Renal Flashcards
What 2 factors can you look at to diagnose AKI?
1) Urine output
2) Creatinine
How many AKI grades are there?
3
Give the creatinine criteria for each AKI grade
1) Rise of >26 umol/L or 1-1.9x baseline
2) Rise of 2.0-2.9x baseline creatine
3)
- > 3.0x baseline creatine or
- > 353.6 umol/L or
-initiation of renal replacement therapy or
- decrease of eGFR to < 35 mL/min
Give the urine output criteria for each AKI grade
1) <0.5 ml/kg/hr for 6 hours
2) <0.5 ml/kg/hr for 12 hours
3) <0.3 ml/kg/hr for >24h or anuria for 12h
What should you ALWAYS ask for when interpreting investigations?
Previous investigations to compare
What is the earliest clinical marker of a developing AKI?
Urine output
Why is creatinine a good marker of renal function?
As it is almost 100% filtered by kidney
What renal function changes are acceptable after starting an ACEi?
A rise in the creatinine and potassium may be expected after starting ACE inhibitors.
Acceptable changes are an increase in serum creatinine, up to 30%* from baseline and an increase in potassium up to 5.5 mmol/l*.
What rise in serum creatinine is acceptable after starting ACEi?
Up to 30% from baseline
What rise in serum potassium is acceptable after starting ACEi?
Up to 5.5 mmol/l
What is the most common group of causes of AKI?
Pre-renal e.g. 2ary to dehydration or sepsis
ECG signs of hyperkalaemia?
1) tall, tented T waves
2) flattened P waves
3) broad bizarre QRS
Emergency management of hyperkalaemia?
1) IV calcium gluconate 10%
2) Salbutamol 5mg nebulised
3) Insulin dextrose infusion
4) Dialysis/haemofiltration if not responding
How long should Abx be prescribed for in women >65?
3 days (also send a urine culture)
Next steps in suspected UTI if associated with visible or non-visible haematuria?
Send an MSU for all women with a suspected UTI if associated with visible or non-visible haematuria
Why are patients with nephrotic syndrome at an increased risk of VTE?
Due to loss of antithrombin III
What testicular volume indicates onset of puberty?
> 4ml
What is the treatment for acromegaly?
Ocreotide
How can the SAAG gradient be calculated?
Serum albumin - ascitic albumin = SAAG gradient
What does a high SAAG indicate (i.e. >11 g/L)?
Low levels of protein in ascitic fluid e.g. portal HTN, RHF
What cause of nephrotic syndrome is frequently associated with malignancy?
Membranous nephropathy
What is SAAG used to determine?
Whether ascites has been caused by portal HTN or not.
What is Budd Chiari syndrome?
Hepatic vein thrombosis
Can lead to portal HTN
How can rhabdomyolysis cause AKI?
Due to acute tubular necrosis –> myoglobin is nephrotoxic.
What condition typically presents with haemoptysis + AKI/proteinuria/haematuria?
Anti-GBM disease (Goodpasture’s)
What is the most likely outcome following the diagnosis of minimal change nephropathy in a 10-year-old male?
Full recovery but with later recurrent episode
What condition should you consider in a young female patients who develop AKI after the initiation of an ACE inhibitor?
Fibromuscular dysplasia
What can be seen in urine in AIN?
White cell casts & eosinophils
Why is nephrotic syndrome associated with a hypercoaguable state?
Due to loss of antithrombin III in the kidneys
How can hypothyroidism affect sodium?
Severe hypothyroidism can result in SIADH.
This dilutes blood conc of Na+ (euvolaemic hyponatraemia).
What is the most common cause of AKI?
Acute tubular necrosis (intrarenal AKI)
Give some causes of ATN
1) Ischaemia (e.g. from pre-renal cause)
2) Nephrotoxins:
- aminoglycosides
- myoglobin (from rhabdo)
- uric acid (tumour lysis syndrome)
- IV contrast
- ethylene glycol
How do penicillins vs aminoglycosides cause AKI?
Penicillin - AIN
Aminoglycosides - ATN
What is typically seen in urine in ATN?
Muddy brown casts
What are the 3 key causes of intrarenal AKI?
1) ATN
2) AIN
3) Glomerulonephritis
What are some causes of AIN?
Drugs - penicillins, NSAIDs, diuretics
Features of AIN?
- AKI features
- eosinophilia
- fever
- rash
creates an allergic picture
How can ACEi affect creatinine?
What rise is acceptable?
Can cause rise in creatinine.
Rise of up to 30% from baseline is acceptable.
How can uraemia affect the heart?
Can cause pericarditis
Urine osmolality in pre-renal azotemia vs ATN?
Pre-renal –> high urine osmolality (i.e. very concentrated as the kidneys hold on to sodium and water)
ATN - low urine osmolality (i.e. less concentrated as the kidneys lose sodium and water)
Urine sodium in pre-renal azotemia vs ATN?
Pre-renal –> low
ATN –> high
2 drugs used for proteinuria in CKD?
1) ACEi
2) SGLT-2 inhibitors
What is the SGLT-2 inhibitor licensed for CKD?
Dapagliflozin
4 key complications of AKI?
1) Hyperkalaemia
2) Uraemia - pericarditis & encephalopathy
3) Metabolic acidosis
4) Fluid overload - pulmonary oedema & HF
Via what 2 ways can damage to kidney cells occur in ATN?
1) Ischaemia due to hypoperfusion
2) Nephrotoxins
How is iron replaced in anaemic patients on haemodialysis?
IV iron (instead of oral iron)
What is the main class of Abx that should be stopped in AKI?
Aminoglycosides
What is the threshold for stopping metformin in AKI?
eGFR <45
Serum urea:creatinine ratio in pre-renal AKI vs ATN?
Pre-renal - raised
ATN - normal
What murmur can anaemia cause?
Aortic flow murmur (ejection systolic)
what is taken into account in eGFR calculation?
CAGE
Creatinine
Age
Gender
Ethnicity
What are the drugs that can cause ED?
- antihypertensives
- beta blockers
- diuretics
- antidepressants
- antipsychotics
- alcohol
- recreational drugs
What are 3 key contraindications for PDE-5 inhibitors (sildenafil)?
1) Concurrent nitrate use (risk of severe hypotension)
2) Hypotension
3) Recent stroke/MI - wait 6 months
What test should all patients with ED have?
Serum testosterone
What is the most common organic cause of ED?
Vascular causes e.g. CVD, diabetes, HTN, smoking
What is 1st line for renal colic pain?
IM diclofenac
What can be given instead of IM diclofenac in renal colic if NSAIDs are contraindicated or not giving sufficiency pain relief?
IV paracetamol
Cause of periureteric fat stranding vs perinephric fat stranding?
Periureteric = passed stones
Perinephric = pyelonephritis
What is preferred for the removal of renal stones in pregnancy women?
Ureteroscopy
What 2 types of renal stones are radiolucent?
Urate & xanthine stones
Mx of renal stones depends on size.
a) <5mm
b) 5-10mm
c) 10-20mm
d) >20mm
a) watchful waiting (if asymptomatic)
b) shockwave lithotripsy
c) shockwave lithotripsy OR ureteroscopy
d) percutaneous nephrolithotomy
Mx of ureteric stones?
<10 mm –> shockwave lithotripsy +/- alpha blockers
10-20mm –> ureteroscopy
1st line imaging in renal stones?
Non-contrast CT KUB
Infection with which organism is most likely in struvite renal stones?
Proteus mirabilis
