Session 8: Glomerular Pathology Flashcards
Give examples of where glomerular damage might occur in within the glomerulus.
Subendothelial damage
Glomerular basement membrane damage
Subepithelial damage and damage to podocytes
Mesangial damage and paramesangial damage
Why is it important to know where the damage in the glomerulus has occured?
Because the site of glomerular injury will determine the clinical presenation of the condition.
How can you determine where the damage has occurred in the glomerulus?
By biopsy and then light microscopy to investigate the histology.
Give examples of histological apperances in glomerular conditions.
Focal
Diffuse
Segmental
Global
Membranous
Proliferative
Crescent
Glomerulosclerosis
Glomerulonephritis
Explain focal pathology
Involving less than 50% of the glomerulus on light microscopy
Explain diffuse pathology
Involving more than 50% of glomerulus on LM
Explain segmental pathology
Involving part of the glomerular tuft
Explain global pathology
Involving the entire glomerular tuft
Explain membranous pathology
Thickening of the glomerular capillary wall
Explain proliferative pathology
Increased number of cells in the glomerulus. These can either be glomerular cells or invading inflammatory cells.
Explain crescent pathology
Accumulation of cells in the Bowman’s space
(Associated with more severe disease)
Explain glomerulosclerosis pathology appearance
Segmental or global capillary collapse. No filtration occuring at the sclerotic area
Explain glomerulonephritis pathology appearance
Any condition associated with inflammation of the glomerular tuft
What is nephrotic syndrome?
A triad of symptoms involving damage of the subepithelial region and specifically to the podocytes of the glomerulus. The podocytes are responsible for fine filtration and selectivity of substances across the glomerulus and into the tubular duct.
What is the triad of symptoms in nephrotic syndrome?
Proteinuria of over 350mg/mmol in 24 hours
Hypoalbuminaemia
Oedema
Explain the pathophysiology of nephrotic syndrome.
Podocyte damage leads to less selectivity of the glomerular filtration barrier. This leads to an increase in number of proteins being able to enter the tubular lumen. A large amount of these proteins will be albumin.
This leads to a decreased concentration of albumin in the blood leading to lower capillary oncotic pressure. As the oncotic pressure has decreased the net force between the capillary oncotic pressure, the capillary hydrostatic pressure and the hydrostatic interstitial pressure has now changed.
This leads to the oedema. Commonly the oedema can be found peripheral in hands and feet as well as periorbital oedema.
State of GFR and blood pressure in nephrotic syndrome.
Usually normal
Give another common clinical presenation of nephrotic disease that isn’t included in the triad of symptoms.
Hyperlipidaemia
Explain why hyperlipidaemia might occur in nephrotic syndrome.
As the albumin is low the liver will start to produce more albumin to compensate.
It is thought that this mechanism is accompanied by hepatic synthesis of lipids (cholesterol) as well.
Give common primary causes of nephrotic syndrome.
Minimal Change Glomerulonephritis
Focal Segmental Glomerulosclerosis (FSGS)
Membranous Glomerulonephritis
Give common secondary causes of nephrotic syndrome.
Diabetes Mellitus (T1 &T2)
Renal amyloidosis
Connective tissue disorders such as Systematic Erythematous Lupus (SLE)