What is the definition of AKI?
Abrupt (<48h):
increase in serum creatinine (>26.4)
increase in creatinine by 50%
reduction in urine output
one of the above
What needs to be done before you can diagnose a patient with AKI?
Attempt fluid resuscitation
Exclude obstruction
What are some pre-renal causes of AKI?
Hypovolaemia
Hypotensive (cardiogenic, septic, anaphylactic)
Certain drugs
What are the definitions of
a) normal urine output
b) oligouria?
a) 0.5ml/kg/hr
b) < 0.5ml/kg/hr
If patients are sick (e.g diarrhoea, vomiting), which drugs should they stop to prevent AKI?
Antihypertensives
e.g ACE inhibitors, ARBs, diuretics
What happens if pre-renal AKI isn’t treated?
Acute tubular necrosis
What commonly causes pre-renal AKI?
Hypovolaemia, hypotension due to
sepsis
dehydation
Also:
drugs
rhabdomyolysis
What are signs and symptoms of dehydration?
Hypovolaemia
Tachycardia
Low urine output
Low JVP
Cap refill > 2s
Oedema
How is pre-renal AKI treated?
Fluid challenge for hypovolaemia and hypotension
500ml 0.9% NaCl over and over until improvement
What are some
a) vascular
b) glomerular
causes of renal AKI?
a) Vasculitis, renovascular disease (renal artery stenosis)
b) Glomerulonephritis
Which drugs can cause nephritis?
Antibiotics
PPIs
Gold, pencillamine
methotrexate
gentamicin
What are the symptoms of AKI?
Constitutional - anorexia, weight loss, fatigue..
N&V
Itch
Fluid retention
Which infection commonly causes glomerulonephritis?
GAS
What types of GN are suggested by
a) sore throat in the past 2-3 weeks
b) rash
c) joint pain
d) haemoptysis?
a) Post-streptococcal glomerulonephritis
b) Vasculitic nephritis
c) Lupus nephritis
d) Goodpasture’s syndrome
Why can compartment syndrome cause AKI?
Rhabdomyolysis
What are some blood tests which should be done for those with AKI?
U&Es - particularly hyperkalaemia
FBC - for anaemia, prolonged clotting
What’s a quick test which can be done to pick up proteinuria / haematuria?
Urinalysis
What imaging is first line for looking at the kidney?
What can it pick up?
USS
Stones
Which causes of AKI are associated with
a) ANA
b) ANCA
c) GBM antibody?
a) SLE (not really)
b) Small vessel vasculitis
c) Goodpasture’s syndrome
What are signs of multiple myeloma on blood test?
Hypercalcaemia
Anaemia
When would a renal biopsy be indicated?
Rapidly progressing GN
Positive antibodies for something
Don’t know what’s wrong
Which scan is used to guide renal biopsies?
USS
What are some signs of life-threatening AKI?
Hyperkaleamia
Resistant fluid overload (pulmonary oedema with no urination)
Severe metabolic acidosis
Severe uraemia
What causes post-renal AKI?
Obstruction of urinary tract
What problem is caused by an obstructed urinary tract?
Hydronephrosis
How does hydronephrosis cause AKI?
Loss of kidney’s ability to concentrate urine
What can cause obstruction of the urinary tract?
Renal calculi
Malignancy
Strictures
Prostate enlargement
What is a life-threatening electrolyte imbalance caused by AKI?
Hyperkalaemia
What causes death in hyperkalaemia?
Arrythmia
What is the normal range of potassium concentrations in the body?
What level is hyperkalaemic?
What level is life-threatening?
3.5 - 5.0
Hyperkalaemia: >= 5.5
Life-threatening hyperkalaemia: >= 6.5
How is hyperkalaemia assessed?
U&Es
ECG
Muscle weakness
What are the ECG manifestations of hyperkalaemia?
Bradycardia
Tall, tented T waves
Prolonged PR interval
What drug is given first to protect the myocardium in hyperkalaemia?
Calcium gluconate
What is given to
a) protect the myocardium
b) move K+ into cells
c) correct metabolic acidosis
d) prevent K+ absorption in the bowel
in a patient with hyperkalaemia?
a) Calcium gluconate
b) IV insulin + dextrose (to prevent hypoglycaemia, INH salbutamol
c) Sodium bicarbonate
d) Calcium resonium
If AKI is very severe and isn’t being controlled by drugs, how is it treated?
Haemodialysis
In what situations would you put a patient with AKI on dialysis?
Severely hyperkalaemic
Severe metabolic acidosis
Severely fluid overloaded
Severely uraemic