Glomerulonephritis Flashcards
What does focal mean with regards to glomerulonephritis?
affecting only some glomeruli
What does diffuse mean with regards to glomerulonephritis?
affecting all glomeruli
What does segmental mean with regards to glomerulonephritis?
affecting only part of glomerulus
What does global mean with regards to glomerulonephritis?
affecting whole glomerulus
What does proliferation mean with regards to glomerulonephritis?
increase in number of cells
What does expansion mean with regards to glomerulonephritis?
increase in intercellular matrix
What does crescent mean with regards to glomerulonephritis?
proliferation of cells within Bowman’s space
Describe some mechanisms underlying glomerulonephritis
Immunological:
- antibody binding to intrinsic glomerular antigens eg. Goodpasture’s disease
- antibody binding to ‘planted’ glomerular antigens eg. post-strep glomerulonephritis
- deposition of circulating antigen-antibody complexes eg. lupus nephritis
- non-specific deposition of circulating antibody eg. IgA nephropathy
Vascular:
- ‘pauci-immune’ capillary inflammation (eg. systemic vasculitis)
Indications for renal biopsy
nephrotic syndrome (adults)
renal dysfunction of unknown cause (particularly acute)
to guide treatment or assess prognosis when diagnosis known
dysfunction of transplant kidney
(haematuria)
(proteinuria)
Complications of renal biopsy
pain
bleeding
Absolute/relative contraindications to renal biopsy
abnormal clotting/thrombocytopenia
drugs (aspirin, clopidogrel, warfarin, DOACs etc)
uncontrolled hypertension (>170/100)
single kidney
hydronephrosis
UTI (pyelonephritis)
How are renal biopsies interpreted?
light microscopy
immunostaining (looks for immunoglobulin or complement components)
electron microscopy (ultrastructural detail including immune deposits)
Modes of presentation of renal disease
haematuria
proteinuria
hypertension
nephrotic syndrome
nephritic syndrome
AKI
CKD
Nephrotic syndrome signs/symptoms
proteinuria
hypoalbuminaemia
oedema
Describe minimal change disease
commonest cause of nephrotic syndrome in children
electron microscopy = fusion of podocyte foot processes
steroid-responsive
usually idiopathic
What is the commonest cause of nephrotic syndrome in children?
minimal change disease
Minimal change disease causes
usually idiopathic
drugs (eg. NSAIDs)
lymphoma
How does focal segmental glomerulosclerosis (FSGS) present?
nephrotic syndrome +/- renal impairment
focal involvement of kidney - may be missed on biopsy
Causes of focal segmental glomerulosclerosis
obesity
IV heroin use
HIV
drugs (eg. pamidronate)
What is the commonest cause of nephrotic syndrome in adults?
membranous nephropathy
What does histology show in membranous nephropathy?
spikes on basement membranes
IgG deposition
What conditions/causes is membranous nephropathy associated with?
malignancy (solid organ -> lung, colon, breast)
drugs (eg. gold, penicillamine, captopril)
infections (eg. hepatitis, malaria)
How can mesangiocapillary glomerulonephritis present?
several ways –> including nephrotic and nephritic syndromes
can recur following transplantation
Biopsy findings in mesangiocapillary glomerulonephritis
mesangial proliferation
thickened capillary walls
‘double contouring’ of basement membrane
positive immunofluorescence (eg. C3)
What conditions is mesangiocapillary glomerulonephritis associated with?
infections (hepatitis, malaria, endocarditis, shunt nephritis)
cryoglobulinaemia
malignancy
How does diabetic nephropathy present?
patients usually have other microvascular complications eg. retinopathy, peripheral neuropathy
earliest feature = low level proteinuria (‘microalbuminuria’)
proteinuria then becomes heavier
What does histology show in diabetic nephropathy?
Kimmelstiel-Wilson lesions (nodular glomerulosclerosis)
How can amyloidosis affecting the kidneys present?
heavy proteinuria +/- nephrotic syndrome +/- renal failure
What stain is used for amyloidosis?
congo red - apple green birefringence under polarised light
What are the 2 subtypes of amyloidosis?
AL - light chain deposition (eg. myeloma)
AA - chronic inflammation (eg. infection, connective tissue disorders)
What is the commonest form of glomerulonephritis?
IgA nephropathy (Berger’s disease)
What occurs in IgA nephropathy?
deposition of circulating IgA within mesangium leading to expansion of mesangial matrix and mesangial cell proliferation
IgA nephropathy presentations
asymptomatic microscopic haematuria
episodic macroscopic haematuria (eg. exercise, respiratory tract infection)
progressive renal impairment, end stage renal failure
What is a nephritic pattern?
hypertension
haematuria
renal impairment
(oedema)
When does post-streptococcal glomerulonephritis occur?
2-3 weeks after group A streptococcal infection (throat, skin)
usually presents as nephritic illness
How is post-infectious glomerulonephritis treated?
supportive treatment
Which vasculitides are more likely to affect the kidneys?
small vessel
Systemic vasculitis affecting kidneys signs on biopsy
focal necrotising glomerulonephritis +/- crescents
pauci-immune
Antibody present in Goodpasture’s disease
anti-GBM (glomerular basement membrane)
How does Goodpasture’s disease present?
AKI and/or pulmonary haemorrhage
Goodpasture’s disease biopsy findings
focal necrotising glomerulonephritis +/- crescents
linear antibody deposition
Goodpasture’s disease treatment
may respond if treated early - immunosuppression +/- plasma exchange
How does rapidly progressing glomerulonephritis (crescentic nephritis) present?
nephritic illness with rapidly deteriorating renal function
(can be caused by systemic vasculitis and Goodpasture’s disease)
Rapidly progressing glomerulonephritis renal biopsy findings
acute inflammatory process with crescent formation - cellular proliferation in Bowman’s space
Investigations to consider in patients with glomerular disease
Urine:
- dipstick
- microscopy
- culture
- protein quantification
blood:
- FBC, ESR, coag, blood film, U&E, LFT, Ca, PO4, CRP
- autoantibodies (ANA, ANCA, anti-GBM)
- serum immunoglobulins and electrophoresis
- serum free light chains
- cryoglobulins
- complement levels
- blood cultures
- serology (hepatitis B/C, HIV, ASO titre)
renal biopsy
