2. Acute Kidney Injury
Goals of talk
Renal/prerenal/post renal
Definition of acute renal failure
Case based
Emergency management
Investigations
Drugs
3. Definition
Rise in
Rapid
creatinine of of renal function
deterioration 26 mmol/l in 48h
>50% rise in creatinine over 7 days and acid Inability to maintain fluid, electrolyte
base balance
<0.5ml/kg/hour
for more than 6 hours
4. Important?
13-18%
£500
of all hospital admissions
million/year
2009
national inquiry – 50% who died of AKI had
“good care”
Inpatient
mortality 25-30%
Prognosis
proportional to severity of AKI
5. Risk Factors
CKD
IV
Heart
Liver
failure
failure
contrast
Urological
obstruction
Diabetes
Age
History
Oligo-uria
of AKI
Hypovolaemia
Sepsis
Nephrotoxics
8. „Renal Causes‟ of Renal failure
Large Vascular
Small vascular and Glomerular
Interstitial nephritis
Acute tubular necrosis
Myeloma
Cast nephropathy
Light chain deposition
Amyloid
Hypercalcaemia, hyperuricaemia, fluid depletion
9. „Renal Causes‟ of Renal failure
Large Vascular
Renal artery thrombosis/dissection
Cholersterol emboli (recent Cardiac cath/aortic surgery)
Renal vein Thrombosis (hypercoagulable, ? Nephrotic)
Renovasc disease + ACEI
History and risk factors are key
Acute Glomerulonephritis (GN)/Small vascular
IgA nephropathy, lupus nephritis, FSGS
Vasculitis
HUS/TTP
Malignant hypertension
Urine dip and inflammatory markers key
Needs full renal screen (OHCM) and diagnose with biopsy
10. „Renal Causes‟ of Renal failure
Acute Tubulo-Interstitial Nephritis (AIN)
Drug related (NSAID, antibiotics, diuretics, allopurinol)
Infections/TB/Autoimmune disease
Fever, arthralgia, rash
Normal interval 3-21 days
Bland urine dip or with mild blood/prot
Possibly eosinophils in urine
Diagnose with biopsy
16. Case 1 questions
What is your diagnosis/differential?
What investigations?
Does this lady have AKI?
What are the causes for the raised creatinine
What medications would you stop/start?
17. Case 1 questions
What is your diagnosis/differential?
What investigations
Depends on previous renal function.
What are possible causes for the raised creatinine
Urine dip/MC+S, Abdo/Renal tract USS, ?CT
Does this lady have AKI?
Appendicitis/pyelonephritis
Sepsis, pre-renal, medication
What medications would you stop/start?
Pyelonephritis, temporarily stop ramipril, avoid NSAIDs
for pain, stop spironolactone
18. Case 1
Always do a urine dip, and MC+S
Use computer/GP records to review old MC+S and creatinine
Stop potentially nephrotoxic medications
Especially avoid NSAIDs
19. Case 2
78 male
PMH
1 day post Right Hemiarthroplasty
Poor U/O 10 mls/h for 4 hours
T2DM
OA
CCF
DHx
Lisinopril 10mg OD
Metformin 500mg TDS
Diclofenac 50mg OD
Paracetamol 1g QDS
Bisoprolol 5mg OD
20. Review
What are you looking out for when reviewing him?
What investigations do you want to do?
21. Review
What are you looking out for when reviewing him?
Fluid status – dry? Fluid input/output chart. Obs. Review medications. Review
hip wound, check for palpable bladder, catheter working?
What investigations do you want to do?
Bloods, urine dip +/- MSU
Renal tract USS
22. Review
O/E
BP 96/60, HR 110
Chest clear
Apyrexial
Abdomen SNT
Dry mucous membranes
JVP down
U/O in last 6 hours – 100mls
Fluid in – nil
26. Case 3
85 male
1/12 gradually
worsening back pain
1/7 confusion
No urine for last day
Now unable to get out
of bed and fluctuating
conscious level
Nocturia x 3
Negative urine dip by
GP
PMH
DH
Amlodipine
Omeprazole
NKA
Paracetamol
SH
Lives with wife
No carers
27. Case 3 – On Examination
Bp 160/100, PR 100,
sats 92% on air, T 36
Dry
skin
JVP difficult
Ankle oedema
GCS 12/15
Not able to answer
questions
CVS
Systolic
murmur
Resp
Bibasal creps
Abdo
Soft non tender
suprapubic mass
PR smooth large
prostate
Neuro
Nil focal but weak with
muscle pain and power
3/5 globally
28. Initial questions
What are the first steps in this patients management?
Are there any particularly concerning features which point to severe acute
renal failure?
What is the most likely diagnosis?
29. Initial questions
What are the first steps in this patients management?
Are there any particularly concerning features which point to acute renal
failure?
ABC, ECG/monitor, bloods/ABG for K
Decreased conscious level, weakness and muscle pain, heart murmur,
clinical fluid overload
What is the most likely diagnosis?
Obstructive renal failure
36. Question 2
What are the indications for emergency dialysis?
Hyperkalaemia
Pulmonary oedema
Severe acidosis
Uraemia – (pericardial rub, encephalopathy)
38. Question 3
How would you investigate the underlying diagnosis?
Bloods
LFTS (Ca/ALP/Alb), PSA (when well), myeloma screen
PR – when catheterised
Abdo USS
Bone scan
Urology opinion with CT/MRI pelvis
39. Question 4
What does the enlarged non-tender bladder imply about the aetiology?
Can people present with obstructive renal failure when no bladder is
palpable, or when they are still passing urine?
40. Question 4
What does the enlarged non-tender bladder imply about the aetiology?
Chronic
Can people present with obstructive renal failure when no bladder is
palpable or when they are still passing urine?
Yes (tumour/stone/extrinsic compression affecting ureters)
Only one kidney being obstructed can still cause RF
41. Case 3
Acute management of hyperkalaemia
Emergency dialysis
Obstructive renal failure
chronic v acute
USS crucial, as can still be passing urine and bladder may not be enlarged
Other treatments to decompress (nephrostomy/stents)
42. Urine Dip
Colour
Turbidity
pH
4.5-8 but most often acidic
Important in RTA
Haematuria/haemoglobinuria/myoglobinuria
Proteinuria
Renovascular, glomerular, tubule-interstitial disease
Overflow of abnormal proteins (MM)
Glucose
Nitrites
50% sensitive, 90% specific
Positive suggests presence in sig numbers (>10000/ml)
Leucocytes
65% sensitive, 20-90% specific
Much higher accuracy in urology patients
43. ARF Screen
ARF Screen
BASICS
FBC/U+E/LFT/Ca/Phos/Mg/Gluc/Lipid/Bic/CRP
Lactate/COAG /G+S/SEP/Blood cultures
If needs HD - Hep B+C+HIV serology
Venous/Arterial Gas
Urine DIPSTICK/ PCR + BJP/ MC and S.
CXR, urgent USS
ECG +/- monitor if K high
GN SCREEN (think about specific diagnoses)
ANCA/ANA/antiGBM/ASOT/Igs/C3/C4/LDH/blood film
+/- Cryoglobulins (take to lab warm)/RhF
Chronic – PTH/haematinics once during admission
44. Conclusion
Acute renal failure
Always think pre/intrinsic/post
First ensure safe potassium and volume status
Drugs are often implicated
Urine dip is vital and often not done
If patient unwell with renal failure involve a senior early
Editor's Notes
Note how to differentiate between ATN and pre renal renal failure – loss of concentrating mechanism. In ATN urine sodium is high and osmolartiy is low, in pre renal ARF urine Na is low and osmolarity high to preserve water.
urine dip positive for leucocytes +/- nitrites would be expected.
urine dip positive for leucocytes +/- nitrites would be expected.
