renal disorders

Question 1

Sumiko, age 72, recently had a heart attack, damaging her left ventricle. She appears to have left-sided heart failure. Stroke volume, blood pressure, and cardiac output are all reduced.

Sumiko’s renal function may be impaired. Serum blood urea nitrogen (BUN) and creatinine (Cr) levels are increasing and glomerular filtration rate (GFR) is significantly reduced. Oliguria is present, as is edema of the face and extremities.

Sumiko seems to be becoming more confused and disoriented. Further blood laboratory values reveal hypocalcemia, hyperkalemia, and anemia.

Based on the information provided, which type of renal dysfunction is most likely in Sumiko’s case: prerenal, intrarenal, or postrenal?

Answer 1

prerenal

The most likely renal failure type is prerenal. Prerenal failure occurs when the kidneys are not adequately perfused. In Sumiko’s case, her heart failure is likely resulting in reduced blood flow to the kidneys. The increasing levels of BUN and Cr, along with decreasing GFR, shows Sumiko’s kidneys are not functioning normally.

Question 2

In Sumiko’s condition, why is GFR lower than normal?

Answer 2

deceased perfusion of the kidney

Sumiko’s heart failure likely makes maintaining adequate perfusion of body tissues difficult. As perfusion of the kidneys declines, so does the GFR.

Question 3

Why are BUN and Cr levels higher than normal in Sumiko?

Answer 3

decreased GFR

Sumiko’s BUN and Cr are increasing because normally these substances are filtered by the kidney and partially removed from the blood. When GFR decreases, these factors increase in the blood.

Question 4

Why is oliguria occurring in Sumiko?

Answer 4

decreased renal perfusion and GFR

Sumiko is experiencing oliguria for the same reason BUN and Cr levels are elevating: the kidneys are not adequately perfused. Urine is only formed when the blood is filtered. If insufficient blood is available for filtration, urine formation decreases.

Question 5

Which of the following may explain Sumiko’s anemia? Select all that apply.

Answer 5

-decreased erythropoietin
-toxin destruction of red blood cells
-glomerular damage

The kidneys produce erythropoietin to maintain red blood cells levels. If the kidneys are damaged, erythropoietin levels may fall. Intrinsic factor is found in the stomach and is not altered by kidney failure. If the glomeruli are damaged, red blood cells may be filtered into the urine, leading to hematuria. When the kidneys cannot filter the blood properly, toxins may build up. These toxins may destroy red blood cells.

Question 6

What type of edema is Sumiko likely to experience with renal failure?

Answer 6

periorbital edema

Edema manifests in a number of ways in the body, but a particular form of edema, periorbital edema, may signify renal failure. The swelling around the eyes often develops with increased fluid accumulation.

Question 7

Why does Sumiko experience disorientation as a result of renal failure?

Answer 7

elevated toxin levels in the blood

Encephalopathy may develop with acute or chronic renal failure when toxins buildup in the blood. These toxins begin to compromise brain function.

Question 8

What treatment option should be considered first for Sumiko’s condition?

Answer 8

adequate fluid maintenance

Question 9

Acute kidney injury (AKI) develops most commonly in response to which type of failure?

Answer 9

prerenal failure

Question 10

Which of the following conditions result from autoantibodies attacking the glomeruli?

Answer 10

goodpasture’s syndrome

Question 11

What is the cause of polycystic kidney disease?