Nephrology Flashcards
What is GFR as a neonate and when does it become similar to adults?
Neonate=20-30ml/min/1.73m2
Age 2yrs equals adult 90-120
(Kidney receives 25% of CO/min)
What are the functions of the kidney?
- Waste handling- urea and creatinine
- Water handling
- Salt balance-Na & calcium phosphate
- Acid base control-bicarb
- Endocrine-red cells/BP/bone health-erythropoietin, renin angiotensin aldosterone system, parathyroid hormone
How do those with glomerulopathy present?
Blood & protein in varying amounts dictate clinical presentation & suggests diagnosis
Injury to one part of the GFB affects the other components
What does proteinuria signify?
Signifies glomerular injury
Acquired glomerulopathy is common and what type depends on what components of GFB is affected. What are these types?
Minimal change disease=epithelial cell (podocyte)
PIGN=basement membrane
PIGN, HUS=Endothelial cell
HSP/IgA nephropathy=mesangial cell
Congenital glomerulopathy is rare and the type depends on the layer involved, what are they?
Congenital nephrotic syndrome (proteins=podocin (AR), nephrin (AR))
Alport syndrome (AL)
Thin basement membrane disease (AD)
Complement regulatory proteins (MPGN)
How much proteinuria is too much and how is this checked?
- Dipstix
Give concentration
≥ 3+ usually abnormal
False positives and negatives - Protein Creatinine Ratio (practical)
Early morning urine (best)
normal: Pr:CR ratio <20mg/mmol
Nephrotic range: >250mg/mmol
>500mg/mmol - oedema - 24hr urine collection (gold standard)
normal <60mg/m²/24hrs
Nephrotic range>1g/m²/24hrs
Adults >3.5g/24hrs
What is NephrOtic syndrome?
- Nephrotic range proteinuria
- Hypoalbuminemia
- Oedema (increasing 3rd space fluid v)
After what do children usually present with minimal change disease or steroid sensitive nephrotic syndrom?
Intercurrent illness such as gastroenteritis
What does a urine sodium <20 mean?
You are holding onto water
What are the features of MCD (nephrotic syndrome)?
- Age 1-10
- Normal BP
- No frank haematuria
- Normal renal function
Atypical features:
- Suggestions of autoimmune disease
- Abnormal renal function
- Steroid resistance (failure to go into remission after 4 weeks of high dose oral steroids)
ONLY then consider a renal biopsy
How is nephrotic syndrome treated?
If typical features=PREDNISOLONE 8 WEEKS
What can be done about the infection risk that is increased from the use of high dose glucocorticoids?
- Varicella status
- Pneumococcal vax
- Abx prophylaxis
What does steroid sensitivity predict?
Diagnosis and prognosis
90% steroid sensitive=MCD
Steroid resistance is more suggestive of focal segmental glomerulosclerosis
What is the pathogenesis of Nephrotic syndrome?
Interaction between lymphocytes (T&B) and podocytes
What is the outcome of steroid sensitive nephrotic syndrome?
Remission
95% in 2-4 weeks
Relapse
80%
80% long term remission
Frequently relapsing=
Second line immunosuppression
- Steroid toxicity
- Steroid dependant and frequent relapses (>4/year)
What are the causes of steroid resistant nephrotic syndrome?
Acquired:
Focal Segmental Glomeruloscerosis (FSGS)
- Podocyte loss
- Progressive inflammation and sclerosis
(50% of these children will
need renal replacement therapy in five years.)
Congenital:
Infant presentations
NPHS1 – nephrin
NPHS 2 – podocin
Podocyte loss
What is the investigation for microscopic haematuria?
Dipstix adequate
Investigate if >trace on 2 equations
Haemoglobinuria=stix +ve & microscopy negative
Associated proteinuria = glomerular disease
What can cause haematuria?
Systemic
- clotting disorders
Renal
- Glomerulonephritis
- Tumour
Wilm’s - nephroblastoma
- Cysts
Malignancies - sarcomas
Stones
UTI
Trauma
Urethritis
How does Nephritic syndrome present?
Clinical diagnosis describes glomerulonephritis
Haematuria and proteinuria
Reduced GFR (creatinine)
- Oliguria
- Fluid overload (Raised JVP, oedema)
- Hypertension
- Worsening renal failure = Rapidly Progressive GN
Intrarenal cause of Acute kidney injury (AKI)
What does raised creatinine indicate?
Abnormal renal function
Acquired glomerulopathy: which components can be affected and if they are what condition do they cause?
Epithelial cell (podocyte) = MCD, FSGS, Lupus
Basement Membrane = Membranous glomerulopathy, MPGN, PIGN
Endothelial cell = post infectious glomerulonephritis (PIGN), Haemolytic Uraemic Syndrome, Membranoproliferative Glomerulonephritis (MPGN), Lupus, ANCA vasculitis
Mesangial cell = HSP / IgA nephropathy, Lupus
For nephritic syndrome for example how is it investigated?
Radiology
Renal USS – normal
Chase most likely diagnosis
- ASOT - Raised 1200
- Positive throat swab group A strep
Immunology workup
- Complement C3 low, normal C4
- Autoimmune diseases (ANA, ANCA negative)
Biopsy
Not required at present
What is acute post infectious glomerulonephritis and what causes it?
Age of onset-usually 3-5years
Cause:
- Usually group A strep
- Beta haemolytic
- Site (throat 7-10 days, skin 2-4weeks)
Acute post infectious glomerulonephritis is SELF LIMITING: How is it diagnosed?
- Bacterial culture
- positive ASOT
- low C3 normalises
Remember differential diagnosis (IgA / Lupus / MPGN)
ASOT – Anti streptolysin O titre
What is the treatment of Acute post infectious glomerulonephritis?
- Abx
- Support renal functions (electrolyte/acid base)
- Overload/HT-Diuretics
NOT RECURRENT
What is the commonest glomerulonephritis and how does it present?
Most common glomerulonephritis
1-2 days after URTI
Usually older children and adults
Clinically:
Recurrent macroscopic haematuria
+/-Chronic microscopic haematuria
Varying degree of proteinuria
Clinical diagnosis
How is IgA nephropathy diagnosed?
Clinical picture - Negative autoimmune workup and normal compliment
Confirmation biopsy (IgA deposits within the mesangial cells)
What is the treatment for IgA nephropathy: mild & severe?
Mild=proteinuria with ACEI
Moderate to severe=Immunosuppression (KDIGO)
What is the age of onset of HSP IgA related vasculitis?
Age of onset=5-15 years