Chronic Kidney Disease

Question 1

Define CKD

Answer 1

Decreased GFR (<60ml/min) for more than 3 months, with or without evidence of renal damage.

Question 2

What are the risk factors for CKD?

Answer 2

1. Age
2. Hypertension
3. Diabetes mellitus
4. Obesity
5. Cardiovascular disease

Question 3

How does hypertension cause CKD?

Answer 3

1. Long term hypertension causes the arteries supplying the kidney to thicken.
2. Thickened arteries provide a decreased oxygen and nutrient supply to glomerular cells.
3. Ischaemic injury causes immune cells to arrive and release growth factors
4. Growth factors cause Mesangial cells to convert to mesangioblasts and produce extracellular matrix.
5. This extracellular matrix builds up and causes glomerular sclerosis and scarring = decreased GFR

Question 4

How does diabetes mellitus cause CKD?

Answer 4

1. Excess glucose in blood sticks to proteins in the efferent arteriole of the kidney.
2. Efferent arteriole gets stiff and narrow (arterial sclerosis)
3. Increased pressure in the glomerulous = hyperfiltration
4. Mesangial cells produce more extracellular matrix as a response and over time result in a glomerulo sclerosis = decreased GFR.

Question 5

What is the epidemiology of CKD?

Answer 5

1. Increases with age.

2. associated with other conditions (CVD)

Question 6

What are the presenting symptoms of CKD?

Answer 6

Often asymptomatic

1. Fatigue
2. Nausea and vomiting
3. Peripheral oedema
4. Pulmonary oedema
5. Pruritus
6. Muscle cramps

Question 7

Why does someone with CKD feel fatigued and nauseous?

Answer 7

1. Fatigue is because of the decrease in EPO production = anaemia
2. Nauseous = build up of urea in the blood

Question 8

How is renal osteodystrophy caused in CKD?

Answer 8

1. Vitamin D is no longer activated in the kidney - this leads to decreased Ca2+ absorption.
2. Hypocalcaemia = more parathyroid hormone released.
3. Bones lose Ca2+ and become weaker and brittle (Renal Osteodystrophy)

Question 9

What are the signs of CKD on physical examination?

Answer 9

1. Signs of anaemia
2. Uraemic tinge in skin
3. Hypertension
4. Peripheral oedema
5. Heart arrhythmia

Question 10

Why do you get heart arrhythmia with CKD?

Answer 10

CKD causes potassium retention.

Hyperkalaemia leads to heart arrhythmias

Question 11

What are the appropriate investigations for CKD?

Answer 11

1. Bloods - U&E’s, Hb, Glucose, potassium raised
2. Renal function - Isotopic GFR (GOLD STANDARD)
3. Autoimmune antibodies - ANA (SLE), c-ANCA (polyangiitis)
4. Urinanalysis
5. Ultrasound and CT KUB