Pathology + clinical of glomerular disease Flashcards
Define glomerulonephritis
Umbrella term for diseases of the glomerulus (can be inflammatory OR non-inflammatory)
Function of podocytes
Line and wrap the outside of the glomerular capillaries with their foot like processes
-help prevent proteins/other large molecules from being filtered out of blood into bowman’s space
Function of mesangial cells
Lie between the loops of glomerular capillaries and hold them together, supporting them
What things don’t get filtered into bowman’s space from the afferent arteriole
Blood cells
Albumin/ immunoglobulins (antibodies)/ other large proteins
Common aetiology of glomerulonephritis
Leukocyte infiltration, antibody deposition, and complement activation
Glomerulonephritis commonly presents in the following 4 ways (separate presentations)
Haematuria - usually microscopic
Heavy proteinuria - leg oedema
Slowly increasing proteinuria
Acute renal failure
Main causes of haematuria (4 - 3 common, 1 less common)
Urinary tract
- infection
- stone
- tumour
Glomerulonephritis (LESS COMMON CAUSE)
Pathophysiology of IgA nephropathy (a type of glomerulonephritis)
Idiopathic but associated with formation of circulating IgA immune complexes that are prone to depositing in the mesangium of the glomerulus –> irritates the mesangial cells and causes them to proliferate which produces a bigger mesangial matrix –> disrupts filtering ability –> blood and proteins leak into urine
IgA nephropathy (a type of glomerulonephirits) appears within 48 hours of what
URTI or gastroenteritis
IgA nephropathy presents as nephritic syndrome which means they present with what urine findings (2)
VISIBLE haematuria
Proteinuria - less significant than the haematuria
Prognosis of IgA nephropathy
Only self limiting, usually return to normal
Investigations of IgA nephropathy + findings (3)
Urinalysis - urine dipstick +ve for blood
Urine microscopy - shows RBCs, RBC casts
RENAL BIOPSY (DEFINITIVE)
- light microscopy - shows enlarged mesangial matrix
- immunofluoroscence - lights up IgA deposits
3 types of haematuria
Invisible
- microscopic
- dipstick
Visible (macroscopic)
Presentation of membranous nephropathy (think: it’s a non-proliferative form of GN)
Nephrotic syndrome
- oedema
- proteinuria –> FOAMY urine
- hypoalbuminaemia
- hyperlipidaemia –> xanthelasma
Pathophysiology of PRIMARY membranous nephropathy/glomerulonephritis (commonest cause of nephrotic syndrome in ADULTS)
-what happens to GBM
Idiopathic/autoimmune mechanism
-IgG immune complex deposits in the glomeruli –> activates complement system which recruits inflammatory cells to the area which promote inflammation and THICKENING OF GBM –> podocytes become effaced (erased) allowing things to leak into urine
Membranous nephropathy where the glomerular basement membrane becomes very leaky because podocytes are lost, large weight molecules like albumin are easily lost so it’s one of the biggest causes of what syndrome
Nephrotic syndrome
2/3 cases of membranous nephropathy are primary (idiopathic), 1/3 are secondary to (4)
Autoantibodies in response to underlying conditions
Autoimmune diseases- SLE
Hepatitis
Lung/colon cancer
Primary membranous nephropathy is IDIOPATHIC
but has been found to be associated with circulating auto-antibodies to what receptor to form immune complexes
Phospholipase A2 receptor (PLA2R) on podocytes
What test must you do first before renal biopsy
Clotting screen - to determine risk of bleeding from the biopsy
Pathophysiology of diabetic nephropathy* (3)
*Defined by characteristic mesangial expansion, GBM thickening, and glomerular sclerosis leading to the development of Kimmelstiel-Wilson nodules
Due to excess blood glucose OVER-RIDING renal threshold for glucose –> glycosuria
High BG from untreated DM causes high BP which puts strain on the tiny glomerular capillaries as it causes mesangium to expand through stretch
High BG also causes glycation of proteins which stimulate expansion and THICKENING OF GBM –> hyaline arteriosclerosis –> becomes LEAKY
Glomerular filtration barrier consist of 3 layers
fenestrated endothelium, the glomerular basement membrane, and the epithelial podocytes
In diabetic nephropathy, what happens to the mesangium
expands and proliferates which compresses the glomerular capillaries
In diabetic nephropathy, mesangial matrix expansion starts to invade the glomerular capillaries and produces nodules of excess mesangial matrix called
Kimmelstiel-Wilson nodules,
What is crescentic glomerulonephritis (aka rapidly progressive GN)
Just a name used to describe forms of glomerulonephritis that are characterised by CRESCENT SHAPED PROLIFERATION OF CELLS in bowman’s space
usually are RAPIDLY PROGRESSIVE forms of GN and associated with a poor prognosis
Crescentic glomerulonephritis (a name used to describe forms of glomerulonephritis that are characterised by CRESCENT SHAPED PROLIFERATION OF CELLS in bowman’s space)
What composes the crescents
Cellular proliferation and macrophages
What is granulomatosis with polyangiitis (aka Wegener’s granulomatosis)
A form of crescentic glomerulonephritis
-is a systemic vasculitis that involves inflamed vessels in the kidneys, lungs