Renal system Flashcards
where are the location of the kidneys?
located in retroperitoneum (behind peritoneum)- correspond to vertebrae T12-L3- right kidney slightly lower (due to liver)
how does the psoa major muscle affect kidneys?
20 degree tilt of kidney to vertical (upper pole is closer to midline) & 30 degree rotation of kidneys (medial surface more anterior than lateral border)- upper poles are more posterior than lower poles
how far does do kidneys move with respiration?
up to 1 cm- images are usually expiratory in supine patient
how is the kidney protected?
renal fascia attaches kidney to abdominal wall (fused to peritoneum)- layer of adipose tissue within abdominal cavity (provides enough contrast to make outline visivle on plain radiograph)- fibrous capsule adheres to renal tissue- damage to kidneys could lead to haemorage
what is renal hilus entry/exit point for?
renal artery, renal vein, ureter
what are the divsions of the kidney?
outer cortex & inner medulla
what does the cortex project into medulla as?
projects into medulla as columns
what do the columns divide medulla into?
pyramids
what does each pyramid empty into?
minor calyx
what do minor calyces empty into?
major calyces
what do calyces converge to form?
renal pelvis
where does the renal pelvis drain in to?
ureter
what is a lobe made up of?
pyramid, overlying cortex, surrounding column
what is the blood supply of kidneys?
renal arteries originating from aorta- number 1 job is to filter the blood
what does the renal artery divide in to?
segmental artery to interlobar arteries move out through coluums to cortex to arcuate arteries and run along border between cortex & medulla to interlobular arteries to supply cortex via afferent arterioles
what do afferent arterioles supply?
glomerular capillaries (place where blood is filtered & urine production occur)
what do efferent arterioles drain?
glomerular capillaries
what are the phases of renal enhancement?
corticomedullary phase, nephrographic phase, excretory phase
what is the volume & rate of contrast medium in kidneys?
volume is 150mL & rate is 2-3mL/sec
what is the corticomedullary phase?
occurs 24 to 80 secs after start of injection, will be delayed with renal dysfunction, blood is in cortical capillaries so cortex is enhanced & contrasts with medulla
what is the nephrographic phase?
begins 85 to 120 secs after injection- fluid in tubule system carries contrast medium (cortex & medulla appear similar)- also delayed in renal dysfunction
what is the excretory phase?
begins 3 to 5 mins after injection- fluid containing contrast medium has reached calyces- may indicate mass/renal tumour or cysts if it doesn;t have contrast
what are the ureters?
continuos with renal pelvis, vary in diameter from 1mm-1cm- urine conveyed from kidneys to urinary bladder by peristaltic contractions of ureters
what is the course of ureters?
course along psoas major, pass over common iliac vessels, enter bladder dorsolaterally
what are 3 constriction points of the ureters?
ureteropelvic junction, brim of pelvis, uterreovesicular junction
where is urinary bladder located in females?
anterior to uterus & vagina, posterior to pubic symphysis
where is urinary bladder in males?
anterior to rectum, posterior to pubic symphysis
what is urinary bladder made up with & lined with?
detrussor muscle (Smooth muscle) & lined by transitional epithelium with rugae
what the 3 openings of bladder?
2 for ureters & 1 for urethra- form the trigone
how many pelvic fractures result in ruptured bladder?
occurs in 10% of pelvic fractures- can show via contrast injected in to the bladder and if it leaks out it oculd indicate a rupture- urine can be contained by the peritoneum- US would be better to view free fluid in abdomen
what does the urethra run between?
urinary bladder & external urethral orifice
what occurs to detrussor muscle during fillind of bladder?
detrussor must relax to fill while urethral sphincter remain closed
what is the role of internal & external urethral sphincters?
internal sphincter (smooth muscle- involuntary control)- external sphincter (skeletal muscle- voluntary control- made up of muscles of pelvic floor)
what is the role of female urethra?
conveys urone only- opens anterior to vaginal orifice
what is the role of male urethra?
conveys urine & semen- three parts: prostatic, membraneous, penile
how much cardiac output goes to kidneys?
approx. 25%- 180L of flomerular filtration per day to produce 2L of urine- the rest is absorbed
what is the GFR?
how much filtration is occuring the kidneys- indicate how well a persons kidneys are functioning & risk of adverse reactions to contrast media- GFR decreases as they age
how can glomerular filtrate rate (GFR) be estimated?
serum creatinine concentration, age, sex - provides indication of renal function & risk of adverse reactions to contrast media
does GFR decrease with age?
yes but is offset by diminshing muscle bulk & creatinine excretion - creatinine is from muscles
is glomerular filtration selective?
non-selective only blood cellls & proteins are not filtered
where does reclamation of essential substances occur?
tubule system
what is micturition (urinating) controlled by?
spinal reflexes influenced by higher centres
what is inconinence caused by?
brainstem, cerebellar & cerebral lesions cause overflow, oestrogen deficiency reduces sympathetic sensitivty, congenital ectopic ureters & urinary fistulas (investigated by imaging)
how common is congenital abnormalities?
10% of people- common due to complexiity of embryological development
what are examples of renal congential abnormalities?
duplicated collecting system/partial duplication bifid renal pelvis, horseshoe kidney (joined across midline), crossed ectopia, pelvic or intrathoracic kidney, renal hypoplasia, renal agenesis
what are the main indication for imaging urinary system?
haematuria (calculi, tumours), flank pain (tumours), renal failure (presence of obstruction, size of kidneys), infection
what can plain radiographs identify in kidneys?
calcifications, size, shape- use is decreasing (60% sensitivty in detecting calculi & poor in detecting tumours)-
what are plain radiographs used for in kidney?
primary study before contrast media, identigy residual contrast from previous studies, assessing position of drains & stents, assess trauma
what can intravenous urography used for in kidney?
detects calculi- requires bolus injection of contrast medium- used from visualising renal collecting system & ureters, idetify urethral obstruction, demonstrate renal function- replaced by CT
what is the gold standard for imaging renovascular disease?
angiography - also good to use if person has high BP
what is uroradiology?
urethrography & cystography- contrast medium into urethra bladder
what is visualised during voiding cysturethrography?
contrast filled bladder & urethra are visualised during voiding
what is CT used for in diagnosing kidneys?
characterisation of a renal or peri-renal mass, tumour staging, identify calculi, used to evaluate excretion
what can haematuria (blood in urinary tract) be caused by?
urolithiasis (formation of stones), UTI, malignancy, iatrogenic causes & trauma
what is CT urography?
noncontrast phase for identification of stones, nephrogenic phase for evaluating renal masses, excretory phase for assessment of filling defects in collecting system
what is urolithiasis (calculi)?
calcium oxalate & struvite most common, radioopaque appearance- result for high urinary mineral concentration, changes in pH and factors such as drugs & diet - associated with UTI’s- stones form in calyces & bladder- cause hydronephrosis (swelling of kidneys)
what are clinical signs of urolithiasis?
pain & haematuria
how is urolithiasis cured?
muscle relaxtant to release passage for stones
what is the most common renal tumour?
renal cell carcinoma
what is most common bladder tumour?
transitional cell carcinoma
what is the main issue in identifying tumours?
differentiating cysts from masses- most identified incidentially during imaging for other clinical reasons
what cysts are more likely to be malignant?
more complex cystic masses
what is more useful for imaging tumours?
imaging more useful than biopsy
what are masses composed of?
vascularised tissue (enhance with contrast agent) - contain little or no fluid
how do we characterise a cyst?
precontrast & postcontrast images as confusion arises when there is soft tissue density in cysts- benign cysts can also show internal nonenhacing soft tissue
what does it indicate when there is an enhancement of solid components in cyst?
a malignant lesion- simple cysts are totally fluid filled
what is hydronephrosis due to?
distension of calyces & pelvis due to anatomical abnormaltiy or outflow obstruction in calculi of adult or prostatic hyperplasia or carcinoma in older adults- use imaging to identify obstruction- ultrasound is best
what are infection of urinary tract system caused by?
intestinal flora- more common in women due to short, wider urethra- can ascend the tract from bladder to kidneys
what is pyelonephritis?
UTI that generally begins in your urethra or bladder and travels to one or both of your kidneys- imaging not usually necessary but it is used to evaluate renal infection in high-risk patients & evaluation for complications- pus present in the kidneys
what is the initial screening for trauma of kidney?
FAST (Focused Assessment with Sonography for Trauma) is initial screen
what is the gold standard for screening abdominal trauma?
contrast-enhanced CT of abdomen & pelvis- can impact renal function - levels of creatinine increase by 25%
what is used to diagnose collecting system leaks?
excretory phase CT in patients with suspected UTI
what is used to investigate male urethra trauma?
retrograde urethrography
when does contrast induced nephropathy appear?
25-48 hours after procedure- characterised by 25% increase in serum creatinine
what is renal failure?
acute or chronic- disease may have been developing for many years - need dialysis or kidney transplant to survive
where can acute kidney injury occur?
prerenal, renal & post renal (obstructive)
what occurs to kidney is chronic or acute kidney disease?
chronic (smaller kidneys due to contraction of scar tissue)- acute (large due to swelling & inflammation)
what happens if you can’t differentiate between cortex & medulla?
could indicate a disease
what is a congenital ectopic ureter?
urine leaks out of urehtra causing incontinence- ureter goes directly to urethra and bypasses the sphincter
why is imaging the prostate better than biopsy?
very invasive- have to go through perineum - not accurate- MRI may be better to investigate
what are the 2 types of tumours found in kidneys?
ball type (bulges out) & bean type (contain within capsule)
