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Last reviewed: 21 Oct 2024
Last updated: 17 Sep 2024

Summary

Definition

History and exam

Key diagnostic factors

  • hypotension
  • risk factors
  • kidney insults
  • reduced urine production
  • lower urinary tract symptoms
  • symptoms of volume overload/pulmonary oedema
  • vomiting/nausea
  • fever, rash, and/or arthralgia
  • haematuria (visible or non-visible)
  • palpable bladder and/or enlarged prostate and/or abdominal distension

Other diagnostic factors

  • dizziness and orthostatic symptoms
  • hypertension
  • altered mental status
  • pericardial/pleural rub
  • muscle tenderness
  • haemoptysis
  • abdominal bruit

Risk factors

  • advanced age
  • underlying kidney disease
  • diabetes mellitus
  • sepsis
  • exposure to nephrotoxins (e.g., aminoglycosides, vancomycin + cancer therapies, non-steroidal anti-inflammatory drugs)
  • excessive fluid loss
  • surgery
  • haemorrhage
  • recent vascular intervention
  • cardiac arrest
  • pancreatitis
  • trauma
  • malignant hypertension
  • connective tissue disease
  • sodium-retaining states (e.g., congestive heart failure, cirrhosis, nephrotic syndrome)
  • drug overdose
  • nephrolithiasis
  • drug abuse
  • alcohol abuse
  • excessive exercise
  • recent blood transfusion
  • malignancy
  • genetic susceptibility
  • use of renin-angiotensin system inhibitors
  • proton pump inhibitors
  • herbal therapy
  • iodinated contrast
  • myeloproliferative disorders, such as multiple myeloma

Diagnostic investigations

1st investigations to order

  • basic metabolic profile (including urea and creatinine and liver function tests)
  • serum potassium
  • FBC
  • bicarbonate
  • C-reactive protein
  • blood culture
  • urinalysis
  • urine culture
  • urine output monitoring
  • fluid challenge
  • venous blood gases
  • CXR
  • ECG

Investigations to consider

  • renal tract ultrasound
  • abdominal CT or MRI scan
  • nuclear renal flow scan
  • urine osmolality
  • urine sodium concentration
  • fractional excretion of sodium/urea
  • urinary eosinophil count
  • serum creatine kinase
  • ANA (anti-nuclear antibodies)
  • anti-dsDNA
  • complement (C3, C4, CH50)
  • anti-glomerular basement membrane antibody
  • anti-neutrophil cytoplasmic antibodies (ANCA)
  • acute hepatitis profile
  • HIV serology
  • cryoglobulins
  • anti-streptolysin-O antibody
  • serum/urine electrophoresis
  • cystoscopy
  • kidney biopsy

Emerging tests

  • novel serum and urinary biomarkers

Treatment algorithm

Contributors

Expert advisers

Jonathan Murray, BSc (Hons), MBBS (Hons), MRCP

Consultant Nephrologist

South Tees Hospitals NHS Foundation Trust

Middlesbrough

UK Kidney Association Acute Kidney Injury Specialist Interest Group Co-Chair

UK

Disclosures

JM is co-chair for the UK Kidney Association Acute Kidney Injury Specialist Interest Group, co-chair for the UK Kidney MedTech Research Network, and a member of the Renal Service Transformation Programme Acute Kidney Injury Workstream. JM was a Specialist Committee Member Update to NICE Acute Kidney Injury Quality Standard update, and an Expert Commentator for NICE Medtech Innovation Briefing. JM has co-authored national guidelines for the UK Kidney Association, providing best practice guidance for providing renal support for critically ill patients during the COVID-19 pandemic (published November 2020). JM recently co-authored two articles evaluating technology to enable monitoring of kidney tests; he received no payment and has no vested interest in the technologies used. JM delivered a lecture at the Society for Acute Medicine meeting about acute kidney injury (September 2022) and a lecture about one of the above studies at the Royal College of Physicians, in Edinburgh (April, 2020). JM is due to lead a national acute kidney injury summit meeting in September 2023, within his role as co-chair for the UK Kidney Association Acute Kidney Injury Specialist Interest Group. All roles disclosed above are unpaid.

Acknowledgements

BMJ Best Practice would like to gratefully acknowledge the previous expert contributors, whose work has been retained in parts of the content:

Andrew Lewington BSc (Hons), MBBS, MEd, MD, FRCP

Consultant Renal Physician

Honorary Associate Professor

Nephrology Department

Leeds Teaching Hospitals NHS Trust

Head of MBChB

School of Medicine

University of Leeds

Leeds

UK

Richard A. Lafayette MD

Professor of Medicine

Nephrology Division

Stanford University Medical Center

Stanford

CA

Disclosures

AL has been the principal applicant/co-applicant for a number of grants including: Engineering and Physical Sciences Research Council Research - Multiplexed AKI biomarker detection with a single molecule biosensor; Leeds Cares - A novel, non-invasive diagnostic approach to assess kidney transplant health through the targeted measurement of biomarkers of kidney injury and immune response in kidney transplant recipients at the Leeds Teaching Hospitals NHS Trust; Kidney Research Yorkshire - Use of enhanced technology to characterise haemodialysis treatment for acute kidney injury (AKI); Bringing It Home - Validation of a micro-sampling technique for measuring tacrolimus and creatinine remotely; and to fund a research nurse; British Renal Society - Renal function assessment with point of care creatinine in diverse populations (RAPID), and several NIHR grants including on a) Improving the quality of post-discharge care following AKI b) An investigation into the use of remote blood sample collection to reduce health inequalities in patients with mental health disorders c) A comparison of remote blood collection devices: a human factor use study d) Defining the characteristics for a novel automatic device to monitor urine output in catheterized patients e) Leeds Medtech and In-vitro Diagnostic Cooperative Grant Extension f) Surgical MedTech Co-operative for the 2019/20 proof-of-principle funding stream g) A pilot investigation into the use of beta-trace protein for residual renal function estimation in haemodialysis h) Application of functional MRI to improve assessment of chronic kidney disease (AFiRM study) i) SuperResPath-Renal: Quantitative super-resolution technology for a fast, decentralised clinical diagnosis of renal pathologies. AL is the co-author of a number of manuscripts including on extracorporeal treatments, AKI, kidney function testing prior to contrast-enhanced CT, plasma exchange and glucocorticoids in severe ANCA-associated vasculitis, COVID-19 rapid diagnostics, multimodal image-guided ablation on management of renal cancer in Von-Hippel-Lindau syndrome, and on a summary of NICE guidance on CKD. AL is the author of several book chapters on nephrology and AKI. AL has received expenses for accommodation and travel for conferences at which he has given lectures, other than those delivered virtually. AL was a member of the AKI Scientific Program Committee for the ISN World Congress of Nephrology 2020-2021 and Chair of this same committee in 2021-2022. RAL works as a consultant and researcher for Relypsa, Inc. Although unrelated to this topic area, RAL also works as a consultant for Fibrogen, Inc.; Mallinckrodt, Inc.; and Omeros, Inc.; and as a researcher for Genentech, Inc.; Mallinckrodt, Inc.; GlaxoSmithKline, Inc.; Rigel, Inc.; Aurinia, Inc.; and the NIH.

Peer reviewers

Suren Kanagasundaram

Consultant Nephrologist

Newcastle upon Tyne Hospitals NHS Trust

Clinical Lead 

Newcastle Hospitals Haemodialysis Service 

Honorary Clinical Senior Lecturer 

Newcastle University

Newcastle

UK

Disclosures

SK was an expert adviser to the National Confidential Enquiry into Patient Outcome and Death (NCEPOD) report into AKI and is lead author of the UK Renal Association clinical practice guideline on AKI.

Editors

Tessa Davis

Section Editor, BMJ Best Practice

Consultant in Paediatric Emergency Medicine

Royal London Hospital

London

UK

Disclosures

TD declares that she has no competing interests.

Jo Haynes

Head of Editorial, BMJ Knowledge Centre

Disclosures

JH declares that she has no competing interests.

Julie Costello

Comorbidities Editor, BMJ Best Practice

Disclosures

JC declares that she has no competing interests.

Adam Mitchell

Drug Editor, BMJ Best Practice

Disclosures

AM declares that he has no competing interests.

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