patho week 10 Flashcards
where do the kidneys sit in the body
they sit in the retroperitoneal space (behind the peritoneum)
how much blood is filtered every hour by the kidneys
5L is filtered every hour (total adult blood volume)
how many litres of urine is formed per day
1-3L
what is the functional unit of the kidney
the nephron
what are the parts of a nephron
Bowmans capsule, PCT, DCT and loop of hence
what are the 3 layers of the glomerulus
endothelial cells (inner most)
basement membrane (repels negatively charged particles)
epithelial cells on the outside
what type of charge is the basement membrane of the glomerulus
negatively charged
where is the glomerulus
in the Bowmans capsule
how can small particles pass into filtrate of glomerulus
through fenestrations
why cant albumin pass through the glomerulous
because its negatively charged (basement membrane repels it)
what are the three forces that control glomerular filtration and do they push or pull
hydrostatic pressure: push
colloid osmotic pressure: pull
capsular hydrostatic pressure: pull
what is glomerular hydrostatic pressure
55mmhg
what is blood colloid osmotic pressure
30mmhg
what is capsular hydrostatic pressure
15mmhg
what are all the steps in microvascular urine formation
- Bowmans capsule collects glomerular filtrate and funnels it into the PCT
- the PCT will reabsorb 80% electrolytes, 100% glucose, 70% water
- then the loop of hence will concentrate the urine
- then the distal convoluted tubule where more water and electrolytes are absorbed
what electrolytes are absorbed in the PCT
Na, K, Cl, Ca, etc
80% electrolytes
100% glucose
70% water
all reabsorbed
how do the kidneys auto regulate in response to high BP
they will decrease GFR by constricting afferent arteriole and dilating efferent arteriole
(arteriole going in will constrict so less comes in, and effecernt arteriole will dilate so that more goes out to lower GFR/BP)
how do they kidneys auto regulate in response to too little/low Bp
they will increase GFR by dilating afferent arteriole and constricting efferent arteriole
what is the limitations of auto regulation
if fails if BP drops below 65-70mmHg
what are the 3 hormonal kidney functions
1) production and secretion of renin (RAAS)
2) production of erythropoietin (stimulates production of RBCs)
3) activation of vitamin D
copy the RAAS from memory
what are the two things you need for adequate kidney function
1) adequate glomerular perfusion
2) functional nephrons
what type of abnormal blood work findings would you see in abnormal kidney function
increased BUN and creatinine
failure to maintain Na and K balance
water retention and
weird acid base balance
what is azotemia
an accumulation of metabolic waste products in the blood
what is uremias
a group of sings and symptoms that occur with inadequate renal function
what is oliguria
urine output that is less than normal (less than 400 mL a day)
what is anuria
an absence of urine pridutcion (less than 40 mL a day)
whats the difference in onset between CKD and AKI
CKD: gradual onset
AKI: sudden onset (hours to days)
what is the difference in cause for CKD vs. AKI
CKD: diabetic neuropathy
AKI: acute tubular necrosis
what is the difference in prognosis for CKD vs AKI
CKD is progressive and irriversable
AKI is potentially reversible
what is the most common cause of death between CKD vs. AKI
CKD: cardiovascular disease
AKI: sepsis
what causes CKD (patho)
usually caused by a progressive, irreversible loss of kidney function through loss of nephrons
what are the most common causes for CKD
diabetic neuropathy and hypertension
how many nephrons are lost in CKD before you see symptoms
50%
how many nephrons can you lose before you need renal replacement therapy
90%
what is glomerulosclerosis
due to loss or nephrons, remaining nephrons need to work harder. this hyperfiltration causes fibrosis and scarring of the kidneys over time.
what stage of CKD will a patient start to develop uremic symptoms
usually around 4th stage
what are the 6 symptoms of uraemia
fluid retention
electrolyte imbalance
waste product accumulation
hormone insufficiency
increase in blood lipoproteins
changes in bone metabolism
which lab value is the best indicator of kidney function
eGFR (estimated glomerular filtration rate)
why does urea and creatinine rise in CKD
because theyre the main products that the kindey gets rid of, if theyre not working then they cant excrete these things
what happens to electrolytes with CKD
- sodium will initially be low but become high as body tries to hold on to it as disease progresses
-increased potassium, phosphate and magnesium
-decreased calcium - everything will be high except calcium
how will GFR look to get an official diagnosis of CKD
if GFR is less than 60mL/min for over 3 months (stage 3)
how does CKD cause acidosis
kidneys cant excrete excess hydrogen like they normally do so acid levels will increase with decreased GFR.
kidneys also cant reabsorb bicarb as well
how will the body initially compensate to CKD acidosis
increased respirations (kussmaul’s respirations ofc)
what are the most common haematological (blood) issues with CKD
anemia: d/t decreased erythropoietin
platelet aggrigation won’t work as well (GI bleed is common)
altered leukocyte function which leads to impaired immunity
what are some symotims of ureic encephalopathy
fatigue, headache, seizures, sleep disturbances, coma
what is uremic neuropathy and what are the symptoms
its a buildup of toxins affecting nerves, causes parenthesis, asterixis, tremors and twitching
what are the characteristics of stage 3 kidney disease
- moderate reduction in renal function
- greater nephron damage
what is the GFR for stage 3 renal disease
30-59
what is the GFR for stage 4 renal disease
15-29
what is the GFR with ESRD
less than 15
what stage does CKD start to be symptomatic
stage 3, stage 2 you may see less concentrated using
how does CKD cause renal osteodystrophy
due to PTH being released to reabsorb calcium due to low vitamin D or high phosphate
how does phosphate affect calcium
CKD causes phosphate retention, she binds to calcium. this causes a decrease in serum calcium which releases PTH to reabsorb calcium in the bones. this will bind to phosphate and overall not increase calcium levels and make the bones v brittle over time (make sure this is correct)
what is uremic pericarditis and what causes it
inflamed layers of the heart rubbing together caused by uremic toxins
what are the main reasons CKD affects respiratory system
due to fluid overload, can cause pulmonary edema, pneumonia
why do the early stages of CKD cause polyuria
because urine cant be reabsorbed as well
what is uremic frost
urea crystals that leech onto the skin
