MedEd renal 1 Flashcards
What is AKI?
Sudden rapid reduction in eGFR with or without oligouria
What criteria is used in AKI
Kdigo
What is Kdigo’s criteria and what is it used for
Used to diagnose AKI
Serum cr= 1.5-1.9 baseline or >26 umol/L increase
Urine output= <0.5mL/kg/h for 6-12 hrs
How much does serum cr rise in AKI?
eGFR 1.5-1.9 x baseline
eGFR >26 umol/L increase
What is stage 1 AKI according to Kdigo’s criteria?
normal Kdigo criteria
eGFR 1.5-1.9 x baseline or >26 umol/L
urine output <0.5 ml/kh/h for 6-12 hrs
What is AKI stage 2 according to Kdigo’s criteria?
eGFR 2-2.9 x baseline
urine output <0.5 l/kh/h for >12 hrs
What is AKI stage 3 according to Kdigo’s criteria?
creatinine 3 x baseline or >354 umol/L
urine output <0.3 ml/kh/h for 24 hrs or anuria for 24 hrs
anyone on renal replacement therapy
What is urine output in AKI?
<0.5mL/kg/hr for 6-12 hrs
What are the 4 complications of AKI? What symptoms does each cause and how is it managed?
Fluid overload- pulmonary oedema, treat with IV furosimide/GTN infusion and heamolysis if refractory
Uraemia- uraemic encephalitis (lethargy and confusion), uraemic pericarditis, treat with haemodialysis
Metabolic acidosis- confusion, tachycardia, jussmaul’s breathing, NV, treat with IV/PO sodium bicarb and dialysis if refractory
Hyperkalemia- asymptomatic, arrhythmia, muscle weakness, cramps, paarsthesia, hypotension, bradycardia, cardiac arrest, treat with connecting to cardiac monitor, calcium gluconate 10% 30 ml IV, 10 units soluble insulin (drives K+ into cells), 50 mls of 50% glucose (to avoid hypo)
What symptom does fluid overload cause in AKI and how is this managed?
Causes pulmonary oedema
Treat with IV furosimide/GTN infusion and heamolysis if refractory
What symptom does uraeamia cause in AKI and how is this managed?
Causes uraemic encephalitis (lethargy and confusion), uraemic pericarditis
Treat with haemodialysis
What symptom does metabolic acidosis cause in AKI and how is this managed?
Causes confusion, tachycardia, jussmaul’s breathing, NV
Treat with IV/PO sodium bicarb and dialysis if refractory
What are mild, moderate and severe levels for hyperkalemia
Mild= 5.5-6 Moderate= 6.1-6.5 Severe= over 6.5 or any level with ECG changes or if symptomatic
What symptom does hyperkaelmia cause in AKI and how is this managed?
asymptomatic, arrhythmia, muscle weakness, cramps, paarsthesia, hypotension, bradycardia, cardiac arrest
Treat with connecting to cardiac monitor, calcium gluconate 10% 30 ml IV, 10 units soluble insulin (drives K+ into cells), 50 mls of 50% glucose (to avoid hypo)
What ECG changes are seen in hyperkalemia
Tall tented T waves Prolonged PR Wide QRS Flattened/ absent p wave Sinusoid rhythm
How do you remember doses for hyperkaelmia treatment?
10, 10, 50, 50
10% 30ml IV calcium gluconate
10 units insulin
50ml 50% glucose
What ix are done for AKI?
Fluid assessment
ABG/VBG
Bloods: UEs, FBC, CRP, LFTs, CK, clotting
Hep screen, HIV screen, vasculitic screen, myeloma screen, anti GBM, sepsis screen if septic
KUB
ECG
Take a good drug hx!!
What aspect of the hx is really important in AKI?
Drug hx
How is AKI managed?
ABCDE approach Find and treat cause Stop any nephrotoxic drugs Fluid manage (IV fluids or offload with diuretics or dialysis) Treat complications Dialysis if needed
What common abx often causes AKI?
Amoxicillin
What causes AKI?
Pre renal= problems with blood supply
Renal= problems with kidney tissue
Post renal= problems with urine outflow
Why might there be decreased kidney perfusion causing pre renal AKI?
Hypovolemia eg acute GI loss, haemorrhage, diuresis, burns, third spacing
Low volume eg heart failure or liver failure
Vascular insult- damage to arteries/arterioles supplying kidneys
What 3 things will cause reduced perfusion to the kidneys?
Hypovolemia
Low volume
Vascular insult
What might damage arteries/arterioles supplying the kidneys?
ACEi/ARBs
NSAIDs
Contrast
Renal artery stenosis
What are the 3 types of obstruction that cause post renal AKI?
Luminal- kidney stones (if urethra pain and anuria if ureter renal colin)
Mural- cancers of renal tract or strictures
Extramural- abdo/pelvic cancers or BPH
What is there obstruction of in post renal AKI?
Urine flow
What are the 4 types of intrinsic renal AKI?
Tubular
Interstitial
Vascular
Glomerular
What are the 2 types of acute tubular necrosis? Explain them
Ischaemic- due to lack of oxygen supply
Toxic- tubules are directly damaged by a nephrotoxic drug
What is the mechanism behind tubular renal AKI?
Acute tubular necrosis
Is acute tubular necrosis reversible?
Yes
What do patients develop after acute tubular necrosis? How is this managed?
Severe diuresis- manage w strict urine input and output
What is acute interstitial AKI?
Immune mediated damage of renal interstitium
Tyoe 4 hypersensitivity reaction
Usually due to medications eg NSAIDs, thiazide diuretics
How do you recongise intersitial AKI?
Rash, fever, arthralgia, eosinophilia
White cell casts on urinalysis
What is are the 2 types of vascular renal AKI?
HUS: haemolytic uraemic syndrome
TTP: thrombocytic thrombocytopenia purpura
What is the triad for HUS?
Haemolytic anaemia
Thrombocytopenia
AKI
What is seen in TTP?
haemolytic anaemia AKI Thrombocytopenia fever neurological symptoms
What will you see in HUS due to haemolytic anaemia?
Dark urine
Petechaie
How do you differentiate TUP from HUS in vascular AKI?
There will be fever and neuro symptoms alongside haemolytic anaemia, thrombocytopenia and AKI
How is vascular AKI due to HUS managed?
Abx
In who is vascular AKI due to HUS more common?
Children
How is HUS caused and what will it present with?
By e coli most commonly
Presents with blood diarrhoea
How is TUP vascular AKI mananged?
What are the 2 presentations of glomerulonephritis?
Nephrotic and nephritic syndrome
What is glomerulonephritis?
Damage to glomerulus
Out of nephrotic and nephritic syndrome which is prolif and which is no prolif
Nephrotic= non prolif Nephritic= prolif
What is the main difference in presentation between nephrotic and nephritic syndrome?
Nephrotic= no haemturia Nephritic= haematuria
What is seen on microscopy in nephrotic vs nephritic syndrome?
Nephrotic= fatty cast Nephritic= red cell cast
What are the 5 main cuases of nephrotic syndrome?
Minimal change disease Membranous GN FSGS Diabetic nephropathy Amyloid nephropathy
What cause of nephrotic syndrome is most common in children? What is it associated with?
Minimal change disease
Associated with non hodgkin’s lymphoma
What are symptoms of nephrotic syndrome?
Puffy face and ankles
How is nephrotic syndrome diagnosed?
Mainly clinical
Do kidney biopsy if treatment doesnt work
What is seen on light and electron microscopy in nephrotic syndrome?
Light= no changes seen Electron= podocyte effacement
How is minimal change nephrotic syndrome managed?
Corticosteorids
What is the most common cause of nephrotic syndrome in adults?
Membranous GN
What are the 2 categories in Kdigo’s criteria that are used to diagnose AKI/
Serum creatinine
Urine output
What happens to HR in hyperkalemia?
Bradycardia
What additional treatment might you give for hyperkalemia?
Salbutamol nebulisers
IV furosemide
IV sodium bicarb (if they are acidotic)
If refractory start haemodialysis
What drugs might cause vascular insult and lead to AKI?
ACEi/ARBs
NSAIDs
What exogenous and endogenous toxins cause acute tubular necrosis?
Endogenous= myoglobulin, uric acid, monoclonal light chains Exogenous= aminoglycosides, cisplatin, NSAIDs, heavy metals, radiocontrast agents
How long does it take to recover from acute tubular necrosis?
It is reversible, takes around 21 days to recover
What is seen on urinalysis in acute tubular necrosis?
Granular muddy brown casts
What is seen on urinalysis in acute interstitial necrosis?
White cell casts
What causes thrombocytic thrombocytopenia purpura?
ADAMTS 13 deficiency (can be congenital or autoimmune)
What is ADAMTs 13 and what does deficiency of it cause?
It is the enzyme responsible for vWF breakdown, deficiency of it causes thrombocytic thrombocytopenic purpura
How is thrombocytic thrombocytopenia purpura treated?
Plasmapherisis
Rituximab
How does nephrotic syndrome present?
Massive proteinuria (>3.5 g/day)
Foamy urine
Oedema
Hyperlipidaemia and lipiduria
What is seen on urine microscopy in nephrotic syndrome?
Fatty casts
What are proteinuria levels in nephrotic syndrome?
> 3.5 g/day
How does nephritic syndrome present?
Haematuria Proteinuria (1-3.5g) Oedema Progressive renal impairment HTN
How does proteinuria levels differ between nephrotic and nephritic syndrome?
Nephrotic= 3.5 g/day (very high) Nephritic= 1-3.5 g/day
What acronym is used to remember how nephrotic vs nephritic syndrome present and what does it stand for?
Nephrotic= protein coal= proteinuria, cholesterol up, oedema, albumin down, lipids up Nephritic= protein hob= proteinuria, haematuria, oedema, blood pressure up
How is nephrotic syndrome due to minimal change disease managed?
Corticosteroids
What is glomerular nephropathy?
Subepithelial deposition of immune complexes on the basement membrane causing nephrotic syndrome
Where are immune complexes deposited in membranous glomeulonehropathy?
Subepithelium of basement membrane
What are some RF for membranous glomerulonephropathy?
Autoimmune disease Hep b/c syphillis malignancy medications like lithium, nsaids
What is immunoflourescence in minimal change disease/
Negative
How is membranous glomerulonephropathy diagnosed?
renal biopsy for definite diagnosis
light microscopy will show basement thickening
electron microscopy will show spike and dome appearance and podocyte effacement
What antibodies are seen in membranous glomerulonephropathy and what are they against?
IgG4 antibodies against phospholipase A2 receptors
How is membranous glomerulonephropathy treated?
symptomatic management
low response to corticosteroids but they might still be offered
cytotoxic/immunosupressive therapy
What is focal segmental glomerulosclerosis (FSGS)
Injury to podocytes causing nephrotic syndrome
What are RF for FSGS?
HIV, heroin use, congenital malformations, INF treatment
How is FSGS diagnosed?
Renal biopsy- focal segmental areas of collapse and sclerosis
Electron microscopy- effacement of foot processes of podocytes
How is FSGS managed?
Corticosteroids and symptomatic management
What nodules are present in the kidney in diabetic nephropathy?
Kimmelstiel Wilson nodules
What is seen on light microscopy in diabetic nephropathy?
Mesangial expansion
GBM thickening
Kimmelstiel Wilson nodules
How is diabetic nephropathy treated?
Good control of diabetes
ACEi/ARB
What are the 2 causes of nephritic syndrome?
MPGN
RPGN/ cresenteric glomerulonephropathy
