Alterations Of Renal Function Flashcards
As the glomerular filtration rate goes down, plasma creatinine levels also go down.
False
Normally the kidneys filter and excrete creatinine. Therefore, if glomerular filtration decreases (as we see in renal failure), then plasma creatinine levels will start to rise. Elevated plasma creatinine levels is one of the primary labs we use to assess renal function.
Urinary tract obstruction due to a kidney stone in the right ureter can result in:
hydronephrosis
If a kidney stone obstructs a ureter, the back up of urine into the renal pelvis and kidney causes dilation of the urinary tract structures, a condition called hydronephrosis. The Latin derivation of this term is ‘water on the kidney’.
The principle manifestation of a kidney stone in a ureter is:
flank pain
The ureters connect the kidneys, which are located in the posterior abdominal cavity around the 12th rib, to the bladder which is located in the pelvis. Kidney stones tend to get obstructed where the renal pelvis narrows and becomes the ureter. Therefore kidney stones tend to cause ‘flank’ pain, which is pain in the mid-lateral back region.
Risk factors for developing a urinary tract infection (UTI) include
urinary catheters.
older age.
urinary retention.
diabetes mellitus.
Female sex due to shorter urethra
Pyelonephritis is a bacterial infection of the:
kidney
By definition, pyelonephritis (pyelo- = pus and -nephritis is referring to the kidneys) is an infection that has reached the renal pelvis and kidneys. Pyelonephritis is generally a complication of a bladder infection, where bacteria have ascended the ureters.
Acute glomerulonephritis is caused by:
streptococcal pharyngeal infections.
The majority of cases of acute glomerulonephritis are caused by group A beta hemolytic streptococcus infections of the throat and in some cases, skin or wound infections. The immune system produces antibodies to fight the strep infection, but in 10% of cases of untreated strep infection the antibodies get into the blood stream and bind to the endothelial cells in the glomerulus. The resulting inflammatory response caused injury to the glomerular membrane.
Clinical manifestations of glomerulonephritis include:
proteinuria
hematuria.
Oliguria - due to scar tissue deposition at the glomerular membrane.
The glomerular membrane injury caused by the autoimmune response in glomerulonephritis leads to the loss of protein and red blood cells into the urine filtrate. This results in proteinuria (protein in the urine) and hematuria (blood in the urine) respectively.
Nephrotic syndrome is defined as:
the abnormal loss of protein in the urine. (3g or more/ day)
By definition, nephrotic syndrome is the loss of large amount of plasma proteins (mainly albumin) in the urine. Normally the urine should contain no protein because plasma proteins cannot filter across the glomerular membrane.
Nephrotic syndrome is caused injury to the glomerular membrane.
Clinical findings in individuals with nephrotic syndrome include:
edema.
Loss of albumin in the urine in nephrotic leads to a decrease in what’s called the plasma oncotic pressure. A decrease in the plasma oncotic pressure leads to the loss of fluid into the tissues since the plasma proteins attract water into the capillaries. This loss of fluid leads to edema.
Which clinical laboratory values reflects a diagnosis of acute kidney injury?
Increased plasma creatinine
Creatinine is produced at a constant rate by muscle metabolism. When creatinine is filtered by the kidneys, 100% of what was filtered is excreted in the urine. This makes plasma creatinine levels a good measure of renal function. If glomerular filtration goes down in acute kidney injury, plasma creatine level goes up since the kidneys can’t get rid of it.
Prerenal acute kidney injury (acute renal failure) is caused by:
decreased blood flow to the kidneys.
By definition, pre-renal acute kidney injury (acute renal failure) is caused by factors that decrease renal blood flow. Pre- is referring to the fact that the cause of the renal failure is occurring before the kidneys. Common causes include hypotension and renal artery stenosis.
A common cause of chronic kidney disease (chronic renal failure) is:
atherosclerosis of the renal arteries.
A common cause of chronic kidney disease (chronic renal failure) is renal artery stenosis caused by atherosclerosis of the renal arteries. This leads to a gradual decrease in oxygen delivery to the kidneys, eventually leading to hypoxic injury and death of the renal tissues.
Other cause is:
Hypotension due to blood loss, dehydration, left ventricular failure.
Why do individuals with chronic kidney disease (chronic renal failure) often develop anemia?
Injury to the kidneys leads to decreased erythropoietin secretion.
There is a regional the area near the glomerulus called the juxtaglomerular apparatus where a hormone called erythropoietin is secreted into the bloodstream. Erythropoietin stimulates the production of red blood cells by the bone marrow, so when kidney function decreases, erythropoietin levels drop and anemia develops. If erythropoietin production is completely stopped, then RBC production drops by 50%.
An important risk factor in the development of kidney stones (calcium stones 70-80%) is:
Dehydration
Other risk factors include:
Hypercalcemia
Diet high in oxalate
Which clinical manifestations would make you suspect that a person has a kidney stone?
Sudden, severe pain in the flank area and pain in the pelvis region.
Urinary tract obstruction
Hematuria- hydronephrosis (dilation of the renal pelvis) if stone is obstructed in the ureter.
(Chronic damage to the kidney can occur if the obstruction is not removed.)
