Nephrology Flashcards
Glomerular disease causes what?
Nephrotic syndrome
Nephritic syndrome
AKI causes what?
HUS
How much blood is received through the kidneys?
Very high blood
25% CO / min
GFR in neonates compared to adults
20-30ml/min/1.73m2
So when dealing with neonates there is already compromised system
5 functions of the kidney
Waste handling (urea, creatinine) Water handling Salt balance (Na, K, Ca, P) Acid base control (bicarbonate) Endocrine (red cells, BP, bone health)
What part of the glomerular filtration barrier is vulnerable to immune mediated injury?
The endothelial cell
Features of the endothelial cell of the glomerular filtration barrier
Fenestrated
Two proteins of the glomerular filtration membrane
Type IV collagen (COL4)
Laminin
How is the glomerular filtration membrane synthesised?
From
- podocytes
- endothelial cells
Functions of mesangial cells
Glomerular structural support
Embedded in GBM
Regulates blood flow of glomerular capilaries
Presentation of glomerulopathy
Haematuria
Proteinuria
Indications towards nephritic syndrome
Increasing haematuria
Intravascular overload
Indications towards nephrotic syndrome
Increasing proteinuria
Intravascular depletion
Pathology of acquired glomerulopathy
White component affected
- epithelial cell (podocyte) - Minimal change disease, FSGS, lupus
- Basement membrane - membranous glomerulopathy, MGPN, PIGN
- Endothelial cell - HUS, MPGN, lupus, infection associated glomerulonephritis (PIGN)
- mesangial cell - HSP, IgA nephropathy, lupus
Is acquired glomerulopathy common?
Yes
Is congenital glomerulopathy common?
No - it is rare
Layers involves in congenital glomerulopathy
Podocyte skeletal integrity
Basement membrane proteins
Endothelial / microvascular integrity
Presentation of nephrotic syndrome
3 - 4 days Nephrotic range proteinuria Frothy urine Blood in urine - not usually frank Hypoalbuminaemia Swollen face which is worse in the morning One eye closed in the morning Oedema - Periorbital - legs (pitting) - Ascites - small pleural effusions Well but pale Weight up from baseline BP can be raised Normal creatinine Protein creatinine ratio >250mg/mmol High levels of fat / lipids in the blood
Pathology of nephrotic syndrome
Interaction between lymphocytes (T and B cells) and podocytes
Loss of size and charge barrier of the GFB
Oncotic (Osmotic) vs hydrostatic
Protein (osmotic) = magnet to water
Can nephrotic syndromes have FH?
yes
How do you test for proteinuria?
Dipstix
- gives concentration ; > 3+ usually abnormal
Protein creatinine ratio
- > 250 = nephrotic
24 hour urine collection (gold standard)
- normal < 60mg/m2/24hrs
- nephrotic = >1g/m2/24 hours in children
Normal protein creatinine ratio
< 20mg/mmol
Nephrotic range for protein creatinine ratio
> 250 mg/mmol
What is the gold standard investigation for proteinuria?
24 hour urine collection
Treatment of nephrotic syndrome
Prednisolone for 8 weeks
S/Es of prednisolone
Behaviour (irritable, moody, dont sleep) High BP Facial change Growth (only if recurrent courses) GI distress
Other considerations when treating nephrotic syndrome
Varicella status and pneumococcal vaccination as both act as immunosuppressants
What indicates minimal change disease/
Response to steroids
If steroid resistance / dependent when treating nephrotic syndrome, what does this indicate?
maybe not dealing with minimal change disease
Presentation of minimal change disease
Resolving microscopic haematuria Proteinuria Oedema Weight gain Normal renal function Normal BP Atypical features - suggestions of autoimmune disease - abnormal renal function - steroid resistance Nephrotic syndromes
What age gets minimal change disease?
2 - 5 y / o
What presentation in minimal change disease would make you consider a renal biopsy?
Atypical features
- suggestions of autoimmune disease
- abnormal renal function
- steroid resistance
Prognosis of Nephrotic syndrome
Remission 95% in 2 - 4 weeks
relapse 80%
- 50% frequent - 2 in 6 or 4 in a year
80% long term remission
If really frequent recurrences of nephrotic syndrome, what may be the problem?
Prednisolone toxicity
Acquired steroid resistant nephrotic syndrome condition and its pathology
Focal Segmental Glomeruloscerosis (FSG)
- podocyte loss
- progressive inflammation and sclerosis
What type of haematuria should always be investigated?
Macroscopic
When is microscopic haematuria investigated?
> trace on 2 occasions
Important causes of macroscopic haematuria
Glomerulonephritis Post infect GN IGA / HSP UTI (dysuria) Trauma Stones (pain)
Important causes of microscopic haematuria
Glomerulonephritis Post infect GN IGA / HSP UTI Trauma Stones / hypercalciuria
Symptoms of nephritic syndrome
Haematuria Reduced GFR oliguria fluid overload - raised JVP - oedema HTN Worsening renal failure - rapidly progressive FN
What is nephritic syndrome an intrarenal cause of?
AKI
Causes of glomerulonephritis
Post infectious GN HSP / IgA nephropathy Membranoproliferative GN Lupus nephritis ANCA positive vasculitis
Investigations of nephritic syndrome
Renal USS Chase the most likely diagnosis - ASOT - throat swabs - complement tests ANA, ANCA testing Biopsy - not needing when have a secure diagnosis
Age of onset of acute post infectious glomerulonephritis
2 - 5
Causes of acute post infectious glomerulonephritis
Usually group A strep
- beta haemolytic so completely haemolysis
Post throat infection 7-10 days
Post skin infection 2 - 4 weeks (impetigo common)
Investigations of acute post infectious glomerulonephritis
Bacterial culture
positive ASOT
Low C3 normalises
Prognosis of acute post infectious glomerulonephritis
Self limiting
good prognosis
can have haematuria for 1 - 2 years after but the function will improve