Renal: Acute Nephritis Flashcards
What causes of acute nephritis are there?
Post infectious
Vasculitis (Henoch-Schonlein Purpura or rarely SLE, Wegener granulomatosis, polyarteritis nodosa,
IgA neohropathy
Antiglomerular basement membrane disease (Goodpasture syndrome)
Why is GFR decreased?
There is increased glomerular cellularity, which restricts glomerular blood flow
What factors characterise acute nephritis?
Decreased urine output and volume overload
Hypertension - may cause seizures
Oedema - typically periorbital initially
Haematuria
Proteinuria
How is acute nephritis typically managed?
Attention to water and electrolyte balance
Diuretics
Rarely there may be rapid deterioration in renal function - immunosuppression and plasma exchange may be necessary to prevent irreversible CKD
Post strep/post infectious nephritis is usually diagnosed by…
Evidence of recent streptococcal infection - culture of organism, raised ASO/anti-DNAse B titres and low complement C3 levels that return to normal after 4 weeks
What features are associated with Henoch-Schonlein purpura?
Rash - symmetrical over buttocks, extensor surfaces of arms and legs and ankles. Initially urticaria then maculopapular and purpuric, can be palpable
Arthralgia - particularly knees and ankles
Periarticular oedema
Colicky abdominal pain - GI involvement can cause haematemesis and melaena, nausea and vomiting common, intussusception can occur
Occasionally orchitis and CNS involvement
Glomerulonephritis- over 80% have microscopic/macroscopic haematuria or mild proteinuria
Henoch-Schonlein purpura usually occurs among what age group?
3-10 years
More common in boys
Peak during winter
What is Henoch-Schonlein purpura often preceded by?
URTI - especially streptococcal in prior 1-3 weeks
Some report previous GI infections
In Henoch-Schonlein purpura, what risk factors are there for progressive chronic kidney disease?
Heavy proteinuria
Oedema
HTN
Deteriorating renal function
Is the rash in Henoch-Schonlein purpura blanching?
No
How is HSP treated?
No specific treatment, symptoms usually go away after a few weeks
Paracetamol for joint pain
Steroids if severe symptoms
All children with HSP should be followed up for a year to detect those with persisting haematuria or proteinuria
HTN and progressive CKD may develop after an interval of several years
What causes HSP?
Unknown, but it is characterised by the deposition of immune complexes containing IgA
In kidney the deposition is in mesangium (hence resembling IgA nephropathy)
What is the most common vasculitis to involve the kidney?
Henoch-Schonlein purpura
Is HSP often more severe in children less than 10 or adults?
Adults - can cause renal damage
What type of nephropathy is HSP?
It is believed to be a type 3 immune complex mediated hypersensitivity reaction - tissue deposition of IgA containing immune complexed within affected organs
It is though to be similar to IgA nephropathy
What do immunofluorescene studies show in HSP?
IgA, complement component C3 and fibrin deposition within walls of affected vessels
What is the most common GI complication with HSP?
Intussusception
Describe the renal symptoms in HSP
Vary from mild e.g asymptomatic haematuria and/or proteinuria to severe, rapidly progressing nephritis, nephrotic syndrome and renal failure
What is the mandatory criteria for HSP diagnosis?
Palpable purpura not due to thrombocytopenia or coagulopathy
And one or more of:
Abdominal pain - diffuse, acute onset
Arthritis or arthralgia
Renal involvement - proteinuria, haematuria
How is HSP diagnosed?
Classic signs and symptoms
No laboratory test is diagnostic
Helpful tests:
- coagulation studies to rule out thrombocytopenia (normal in HSP)
- serum creatinine and electrolytes (elevated creatinine indicates renal impairment)
- ESR raised in 75%
- serum IgA may be raised
- autoantibody screen: ANA, ANCA, complement levels (help to differentiate from other vasculitides)
- urinalysis for haematuria, proteinuria, casts
Biopsy can be done to confirm diagnosis in unusual presentation e.g of skin, renal
Bowel USS - intussusception or perforation
What is the commonest cause of glomerulonephritis worldwide?
IgA nephropathy
How does IgA nephropathy classically present?
Macroscopic haematuria in young people following URTI
Among what age group does IgA nephropathy typically occur?
20-30 years
What causes IgA nephropathy ?
Mesangial deposition of IgA immune complexes (positive immunofluorescene for IgA and C3)
Considerable pathological overlap with Henoch-Schonlein purpura
Describe the typical presentation of IgA nephropathy
Young male, recurrent episodes of macroscopic haematuria
Typically associated with mucosal infections
Nephrotic range proteinuria is rare
Renal failure only in minority
How do you differentiate between IgA nephropathy and post streptococcal glomerulonephritis?
Post strep is associated with low complement levels
Main symptom in post strep is proteinuria although haematuria can occur
There is typically an interval between URTI and the onset of renal problems in post strep glomerulonephritis e.f 1-2 weeks compared to days in IgA nephropathy
How is IgA nephropathy managed?
ACEi/ARB to reduce proteinuria and protect renal function
Corticosteroids if proteinuria persists
What is the most common familial nephritis?
Alport syndrome - x linked recessive
Describe Alport syndrome
Due to gene mutation that codes for type IV collagen
Haematuria and proteinuria
Usually progresses to end stage chronic kidney disease by early adult life in males
Associated with sensorineural deafness and ocular defects
