Pathology 1 Flashcards
What is unusual about the basement membrane?
It is charged
What comprises the basement membrane?
Basement membrane has specalized structure; includes Type IV collagen and negatively charged proteoglycans
What lines the surface of the capillaries?
What is special about them?
Endothelium
Fenestrated
What are mesangial cells?
In the stalk that supports the capillaries
What are the components of nephrotic syndrome?
- oedema, typically affecting the whole body
- proteinuria (generally more than 3 or 4 g/day)
- hypoalbuminaemia
- hyperlipidaemia (liver responds with this)
What is alport syndrome?
Some people inherit an abnormal gene coding for the collagen subtype in the glomerular basement membrane
What happens if the basement membrane is not negative?
Rats with reduced negative charge in the GBM lose protein
What else can go wrong in the foot space?
There is a mutation in the proteins sitting in the fine space between adjacent podocytes
Common causes of proteinuria?
Diabetes mellitus
Some forms of glomerulonephritis
–Minimal change disease
–Membranous glomerulonephritis
–Others
Amyloid deposition
Inherited abnormalities in those proteins between adjacent podocytes
What is the only cause of proteinuria?
Proteinuria results from a glomerular filtration abnormality
What is acute renal failure?
Not enough renal filtrate to filter enough urea and creatinine
What is pre-renal ARF?
Not enough blood perfusing the kidney for it to do its job
What is renal ARF?
Some problem with the machinery itself, whether glomerular, tubular etc.
What is post-renal ARF?
problems downstream of the kidney, like prostatic obstruction
Causes of ARF?
Acute tubular necrosis or ATN (the commonest renal cause of acute renal failure)
Acute glomerulonephritis
Acute interstitial nephritis
Others e.g. vascular disease
What is the most common of glomerulonephritis?
Prone to trapping of immune complexes in the tuft
Activate complement
Chemoattractant
How many types of glomerulonephritis are there?
Many - each have different progressions
What are the different forms of GN?
–The first form described well was Acute Post Infectious GN, following Scarlet Fever (Gp A Streptococcus infection)
–The commonest form in Australia is IgA Nephropathy (leading typically to haematuria, often without acute renal failure)
–A common form causing proteinuria is Membranous Nephropathy
How do Glomeruli react to immune complex-mediated injury?
i) The glomerular cells proliferate
a. Mesangial
b. Endothelial
c. Epithelial / podocytes
ii) Inflammatory cells may arrive
a. Neutrophils
b. Lymphocytes and monocytes
c. The basement membrane may proliferate
i. New layers of b.m.
ii. Spikes or protrusions on the epithelial surface
What do diffuse and focal mean?
Every glomerulus in her biopsy is abnormal (Diffuse, not Focal GN)
What do Global and segmental mean?
all or most of each glomerulus is involved= Global. Segmental = part
How is glomerular disease diagnosed?
- Clinical findings
- Light microscopy
- Immunostains
- Electron microscopy
What are a couple of causes of nephropathy from diseases?
Glomerulonephritis in Systemic Lupus Erythematosis
IgA Nephropathy
Membranous Glomerulonephritis with immune complex deposits lying on the outside of the basement membrane, under the podocytes.
What is a cresent?
Necrosis of a segment of the glomerulus often leads to a characteristic response, seen generally in clinically severe cases of acute renal failure
It is called a Crescent and consists of exuded fibrin, monocytes and podocytes
It is not specific for any one form of GN, rather it is the response to severe injury with necrosis of a segment of the glomerular tuft
What is diabetic nephropathy?
Early on, DM is a major cause of protein leakage and nephrotic syndrome
Later as damage accumulates, it is a major cause of chronic renal failure
