8.13 Glomerular And Tubular Disease

Question 1

When doing renal biopsies; at what part do you look?

Answer 1

Renal cortex (glomeruli)

Question 2

Macroscopy vs. Microscopy

Answer 2

• macro - can see with eyes
• micro - look through microscope

Question 3

What does the filtration barrier consist of?

Answer 3

Filtration barrier = endothelial cells + basement membrane + epithelial cells (podocytes with foot processes)

Question 4

Functions of kidneys:

Answer 4

• eliminate metabolic waste products
• regulate fluid and electrolyte homeostasis
• influence acid- base balance
• hormone production

Question 5

What hormones are produced by the kidneys?

Answer 5

• prostaglandins - affect salt & water regulation
• erythropoietin - stim RC production
• 1,25-dihydroxycholecalcififerol - enhances calcium absorption from gut-phosphate reabsorption by renal tubules
• renin - acts on angiotention pathway to ⬆️ vascular tone

Question 6

Classify Glomerular disease:

Answer 6

Primary - kidney is prime target (disease is in the kidney)
Secondary - glomerular injury sec to events elsewhere in the body (eg DM)
Immunological - nephrotoxic antibody; immune complex deposition
Non-immunological

Question 7

What is a Diffuse glomerular injury?

Answer 7

A lesion involving the majority, or all, of the glomeruli (>50%) - kidney/biopsy

Question 8

What is a focal glomerular injury?

Answer 8

A lesion involving some glomeruli (<50%)

Question 9

What is a global glomerular injury?

Answer 9

The whole glomerulus is affected

Question 10

What is a segmental glomerular injury?

Answer 10

A part of glomerulus is affected

Question 11

Crescentric

Answer 11

• Proliferation of cells in Bowman’s space
• compresses the glomerulus

KNOW PICTURE ON SLIDE 25

Question 12

Clinical presentation of Nephrotic syndrome

Answer 12

• severe proteinuria (>3,5 gm per 24hrs)
• resultant hypoalbuminaemia
• leading to oedema
• also hypercholestrolaemia

Question 13

Goodpasture’s syndrome

Answer 13

Anti-GBM disease
- in men
- immunological: nephrotoxic antibody
- IgG antibodies formed against glycoprotein in own glomerular basement membrane (GBM)
- antibody bind with antigen in collagen IV
- binding of IgG activates complement cascade, neutrophils attracted -> proliferative (hypercellular) glomerulonephritis results
- uncommon form of glomerulonephritis <1%
- part where kidney disease occurs together with pulmonary haemorrhage

Presentation:
- presents with rapidly progressive renal failure, sometimes haematuria, proteinuria or nephrititc syn
- hemoptysis

Histologically:
- segmental necrosis with crescent formation can occur

Question 14

Membranous glomerulonephritis

Answer 14

Antiphopholipase A2 receptor = primary

Question 15

Crescentic glomerulonephritis
Clinical features
Three groups

Answer 15

• rapidly progressive glomerulonephritis

Clinical features:
- rapid deterioration. - loss of renal function within few weeks
- within immediate treatment with immunosuppression / Plasmapheresis pt can recover
- chance of permanent damage remains ⬆️

Three groups
1. Anti-GBM disease - goodpasture’s syn
2. Severe forms of IC disease - postinfec GN (complications of other forms of GN)
3. Pauci-immune - no or minimal immune complex material present. Most of these patients (pauci- immune group) have anti-neutrophil cytoplasmic antibodies (ANCA) in the serum, which play a role in some vascular diseases

Question 16

Minimal change disease

Answer 16

• Also known as lipoid nephrosis - lipid in tubular epithelium most obvious LM abnormality
• Pathogenesis - not clear - loss of negative charge of the basement membrane
• Occurs at all ages-in particular in children 2–4
• Usually responds to steroids without permanent damage

Question 17

Systemic lupus erythematosus

Answer 17

• Systemic condition affecting multiple organs - skin, joints, serosal membranes, heart and lungs
• Kidneys involved in about 70% - important cause of morbidity and mortality
• Occurs particularly in women 15 - 40

Question 18

Diabetes mellitus

Answer 18

• Damage involving blood vessels large + small throughout body
• Medium and large arteries: Atherosclerosis
• Small: Arteriosclerosis
• Involvement of the microcirculation, in addition to causing lesions in the retina, nerves and skin, significantly affects the kidneys – diabetic nephropathy
• Diabetic glomerulopathy can cause proteinuria and renal failure
• Basement membrane thickening – yet more permeable to protein
• Nodular expansion of mesangium – nodular glomerulosclerosis
• necrotising papillitis
• Renal papillary necrosis also occurs more frequently in diabetics, with acute pyelonephritis

Question 19

Amyloidosis

Answer 19

Abnormal folded proteins deposited as extracellular material in many organs (kidneys)

Question 20

Can glomerular disease cause vascular damage?

Answer 20

Yes