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Acute Kidney Injury

Finals Teaching 2014Alison Portes FY1

+Objectives

Be able to recognise and define acute kidney injury

Understand risk factors for developing AKI

Describe causes of AKI

Identify relevant features of history, examination and investigations

Know key features of management of both AKI and hyperkalaemia

+Which of these patients has AKI?

89 year old lady found on the floor by her carer, Ur 7, Creat 190

50 year old presenting at A&E following 2 days of severe vomiting and diarrhoea, Ur 20 Creat 205

70 year old on the ward being treated for CAP, nurses are concerned he is not passing urine

+Definition

A rise in serum creatinine (of 26 μmol/l or greater) within 48 hours)

A 50% or greater rise in serum creatinine known or presumed to have occurred within the past 7 days

A fall in urine output (to less than 0.5 ml/kg/hour for more than 6 hours in adults and more than 8 hours in children and young people)

“Rise in serum creatinine from normal baseline over hours or days”

+Causes

Pre-renal (hypoperfusion) Hypovolaemia Sepsis Drugs e.g., NSAIDs Renal artery stenosis

Renal Glomerulonephritis Drugs e.g., gentamicin Rhabdomyolysis Myeloma Haemolytic-uraemic syndrome

Post-renal (obstruction) Tumours BPH Retroperitoneal fibrosis

+History

Think of causes: Infection (UTI/sepsis) Hypovolaemia (D+V, acute blood loss) Drugs (any nephrotoxic/new meds?) Urine: output (&symptoms of UTI/prostate) Weird and wonderful (nosebleeds, haemoptysis,

backpain/weight loss) PMHx: Diabetes, bladder/prostate Ca, FHx (PKD)

+Examination

General

Fluid status: BP, skin turgor, mucous membranes, JVP, oedema (peripheral/pulmonary), urine output

Abdominal (in exams) Palpable bladder? Ballotable kidneys?

+Investigations

Observations

Bedside Urine Dip, ECG, ABG, BM

Bloods FBC, U&Es, renal screen – complement, autoantibodies, myeloma screen

Imaging USS renal tract CXR

Special tests Biopsy

+Management of AKI

Treat the cause!

Conservative: Oral fluids, STOP CANDA, diet

Medical IV fluids, treat life-threatening complications,

catheter (if bladder/prostate obstruction), steroids for certain types of GN

Dialysis

Surgical Obstruction, bleeding

+Complications of AKI

Hyperkalaemia

Metabolic Acidosis

Pulmonary Oedema

Uraemia

+ECG changes in hyperkalaemia

Tall tented T waves Low flat P waves Broad, bizarre QRS

+Treatment of hyperkalaemia

Protect the heart Monitor Calcium Gluconate

Shift the potassium Insulin/dextrose Salbutamol nebs

Treat the cause

Reassess

+Indications for Dialysis

AEIOU

Acidosis – refractory metabolic acidosis

Electrolyte imbalance (refractory hyperkalaemia)

Intoxication – poisoning with dialysable substances

Overload – refratory pulmonary oedema

Uraemic symptoms – pericarditis, encephalopathy

+Key points

History and Examination – concentrate on doing the basics well

Investigations – what differential will it rule out?

Learn the essentials now and keep repeating them… Pre-renal, renal, post-renal CANDA ECG changes in hyperkalaemia Treatment of hyperkalaemia Indications for dialysis

Practice communication task

Questions?