Urinary Week 9 - glomerular injury Flashcards
What renal compartments can be damaged in renal disease
Glomerular
Tubular
Interstitial
Vascular
Sites of glomerular injury
Subepithelial
Glomerular basement membrane
Subendothelial
Mesangial
Secondary causes of glomerular injury
Diabetes
Hypertension
What occurs in blockage of the glomerulus
Renal failure (nephritic syndrome)
Low GFR
High stage AKI
Haematuria due to degradation of the glomerulus
Hypertension due to failure to control blood volume
What occurs in leakage of the glomerulus
Proteinuria including nephrotic syndrome
Haematuria
Criteria for nephrotic syndrome
> 3.5g filtered in 24 hours
Isolated proteinuria suggests what site of glomerular injury
Sub epithelial
Symptoms of nephrotic syndrome
Hypoalbuminaemia causes generalised oedema
Poor renal perfusion pressure leads to RAAS activation so more fluid retention
Primary causes of nephrotic syndrome/proteinuria
Minimal change glomerulonephritis
Focal segmental glomerulosclerosis
Membranous glomerulonephritis
Secondary causes of nephrotic syndrome/proteinuria
Diabetes mellitus (causes microvascular damage, BM thickening, mesangial sclerosis, progressive proteinuria and progressive renal failure) Amyloidoses
Describe minimal change glomerulonephritis - demographic, symptoms, treatment, outcome, histology
Presents in childhood/adolescence and incidence decreases with increasing age
Causes heavy proteinuria or nephrotic syndrome
Responds well to steroids
Usually doesn’t progress to renal failure
Under an EM, widened filtration slits are visible
Pathogenesis of minimal change glomerulonephritis
Unknown
Damage caused by a circulating factor that is not an immune complex
What does focal segmental glomerulosclerosis include
Focal - <50% glomerulus affected
Segmental - involves glomerular tuft
Glomerulosclerosis - patchy scarring of glomerulus
Describe focal segmental glomerulosclerosis - demographics, symptoms, treatment, outcome
Presents in adults
Causes nephrotic syndrome and glomerulosclerosis
Not very responsive to steroids
Can progress to renal failure
Pathogenesis of focal segmental glomerulosclerosis
Unknown
Damage is caused by a circuiting factor which is not an immune complex
What is an immune complex
Antigen-antibody complex that circulates and activates complement
Describe membranous glomerulonephritis - demographics, symptoms, outcome, histology
Commonest cause of nephrotic syndrome in adults
Complement activation causes cell damage
1/3 recover, 1/3 don’t improve and 1/3 progress to renal failure
Capillary loop is thickened and BM appears spiky due to immune complex deposition
Pathogenesis of membranous glomerulonephritis
Antigen and IgG are filtered and react in the sub epithelial space to produce immune complexes I.e it has an autoimmune basis
May also be secondary to malignancies likely lymphoma which triggers the immune system
Causes of haematuria
IgA nephropathy
Hereditary nephropathy
Causes of nephritic syndrome
Good pasture syndrome
Vasculitis
Demographics of IgA nephropathy
Any age
Presentation of IgA nephropathy
Haematuria
Triggered by mucosal infections (IgA secreted onto mucosa and activated in infection)
May be proteinuria
Treatment and outcome of IgA nephropathy
No treatment (can have transplant) Significant number progress to renal failure
Where is IgA usually deposited and why
Mesangium because there is no basement membrane between the mesangium and blood
What are the types of hereditary neuropathies
Thin glomerular basement membrane neuropathy
Alport syndrome
Describe thin glomerular basement membrane nephropathy
Isolated haematuria
Thin glomerular basement membrane
Benign
Describe Alport syndrome
X linked condition Abnormal collagen IV production Deafness Abnormal glomerular basement membrane Progresses to renal failure
Describe good pasture syndrome
Rapidly progressing glomerular nephritis
What is common in smokers with good pastures syndrome
Haemoptysis
Cause of good pasture syndrome
Autoantibody (IgG) against collagen IV glomerular basement membrane
Outcome of untreated good pasture syndrome
Loss of kidney architecture (irreversible) so fibrosis occurs
Treatment of good pasture syndrome
Immunosuppression
Plasmapheresis
What is vasculitis
Group of systemic disorders causing inflammation of blood vessels
Describe vasculitis
Blood vessels are attacked in the glomerulus by anti neutrophil cytoplasmic antibodies (ANCA) which damage endothelia by activating neutrophils
What is required in suspected vasculitis
Urgent biopsy to confirm
Histological appearance of vasculitis
Segmental necrosis and crescent formation on a light microscope
