Acute Kidney Injury

Jingzhou He

Acute Kidney Injury

Goals of talk

Renal/prerenal/post renal

Definition of acute renal failure

Case based

Emergency management

Investigations

Drugs

Definition

Rise in creatinine of 26 mmol/l in 48h>50% rise in creatinine over 7 days<0.5ml/kg/hour for more than 6 hours

Rapid deterioration of renal functionInability to maintain fluid, electrolyte and

acid-base balance

Important?

13-18% of all hospital admissions £500 million/year 2009 national inquiry – 50% who died of AKI

had “good care” Inpatient mortality 25-30% Prognosis proportional to severity of AKI

Risk Factors

CKDHeart failureLiver failureDiabetesHistory of AKIHypovolaemiaSepsisNephrotoxics

IV contrastUrological

obstructionAgeOligo-uria

Causes

Prerenal

Volume depletionOedematous

stateHypotensionCardiovascularRenal

hypoperfusion

‘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

‘Renal Causes’ of Renal failure

Large Vascular Renovasc disease + ACEI

Renal artery thrombosis/dissection

Cholersterol emboli (recent Cardiac cath/aortic surgery)

Renal vein Thrombosis (hypercoagulable, ? Nephrotic)

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

‘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

‘Renal Causes’ of Renal failure

Acute Tubular Necrosis (ATN) Ischaemic – Hypotension, shock, devascularization (AAA)

Nephrotoxic

endogenous

Haemaglobinuria

Myoglobinuria

Myeloma casts

Crystals (Tumour lysis syndrome etc...) exogenous

Nephrotoxic drugs

Radio contrast

Postrenal

CalculusBlood clotUrethral strictureBPH/malignancyBladder tumourPelvic malignancy

Case 1

70 female GP referral to EMU

Febrile RIF pain Treated in

community for UTI

PMHx HTN CCF

Case 1

DHxDrug Dose Frequency

Ibuprofen 400mg TDS

Ramipril 10mg ON

Paracetamol 1g QDS

Bisoprolol 2.5mg OD

Spironolactone 25mg OD

Trimethoprim 200mg BD

Bloods

Na 140

K 5.0

Cr 195

Ur 8.8

Bic 24

Hb 13.1

WCC 16.6

Plt 345

CRP 96

Amylase 30

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?

Case 1 questions

What is your diagnosis/differential? Appendicitis/pyelonephritis

What investigations Urine dip/MC+S, Abdo/Renal tract USS, ?CT

Does this lady have AKI? Depends on previous renal function.

What are possible causes for the raised creatinine Sepsis, pre-renal, medication

What medications would you stop/start? Pyelonephritis, temporarily stop ramipril, avoid

NSAIDs for pain, stop spironolactone

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

Case 2

78 male

1 day post Right Hemiarthroplasty

Poor U/O 10 mls/h for 4 hours

PMH

OA

T2DM

CCF

DHx

Lisinopril 10mg OD

Metformin 500mg TDS

Diclofenac 50mg OD

Paracetamol 1g QDS

Bisoprolol 5mg OD

Review

What are you looking out for when reviewing him?

What investigations do you want to do?

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

Review

O/E

BP 96/60, HR 110

Apyrexial

Dry mucous membranes

JVP down

U/O in last 6 hours – 100mls

Fluid in – nil

Chest clear

Abdomen SNT

Investigations

Urine dip

Bloods

Blood 1+

Protein 1+

Nitrites Neg

Leuc Neg

pH 6

Na 140

K 5.8

Cr 230 (baseline 140)

Ur 14 (baseline 8)

Wcc 9

CRP 160

Hb 85 (pre-op 100)

Management

What do you do now?

Case 2

Post-operative risk

Pre-renal common

Review medications

IV fluids

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

NKA Amlodipine Omeprazole Paracetamol

SH Lives with wife No carers

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

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?

Initial questions

What are the first steps in this patients management? ABC, ECG/monitor, bloods/ABG for K

Are there any particularly concerning features which point to acute renal failure? Decreased conscious level, weakness and muscle pain, heart

murmur, clinical fluid overload

What is the most likely diagnosis? Obstructive renal failure

Bloods

Na 140

K 7.3

Cr 745

Ur 50.5

Bic 8

Hb 10.3

WCC 14.2

Plt 345

CRP 43

Glu 7

ECG

CXR

Question 1

Outline your management at this point

Question 1

Outline your management at this point

Cardiac monitor, IV Calcium, insulin/dextrose CAUTION INSULIN DOSE (10u/DEXTROSE DOSE/POST TX HYPO)

Salbutamol neb Oxygen, sit up Catheterise (note residual at 15 mins, hourly UO) Tell senior (HDU/ITU) Stop all unnecessary meds Dip and send urine Full acute screen (OHCM)

Question 2

What are the indications for emergency dialysis?

Question 2

What are the indications for emergency dialysis?

Hyperkalaemia

Pulmonary oedema

Severe acidosis

Uraemia – (pericardial rub, encephalopathy)

Question 3

How would you investigate the underlying diagnosis?

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

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?

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

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)

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

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

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