Glomerular Pathology Flashcards
What makes up the filter in the glomerulus?
The filter in the glomerulus is made up from the podocytes on the tubular side creating slit diaphragms, then the basement membrane made up of charged particles and a lattice work of collagen to physically and electrostatically repel particles and finally the endothelium with large pores (that don’t really filter) its role is more to maintain structures, blood flow and prevent thrombus formation.
Why will disease effecting the blood supply to a glomerulus also effect the rest of the nephron?
As the efferent arteriole supplies the whole nephron after it leaves the glomerulus.
What’s the difference between nephrotic and nephritic syndrome?
Two main syndromes associated with glomerular pathology one called the nephrotic syndrome – loss of lots of protein mostly albumin – hypoalbuminemia leading to oedema – usually present without renal failure. Hypercholesterolaemia and lipiduria. May also have increase DVT and PE risk due to loss of anti thrombin III.
Nephritic syndrome – Generalise inflammation of the glomeruli causing reduction in GFR, mild oedema, and hypertension from salt and water retention. Hameaturia and proteinuria.
What are immune complexes and how do they cause damage?
Immune complex deposition (antigen antibody)/circulating factors forming a mass that is filtered into the kidney activating complement leading to cell damage.
What are the common primary and secondary causes of nephrotic syndrome?
Likely to be podocytes/sub epithelial damage. Common primary cause is minimal change Glomerulonephritis, focal segmental glomerulosclerosis (FSGS) and membranous glomerulonephritis. Common secondary causes – diabetes mellitus and amyloidosis.
What is minimal change glomerulonephritis?
Childhood/adolescence, incidence reduces with increasing age, heavy proteinuria. Responds to steroids, may recur and usually no progression to renal failure. Called minimal change because the glomerulus looks normal macroscopically but under an EMS all the podocytes have been lost (podocyte is said to be defaced). The reason this occurs is unknown.
What is FSGS (Focal segmental glomerulosclerosis) spectrum?
Spectrum from Minima, change to FSGS. FSGS occurs in adults, less responsive to steroids, glomerulus becomes scarred, circulating factora cause it, somehow damaging podocytes. Progressive to renal failure.
What is Membranous glomerulonephritis?
Most common cause of nephrotic syndrome in adults. Rule of thirds – 1/3 get better/1/3 stay the same and 1/3 progress to renal failure and require dialysis. Immune complex deposits probably autoimmune associated. May be secondary to other pathologies such as lymphoma (usually malignancies). Occurs because the capillaries becomes very thick with immune deposits.
How do the sub epithelial deposits in membranous Glomerulonephritis occur?
Sub epithelial deposits – we amount an immune response to an antigen on the podocytes. Antibody IgG is small enough to get through to the podocytes.
How does diabetes mellitus cause nephrotic syndrome?
Progressive proteinuria, progressive renal failure, microvascular – small blood vessels are damaged – mesangial sclerosis nodules and basement membrane thickening. All constituents of the glomerulus is damaged by the high blood glucose.
Which glomerular disease cause haematuria and Nephritic syndrome?
Haematuria - IgA nephropathy, thin glomerular basement membrane disease/hereditary nephropathy (Alport)
Nephritic syndrome - good pasture syndrome (Anti-GBM disease), vasculitis.
What do immune complexes look like under an EM?
Looks like lumps of coal (any immune complex deposit).
What is IgA nephropathy?
Most common glomeurlar disease. IgA deposited in the glomerulus. Any age, classically present with visible/invisible haematuria, relationship with mucosal infections as IgA protects our mucosal surfaces, variable histological features and course, +/- proteinuria, significant proportion progress to renal failure and there is no effective treatment. Glomerulus looks very cellular and there is mesangial damage because this is where most of the IgA is deposited as there is no filter (no BM) at the mesangial.
What is Alport’s syndrome?
Alport syndrome – X linked, abnormal collagen IV associated with deafness, abnormal appearing GMB, progresses to renal failure.
What is thin GBM nephropathy?
Thin GBM nephropathy – benign familial nephropathy, isolated haematuria, thin GBM benign course. i.e no renal failure
