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Renal System (Pathophysiology)
Terms in this set (61)
6 main jobs of the kidneys
Make and Release Renin
Activate Vitamin D
How does the kidney filter the blood?
Excretion of metabolic waste products, especially Protein by-products (creatinine,
urea, ammonia) and many drugs
How does the renal system regulate blood pressure?
Regulated by adjusting blood volume and serum osmolarity (by concentrating
or diluting the urine) and secreting the hormone RENIN.
How does the renal system regulate acid-base balance?
Through reabsorption or excretion of Hydrogen ions [H+] and bicarbonate [HCO3]
The renal system releases erythropoietin that does what?
Erythropoietin signals the bone marrow to create Red Blood Cells (RBCs).
Without Erythropoietin, the body would not be able to make new RBCs which would lead to
ANEMIA, and anemia leads to fatigue and s/s of hypoxia.
The renal system makes and releases Renin what does renin do?
Renin plays an important role in the renin-angiotensin-aldosterone
system (RAAS) in the body. When released, this system works to INCREASE BLOOD PRESSURE.
With no renin, the RAAS system won't work. This will lead to hypotension.
The renal systems activate Vitamin D, why is this important?
Activated Vitamin D allows the GI tract to absorb more Calcium. Without Vitamin D, the GI tract would not be able to absorb as much calcium, so would have a risk for
hypocalcemia (see what that means later in the lecture notes).
BUN normal range
less than 20
What is blood urea nitrogen? what can it tell us?
Urea is the byproduct
of protein metabolism in the liver. The ammonia formed in this process is
synthesized to urea in the liver. Creation of BUN is the most important catabolic
pathway for eliminating excess nitrogen in the human body. Measuring how much BUN
is in the blood is an indicator of kidney damage. However, BUN is also affected by
dehydration, so it only indicates kidney damage if Creatinine levels are also elevated.
What is Creatinine? what does it tell us if elevated?
a waste product from the normal breakdown of muscle tissue. As
creatinine is produced, it is filtered through the kidneys and excreted in urine as a normal product of metabolism. If Creatinine is elevated in the blood that means it is not being excreted through
the kidneys. An elevated creatinine along with an elevated BUN value, indicate kidney damage.
Glomerular filtration rate (GFR)
The GFR is 125 mL/min (normal range is 85-135 mL/min). It is a
measure of how much blood (in mL) gets filtered by the glomeruli every minute. The GFR helps to
detect kidney disease in its early stages more reliably than the creatinine test alone. GFR is affected by
anything that would decrease the amount of blood flowing through the kidneys. This could include heart
failure, atherosclerosis or hypotension, among other things.
breaks down what is being filtered in the kidney.
Specific Gravity normal value, what does it measure?
1.010-1.030, measures how dilute or concentrated the urine is.
What does fixed specific gravity mean?
the SG stays the sam through several tests which indicates the kidney can no longer concentrate or dilute urine. (kidney death)
RBC's in urinalysis indicate
possible kidney stones, infection, bladder inflammation, kidney damage.
WBC's in urinalysis indicate
more than a few WBCs indicate the presence of infection
Protein in urinalysis indicate
kidney is damage allows large protein molecules to escape
Glucose in urinalysis indicate
if blood sugar is too high, glucose will spill into the urine
Casts in urinalysis indicate
pieces of mineral deposits that are breaking loose and being shed into the urine.
also provides an estimate of kidney function and of the actual GFR. However, in
addition to the serum (blood sample) creatinine, this test requires a timed urine collection (24 hours) for urine
creatinine measurement in order to compare blood and urine creatinine concentrations and to calculate the
increased BUN and Creatinine (in the blood) WITHOUT systemic s/s
increased BUN and Creatinine with multiple system organ failures
excessive production of urine
decreased urine output
no urine production (kidney failure)
describe steps in RAAS Blood pressure regulation by renal system.
1. Initiated by decreased perfusion to the kidneys.
2. The kidneys release renin.
3. Renin combines with angiotensinogen (from the liver) to form
Angiotensin I. This takes place in blood stream.
4. Angiotensin I is converted in the lungs to angiotensin II by
Angiotensin Converting Enzyme (ACE).
5. Angiotensin II stimulates the adrenal cortex to release aldosterone.
6. Aldosterone directs the kidney to reabsorb more sodium.
7. Water follows the sodium back into the blood stream and
blood pressure is increased.
antidiuretic hormone (ADH)
Secreted by the posterior pituitary gland, released in response to increase osmolarity. Regulates water in the body by signaling the kidney to retain water and sodium.
Natriuretic Hormones: ANP/BNP
Atrial: is released by the heart atria, blocks aldosterone secretion and action; and inhibits renin secreation
Brain: released from heart ventricles. when they are stretched
Action of Natriuretic hormones
cause the kidney to excrete sodium. Since water follows sodium out of the body, this will decrease overall fluid volume and bp will go down.
Prerenal causes (Renal dysfunction)
severe decrease in blood flow to the kidneys
intrinisic causes (renal dysfunction)
damage to the structures within the kidney
postrenal causes (renal dysfunction)
obstruction of urine leaving the kidney
Renal Compensation in Shock
1. Increase in ADH=fluid retention
2. Aldosterone Na & Fluid retention
What is the pathophysiology of stone formation?
High urine concentrations of stone forming substances precipitates into a crystal
Alkaline urine increases aggregates of calcium phosphate
Acid urine promotes crystallization of uric acid
Stone growth in pelvis or calyces
Risk of obstruction if stone > 5 mm
clinical manifestations of kidney stones
renal colic, hematuria, nausea and vomiting, flank pain or pain that spreads to the lower abdomen/groin. Pain caused by a kidney stone may change for instance, shifting to a different location or increasing in intensity as the stone moves through the urinary tract. Pain associated with kidney stones can be severe (give narcotic pain meds) and IV fluids to help flush the kidney.
Signs and Symptoms of UTI in the elderly
AMS, bacteria in urine can spread to the blood stream and cross the blood-brain barrier, confusion and other cognitive difficulties can be the result.
cystitis (UTI's), urinary tract obstruction with reflux infection with E. coli, proteus, or pseudomonas.
Most common cause of pyelonephritis is?
backward flow (reflux) of infected urine from the bladder to the upper urinary tract.
other causes of pylonephritis
-blockage or abnormality of the urinary system.
-the bacteria most likely to cause pyelonephritis are those that normally occur in the feces.
Clinical manifestations of Pyelonephritis
Acute glomerulonephritis (GN)
inflammation of the glomeruli, immune complex disease, leading to increased permeability of the filtration membrane.
What can glomerulonephritis result in?
SYNDROME is an acute inflammatory process that occludes the glomerular capillary
lumen and damages the capillary wall. It may occur as a renal-limited primary disorder, such as acute post infectious
glomerulonephritis, or as a secondary complicating disorder in systemic diseases, such as Diabetes or Lupus.
permeability of the glomerular pores allows large losses of protein
molecules through the kidney - just proteinuria, not hematuria.
what does Nephrotic syndrome do to blood pressure?
increases it, loss of protein, leads to fluid imbalance, increased salts which increases volume and then pressure.
causes of nephrotic syndrome?
Genetic defects in the glomerular
Systemic diseases (Diabetes, Lupus, etc.)
what S/S would you expect to see if a person has lost
protein through their urine as occurs in Nephrotic Syndrome?
Edema, When kidneys are malfunctioning, the body retains water and causes full body edema
Pathophysiology & manifestations of nephrotic syndrome
Increased glomerular membrane permeability to protein proteinuria
Loss of plasma proteins: Hypoalbuminemia decreased oncotic pressure
Loss of immunoglobins increased susceptibility to infection
Loss of specific transporter proteins (E.g. Decreased transport of vitamin D3
decreased calcium absorption)
Hyperlipidemia: increased hepatic synthesis of lipids combined with
decreased albumin levels
Increased LDL & VLDL increased risk of atherosclerosis
Lipiduria (fats in the urine)
Acute Tubular Necrosis
Damage to the tubule cells of the kidneys, which can then lead to
acute kidney failure. Acute tubular necrosis (ATN) is usually caused by a lack
of oxygen to the kidney tissues (ischemia of the kidneys). It may also occur if
the kidney cells are damaged by a poison or harmful substance.
Risks for Acute tubular necrosis
-Low blood pressure (hypotension) lasting longer than 30 min.
-Septic shock due to severe infection
-Dye (contrast) used for x-ray studies
-Medications that are toxic to the kidneys (such as aminoglycoside antibiotics or amphotericin)
-Injury or trauma that damages the muscles (release of myoglobin from muscles kidneys cannot filter this is a large molecule so it causes kidney damage)
-Blood transfusion reaction
-Recent major surgery
Sings and Smptoms of ATN
CNS: change of LOC
Oliguria or Anuria
Full body Edema
Cardiac problems (potassium imbalance.)
Fixed specific gravity
Prognosis for ATN
reversible in most healthy people. can be fatal in immunocompromised/elderly patients.
refers to temporary or permanent damage to the kidneys that result in loss of normal kidney function.
two different types of renal failure
acute and chronic
Acute renal injury S/S
Oliguria or Anuria
Anemia s/s (fatigue/short of breath)
Nausea and vomiting
Edema (due to fluid retention)
Pale skin (due to anemia, ⬇ erythropoietin)
History of taking certain medications
History of trauma
History of recent infection
SEE Acute Tubular Necrosis (ATN)
chronic renal failure s/s
o Poor appetite, Vomiting
o Bone pain
o Stunted growth in kids
o High urine output (Diuresis phase)
or no urine output (Oliguric phase)
o Recurrent urinary tract infections
o Urinary incontinence
o Pale skin (anemia)
o Full body edema
Poor muscle tone
Change in mental alertness
Labs = High BUN and creatine
Electrolyte imbalances (sodium loss and
potassium retention) in oliguric phase
Detectable abdominal mass
Main factors characteristic of acute kidney injury
-Decreased blood flow to kidneys
main factors characteristic of chronic renal failure
kidney failure and diabetes
Kidney damage is caused by high blood glucose levels which triggers the
INFLAMMATORY RESPONSE leading to blood vessel injury in the kidneys. The kidney's
then do not receive adequate oxygen leading to chronic renal failure and the inability of
the kidneys to filter blood. A prominent S/S that diabetes is damaging the kidney is the
finding of protein in the urine (called "proteinuria" or "albuminuria.")
kidney failure and hypertension
Hypertension is the 2nd most
common cause of CRF and can be seen not only as a cause of kidney disease but also as a result of damage created
by the disease. As kidney disease progresses, physical changes in the kidneys lead to increased blood pressure.
Therefore, a dangerous spiral, involving rising blood pressure and factors that raise blood pressure occurs.
Remember that ATHEROSCLEROSIS of blood vessels causes INFLAMMATION and HYPERTENSION.
primary sign of kidney damage
Sets with similar terms
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