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Acute Kidney Injury. Dr Alexis Missick FY2. Presentation. Case Objectives Definition & Aetiology Investigation Management Complications. Clinical Scenario.
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Acute Kidney Injury Dr Alexis Missick FY2
Presentation • Case • Objectives • Definition & Aetiology • Investigation • Management • Complications
Clinical Scenario • History: 55 year old lady presents to A&E with a 5 day history of diarrhoea and vomiting. She believes this was caused by a Chinese take away she had a day before developing symptoms. She has been unable to keep anything down including water and now feels very poorly. • PMHx: HTN managed with ramipril. • SHx: non-smoker, drinks alcohol occasionally. • O/E: she appears very dry and has reduced skin turgor. BP is 100/70 and HR 95. Examination is otherwise unremarkable
Clinical Scenario • History: 55 year old lady presents to A&E with a 5 day history of diarrhoea and vomiting. She believes this was caused by a Chinese take away she had a day before developing symptoms. She has been unable to keep anything down including water and now feels very poorly. • PMHx: HTN managed with ramipril. • SHx: non-smoke, occasional alcohol. • O/E: she appears very dry and has reduced skin turgor. BP is 100/70 and HR 95. Examination is otherwise unremarkable • Ix: normal FBC, Na 149, K 6.7, Urea 17.0 and Creatinine 258
Objectives • Recognition of AKI • Learn classification of causes and common examples • Identification of appropriate investigations • Understand principles of management of AKI • Knowledge of indications for dialysis • Awareness of complications and management of hyperkalaemia (common complication)
Definition • Rapid impairment in renal function resulting in raised plasma urea/creatinine, fluid and/or acid-base imbalance which is reversible. • AKIN Criteria for diagnosis of AKI • Time course – rapid (<48hours) • Reduction in Kidney function • Rise in serum creatinine (absolute increase of >0.3mg/dl or percentage increase of > 50%) • Reduction in urine output (<0.5ml/kg/hr for >6hours) • RIFLE criteria (prosposed by ADQI) for staging of AKI: Risk, Injury, Failure, Loss, End stage kidney disease
Staging RIFLE Criteria • Proposed by ADQI • Severity (Stage 1-3) • Risk: GFR decrease >25%, serum creatinine increased 1.5 times OR urine production of <0.5 ml/kg/hr for >6 hours • Injury: GFR decrease >50%, doubling of creatinine OR urine production <0.5 ml/kg/hr for 12 hours • Failure: GFR decrease >75%, >tripling of creatinine or creatinine >355 μmol/l (>4 mg/dl) OR urine output below 0.3 ml/kg/hr for 24 hours • Outcome • Loss: persistent AKI or complete loss of kidney function for more than 4 weeks • End-stage renal disease: need for renal replacement therapy (RRT) for more than 3 months
Aeitology http://www.medicalassessmentonline.net/terms.php?R=3
Presentation • Symptoms • Malaise • Anorexia, Nausea and Vomiting • Pruritis • Dehydration • Confusion, convulsions • Signs • Hypertension • Fluid overload: peripheral oedema, SOB/ bibasal crackles/raised JVP • Dehydration: postural hypotension, poor urine output (palpable bladder)
Investigations • Bedside: BP (lying and standing), urine dip (?haematuria ?proteinuria), ECG • Biochemistry: ABG, FBCs, U+Es, LFTs, CRP/ESR, Ca2+, blood culture • Imaging: CXR, USS KUB or CT KUB • Special tests: • CK, blood film, Myeloma screen (Bence-Jones protein), Renal Screen (ANA, ANCA, anti-BM) • Urine osmolality and cast cells • Renal biopsy • Doppler Renal USS and/or Angiography
Management • Assess fluid status • Fluid resuscitation • Stop nephrotoxic drugs • Treat the cause • Infection – give antibiotics, renal doses • Intrinsic renal disease – R/v medication • Obstruction- ?catheters ?calculus removal ?nephrostomies ?surgery
Complications – Indication for Immediate Dialysis!! • Hyperkalaemia (persistent >7mmol/L) • Metabolic Acidosis (if pH<7.2, bicarbonate <12) • Pulmonary Oedema (refractory) • Pericarditis • Symptomatic ureamia - Encephalopathy http://homeopathyexpert.blogspot.co.uk/2011/05/chronic-renal-failure.html
Hyperkalaemia • Potassium range is 3.5 – 5mmol/L • Rise in serum K+ >5mmol/l • Signs/symptoms: muscle weakness • ECG changes: • Flattened P waves • Broad QRS complex • Slurring of ST segment • Tall tented T waves http://www.aafp.org/afp/2006/0115/p283.html
Hyperkalaemia • Potassium >6.0 mmol/L • Calcium resonium 15g QDS PO • If septic or rising quickly treat as though K+ 6.5 • Potassium >6.5 mmol/L • Dextrose-insulin (50ml 50% Dextrose with 10units Actrapid insulin, IV over 5mins) Monitor BM • Calcium resonium 15g QDS PO
Hyperkalaemia • Potassium >7 mmol/L • Calcium gluconate (10ml of 10% solution into central vein or diluted into 40ml 0.9% saline into peripheral vein over 10mins, with cardiac monitor) • Dextrose insulin • Nebulised salbutamol 5mg • IV sodium bicarbonate (50ml 8.4% over 5mins centrally or 500mls 1.26% over 30mins peripherally • Calcium resonium