Acute Kidney Injury Flashcards
Diagnosis of AKI
Rise in Creatinine > 26 micromol/L in 48 hrs (above baseline)
Rise in Creatinine > 50% ( best figure in last 6 months ) within 7 days
Urine output < 0.5ml/kg/hr for > 6 consecutive hours
Need only one of these criteria
Which one has got AKI:
1) 23 F , baseline Cr-60 , presented with Cr-100, normal UO
2) 30M, 70kg, baseline Cr-100, admitted with Cr-120 , UO 50ml/hr
3) 80 F, 50kg, a/w long lie on the floor , baseline Cr-200, now Cr-250, UO-30ml/hr
4) 20M, involved in car accident , injury to abdomen , Baseline Cr-60 , now Cr-80 , UO- 10ml/hr for 7hrs
Which is the sickest?
1) Yes
2) No
3) Yes
4) Yes
3 or 4 (abdo damage could mean crushed kidney) is the sickest
45F , just had bilateral nephrectomy for RCC , baseline Cr-80 , now Cr-100 , No UO for last 2 hrs .
Has she got AKI ?
Does she need RRT (Renal Replacement Therapy)?
Why?
Yes she has AKI as has no kidneys
RRT is needed
Normal creatinine level for male middle aged
50-60
Types of causes of AKI
Pre-renal
Renal
Post-renal
Pre-renal causes of AKI
(Reduced blood flow to kidney) Fluid loss from body - diarrhoea and vomiting Trauma Burns Heart failure Any cause of shock (Sepsis)
Renal causes of AKI
Drugs e.g. steroids (NSAIDs)
Infection/Inflammation of kidney
Trauma
Renal nephritis
Post-renal causes of AKI
Kidney stone
Cancer of ureter, bladder or prostate (in men)
Luminal - stone in ureter, blood clot in ureter
Stone in bladder or blood clot in bladder
Prostate enlargement
Assessment of patient with AKI
Start with ABCDE (patient is able to talk to you)
History - assess pre-renal, renal, post-renal
Physical examination
Differential diagnosis
Investigations
Initial management
As well as bloods, what other investigations can be done?
Urine dip
Ultrasound of kidney, ureter, bladder (blood clot tumour)
Monitoring of urine output
Urine dip - what does it show?
Protein
True or False:
In initial management of AKI, its always ok to prescribe some IV fluid
Mostly True except in case of heart failure
Medical emergency associated with AKI
Hyperkalemia
Failing kidneys wont be able to excrete potassium
Other than a blood test, what else could show hyperkalemia
ECG
large T waves and small/indiscernible P waves in V2-6
Management of hyperkalemia
First Insulin and Dextrose
Then:
Calcium gluconate (membrane stabiliser of heart)
IV fluid
Salbutamol (B2 agonist)
(calcium resonium - but can cause serious constipation)
In management of hyperkalemia, what is action of insulin
Drive potassium from blood stream into cell
True or False:
in management of hyperkalemia, calcium gluconate helps reduce potassium levels in blood
False
Has no effect on potassium in the blood
Is a membrane stabiliser of heart
Give to any patient with ECG changes
Management of AKI
Stop nephrotoxic drugs Identification of risk factors Thinking about common causes Assessment of the patient with AKI Investigations When to refer to a nephrologist Indications for dialysis
What is dialysis
The process of removing excess water, solutes, and toxins from the blood in people whose kidneys can no longer perform these functions naturally.
Risk factors of AKI
Older Age
Comorbidities
Drugs (e.g. antibiotics)
Reason of admission (e.g. heart failure, vomiting, diarrhoea, sepsis) - being in hospital increases AKI risk
Investigations of AKI
full examination, creatinine, urea, electrolytes, liver enzymes, clotting, glucose, urine dipstick, autoantibodies (anti-GBM, ANCA), renal USS
Imaging (CT-KUB?)
Things to do before referral to nephrologist
First treat/stabilise and hyperkalemia Proper history and examination (blood pressure, medication on) Blood tests & Imaging IV fluid Urine dip sticks Review of drugs Fluid balance ( intake /output ) Current volume status (dry/dehydrated or wet/HF)
When to refer to nephrologist
Treat the urgent causes first !
Hyperkalaemia or fluid overload unresponsive to medical treatment
Urea > 40mmol/L +/- signs of uraemia (e.g. encephalopathy, pericarditis etc)
No obvious cause
Creatinine > 300 or rising > 50micromol/L per day
Complications fo AKI
Hyperkalemia
Pulmonary oedema
Uraemia
Acidemia
Indications of dialysis
Refractory pulmonary oedema (fluid bluids up in lungs) Persistent hyperkalaemia (no difference after insulin and dextrose) Severe metabolic acidosis Uraemic encephalopathy or pericarditis Drug overdose – BLAST (Barbiturate, Lithium, Alcohol-ethylene glycol, Salicylate, Theophylline)
Prognosis of AKI - put these in order from highest prognosis to lowest:
Medical illness, Obstetric/poisioning, Trauma/surgery, Burns
Burns, Trauma/surgery, Medical illness, Obstetric/poisioning
What % of AKI are preventable
30%
Prevention of AKI
Drugs
Diagnose early and give IV fluids to keep hydrated
