial cell carcinoma - risk factors
Age
Gender (M>F)
Carcinogens - smoking, arylamines, cyclophosphamide, radiotherapy
Urothelial cell carcinoma - presentation
Haematuria - most common
Urinary frequency
Pain on urination
Urinary tract obstruction
