[W3] Renal Disease

Question 1

Where are the kidneys located in the body?

Answer 1

On either side of the spine, under the lower ribs.

Question 2

What is the typical size of an adult male kidney?

Answer 2

10–14 cm long and 3–5 cm wide.

Question 3

What are the two main tissue layers of the kidney?

Answer 3

Cortex and medulla.

Question 4

What percentage of cardiac output do the kidneys receive?

Answer 4

25%.

Question 5

List five key functions of the kidneys.

Answer 5

• Regulate extracellular fluid volume and blood pressure
• Electrolyte balance
• Acid-base balance
• Waste excretion
• Endocrine functions

Question 6

How do the kidneys participate in Vitamin D metabolism?

Answer 6

They convert 25-Hydroxy Vitamin D to the active form 1,25 Dihydroxy Vitamin D.

Question 7

What is erythropoietin and what produces it?

Answer 7

A hormone produced by the kidney that stimulates red blood cell production.

Question 8

What system is activated by renin secretion from the kidney?

Answer 8

The renin-angiotensin-aldosterone system (RAAS).

Question 9

What is a nephron?

Answer 9

The functional unit of the kidney.

Question 10

How many nephrons are in each kidney?

Answer 10

Approximately 1 million.

Question 11

What are the two main parts of the nephron?

Answer 11

The glomerulus and the renal tubule.

Question 12

What is the glomerulus?

Answer 12

A cluster of capillaries acting as a high-pressure filter.

Question 13

What is Bowman’s capsule?

Answer 13

A structure that collects glomerular filtrate.

Question 14

What molecules are allowed through the glomerular filter?

Answer 14

• Water
• Glucose
• Electrolytes
• Amino acids
• Small proteins
• Waste products

Question 15

What size of proteins are normally not filtered by the glomerulus?

Answer 15

Proteins larger than ~68 kDa, like albumin.

Question 16

Where does most reabsorption in the nephron occur?

Answer 16

In the proximal convoluted tubule.

Question 17

What is the main function of the loop of Henle?

Answer 17

Concentration of urine via counter-current mechanism.

Question 18

What regulates water reabsorption in the collecting ducts?

Answer 18

Antidiuretic hormone (ADH).

Question 19

What are three main types of renal function tests?

Answer 19

• Measurement of plasma waste (e.g. creatinine)
• GFR estimation
• Urine protein measurement

Question 20

What is the normal range for GFR?

Answer 20

90–120 mL/min.

Question 21

What is creatinine?

Answer 21

A waste product from muscle metabolism, used to assess kidney function.

Question 22

Why is creatinine not ideal for detecting early kidney disease?

Answer 22

GFR can fall by 50% before serum creatinine rises outside the reference range.

Question 23

Where is urea produced and what does it indicate?

Answer 23

Synthesised in the liver; it’s a marker of protein metabolism and renal excretion.

Question 24

What factors increase urea independently of renal function?

Answer 24

• High protein diet
• Dehydration
• Catabolism
• GI bleeding

Question 25

What is cystatin C and when is it preferred over creatinine?

Answer 25

A peptide marker of GFR not affected by muscle mass; useful in bodybuilders or elderly.

Question 26

What is the gold standard method of measuring GFR?

Answer 26

Inulin or isotope clearance tests (e.g. iohexol, 51Cr-EDTA).

Question 27

What formula is commonly used in the UK for eGFR?

Answer 27

The CKD-EPI formula.

Question 28

What factors affect the accuracy of eGFR?

Answer 28

* Muscle mass * Diet * Age * Certain ethnic groups

Question 29

What causes proteinuria?

Answer 29

Impaired glomerular barrier allowing protein leakage into urine.

Question 30

What is the preferred test for proteinuria?

Answer 30

Albumin:Creatinine Ratio (ACR).

Question 31

What is nephrotic syndrome?

Answer 31

A condition with high proteinuria and oedema due to glomerular damage.

Question 32

What is AKI?

Answer 32

Rapid loss of kidney function within 7 days.

Question 33

What are the three main causes of AKI?

Answer 33

* Pre-renal (e.g. shock) * Intrinsic renal (e.g. glomerulonephritis) * Post-renal (e.g. obstruction)

Question 34

What lab test alerts to possible AKI in UK hospitals?

Answer 34

Creatinine-based AKI staging algorithm (stages 1–3).

Question 35

Name key biochemical features of AKI.

Answer 35

* ↑ Creatinine * ↑ Urea * ↑ Potassium * ↓ Calcium * Metabolic acidosis

Question 36

What defines CKD?

Answer 36

GFR <60 mL/min for ≥3 months or ACR >3 mg/mmol.

Question 37

What are common causes of CKD?

Answer 37

* Diabetes * Hypertension * Glomerular disease * Nephrotoxins

Question 38

What are complications of CKD?

Answer 38

* Anaemia * Electrolyte imbalances * Bone mineral disorder * Cardiovascular disease

Question 39

What is CKD-MBD?

Answer 39

Mineral and Bone Disorder related to CKD, includes hypocalcaemia and high phosphate.

Question 40

How can CKD progression be slowed?

Answer 40

* Blood pressure control * ACE inhibitors * SGLT2 inhibitors * Dietary management

Question 41

What is the role of the Kidney Failure Risk Equation?

Answer 41

Estimates 5-year risk of needing renal replacement therapy.

Question 42

What regulates sodium reabsorption in kidneys?

Answer 42

RAAS (renin-angiotensin-aldosterone system).

Question 43

What hormone regulates water reabsorption in the collecting duct?

Answer 43

Antidiuretic hormone (ADH).

Question 44

What is hyponatraemia and what causes it?

Answer 44

Serum Na+ <133 mmol/L; caused by Na loss, water excess, or both.

Question 45

What is hypernatraemia and what causes it?

Answer 45

Serum Na+ >146 mmol/L; often caused by dehydration or diabetes insipidus.

Question 46

What hormone stimulates potassium excretion?

Answer 46

Aldosterone.

Question 47

What is hyperkalaemia and why is it dangerous?

Answer 47

K+ >5.5 mmol/L; can cause cardiac arrest.

Question 48

What is hypokalaemia and what are its symptoms?

Answer 48

K+ <3.5 mmol/L; causes muscle weakness, constipation, arrhythmias.