Glomerular Disease (Pathology) Flashcards
What molecules are not filtered at the glomerulus?
All proteins equal to or larger than albumin
- Including Immunoglobulins (antibodies)
What are the layers of the glomerular membrane?
- Endothelium (w fenestrations)
- Basal lamina
- Podocyte foot processes (pedicels)
What is the mesangium?
- ‘tree-like’ group of cells which support capillaries at the glomerulus
- It is continuous with the smooth muscles of the arterioles. It’s outside the capillary lumen, but surrounded by capillaries
Describe the flow of blood at the glomerulus
- Blood enters via the afferent arteriole
- 20% of plasma is filtered into Bowmans capsule along with smaller molecules
- Blood containing larger proteins and immunoglobulins leave via the efferent arteriole
What is Glomerulonephritis?
Disease of the glomerulus
- According to slides: can be inflammatory or non-inflammatory
What are the 4 common presentations of glomerulonephritis?
- Haematuria
- Heavy proteinuria (nephrotic syndrome)
- Slowly increasing proteinuria
- Acute renal failure
What are the main causes of haematuria?
- UTI
- Urinary tract stone
- Urinary tract tumour
- Glomerulonephritis
How does IgA cause nephropathies?
Deposition of IgA at the glomerulus causes the proliferation of mesangial cells and increased mesangial matrix deposition
- This causes RBCs to leak into the urine (mechanism unknown)
What is the prognosis for IgA mediated nephropathy?
- Usually self limiting, return to normal
- Small percentage go to chronic renal failure due to continued deposition of matrix and cell proliferation within the mesangium, which obstructs normal blood flow at the glomerulus
If a patient presents with swollen legs and feeling unwell, what is a possible renal ddx?
Glomerulonephritis
- need to test urine protein and serum albumin
- Most likely albumin is being filtered and excreted in the urine
How does IgG lead to membranous glomerulonephritis?
- IgG becomes deposited between podocyte and basal lamina, too big to be filtered into urine
- Basal lamina thickens in attempt to surround and remove the deposit
- IgG activates compliment C3 which punches holes in the glomerular filter
- Leaky filter allows albumin through
What is the prognosis for membranous glomerulonephritis?
25% develop chronic renal failure within 10 years
How does prolonged hyperglycaemia lead to diabetic nephropathy?
- Glycated molecules become deposited in basal lamina and mesangial matrix
- Increased mesangial matrix compresses arterioles and blood flow to glomerulus
- Basement membrane becomes thickened but leaky due to deposits of glycated molecules
- Albumin leaks into urine, membrane may even adhere to Bowmans capsule to prevent mass leakage
What is a Kimmelsteil-Wilson lesion?
Gross excess of mesangial matrix due to diabetic nephropathy, leads to formation of nodules
What is Crescentic glomerulonephritis?
- Cellular proliferation and influx of macrophages (inflammation) into the Bowmans space, around the glomerulus. Crushes the glomerulus
What are some possible causes of crescentic glomerulonephritis?
Granulomatosis with polyangiitis
Microscopic polyarteritis
Antiglomerular basement membrane disease
Other - Many other forms of glomerulonephritis
What is granulomatosis with polyangiitis? (Wegener’s granulomatosis)
A disorder that causes inflammation of the blood vessels (vasculitis) in your nose, sinuses, throat, lungs and kidneys
- Can lead to crescentic glomerulonephritis
What is an investigation that can be done to test for granulomatosis with polyangiitis? (Wegener’s granulomatosis)
- Serum anti-neutrophil cytoplasmic antibodies (ANCA)
How do anti-neutrophil cytoplasmic antibodies (ANCA) cause the inflammation in crescentic glomerulonephritis?
- They are antibodies against enzymes in the primary granules of neutrophils
- Antibodies produce tissue damage via interactions with primed neutrophils and endothelial cells
- Causes inflammation at glomerulus
What is the prognosis for granulomatosis with polyangiitis? (Wegener’s granulomatosis) Are there any treatments?
- Fatal if left untreated
- Cyclophosphamide – 75% complete remission
