Renal diseases

Question 1

What are the cells of the visceral layer in the bowmans capsule known as?

Answer 1

Filtration slits

Question 2

What does it mean that the plasma membrane of the endothelial cells are fenestrated?

Answer 2

It has pores each covered with a thin membrane

Question 3

Does albumin cross the basement membrane?

Answer 3

Only a small fraction (it is small enough but it is negatively charged and repelled)

Question 4

What is the glomerular filtration rate?

Answer 4

Amount of filtrate produced by kidneys/minute (usually 120-125mL/min)

Question 5

What is the effect of an increase in blood pressure on the GFR?

Answer 5

It would increase (by increasing the hydrostatic pressure)

Question 6

What is the effect of dehydration on the GFR?

Answer 6

It would decrease (total blood volume has dropped)

Question 7

What is the effect of obstructions to urine flow on the GFR?

Answer 7

It would decrease (increasing capillary hydrostatic pressure)

Question 8

What is the effect of glomerular loss on the GFR?

Answer 8

It would decrease

Question 9

How do you calculate clearance?

Answer 9

(subU/subP) x urine volume secreted

Question 10

What is creatinine?

Answer 10

A waste product from energy metabolism in muscle (rate of production determined by total muscle mass)

Question 11

Why is creatine useful for clearance?

Answer 11

• readily filtered
• not reabsorbed
• insignificant amount secreted by tubules

Question 12

What is wrong with creatinine clearance?

Answer 12

• 24hr urine prone to error
• often estimate under actual clearance
  solution: equations using only serum creatinine level

Question 13

What are the 3 categories of glomerular disorders?

Answer 13

• immunological (glomerulonephritis)
• non-immunological (diabetic glomerulosclerosis)
• inherited (types of nephrotic syndrome)

Question 14

What is glomerulonephritis?

Answer 14

Conditions with an inflammatory basis

Question 15

What occurs with glomerulonephritis?

Answer 15

• Damage to the endothelium
• Dramatic changes in the permeability of filtration (allows RBC)
• Decreases in GFR

Question 16

What are causes of glomerulonephritis?

Answer 16

Accumulation of antibodies

• Induced by infectious agents + antibodies being trapped
• Induced by binding of antibodies to membrane

Question 17

What are the 5 clinical manifestations of glomerulonephritis?

Answer 17

• Decrease urine output
• Hypertension
• Haematuria + RBC
• Protein in urine
• Azotaemia (high blood urea)

Question 18

Why does glomerulonephritis cause hypertension?

Answer 18

Less plasma leaves the capillary = greater blood volume

Question 19

What is nephrotic syndrome?

Answer 19

An increased glomerular permeability to protein

Question 20

How is nephrotic syndrome diagnosed?

Answer 20

Substantial proteinuria (>3.5g/day) 
accompanied with: 
-Hypoalbuminaemia + oedema
-Lipiduria
-Hyperlipidaemia

Question 21

What is the mechanism behind primary defects in nephrotic syndrome?

Answer 21

(Inherited)

-minimal change disease where podocytes are absent

Question 22

What is the mechanism behind secondary defects in nephrotic syndrome

Answer 22

Autoimmune disease e.g. lupus or diabetes mellitus

Question 23

What is the mesangium?

Answer 23

network of fibres and cells that hold the glomerulus together

Question 24

what are the 2 types of mesangial cells?

Answer 24

• Phagocytic cells (engulf material that pass through fenestrations but not slits)
• Contractile (reduce SA for filtration)

Question 25

What is diabetic glomerulosclerosis?

Answer 25

- Increased GFR + permeability to protein | - Loss of nephrons

Question 26

What occurs in the early stages of DG?

Answer 26

microalbuminuria (24hr excretion of 30-300mg) - Poor prognosis - indicator of cardiovascular disease

Question 27

What is chronic kidney disease?

Answer 27

- irreversible renal damage - drop in GFR - Often death due to cardiovascular complications before end stage kidney disease

Question 28

When do symptoms and signs become obvious in CKD?

Answer 28

when GFR < 50%

Question 29

What are risk factors for CKD?

Answer 29

- Hypertension - Diabetes - Smoking - BMI > 30 - Family history - >50

Question 30

What are some clinical manifestations of CKD? (1)

Answer 30

- Loss of sodium balance - Elevated blood K+ levels (cardiac arrhythmia) - Depleted blood bicarb level + impaired H+ secretion (metabolic acidosis)

Question 31

What are some clinical manifestations of CKD? (2)

Answer 31

- Chronic loss of renal supportive tissue - Increase in phosphate, less calcum - Less vitamin D (calcitriol) - PTH attacks bones

Question 32

What is a complication of CKD?

Answer 32

Renal rickets / osteodystrophy

Question 33

What is a haematological disorder of CKD?

Answer 33

Erthropoietin production is insufficient (worsens with elevated blood urea nitrogen) - Less RBC - Leads to anaemia

Question 34

What are skin disorders of CKD?

Answer 34

- Dry skin + mouth | - Disorders due to deposition of phosphate + urea crystals (pruritis)

Question 35

What is uraemia?

Answer 35

Azotaemia (elevated BUN))

Question 36

What can uraemia cause (6)

Answer 36

-Hypertension, nausea, vomiting, anorexia, peripheral neuropathy (restless leg), uraemic encephalopathy (alertness)