Renal 3

Question 1

How is kidney function clinically assessed?

Answer 1

A: Kidney function is evaluated through several methods:

• Clinical assessment – recognizing symptoms of altered renal function.

• Medical imaging – using ultrasound, CT, MRI, and scintigraphy to detect structural and functional changes.

• Urinalysis – analyzing urine volume, color, turbidity, pH, specific gravity, and electrolyte composition.

• Blood tests – measuring biomarkers such as blood urea nitrogen (BUN) and plasma creatinine to estimate glomerular filtration rate (GFR).

Question 2

What is the significance of the glomerular filtration rate (GFR) in renal physiology?

Answer 2

A: GFR indicates the volume of plasma filtered by the kidneys per unit time. It is the primary index of renal function; a normal value is approximately 120 mL/min/1.73 m². Reduced GFR reflects impaired waste elimination and homeostatic dysregulation.

Question 3

How is measured GFR (mGFR) determined, and what ideal substance is used for this purpose?

Answer 3

A: mGFR is calculated using renal plasma clearance. An ideal substance (e.g., inulin) is used because it is freely filtered, not reabsorbed or secreted, and is not metabolized. In practice, creatinine clearance is often used as an approximation despite its limitations.

Question 4

What are the key differences between acute kidney injury (AKI) and chronic kidney disease (CKD)?

Answer 4

A:
• AKI: A rapid decline in kidney function over days, often due to pre-renal factors (low blood supply), intrinsic renal damage, or post-renal obstructions. It is characterized by a sudden retention of waste and electrolytes, risking irreversible damage if severe.

• CKD: A progressive, irreversible loss of nephrons over months to years, commonly due to diabetes, hypertension, or glomerulonephritis. It is staged by GFR and associated with albuminuria.

Question 5

What role does haemodialysis play in the treatment of kidney failure?

Answer 5

A: Haemodialysis is a renal replacement therapy used when GFR falls below critical levels (typically in CKD Stage 5). It uses a dialyzer to remove waste products, excess electrolytes, and fluid from the blood. Typical treatment involves 4-hour sessions three times a week, though advancements (such as wearable or bioartificial kidneys) are under investigation.

Question 6

GFR is the best overall index of kidney function; normal is approximately

Answer 6

120 mL/min/1.73 m².

Question 7

Urinalysis assesses

Answer 7

volume, color, pH (4.6–8), and specific gravity (1.001–1.035).

Question 8

BUN and creatinine levels in blood increase as

Answer 8

kidney function declines.

Question 9

AKI can be pre-renal, intrinsic, or

Answer 9

post-renal, with a rapid onset over days.

Question 10

CKD is progressive, irreversible, and

Answer 10

staged by declining GFR and albuminuria.

Question 11

Haemodialysis removes

Answer 11

toxins and fluid when kidney function is critically low.

Question 12

Medical imaging (ultrasound, CT, MRI, scintigraphy) is key for

Answer 12

structural evaluation.

Question 13

GFR remains constant despite kidney injury.

Answer 13

False (GFR decreases with kidney injury or disease.)

Question 14

Inulin clearance is considered the gold standard for measuring GFR.

Answer 14

True

Question 15

Creatinine clearance perfectly reflects true GFR with no error.

Answer 15

False (Creatinine clearance can overestimate GFR due to tubular secretion.)

Question 16

Acute kidney injury is always reversible with proper treatment.

Answer 16

False (Severe or prolonged AKI can lead to irreversible damage.)

Question 17

Haemodialysis can fully replace the endocrine functions of the kidney.

Answer 17

False (Dialysis only substitutes the excretory functions, not the endocrine roles.)

Question 18

______ clearance is used to calculate the measured glomerular filtration rate (mGFR).

Answer 18

Renal plasma

Question 19

______ is the ideal substance for determining GFR because it is freely filtered and neither reabsorbed nor secreted.

Answer 19

Inulin

Question 20

In acute kidney injury (AKI), a major cause is reduced renal blood flow, often due to ______ failure or hemorrhage.

Answer 20

Pre-renal

Question 21

______ is a progressive loss of renal function over months to years, often associated with diabetes and hypertension.

Answer 21

Chronic kidney disease (CKD)

Question 22

A common renal replacement therapy that uses a dialyzer to filter blood is ______.

Answer 22

Haemodialysis

Question 23

Which test is primarily used to stage kidney disease?
A) Urinalysis only
B) Renal ultrasound
C) Estimated Glomerular Filtration Rate (eGFR)
D) Blood pressure measurement

Answer 23

A: C) Estimated Glomerular Filtration Rate (eGFR)

Question 24

What imaging modality uses radiotracers to assess renal structure and function?
A) MRI
B) CT scan
C) Renal scintigraphy
D) Ultrasound

Answer 24

A: C) Renal scintigraphy

Question 25

Which marker is less influenced by dietary intake and is produced at a constant rate, making it a better indicator of GFR? A) Blood urea nitrogen (BUN) B) Plasma creatinine C) Serum sodium D) Urinary protein

Answer 25

A: B) Plasma creatinine

Question 26

In CKD, what is typically observed as the disease progresses? A) Increased GFR and decreased albuminuria B) Reduced GFR and increased blood creatinine C) Stable GFR with increasing urine output D) Reduced GFR with decreased blood urea

Answer 26

A: B) Reduced GFR and increased blood creatinine

Question 27

Which of the following is a common complication of acute kidney injury? A) Hypokalemia B) Metabolic alkalosis C) Hyperphosphatemia D) Hypovolemia

Answer 27

A: C) Hyperphosphatemia (Note: AKI often leads to retention of phosphate.)

Question 28

A 55-year-old patient presents with fatigue, nausea, and reduced urine output. Blood tests reveal elevated BUN and creatinine levels, and the eGFR is measured at 45 mL/min/1.73 m². Question: What stage of kidney disease does this indicate, and what clinical measures should be considered?

Answer 28

A: This suggests moderate CKD (likely Stage 3). Management should include strict blood pressure control, dietary modifications (e.g., low protein and sodium), and close monitoring for progression of kidney damage.

Question 29

A patient develops sudden oliguria following severe dehydration and hypotension. Urinalysis shows concentrated urine, and imaging indicates normal kidney structure. Question: What is the likely diagnosis, and how should it be managed?

Answer 29

A: This is likely acute kidney injury (AKI) due to a pre-renal cause (e.g., hypovolemia). Management should focus on restoring blood volume with fluids and treating the underlying cause to prevent permanent damage.

Question 30

A patient with a history of diabetes and hypertension is found to have albuminuria and an eGFR of 25 mL/min/1.73 m². Question: How would you classify this patient's CKD, and what are the long-term treatment considerations?

Answer 30

A: The patient likely has advanced CKD (Stage 4). Long-term management may include strict control of blood pressure and blood glucose, use of ACE inhibitors or ARBs, dietary modifications, and preparation for potential renal replacement therapy (dialysis or transplant) if the condition progresses.

Question 31

A patient undergoing haemodialysis complains of persistent fatigue and muscle cramps. Blood tests reveal electrolyte imbalances. Question: What might be contributing to these symptoms, and how can treatment be optimized?

Answer 31

A: Inadequate clearance of electrolytes (such as potassium and phosphate) during dialysis may contribute to these symptoms. Optimizing dialysis settings, adjusting treatment frequency, and dietary modifications can help manage these imbalances.

Question 32

Glomerular Filtration Rate (GFR):

Answer 32

The volume of plasma filtered per minute; the key measure of kidney function.

Question 33

Renal Plasma Clearance:

Answer 33

The volume of plasma from which a substance is completely cleared by the kidneys per unit time; used to calculate mGFR.

Question 34

Inulin:

Answer 34

An exogenous marker used to accurately measure GFR because it is freely filtered and neither reabsorbed nor secreted.

Question 35

Acute Kidney Injury (AKI):

Answer 35

A sudden decline in renal function over days, often reversible if promptly managed.

Question 36

Chronic Kidney Disease (CKD):

Answer 36

A progressive loss of renal function over months to years, frequently due to diabetes or hypertension.

Question 37

eGFR:

Answer 37

An estimated value of GFR calculated from serum creatinine and other factors; used to stage kidney disease.

Question 38

Haemodialysis:

Answer 38

A treatment modality that filters blood using a dialyzer to remove waste products and excess fluid when kidney function is severely compromised.