AKI Flashcards
Def of AKI?
Significant decline in renal function over hrs or days manifesting as an abrupt and sustained ↑ in Se U and Cr
General classification of kidney injury?
Pre
Renal
Post
Pre-renal causes of kidney injury?
Commonest
- Shock
- renovascular compromise (e.g. NSAIDs, ACEi)
Renal causes of AKI?
- Acute Tubular Necrosis (ATN)
- Acute tubulointersitial nephritis (TIN): drug hypersensitivity
- Nephritic syndrome
Causes of Acute Tubular Necrosis (ATN)?
- Ischaemia: shock, HTN
- Direct nephrotoxins: drugs, contrast, Hb
Post renal causes of AKI?
SNIPPIN
- Stone
- Neoplasm
- Inflammation: stricture
- Prostatic hypertrophy
- Posterior urethral valves
- Infection: TB, schisto
- Neuro: post-op, neuropathy
Presentation of AKI?
- Uraemia / Azotaemia (nitrogen)
- Acidosis
- Hyperkalaemia
- Fluid overload
Investigations of AKI?
ABG: hypoxia (oedema), acidosis, ↑K+
ECG: hyperkalaemia
CXR: pulmonary odeam
Renal US: hydronephrosis
Pre renal failure Osmolality and Na levels?
urine is concentrated and Na is
reabsorbed →
- ↑osmolality,
- Na <20mM
What is RIFLE classification of AKI?
- 3 grades of AKI (risk, injury, failure)
- 2 outcomes (loss or end-stage kidney disease, ESKD)
- Classification determined by worst criteria
Risk class of RIFLE classification creatinine, GFR, and urine output levels?
- ↑Cr x1.5 ↓GFR >25%
- <0.5ml/kg/h x 6h
Injury class of RIFLE classification creatinine, GFR, and urine output levels?
- ↑Cr x 2 ↓GFR >50%
- <0.5ml/kg/h x 12h
Failure class of RIFLE classification creatinine, GFR, and urine output levels?
- ↑Cr x 3 ↓GFR >75%
- <0.3ml/kg/h x 24h, or anuria x12h
Definition of Loss outcome of RIFLE classification?
Persistent acute renal failure = complete loss of function >1mo
Definition of end-stage kidney disease (ESKD) outcome of RIFLE classification?
complete loss of function >3mo
General management of AKI?
- Stop nephrotoxins: NSAIDs, ACEi, gent, vanc
- Stop metformin if Cr > 150mM
ECG features of hyperkalaemia?
- Peaked T waves
- Flattened P waves
- ↑ PR interval
- Widened QRS
Management of hyperkalaemia?
- 10ml 10% calcium gluconate
- 100ml 20% glucose + 10u insulin (Actrapid)
- Salbutamol 5mg nebulizer
- Calcium resonium 15g PO or 30g PR
- Haemofiltration (usually needed if anuric)
Primary management of pulmonary oedema in AKI?
- Sit up and give high-flow O2
- Morphine 2.5mg IV (± metoclopramide 10mg IV)
- Frusemide 120-250mg IV over 1h
- GTN spray ± ISMN IVI (unless SBP <100)
If no response to primary management of pulmonary oedema, what’s the Rx?
Consider
- CPAP
- Haemofiltration / haemodialysis ± venesection
Indications for acute dialysis of AKI patients?
- Persistent hyperkalaemia (>7mM)
- Refractory pulmonary oedema
- Symptomatic uraemia: encephalopathy, pericarditis
- Severe metabolic acidosis (pH <7.2)
- Poisoning (eg aspirin)
Overview of fluid assessment?
- cardiovascular:
- Tissues
- end organ:
CVS signs of fluid overload?
Postural BP,
Raised JVP,
High HR
Tissue signs of fluid overload
- Cap refill,
- cold/warm hands,
- skin turgor,
- mucous membranes
End organ signs of fluid overload
- urine output,
- mental state
Triple whammy hit drugs for kidneys?
Avoid if possible:
- ACEi or angiotensin II inhibitors (sartan)
- Diuretics
- NSAIDS or COX 2 inhibitors
