the kidney and urinary tract: what are they and how can they go wrong? Flashcards
what is the cortex full of?
glomeruli and PCT
how many glomeruli in normotesnives?
1-2 million per kidney
how many glomeruli per kidney in people with essential hypertension?
0.5-1 million per kidney
why do most people with kidney disease have arterial hypertension?
kidney failure — can’t excrete salt and water — retained in body in circulation system — increases BP
what is a good way to treat hypertension in kidney failure?
remove excess salt and water — dialysis, diuretics (eg. furosemide)
why do you get oedema in kidney disease?
excess salt and water build up and kidney leaks a lot of protein and oncotic pressure falls —> high BP and excess salt and water leak into interstitial space causing oedema
what do the kidneys have a vital role in excreting?
K+
how does hyperkalaemia present on ECG?
peaked T waves
how can hyperkalaemia be treated?
dialysis, or injection of insulin intravenously with glucose
what does the urinary bladder do?
low pressure reservoir which intermittently and completely expels urine per urethra
what is the bladder made of?
smooth muscle bundles under autonomic nervous control
what is the urothelium surface covered in?
hexagonal plats made of uroplakin
what is the function of uroplakin?
makes the urothelium water tight and prevents water and all the excretory products (like urea) from diffusing back into the body
what do parasympathetic nerves release?
ACh
what nerves make the bladder contract, detrusor muscle contract and make rhe bladder void?
parasympathetic nerves
what effect does the adrenergic system have on the bladder?
makes it relax
what happens when the wave of smooth muscle contraction from the top to the bottom of the ureter doesnt work?
build up of urine at the top of ureter — hydronephrosis
what are the key clinical symptoms and signs of disease of the lower renal tract?
- dysuria
- frequency of micturition
- incontinence of urine
- poor urinary stream
- haematuria
- pain (caused by acute bladder outflow obstruction, renal colic, urosepsis etc)
what dont you get a lot of in LOWER urinary tract disease?
proteinuria
proteinuria + haematuria = ?
glomerular kidney disease
primary disease of the lower tract can cause what?
secondary kidney failure mediated by impairment of urine flow
what are they 2 ways of classifying kidney and urinary tract diseases?
CONGENITAL malformations
ACQUIRED — tumorus and non-tumours
genetic and environmental causes
what are the 3 main histological varieties of kidney malformations?
- hypoplasia (too few nephrons)
- dysplasia (undifferentiated kidney sometimes with cysts)
- agenesis (absent kidney)
what are the most common mutations in malformed kidneys?
HNF1B mutations
what is prune belly syndrome?
- aka. Eagle-barrett syndrome
- rare genetic birth defect
- about 97% if those affected are male
- triad of symptoms : partial or complete absence of the stomach (abdominal) muscles, failure of both testes to descend into the scrotum (bilateral cryptorchidism), and/or urinary tract malformations.
babies have massively large bladders
descirbe one of the mutations in prune belly syndrome
mutation in myocardin = necessary for formation of smooth muscle —> mutated means smooth muscle in bladder not working properly so can’t empty bladder
what are ‘pre-renal’ causes of acquired kidney failure?
cant make urine
- shock eg. massive blood loss, septicaemia
- cardiac and liver failure — poor kidney perfusion
what is instinsic kidney disease?
= disease of the kidney itself
- glomerular disease (eg. Alpert syndrome, diabetes mellitus and immune-mediated glomerulonephritis)
- tubular disease (eg. pyelonephritis, autosomal dominant polycystic disease, nephrotoxins)
what are ‘post-renal’ causes of acquired kidney disease?
- urinary flow impairment eg. stones tumours and dysfunctional bladders); need to block BOTH kidneys
what is anti-glomerular basement membrane nephritis?
acquired antibodies that attack glomerular basement membrane
what is glomerular filtration rate in early diabetes mellitus?
actually INCREASED
what happens to glomerular disease in diabetes mellitus without treatment?
there is a progressive decline in renal function with sclerosis of glomeruli
tubular vs glomerular epithelia?
tubular epithelia have the capacity to regenerate, glomerular dont
what does infectious pyelonephritis cause?
tubular disease
describe autosomal dominant polycystic kidney disease (ADPKD)
- ADPKD affects 1/1000 people
- UK Renal Registry: Polycystic kidney disease is the cause of 9% end-stage renal failure in adults
- kidney tubules initially form normally, but as young et older they dilate and squash the useful nephrons in between them —> kidney failure around 40 years old
how is PKD treated?
tolvaptan = vasopressin receptor antagonist — slows down the progression of cyst growth
what kind of kidney stones don’t show up on plain x rays?
uric acid stones
what is the Wilms tumour?
kidney cancer in children
what is the name of the common kidney tumour in adults?
clear cell carcinoma — arises in the proximal tubule
what is the commonest bladder cacner?
transitional cell carcinoma
where does prostate cancer like to metastasise to? describe
- bone
- unlike many other cancers, the bone metastases of prostate cancer are sclerotic - dense areas (vs lytic - make holes in bone)
what feeling of prostate is suggestive of cancer in DRE?
bumpy and hard
kidney failure does not cause one of these signs/symptoms?
A - difficulty breathing
B - high BP
C - jaundice
D - leg swelling
E - sudden death from hyperkalaemia
jaundice
which of these suggests a glomerular cause of kidney disease?
A - bacteria grown from the urine
B - enlarged prostate on palpation
C - family history of kidney disease
D - RBCs and protein in urine
E - renal colic
D - rbcs and protein in urine
