Glomerular Disease (Pathology) Flashcards
What is the molecule size above which substances will not be filtered in the glomerulus and remain in the plasma?
Equal or larger in size than albumin
What is the filter barrier? What are the three parts?
The membrane of the glomerulus
Cell cytoplasm, basal lamina, podocyte
What name is given to the tree-like group of cells which support the glomerular capillaries?
Mesangial cells
What is glomerulonephritis?Is it inflammatory?
Disease of the glomerulus
It can be either
Differentiate between primary and secondary glomerulonephritis
Primary disease affects only the glomerulus
Secondary disease also affects other parts of the body e.g. SLE or Wegner’s
What is the aetiology of glomerulonephritis?
Some are due to immunoglobulin deposition
Some have no deposition foe example diabetic glomerular disease
Give four common presentations of glomerulonephritis
Haematuria (blood in the urine)
Heavy proteinuria (nephrotic syndrome)
Slowly increasing proteinuria
Acute renal failure
What are the main causes of haematuria?
Urinary tract infection
Urinary tract stone
Urinary tract tumour
What should be done for a patient who has discoloured urine that provides a positive dipstick result for blood? If these Ix prove normal, what should be done?
A urine sample should be sent off and an ultrasound arranged
Renal biopsy
What is the result of immunoglobulin deposition in the centre of the glomerulus?
It causes increased proliferation of mesangial cells and gets stuck within them and the mesangium becomes clogged, forming more matrix as it enlarges
What is the prognosis of IgA nephropathy?
It is usually self-limiting and will return to normal, however a percentage continue to proliferate and go onto chronic renal failure as the matrix continues to be deposited
What should be done in a patient whose serum albumin is low and a dipstick test is positive for proteinuria?
Should see a nephrologist and if albumin levels in the urine found to be very high then the clinical diagnosis of nephrotic syndrome can be made as there must be a problem with the glomerular filter
A clotting screen should be done and then a renal biopsy
What occurs in membranous glomerulonephritis?
There is a thickening of the glomerular membrane due to IgG deposition between the basal lamina and podocyte. It remains there and activates a complement which punches holes in the filter, allowing the albumin which would normally stay in the plasma to leak through the filter into the urine = nephrotic syndrome
What is the prognosis of mambranous glomerulonephritis?
A quarter reach chronic renal failure within 10 years
What is the cause of the IgG deposition between the basal lamina and the podocytes in membranous glomerulonephritis?
The cause is unknown but there can sometimes be underlying malignancy
Is mesangial thickening always due to immunoglobulin deposition?
No, in diabetic patients, there is matrix deposition in the basal lamina and the mesangial matrix which leads to thickened but leaky basement membranes (complex punching through) and the mesangial matrix compresses capillaries = nephrotic syndrome - diabetic nephropathy
Describe the histopathological changes in diabetic nephropathy
Small compressed capillary lumens due to compression by the matrix
Thickened capillary walls which leak albumin
Increasing mesangial matrix
Adhesions to Bowmans capsule to try to prevent massive leakage of albumin into the urine
What are Kimmelsteil-Wilson lesions?
Gross excess of nodules of the mesangial matrix seen in nephropathy
What are the two factors which influence an inevitable decline in diabetic nephropathy?
If the nephropathy is established
f the diabetic control is poor
What is thh diagnosis in a patient with rapidly increasing serum creatinine? What is the Ix?
Rapidly rising creatinine means acute renal failure
Ultrasound to check no renal tract lesion
Check clotting then renal biopsy
What are the histolopathological changes in crescentic glomerulonephritis?
There is early endothelial damage with fibrin deposition, cellular proliferation and influx of macrophages forming a crescent around the glomerulus within Bowman’s space
What are some causes of crescentic glomerulonephritis?
WEGNER’S GRANULOMATOSIS - form of vasculitis which affects the kidneys, nose and lungs
Microscopic polyarteritis (like Wegner’s)
Antiglomerular basement membrane disease
WHat is a specific test for Wegner’s?
Serum Anti-Neutrophil Cytoplasmic Antibodies
Outline anti-neutrophil cytoplasmic antibodies
They are not deposited in the kidney, and are directed against proteinase 3 and myeloperoxidase - 2 enzymes in the primary granules of neutrophils
The antibodies produce tissue damage via interactions with primed neutrophils and endothelial cells. The reason for their formation is unknown
