Renal Flashcards
Renal disease can affect different sitdes of the nephron.
How can it be differentiated/ what different sites can be affected?
- Glomerulus
- Tubules and Interstitium
- Blood vessles
(Just one way of classyfiying renal disease, other things also can be different)
How does immune complex deposition in the kidney cause disease?
Generall immune complec is just combination of antibody and antigen
Can deposit in different and several sites of the nephron and therefore can cause different presentation
Can cause
1. Direct obstruction
2. driver further inflammatory responses and therefore cause damage
Recall the components of the normal glumerular filtration Barrier
3 Layers
- Fenestrated epithelium of capillaries
- Basement membrane (with charge)
- Podocytes
What are two different renal syndromes that can appear due to damage to the glomerulus?
What are the most common causes?
Nephrotic syndrome
Primary
- Minimal change disease
- Membranous glomerular disease
- Focal segmental glomerulosclerosis
Secondary
- e.g. diabetes, amyloidosis, SLE
Nephritic syndrome
- Acute post-infection
- IgA nephropathy
- Rapidly progressive glomerulonephritis
- Alport’s syndrome
- Thin basememnt membrane disease
What is Nephrotic syndrome?
(Definition)
Not a single disease but a constellation of features that can be achieved in several renal diseases
1. proteinuria (>3g/24h OR protein:createning ration >300mg/mmol) 2. hypoalbuminaemia (<30g/L), 3. oedema and
(+/- hypercholesterolaemia)
What is the pathophysiology of Nephrotic syndrome?
Damage to podocytes → structural damage of glomerular filtration barrier → massive renal loss of protein
Structural Damage to Glomuerular Filtration barrier leads to
1. Loss of charge of Filtration Barrier –> loss of selectivity of filtration barrier (particularly for albumin)
2. Podocyte damage –> non-selective proteinuria
What are the main primary causes of Nephrotic syndrome?
- Minimal change disease
- Membranous glomerular disease
- Focal segmental glomuerlosclerosis
What are some of the secondary causes of Nephrotic Syndrome?
Most commonly
1. Diabetes
2. SLE
3. Amyloidosis
What is Minimal Change disease?
What is the pathophysiology?
It is a primay glomerular disease usually presenting clinically with nephrotic syndrome (most common cause of nephrotic syndrome in Children)
Exact pathophysiology if know but thought that
1. T-cell release cytokines –> loss of podocytes foot processes–> loss of charge –> selective protienuria
Due to loss of charge.
BUT:
- No changes in light microscopy
- NO immune deposits
What is the aetology of Minimal change disease?
Usually idiopathic
But is associated with
1. recent allergic reaction
2. exzema, astham
What is the Epidemiology and clinical presentaiotn of Minimal Change disease?
75% are in children : most common cause of nephrotic syndrome in children
–> Presentation with
1. Frothy urine/ proteinuria
2. Swelling (periorbital in children)
How is the diagnosis of Nephrotic syndrome/ Minimal change disease usually made?
1. Diagnosis of nephrotic syndrome
- Urine dip: proteinuria, no haematuria
- Urine protein:creatinine ratio >300mg/mmol
- Serum albumin low
- total cholesterol high
- immunoglobulins low
2. Cause of nephrotic syndrome
- exclude other causes (complement levels, urine microscopy, Renal ultrasound)
- Renal biopsy (in adults, avoided in children)
What is the management and prognosis of minimal change disease?
Management: Immunosuppression
- Steroids (Prednisolone)
- Cyclosporin 2nd line
(as pathophysiology due to cytokine release)
Very good prognosis
- 90% respond well to steroids
- under 5% develop end-stage renal failure
What is Membranous glomerular disease?
What is the pathophysiology?
It is a form of Primary (or secondary) Glumoerular disease usually presenting with Nephrotic syndrome
Anti-phospholipase A2 receptor antibodies (anti-PLA2R antibodies)
- bind to PLA2R (an autoantigen in glomerular podocytes) and thereby form immune complexes that activate the complement system,
- leading to podocyte injury
What are the histological changes seen in Membranour glomerulonepthritis (membranous nephropathy)?
- Under Light Microscopy
- Electron microscopy
- and Immunofluorescens
Pathophysiology is due to deposition of antibodies between podocytes and the basal membrane
- On Light Microspy: Diffuse glomerular basement membrane thickening
- Electron Microscopy: subepithelial dense deposits (IgG and C3) with a spike and dome appearance
- Immune complex depositoin along entired Glomerular Basememet membrane
What is the Epidemiolgy and aetiology of Membranous nephropathy?
Most common cause of nephrotic syndrome in adults of European, Middle Eastern, or North African descent (30%)
It can be
1. Primary: Idiopathic (production of antibodies against Phospohlipase A2 receptors)
- Or Secondary: SLE, infections (Hepatitis, syphillis, Drugs, Malignancies
What is the treatment and prognosis of Membranous nephropathy?
1.Steroids (but usually poor response)
2.RAAS inhibitory (to control BP)
3.trial of other immunosuppressive therapies
40% will have end-stage renal failure after 2-20 years
What is Focal segmental Glomerulosclerosis?
What is the pathophysiology?
Primary glumerular disease, and the most common cause of Nephrotic syndrome in adults of afro-carribean descent
Sclerosis of glomeruli → damage and loss of podocytes
What is the aetiology of Focal Segmental glumerulosclerosis?
- Primary : usually idiopathic
can be secondary due ot obesity, HIV or drugs
What is the epidemiology of Focal segmental glomerulosclerosis?
Most common cause of nephrotic syndrome in adults, especially in African American and Hispanic populations
What are the histological changes in Focal segmental Glomerulosclerosis on
1. Light microscopy
2. Electronmicroscopy
3. Immunoflourescence
Pathophysiology: Sclerosis
- LM: Focal and segmental glomerular consulidation and scarring, hyalinosis
- EM: loss of podocyte foot processes
- No immune deposits
What is the management and prognosis of Focal Segmental Glumerulosclerosis?
- trial of immunosuppressants : Steroids (about 50% responsive), Calcineurin inhibitors 2nd line
ACEi, ARB to control BP
Prognosis
1. 50% will develop end-stage renal failure within 10 years
What are the epidemiology and the histopathological features of diabetic nephropathy?
- Leading cause of end-stage renal failure in high-income countries
Changes include
- Thickening of the glomerular basement membrane (increased permeability) (throughout)
- Eosinophilic nodular glomerulosclerosis (Kimmelstiel-Wilson nodules) (yellow)
- Hyaline thickened arteriole (blue overlay)
What is the difference between Nephrotic and Nephritic syndrome?
Both, Nephrotic and Nephrotic syndromes are common clinical manifestations of glumerular diseases
They are defined by different characteristics (table) and have distinctive pathophyshiologies.
Most noticable differences
1. High Loss of proten = Nephrotic syndrome
2. Haematuria = Nephritic syndrome