11.2 Glomerulonephritis

Question 1

What is glomerulonephritis (and the more appropriate term)? Is it acute or chronic?

Answer 1

• Glomerulonephritis is usually regarded as inflammation of the glomeruli in the kidneys
• However, not all GN are inflammatory in histological nature - “glomerulopathy” may be more appropriate
• It can be either acute or chronic

Question 2

Describe the clinical features of glomerulonephritis

Answer 2

• Haematuria
• Proteinuria
• Oedema
• Nausea/vomiting
• Oliguria
• Fatigue
• Decreased GFR

Question 3

Describe some causes (and corresponding treatments) for glomerulonephritis

Answer 3

• Infection (give antibiotics)
• Autoimmune disease (such as lupus nephritis or goodpasture’s disease)
• Generalised vasculitis

Question 4

Is proteinuria worse in nephritic or nephrotic syndromes? What is the threshold of the answer to the previous question in terms of daily protein loss?

Answer 4

Nephrotic (remember Matt Arnold)

Nephrotic threshold is 3.5g/day

Question 5

Why might there be high levels of triglycerides and cholesterol in the blood during nephrotic syndrome?

Answer 5

Because the liver tries to compensate for massive proteinuria, but if it can’t make enough replacement albumin (despite hypoalbuminaemia), it spits out TAGs instead.

Question 6

Nephritic vs nephrotic syndrome

Answer 6

Nephritic: haematuria, proteinuria (less than nephrotic), hypertension

Nephrotic: massive proteinuria (>=3.5g/day), oedema, hypoalbuminaemia, hypercoagulability

Question 7

What is the relationship between glomerulonephritis and nephrotic/nephritic syndrome? Are they categories of one another? The same thing? Explain.

Answer 7

• Glomerulonephritis refers to inflammation of the glomerulus within the kidney
• Nephrotic/nephritic syndromes are exactly that; syndromes. They refer to specific collections of symptoms. Glomerulonephritis can cause these syndromes, but the syndromes themselves are not comparable to GN. They are in different categories.

Question 8

What symptoms make up nephritic syndrome

Answer 8

• Haematuria
• Mild proteinuria
• Oliguria
• Oedema
• Hypertension

Question 9

What symptoms make up nephrotic syndrome

Answer 9

• Heavy proteinuria
• Subsequent hypoalbuminuria
• Heavy oedema (since there is nothing holding the fluid in)
• Hyperlipidaemia (why?)

Question 10

What is rapidly progressive GN?

Answer 10

Acute severe drop in GFR associated with glomerulonephritis.

Question 11

Macro vs microscopic haematuria

Answer 11

Macroscopic: visible to the naked eye
Microscopic: visible only on dipstick/microscopy

Question 12

How do we detect glomerulonephritis?

Answer 12

• Not difficult: do a urine dipstick test
• Looking for blood and protein in urine, both of which are leaked into urine following inflammation of the glomerulus
• Also, urine microscopy shows dysmorphic RBCs with cytoplasmic blebs (acanthocytes; acanthos = thorny flower)

Question 13

Why is it a bad idea to use creatinine to detect glomerulonephritis?

Answer 13

• Inversely exponential relationship
• By the time creatinine is above normal range, over half of GFR is lost

Question 14

How do we diagnose the cause of glomerulonephritis?

Answer 14

• Renal biopsy (we have no blood test at the moment)
• Some aetiologies have diagnostic blood tests

Question 15

What are glomerular crescents? What do they indicate on histology?

Answer 15

• They are proliferation of bowmans capsule endothelium, forming an abnormal crescent-like structure alongside the glomerulus
• They indicate severe glomerulonephritis

Question 16

The world’s most common primary glomerulonephritis is…

Answer 16

IgA glomerulonephritis

Question 17

What is synpharyngitic haematuria? What condition is it known to occur in?

Answer 17

• Haematuria close in time to the development of URTI or GI infection
• Thought to occur in IgA nephropathy

Question 18

Explain the pathophysiological mechanism of IgA nephropathy

Answer 18

• Abnormal IgA produced, which the body attacks with other Abs, forming immune complexes
• These immune complexes deposit in the mesangial cells of the glomerulus, causing localised inflammation and permanent kidney damage

Question 19

Clinical features of IgA nephropathy

Answer 19

• Synpharyngitic haematuria
• Proteinuria
• Oedema (typically in face and legs)
• Hypertension
• Decreased GFR

Question 20

Pathological findings of IgA nephropathy

Answer 20

Mesangial proliferation and signs of IgA deposition in mesangial areas (such as on immunofluorescense staining)

Question 21

Anti-GBM glomerulonephritis/goodpastures pathophys and clinical features

Answer 21

• Loss of tolerance of type IV collagen, which is found in GBM and lungs, leading to autoantibody mediated attack
• Often leads to haemoptysis from lungs
• In terms of kidneys, patients always present with rapidly progressing glomerulonephritis, loss of GFR, proteinuria, and haematuria

Question 22

Pathological findings in goodpasture’s

Answer 22

• IgG autoantibody deposition in GBM

(G for Goodpasture’s)

Question 23

Clinical features of post-strep glomerulonephritis

Answer 23

• Smoky-dark urine (strep = s = smoky)
• Haematuria
• Mild peripheral oedema
• Hypertension
• Hypocomplementaemia
• Varying ARF

Question 24

Pathologgical findings of post-strep glomerulonephritis

Answer 24

Positive antibodies for DNAaseB, streptolysin-O, and hylauronidase