Renal pathology Flashcards
What are the purposes of renal biopsy? (3)
Renal biopsy - aim depends on the presentation, usually:
- to establish the diagnosis
- to assess the severity of the renal disease
- to assess the amount of irreversible damage
What type of kidney sections do we use in kidney biopsy?
Thin sections (3um) -> thick will give false positive impression of increased cellularity
What routine stain is used to identify different cells in the kidney?
H&E stain
(Haemotoxylin and Eosin)
What are PAS and silver stains used for?
To highlight basement membrane and connective tissue
What stain is used for amyloid?
Congo red stain
What is elastin stain used for?
to examine the vessels
What are immunofluorescence or immunohistochemistry techniques used for?
Used to identify immune complexes types and localisation
e.g. anti-GBM, IgA, IgG, complement
What is electron microscopy technique used for?
- immune complex - nature and localisation
- glomerular membrane abnormalities
- foot process effacement /pl zamazanie/
In general, what classification of renal pathology is there?
- Primary renal disease -> disease originating from the kidney (e.g. glomerulonephritis)
- Secondary renal disease -> disease originating from elsewhere but manifesting itself in the kidney (e.g. DM)
Clinical presentation of Nephrotic vs nephritic syndrome
IgA nephropathy
- what happens
- what’s the diagnosis
IgA nephropathy
- the most common type of glomerulonephritis
- Abnormal IgA is formed and deposited in the capillaries of glomeruli
- Diagnosis: renal biopsy (to confirm Dx and decide on type of Rx)
What can we see on histology report of IgA nephropathy?
- mesangial expansion
- endocapillary proliferation
- other features: e.g. crescents and thrombosis
*proliferation - a lot more nuclei in the segment; swelling of the cells
What are other findings (outside of glomerulus) in IgA nephropathy?
What is the difference in chronic vs acute damage to the kidney)?
- Acute -> if we Rx we may reverse the changes (aggressive treatment); Rx active disease to stop the inflammatory process
- Chronic -> if fibrosis has occurred, we would not be able to Rx it (no point to Rx aggressively as pt will get side effects but it would not change anything)
What is the most common cause of proteinuria and nephrotic syndrome in adults?
Membranous glomerulonephritis
What’s histological characteristic of membranous glomerulonephritis?
Thickening of glomerular membrane
*thickening = due to IgG deposition along glomerular membrane
What is seen on the silver stain in membranous glomerulonephritis?
Fenestration or spikes
*these are ‘holes’ in the glomerular membrane -> as silver stain stains only membrane and collagen, it would not stain IgG deposits on the membrane
Is there any investigation to differentiate between idiopathic/ primary and secondary membranous glomerulonephritis?
Diabetic nephropathy
- onset of a disease
- most common symptoms
- what to do to delay the progression
Onset: 10 year or more of history of DM
Most common symptoms: proteinuria
To delay the progression: control hyperglycaemia and hypertension
What histological changes are seen in diabetic nephropathy (in glomerulus)?
Glomeruli:
- nodular sclerosis
- diffuse thickening of glomerular membrane -> mesangium will expand (becomes fibrotic) and forms nodules -> so filtration process is affected
*no splitting or spike formation -> as no immunoglobulin deposition
What are other findings (apart from these in glomerulus) in diabetic nephropathy?
These changes happen due to the increased amount of proteins in the urine -> irritation of the tubules and damage to the epithelium
- Interstitial fibrosis, chronic inflammatory cell infiltrate, tubular atrophy
- vessels affected: thickening and sclerosis
Do we do other investigations (thatn normal histology) in a diabetic person presenting with neuropathy?
Yes, we DO.
- immunofluorescence and electron microscopy
- this is to exclude another pathology, e.g. antigen-antibody mediated glomerular disease
What are the histological features of renal amyloidosis?
deposition of abnormal proteins in the kidney (and other organs)
Congo Red staining used to identify the amyloid
Crescents
- what they are
- what do they mean?
Crescents:
- proliferating epithelial cells -> occur with any injury that breaks capillary wall
- crescentic glomerulonephritis = rapidly progressive renal disease
What is this?
Crescenting glomerulonephritis
*proliferation of the cells -> occupy the space in the Bowman’s capsule (no space between the membrane and capillaries) + compression on the capillary tufts
What do crescents may lead to?
Necrosis and destruction of the glomerulus -> as it is compressing on capillary tufts
