HSC 4558 Exam 4 V2 | HSC 4558 Pathophysiology II | Actual Q&A with
Rationale (HSC4558 Exam 4) | University of Central Florida
1. Which of the following laboratory findings is most characteristic of prerenal Acute Kidney
Injury (AKI)?
A. Urine specific gravity fixed at 1.010
B. BUN to creatinine ratio greater than 20:1
C. Fractional excretion of sodium (FeNa) greater than 2%
D. Presence of muddy brown granular casts
Answer: B
Explanation: In prerenal AKI, the kidneys are structurally intact but hypoperfused, leading
to increased urea reabsorption. This mechanism results in a BUN:Creatinine ratio typically
exceeding 20:1. This helps clinicians differentiate prerenal causes from intrinsic renal
damage where the ratio is usually lower.
2. What is the primary pathophysiology behind the development of Nephrotic Syndrome?
A. Ischemic necrosis of the proximal convoluted tubules
B. Inflammatory destruction of the basement membrane by IgA
C. Decreased hydrostatic pressure in the Bowman capsule
D. Increased glomerular permeability to plasma proteins
Answer: D
Explanation: Nephrotic syndrome is characterized by massive proteinuria due to the loss
of negative charge on the glomerular basement membrane. This increased permeability
allows albumin and other proteins to leak into the filtrate. Consequently, patients present
with hypoalbuminemia, generalized edema, and hyperlipidemia.
3. A patient presents with polydipsia, polyuria, and a urine specific gravity of 1.002. Which
condition is most likely?
A. Diabetes Insipidus (DI)
B. Syndrome of Inappropriate Antidiuretic Hormone (SIADH)
C. Diabetic Ketoacidosis (DKA)
D. Conn Syndrome
Answer: A
,Explanation: Diabetes Insipidus is caused by a deficiency of or resistance to Antidiuretic
Hormone (ADH). This results in the inability of the kidneys to concentrate urine, leading to
the excretion of large volumes of dilute urine. The very low specific gravity confirms the
lack of solute concentration in the renal output.
4. Which hormone is primarily responsible for the clinical manifestations seen in Cushing’s
Syndrome?
A. Aldosterone
B. Thyroxine
C. Epinephrine
D. Cortisol
Answer: D
Explanation: Cushing’s Syndrome results from chronic exposure to excessive levels of
circulating glucocorticoids, primarily cortisol. Excessive cortisol leads to protein wasting,
fat redistribution, and altered glucose metabolism. These physiological changes manifest as
the classic buffalo hump, moon face, and abdominal striae.
5. In the context of Chronic Kidney Disease (CKD), why does secondary hyperparathyroidism
occur?
A. Excessive secretion of erythropoietin
B. Direct stimulation of the parathyroid gland by urea
C. Increased intestinal absorption of calcium
D. Reduced vitamin D activation and phosphate retention
Answer: D
Explanation: As renal function declines, the kidneys fail to excrete phosphate and lose the
ability to activate vitamin D. Lowered serum calcium levels and elevated phosphate levels
trigger the parathyroid glands to secrete excess Parathyroid Hormone (PTH). This chronic
stimulation results in bone demineralization and renal osteodystrophy.
6. Which type of diabetic complication is characterized by damage to the small blood vessels
in the retina?
A. Macrovascular complication
B. Microvascular complication
C. Autonomic neuropathy
D. Somogyi effect
Answer: B
, Explanation: Diabetic retinopathy is a classic microvascular complication resulting from
chronic hyperglycemia. The high glucose levels cause thickening of the capillary basement
membranes and endothelial cell dysfunction. This leads to ischemia, microaneurysms, and
potential vision loss over time.
7. What is the Hallmark sign of Graves’ disease related to the eyes?
A. Exophthalmos
B. Ptosis
C. Nystagmus
D. Miosis
Answer: A
Explanation: Exophthalmos is the protrusion of the eyeballs seen specifically in Graves’
disease due to orbital inflammation. This occurs because autoantibodies stimulate the
fibroblasts in the extraocular muscles to produce glycosaminoglycans. The resulting
accumulation of fluid and tissue causes the eyes to bulge forward.
8. A patient with Type 1 Diabetes presents with deep, rapid respirations known as Kussmaul
breathing. What is the physiological purpose of this?
A. To increase the partial pressure of oxygen
B. To decrease the pH of the blood
C. To reduce the levels of circulating insulin
D. To compensate for metabolic acidosis by blowing off CO2
Answer: D
Explanation: Kussmaul breathing is a respiratory compensatory mechanism for metabolic
acidosis, specifically diabetic ketoacidosis. By increasing the rate and depth of ventilation,
the body excretes excess carbon dioxide to raise the blood pH. This represents the body’s
attempt to restore acid-base balance during a crisis.
9. Which of the following is the most common cause of Acute Tubular Necrosis (ATN)?
A. Glomerulonephritis
B. Urinary tract obstruction
C. Ischemia or nephrotoxins
D. Vesicoureteral reflux
Answer: C
Explanation: Acute Tubular Necrosis is the most frequent cause of intrarenal acute kidney
injury. It is typically triggered by prolonged renal ischemia or exposure to nephrotoxic
Rationale (HSC4558 Exam 4) | University of Central Florida
1. Which of the following laboratory findings is most characteristic of prerenal Acute Kidney
Injury (AKI)?
A. Urine specific gravity fixed at 1.010
B. BUN to creatinine ratio greater than 20:1
C. Fractional excretion of sodium (FeNa) greater than 2%
D. Presence of muddy brown granular casts
Answer: B
Explanation: In prerenal AKI, the kidneys are structurally intact but hypoperfused, leading
to increased urea reabsorption. This mechanism results in a BUN:Creatinine ratio typically
exceeding 20:1. This helps clinicians differentiate prerenal causes from intrinsic renal
damage where the ratio is usually lower.
2. What is the primary pathophysiology behind the development of Nephrotic Syndrome?
A. Ischemic necrosis of the proximal convoluted tubules
B. Inflammatory destruction of the basement membrane by IgA
C. Decreased hydrostatic pressure in the Bowman capsule
D. Increased glomerular permeability to plasma proteins
Answer: D
Explanation: Nephrotic syndrome is characterized by massive proteinuria due to the loss
of negative charge on the glomerular basement membrane. This increased permeability
allows albumin and other proteins to leak into the filtrate. Consequently, patients present
with hypoalbuminemia, generalized edema, and hyperlipidemia.
3. A patient presents with polydipsia, polyuria, and a urine specific gravity of 1.002. Which
condition is most likely?
A. Diabetes Insipidus (DI)
B. Syndrome of Inappropriate Antidiuretic Hormone (SIADH)
C. Diabetic Ketoacidosis (DKA)
D. Conn Syndrome
Answer: A
,Explanation: Diabetes Insipidus is caused by a deficiency of or resistance to Antidiuretic
Hormone (ADH). This results in the inability of the kidneys to concentrate urine, leading to
the excretion of large volumes of dilute urine. The very low specific gravity confirms the
lack of solute concentration in the renal output.
4. Which hormone is primarily responsible for the clinical manifestations seen in Cushing’s
Syndrome?
A. Aldosterone
B. Thyroxine
C. Epinephrine
D. Cortisol
Answer: D
Explanation: Cushing’s Syndrome results from chronic exposure to excessive levels of
circulating glucocorticoids, primarily cortisol. Excessive cortisol leads to protein wasting,
fat redistribution, and altered glucose metabolism. These physiological changes manifest as
the classic buffalo hump, moon face, and abdominal striae.
5. In the context of Chronic Kidney Disease (CKD), why does secondary hyperparathyroidism
occur?
A. Excessive secretion of erythropoietin
B. Direct stimulation of the parathyroid gland by urea
C. Increased intestinal absorption of calcium
D. Reduced vitamin D activation and phosphate retention
Answer: D
Explanation: As renal function declines, the kidneys fail to excrete phosphate and lose the
ability to activate vitamin D. Lowered serum calcium levels and elevated phosphate levels
trigger the parathyroid glands to secrete excess Parathyroid Hormone (PTH). This chronic
stimulation results in bone demineralization and renal osteodystrophy.
6. Which type of diabetic complication is characterized by damage to the small blood vessels
in the retina?
A. Macrovascular complication
B. Microvascular complication
C. Autonomic neuropathy
D. Somogyi effect
Answer: B
, Explanation: Diabetic retinopathy is a classic microvascular complication resulting from
chronic hyperglycemia. The high glucose levels cause thickening of the capillary basement
membranes and endothelial cell dysfunction. This leads to ischemia, microaneurysms, and
potential vision loss over time.
7. What is the Hallmark sign of Graves’ disease related to the eyes?
A. Exophthalmos
B. Ptosis
C. Nystagmus
D. Miosis
Answer: A
Explanation: Exophthalmos is the protrusion of the eyeballs seen specifically in Graves’
disease due to orbital inflammation. This occurs because autoantibodies stimulate the
fibroblasts in the extraocular muscles to produce glycosaminoglycans. The resulting
accumulation of fluid and tissue causes the eyes to bulge forward.
8. A patient with Type 1 Diabetes presents with deep, rapid respirations known as Kussmaul
breathing. What is the physiological purpose of this?
A. To increase the partial pressure of oxygen
B. To decrease the pH of the blood
C. To reduce the levels of circulating insulin
D. To compensate for metabolic acidosis by blowing off CO2
Answer: D
Explanation: Kussmaul breathing is a respiratory compensatory mechanism for metabolic
acidosis, specifically diabetic ketoacidosis. By increasing the rate and depth of ventilation,
the body excretes excess carbon dioxide to raise the blood pH. This represents the body’s
attempt to restore acid-base balance during a crisis.
9. Which of the following is the most common cause of Acute Tubular Necrosis (ATN)?
A. Glomerulonephritis
B. Urinary tract obstruction
C. Ischemia or nephrotoxins
D. Vesicoureteral reflux
Answer: C
Explanation: Acute Tubular Necrosis is the most frequent cause of intrarenal acute kidney
injury. It is typically triggered by prolonged renal ischemia or exposure to nephrotoxic
