AKI Flashcards
1
Q
What is an AKI
A
Increase in serum creatinine
Oliguria
Decreased GFR due to loss of filtration + tube function
2
Q
AKI 1
A
Creatinine >26.5 in 48 hrs or 50% baseline in 7 days
Urine <0.5ml / kg / hr for >6 hours
Normal output = 0.5ml so for average 70kg person = 35ml / hour
3
Q
AKI 2
A
Creatinine 2-3x baseline
Urine <0.5ml / kg / hr for >12 hours
4
Q
AKI 3
A
Creatinine 3x baseline or>354
Urine <0.3ml / kg / hr
Requires RRT
5
Q
When should you act for AKI
A
Don’t wait till creatinine at 400
Creatinine won’t rise till 50% kidney function lost
6
Q
What are the pre-renal causes of AKI
- Inadequate blood supply to kidney
A
Hypotension (50%)
Sepsis - low BP
Hypovolaemia - D+V / haemorrhage / pancreatitis
Dehydration = high urea
MI / cardiogenic shock or failure
Arterial occlusion
Renal artery stenosis - atherosclerosis or fibromuscular dysplasia in children
NSAID / ACEI = constriction renal artery
Hepatorenal due to renal constriction in cirrhosis
Surgery / post op
7
Q
What are the renal / intrinsic causes of AKI
- Reduced filtration of blood
Most common in children
A
Acute tubular necrosis - Pre-renal - Nephrotoxins - Haemoglobinruia - haemolytic anaemia - Myoglobulinuria from rhabdomyolysis - Tumour lysis - Myeloma cast Acute tubular interstitial nephritis (TIN) GN Infections Vasculitis Hypertensive crisis Thrombotic microangiopathy - TTP / DIC / HUS (see haematology) - HUS = most common cause in children
8
Q
What are nephrotoxins
A
Rhabdomyolysis NSAID Gentamicin Diuretic Contrast ACEI
9
Q
What are the RF for contrast toxicity
A
Age DM CKD Dehydration Cardiac failure Use of nephrotoxins Para-protein High volume of contrast
10
Q
What are the post renal causes of AKI
- Obstruction to outflow
Known as obstructive uropathy if causes black pressure into kidney and reduced function
A
Obstruction Kidney stone if bilateral or one kidney Prostatic hypertrophy Prostatic malignancy / cervical / bladder Ca Fibrosis - IgG 4 Ureteric stricture
11
Q
What are the RF for AKI
A
Age Previous AKI CKD Heart failure Liver failure DM Vascular disease Cognitive impairment On nephrotoxins / use of contrast mediums
Often elderly - ill, poor oral intake, multiple medication
12
Q
What are risk events
A
Sepsis Nephrotoxins Hypotension Hypovolaemia Major surgery
13
Q
What is important to look at in pre-renal causes
A
BP
Drugs
Fluid intake
14
Q
What are signs of hypovolaemia
A
Postural BP Low urine Bounding pulse in sepsis or weak if hypovolaemia Tachycardia Dry mucous membrane Flat veins Cold hands Decreased CRT Urea elevated
15
Q
What are signs of hypervolaemia
A
SOB Pulmonary oedema Increased JVP Peripheral oedema Hypotension on dialysis
16
Q
What do you look for in examination
A
Assess fluid balance HR, BP, JVP, CRT Palpate bladder Signs of uraemia CVS - arrhythmia due to complications
17
Q
What bloods should be done in AKI
A
U+E = most important VBG to ensure not acidotic FBC, U+E, LFT, CRP Blood culture + lactate if signs of sepsis ABG - if RR high Bicarb for acid / base Bone profile - Ca, phosphate CK - rhabdomyolysis
18
Q
If platelets low would should be done
A
Film for haemolysis
HUS / TTP
19
Q
What bloods if suspecting intrinsic renal disease
A
Protein on dip
Auto Ab’s / autoimmune screen
Myeloma screen
Complement
20
Q
What else should be done in AKI
A
History Systemic Sx Fluid status + vital signs eGFR URINE DIPSTICK IF SUSPECT AKI - Dark suggest haemo / myoglobulinuria - Cloudy = infection - Glucose / leucocyte / nitrites / protein etc - Red cell cast = GN - White cell cast = infection Urine PCR Renal USS to look for obstruction Biopsy
21
Q
When do you do renal USS
A
Within 24 hours of DK of AKI
- Look for stones
- Size of kidney
- Any thrombosis
22
Q
When do you biopsy
A
If suspect vasculitis or unknown cause of AKI
23
Q
What will pre-renal causes have
A
Hypoperfusion
Low BP
Tachycardia
24
Q
What does post renal cause have
A
No urine output
25
What is a better variable for kidney function
| - What score
```
Creatinine clearance >eGFR
Use CAGE (creatinine, age, gender, ethnicity) score when deciding drugs
```
26
What factors affect result
Obesity
Red meat
Muscle mass
Pregnancy
27
What do you do in presence of risk events or RF
```
STOP AKI
Sepsis
Toxins
Optimise BP and volume
Prevent harm
```
28
Sepsis
Sepsis 6
| Monitor O2 and lactate via ABG
29
Toxins
Stop nephrotoxic drugs
Medication review for any AKI or unwell Patient
Change dose dependent on renal status
Advise on sick day rules
30
What do you do if contrast required
Expand with IV fluid 1 hour pre and 6 hours post
| NAC if very poor but no evidence
31
How do you optimise BP and volume status
```
Avoid dehydration
Maintain adequate fluid to perfuse
Consider IV
Review ant-hypertensive
Consider withholding ACEI, CCB, A blocker, diuretic if hypo
May need inotrope / vasopressor support
Catheter for urine volumes
```
32
How do you prevent harm
Daily U+E
Fluid balance
H2 / PPI
Nutrition
33
What are medications to stop on sick days if severe vomiting / diarrhoea
```
Diuretic
ACEI
ARB
Metformin - lactic acidosis
NSAID
```
34
Major causes AKI
```
Sepsis
Major surgery
Cardiogenic shock
Hypovolaemia
Drugs
Hepatorenal syndrome
Obstruction
```
35
When do you involve consultant
```
AKI 3
AKI 2 not improving
AKI low platelet (HUS)
CKD 4/5
COmplications
Resistant pulmonary oedema
Resistant hyperkalaeia
Rare conditions
Transplant
Unknown cause
```
36
Complications of AKI
Acidosis
Electrolyte imbalance
INtoxication
Overload leading to HF and pulmonary oedema
Uraemia leading to encephalopathy / pericarditis
All lead to cardio / respiratory arrest
37
What are indications for RRT and when is it needed more
```
Acidosis / Decreased HCO3
Increased K refractory
Pulmonary oedema refractory
Intoxication
Symptomatic uraemia - more in CKD
```
If anuric as can't excrete toxins
38
What should you know before call consultant
```
Creatinine trend
Premorbid K, bicarb, lactate, Hb, platelet
Urine dip
Clinical obs / news
Fluid input and output
Examination - hypo or hyper
Co-morbid
Drugs given
```
39
What does management depend on
Underlying pathology
40
Pre-renal
Correct volume depletion / sepsis / cardiac support
41
Renal
Biopsy and specialist
42
Post-renal
Catheter
Nephrostomy
Urological
43
How do you tell the difference between pre-renal and ATN
Pre-renal
- Kidney act to conc urine
- High plasma Na to hold on to volume
- High urine osmolality
- Low urine Na
ATN
- High urine Na
- Kidney lost concentrating ability so once cured increased risk of polyuria and severe dehydration
- Muddy brown casts on urinalysis
44
How do you manage hypovolaemia
Volume replace
Care in cardiac failure
Always examine before
Reassess
45
Risk of 0.9% saline and Hartman
Saline - hyperchloraemic acidosis
Hartman - caution if hyperK or oliguric
Can give 2 salt and 1 sugar (dextrose)
46
How do you manage hypervolaemic
Oxygen if required
Fluid restrict
Diureitc
RRT
47
AKI with overload + oliguria
Urgent referral
Potentially harmful if use diuretic when oliguric
Probably need RRT
48
How do you treat acidosis
Treat underlying
RRT
Adequate O2
Bicarb controversial but can use but dangerous drug
49
What can drug induced renal toxicity cause
AKI
Nephrotic - NSAID / lithium
Renal tubule dysfunction with K wasting
50
What are pharmacokinetic effects of renal disease
Reduced GFR = reduced clearance
Reduced protein = reduced binding
Half life and concentration is increased
51
What are pharmacodynamic effects
BBB more permeable
More sensitive to hypertensive as already hypo
Can't clear drugs until dialysis so same level in blood
52
What are DAMN drugs to stop in AKI
```
Diureitc
ACEI / ARB
- Reno-protective long term
Metformin
NSAID
Aminoglycoside - gent
Contrast
```
53
What does metformin cause
Lactic acidosis
54
What should you never prescribe together
NSAID and ACEI
| Reduce prostaglandin
55
What drugs have narrow therapeutic index / renal excreted so build up in AKI but don't worsen
```
Gentamicin / vancomycin
Metformin
Digoxin
Lithium
Tacrolimus
Opiates
Heparin
Penicillin /cephalosporin
```
56
When is drug AKI most common
Elderly
Hypovolaemic
Polypharmacy
57
What are RF for radio contrast AKI
```
Age
DM
CKD
Renovascular disease
HF
High volume of contrast
Dehydration
Nephrotoins
```
58
When does AKI from contrast present
2-5 days
59
What do you do if someone has poor renal and need to start drug
```
Reduce dose
Increase dose interval
Use liver metabolised drugs
Avoid nephrotoxins
High therapeutic index
```
60
What is good source of info
BNF
Pharmacist
Renal drug handbook - always look
61
What are safe drugs in AKI
```
Paracetamol
Warfarin
Aspirin 75mg
Clopidogrel
BB
```
62
What does NSAID cause
```
AKI
Nephrotic
Hypertension
Hyperkalameia
Pupillary necrosis - where urine enters ureter
```
63
Why does NSAID cause pre-renal
Decreased vasodilator prostaglandin
Reduced renal blood flow and GFR
Can cause nephritis
64
What drugs cause nephrotic syndrome
NSAID
Gold injection
Interferon
65
Other nephrotoxic drugs
```
PPI
Penicillin
Rifampicin
Aciclovir
Anti-convulsant
Cisplastin
Calcineurin inhibitor
```
66
What do aminoglycosidde cause
Tubular necrosis
| 1-2 weeks of therapy
67
What are nephrotoxins not drugs
```
Contrast
Myoglobin in rhabdomyolysis
Haemoglobulinuria
Urate in tumour lyrisis
Myeloma cast
Radiation
```
68
What is Rhabdomyolysis
Breakdown of skeletal muscle after long lie / crush
| Release of intracellular K and myoglobulin which affects kidney
69
Typical history of Rhabdo
Hx trauma / seizure / hypothermia / elderly collapse / ecstasy / statin + macrolide / crush injury
70
How does it present
```
AKI with greatly raised creatinine (acute tubular necrosis) as breakdown products toxic to kidney
Elevated CK
Myoglubilinuria
HYpocalcaemia as myo binds
High phosphate
High K = most dangerous
Metabolic acidosis
```
```
Symptoms
Muscle pain
Oedema
Fatigue
Confusion
Red or brown urine
```
71
How do you Dx
```
Serum / urine myoglobin - +Ve for blood
Plasma CK x5 = best way to Dx
U+E show AKI
Increased K and phosphate
Decreased Ca
Do ECG to look for arrhythmia
```
72
How do you treat
IV fluid
73
What else can cause AKI
Bacteria
Virus
Parasite
74
When should you consider acute interstitial nephritis
All AKI with no obvious pre-renal or post renal cause
75
What drugs cause acute interstitial nephritis
```
Penicillin
Vancomycin
Rifampicin
Aciclovir
NSAID
Phenytoin
PPI / H2
Allopurinol
Furosemide / thiaizde diuretic
Anti-convulsant - phenytoin
Warfarin
```
76
What are other causes of nephritis
```
Infection
SLE
Sarcoid
Sjogren
ANCA
```
77
How does acute interstitial present
```
AKI 3 days post
Eosinophilia cast
Patient well - not hypotensive or septic
Hypertension
May have fever / rash / arthralgia / allergic picture
```
78
How do you Dx
Urine dip = leucocyte + eosinophils as inflammatory where as ATN would not
Biopsy
Sterile pyuria
79
How do you Rx
Stop causative agent
| Steroids
80
What is prognosis
CKD in 40%
81
What is tubulointerstital nephritis with uveitis
```
Young female
Fever
Weight loss
Painful red eyes
Leucocytes and protein on dip
```
82
ATN in urine
No inflammation so no cellular component in urine
| Muddy brown cast
83
When should you consider HUS
Hx of diarrhoea illness
Normocytic anaemia
Thrombocytopenia
Renal failure
84
When should you consider TTP
Same as above
| Neuro signs - headache / confusion / fever
85
FIbromuscular dysplasia
Narrowing arteries
Hypertension
Decreasing renal function / CKD
AKI - when ACEI started
86
Wha is better than eGFR
Creatinine clearance
87
How does hypercalcaemia cause an AKI
Renal tubular damage
| Leads to hypokalaemia, DEHYDRATION, increased Na excretion which causes renal vasoconstriction and AKI
