acute kidney injury Flashcards
what does AKI stand for?
acute kidney injury
what is the definition of acute kidney injury?
increase in serum creatinine:
- by 26.5umol/L or more within 48 hours or
- to >1.5x baseline, which is known or presumed to have occurred within the prior 7 days or
- urine volume <0.5ml/kg/h for 6 hours
how many stages of acute kidney injury are there?
3
what does the immediately dangerous consequences of AKI depend on?
causes
- acidosis
- electrolyte imbalance
- intoxication toxins
- overload
- uraemic complications
what can the causes of AKI be classified into?
pre-renal
intrinsic (renal)
post-renal
what are the normal functions of the kidneys?
- body fluid homeostasis
- electrolyte homeostasis
- acid/base homeostasis
- regulation of vascular tone
- excretory function
- endocrine function
what are possible bad short term and intermediate/long term complications of AKI?
short term (in hospital): death, dialysis, length of stay
intermediate/long term (post-discharge): death, CKD, dialysis, CKD related CV elements
how does mortality change with the stage of AKI?
mortality increases with stage
What does renal hypoperfusion cause
Ischemia of renal parenchyma → prolonged ischemia → intrinsic damage → Acute tubular necrosis (ATN)
what are pre-renal causes of AKI?
Renal hypoperfusion:
cardiac failure( reduced CO)
haemorrhage (hypovolaemia)
sepsis (systemic vasodilatation)
vomiting and diarrhoea
How are causes of intrinsic renal causes of AKI categorised?
Location of pathology:
- Vasculature
- Glomerular
- Tubulointerstitial
what are renal causes of AKI?
-
Vasculature
- Large vessel disease:
- Atherosclerosis (Renal artery stenosis)
- Thromboembolic disease (renal artery thrombosis)
- Dissections (aortic)
- Small vessel disease
- Vasculitidies
- Thromboembolic disease
- Microangioplastic haemolytic anaemias
- Malignant hypertension
- Large vessel disease:
-
Glomerular
-
Primary (no systemic disease association)
- glomerulonephritis
- Secondary (systemic disease association)
-
Primary (no systemic disease association)
- Tubulointerstitial
radiocontrast
myeloma
rhabdomyolysis
what are post renal causes of AKI?
Caused by obstructions:
tumours
prostate disease
stones
how is AKI prevented?
by identifying patients who are at risk
(presence of risk event or risk factor)
what are examples of AKI risk events?
sepsis (pneumonia, cellulitis, UTI)
toxins (x-ray contrast, NSAIDs, gentamicin, herbal medicine)
hypotension
hypovolaemia (haemorrhage, vomiting, diarrhoea)
major surgery
what are some risk factors for AKI?
- age > 75
- previous AKI
- ♡ failure
- liver disease
- chronic kidney disease
- DM
- vascular disease
- cognitive impairment
What is the protocol when identifying patients at risk of AKI?
In presence of risk event or factor consider:
- treat sepsis if present
- avoid toxins
- optimise BP and volume status
- prevent harm
Much of AKI is avoidable, how can it be prevented?
- Avoid dehydration
- Avoid nephrotoxic drugs
- Review clinical status in those at risk and act on findings
What are medicine “sick day rules”?
When you have vomiting or diarrhoea (unless only minor) or fever, sweats and shaking you stop taking certain medications
Restart medications when well (24-48 hours after eating and drinking normally)
When should medicines be restarted after “sick day” rules?
- Restart medications when are well (after 24-48 hours of eating and drinking normally)
What are exampls of medications that should be stopped on “sick days”?
- ACE inhibitors
- ARBs
- NSAIDs
- Diuretics
- Metformin
What investigations should be done for AKI?
- Renal function
- Urine dipstick
- FBC
- USS
- Blood gas
- Specific blood tests if indicated
What parts of the history are important for AKI?
What parts of the examination are important for AKI?
