AKI Flashcards
What are the causes of AKI?
- Pre-renal - i.e. reduced renal perfusion
- E.g. diarrhoea & vomiting, dehydration, sepsis, renal artery stenosis
- Renal - i.e. damage to renal tubules or glomeruli
- E.g. nephrotoxic drugs, rhabdomyolysis, NSAIDs/ACEI, GN
- Post-renal - i.e. obstruction
- E.g. prostatic hypertrophy, renal stones, pelvic Ca
What is the SALFORD treatment of AKI?
- S – treat cause, often sepsis but not always
- A – stop nephrotoxic drugs (e.g. ACEI, ARBs, NSAIDs, metformin, diuretics) & review doses of other meds
- L – labs – daily U&Es
- F – intravenous fluids
- O – Obstruction consider US scan, catheter, examine for distended bladder
- R – referral to ICU / renal for RRT
- D – Urine dipstick – if blood & protein on dipstick consider ‘renal’ causes or UTI, e.g. glomerulonephritis
What is the staging of an AKI?
What stage is this AKI?
Baseline creatinine 72 µmol/l increase to 200 µmol/l
stage 2
What history Qs are important with suspected AKI?
- Nephrotoxic drug use within the last week (especially if hypovolaemic)
- NSAIDS
- ACEIs
- angiotensin II receptor antagonists (ARBs),
- diuretics
- Exposure to iodinated contrast agents within the past week
- Any causes / symptoms of dehydration e.g.
- Lack of mobility
- Sepsis
- Oliguria
-
PMH inlc:
- heart failure
- liver disease
- diabetes mellitus
- CKD
- History of AKI
- Symptoms of retention / obstruction e.g.
- hesitancy
- weak stream
- intermittency
- straining to void
- terminal dribble
- prolonged urination
What should you look for on examination of an AKI patient?
General:
- Rash
- Uveitis
- Joint swelling
Assessment of volume status
- Drowsy, yawning and thirsty
- Core temperature
- Peripheral perfusion (capillary refill)
- Heart rate
- Blood pressure (lying and standing)
- Jugular venous pressure
Signs of renovascular disease
- Audible abdominal bruits
- Impalpable peripheral pulses
Abdominal examination
- Palpable bladder
What is the normal value for creatinine?
70-150micromol/L
What are the signs of kidney damage?
Many patients with early AKI may experience no symptoms. However, as renal failure progresses the following may be seen:
- reduced urine output
- pulmonary and peripheral oedema
- arrhythmias (secondary to changes in potassium and acid-base balance)
- features of uraemia (for example, pericarditis or encephalopathy)
What is the urine dip important for?
What investigations should we do for AKI (after U&Es)?
- Urinanalysis - all patients with suspected AKI should have urinanalysis
- Imaging - if patients have no identifiable cause for the deterioration or are at risk of urinary tract obstruction they should have a renal ultrasound within 24 hours of assessment.
How do you treat hyperkalaemia?
- Initially 10–20 mL, calcium gluconate injection 10%
- soluble insulin (5–10 units) with 50 mL glucose 50% given over 5-15 minutes
What is Acute Tubular Necrosis (ATN)?
ATN:
- the most common cause of acute kidney injury (AKI) seen in clinical practice
- death of tubular epithelial cells
- usually due to ischaemia due to hypoperfusion of kidneys
- can also be due to nephrotoxics or sepsis
3 phases:
- Oliguric
- Maintenance
- Polyuric recovery
What are the features of ATN?
- features of AKI: raised urea, creatinine, potassium
- muddy brown casts in the urine
When should you refer to a nephrologist?
- Renal tranplant
- ITU patient with unknown cause of AKI
- Vasculitis/ glomerulonephritis/ tubulointerstitial nephritis/ myeloma
- AKI with no known cause
- Inadequate response to treatment
- Complications of AKI
- Stage 3 AKI (see guideline for details)
- CKD stage 4 or 5
- Qualify for renal replacement hyperkalaemia / metabolic acidosis/ complications of uraemia/ fluid overload (pulmonary oedema)
What are the stages of ATN?
Oligouric phase:
- he kidneys produce less than 500 mls of urine per day.
- Patients in this phase are vulnerable to fluid overload and electrolyte imbalance especially potassium.
- Creatinine levels usually rise quite rapidly during this phase.
Maintenance phase:
- The patient is no longer oligouric and this increased urinary output helps maintain fluid and electrolyte balance.
- Creatinine level are usually stable or rise very slowly.
Polyuric recovery phase:
- In this phase the kidneys produce large quantities of dilute urine, so large in fact patients can become hypovolaemic and unwell.
- There are a number of causes for this phase postulated
- Patients are also susceptible to electrolyte loss (e.g. hypokalemia) in this phase.
- Creatinine levels falls swiftly in this phase.
What ECG changes occur with hyperkalaemia?
- Tall tented T waves
- Widened QRS
- Prolonged PR
- Loss/flattening of P waves
- ‘sine-wave’ appearance
What are the high, moderate and low risk criteria for sepsis in the history?
What are the high, moderate and low risk criteria for sepsis in the resp and BP?
What are the high, moderate and low risk criteria for sepsis in the circulation obs?
What are the high, moderate and low risk criteria for sepsis in the skin?
