Acute Kidney Injury (AKI)




Staging of AKI: RIFLE Staging

(Acute Dialysis Quality Initiative, 2002 Staging: excludes patients with primary kidney disease, such as glomerulonephritis)

Staging of AKI: Acute Kidney Injury Network (AKIN) Staging

Etiology: Pre-Renal


  • Contrast Nephropathy (see Contrast Nephropathy, [[Contrast Nephropathy]])
    • Epidemiology: uncommonly, some cases of contrast nephropathy manifest pre-renal urine studies, especially early during the oliguric phase
    • Physiology: possible mechanisms include contrast-induced renal vasospasm, increased blood viscosity with decreased renal blood flow, or acute tubular obstruction due to contrast-induced precipitates of Tamm-Horsfall protein
  • Hemorrhage/Hemorrhagic Shock (see Hemorrhagic Shock, [[Hemorrhagic Shock]])
  • Hypovolemia/Hypovolemic Shock (see Hypovolemic Shock, [[Hypovolemic Shock]])

Low Cardiac Output State

  • Cardiogenic Shock (see Cardiogenic Shock, [[Cardiogenic Shock]]): decreased CO state
  • General Anesthesia: causes systemic vasodilation and decreased CO

Increased Renal : Systemic Vascular Resistance Ratio

  • Abdominal Compartment Syndrome (see Abdominal Compartment Syndrome, [[Abdominal Compartment Syndrome]]): due to decreased renal perfusion
  • Amphotericin B (see Amphotericin, [[Amphotericin]]): due to renal vasoconstriction
  • Anaphylaxis (see Anaphylaxis, [[Anaphylaxis]]): due to systemic vasodilation
  • Cyclosporine A (CSA) (see Cyclosporine A, [[Cyclosporine A]]]: due to renal vasoconstriction and direct toxicity
  • Epinephrine (see Epinephrine, [[Epinephrine]]): due to renal vasoconstriction
  • General Anesthesia: due to systemic vasodilation and decreased CO
  • Hepatorenal Syndrome (see Hepatorenal Syndrome, [[Hepatorenal Syndrome]]): cirrhosis (with protal HTN + ascites) is characterized by renal vasoconstriction, increased plasma volume, effective hypovolemia, and systemic vasodilation
  • Hypercalcemia (see Hypercalcemia, [[Hypercalcemia]]): due to renal vasoconstriction
  • Interleukin-2 (IL-2) (see Interleukin-2, [Interleukin-2]]): due to systemic vasodilation and capillary leak
  • Norepinephrine (see Norepinephrine, [[Norepinephrine]]): due to renal vasoconstriction
  • Sepsis (see Sepsis, [[Sepsis]]) (accounts for up to 50% of AKI cases in ICU, most common single etiology of AKI in a general ICU): due to systemic vasodilation
  • Tacrolimus (see Tacrolimus, [[Tacrolimus]])
  • Vasodilators: due to systemic vasodilation
    • Anti-Hypertensives
    • Epoprostenol (Flolan, Veletri) (see Epoprostenol, [[Epoprostenol]])

Renal Hypoperfusion with Impaired Renal Autoregulation

Hyperviscosity Syndromes

Etiology: Renal (Intrinsic)

Renovascular Obstruction

Glomerular/Renal Microvasculature Disease

Acute Tubular Necrosis (ATN)

Ischemic Acute Tubular Necrosis (Due to Hypotension/Shock)

Toxic Acute Tubular Necrosis

Drug-Induced Acute Tubular Necrosis
  • Acetaminophen (Tylenol) (see Acetaminophen, [[Acetaminophen]])
  • Aminoglycosides (see Aminoglycosides, [[Aminoglycosides]]): due to direct tubular toxicity/necrosis
  • Amphotericin B (see Amphotericin, [[Amphotericin]]): AKI occurs in 25-30% of cases -> liposomal amphotericin B is preferred because of reduced nephrotoxicity (19% vs 34%)
  • Cephalosporins (see Cephalosporins, [[Cephalosporins]])
  • Cisplatin (see Cisplatin, [[Cisplatin]])
  • Colistin (Colistimethate Sodium, Polymyxin E) (see Colistin, [[Colistin]])
  • Contrast Nephropathy (Contrast Nephropathy, [[Contrast Nephropathy]]): direct tubular toxicity with local ischemia
  • Cyclosporine A (see Cyclosporine A, [[Cyclosporine A]]): due to renal vasoconstriction and direct toxicity
  • Enflurane (see Enflurane, [[Enflurane]])
  • Foscarnet (see Foscarnet, [[Foscarnet]])
  • Illegal Abortifacients
  • Polymyxin B (see Polymyxin B, [[Polymyxin B]])
  • Tacrolimus (Prograf) (see Tacrolimus, [[Tacrolimus]])
Toxin-Induced Acute Tubular Necrosis
Pigment-Induced Acute Tubular Necrosis
Crystal-Induced Acute Tubular Necrosis
Multiple Myeloma (see Multiple Myeloma, [[Multiple Myeloma]])

Acute Interstitial Nephritis (see Acute Interstitial Nephritis, [[Acute Interstitial Nephritis]])

Drug-Induced (Allergic) Interstitial Nephritis

  • Antipyrine
  • Azathioprine (Imuran) (see Azathioprine, [[Azathioprine]])
  • Gold (see Gold, [[Gold]])
  • Interferons (see Interferons, [[Interferons]])
  • Non-Steroidal Anti-Inflammatory Drugs (NSAID’s) (see Non-Steroidal Anti-Inflammatory Drug, [[Non-Steroidal Anti-Inflammatory Drug]]): including selective COX-2 inhibitors
Proton Pump Inhibitors (PPI’s)
  • Omeprazole (Prilosec) (see Omeprazole, [[Omeprazole]])
  • Lansoprazole (Prevacid) (see Lansoprazole, [[Lansoprazole]])
  • Allopurinol (see Allopurinol, [[Allopurinol]])
  • α-Methyldopa (see α-Methyldopa, [[α-Methyldopa]])
  • Bismuth (see Bismuth, [[Bismuth]])
  • Captopril (see Captopril, [[Captopril]])
  • Clofibrate (Atromid-S) (see Clofibrate, [[Clofibrate]])
  • Coumadin (see Coumadin, [[Coumadin]])
  • Etanercept (see Anti-TNF Therapy, [[Anti-TNF Therapy]])
  • H2-Histamine Receptor Antagonists (see H2-Histamine Receptor Antagonists, [[H2-Histamine Receptor Antagonists]])
    • Cimetidine (Tagamet) (see Cimetidine, [[Cimetidine]]): cimetidine is the H2 blocker most associated with acute interstitial nephritis
    • Ranitidine (Zantac) (see Ranitidine, [[Ranitidine]]): only rare cases have been reported
  • Indinavir (Crixivan) (see Indinavir, [[Indinavir]])
  • Mesalamine (see Mesalamine, [[Mesalamine]])
  • Phenindione
  • Phenylpropanolamine (see Phenylpropanolamine, [[Phenylpropanolamine]])
  • Phenytoin (Dilantin) (see Phenytoin, [[Phenytoin]])
  • Probenecid (see Probenecid, [[Probenecid]])

Infectious Interstitial Nephritis

  • Acute Pyelonephritis (see Urinary Tract Infection, [[Urinary Tract Infection]])
  • Brucellosis (see Brucellosis, [[Brucellosis]])
    • Produces a Histologic Variant of Acute Interstitial Nephritis with Associated Granuloma Formation
  • Chlamydia (see Chlamydia, [[Chlamydia]])
    • Produces a Histologic Variant of Acute Interstitial Nephritis with Associated Granuloma Formation
  • Diphtheria (see Diphtheria, [[Diphtheria]])
  • Enterococcus (see Enterococcus, [[Enterococcus]])
  • Escherichia Coli (see Escherichia Coli, [[Escherichia Coli]])
  • Legionellosis (see Legionellosis, [[Legionellosis]])
  • Leptospirosis (see Leptospirosis, [[Leptospirosis]]
  • Mycoplasma Pneumoniae (see Mycoplasma Pneumoniae, [[Mycoplasma Pneumoniae]])
  • Renal Tuberculosis (see Tuberculosis, [[Tuberculosis]])
    • Produces a Histologic Variant of Acute Interstitial Nephritis with Associated Granuloma Formation
  • Rocky Mountain Spotted Fever (see Rocky Mountain Spotted Fever, [[Rocky Mountain Spotted Fever]])
  • Staphylococcus (see Staphylococcus, [[Staphylococcus]])
  • Streptococcus (see Streptococcus, [[Streptococcus]])
  • Syphilis (see Syphilis, [[Syphilis]])
  • Tularemia (see Tularemia, [[Tularemia]])
    • Produces a Histologic Variant of Acute Interstitial Nephritis with Associated Granuloma Formation
  • Yersinia (see Yersinia, [[Yersinia]])
  • Candidiasis (see Candida, [[Candida]])
  • Coccidioidomycosis (see Coccidioidomycosis, [[Coccidioidomycosis]])
    • Produces a Histologic Variant of Acute Interstitial Nephritis with Associated Granuloma Formation
  • Histoplasmosis (see Histoplasmosis, [[Histoplasmosis]])
    • Produces a Histologic Variant of Acute Interstitial Nephritis with Associated Granuloma Formation
  • Leishmaniasis (see Leishmaniasis, [[Leishmaniasis]])
    • Produces a Histologic Variant of Acute Interstitial Nephritis with Associated Granuloma Formation
  • Toxoplasmosis (see Toxoplasmosis, [[Toxoplasmosis]])
    • Produces a Histologic Variant of Acute Interstitial Nephritis with Associated Granuloma Formation

Infiltrative Interstitial Nephritis

Vasculitis-Associated Interstitial Nephritis

Other Etiologies of Interstitial Nephritis

  • Acute Renal Allograft/Transplant Rejection (see Renal Transplant, [[Renal Transplant]])
  • Immunoglobulin G4-Related Disease (IgG4-Related Disease) (see Immunoglobulin G4-Related Disease, [[Immunoglobulin G4-Related Disease]])
    • Epidemiology: acute interstitial nephritis is the most common renal manifestation of IgG4-related disease
  • Intravenous Drug Abuse (IVDA)
  • Radiation Nephritis (see Radiation Therapy, [[Radiation Therapy]])
  • Idiopathic Interstitial Nephritis

Intratubular Deposition and Obstruction

Renal Allograft/Transplant Rejection (see Renal Transplant, [[Renal Transplant]])

  • xxx

Nephrotic Syndrome (see Nephrotic Syndrome, [[Nephrotic Syndrome]])

  • Crescentic Glomerulonephritis
  • Focal Segmental Glomerulosclerosis
  • Focal Segmental Proliferative Glomerulonephritis
  • Membrano-Proliferative Glomerulonephritis Type 1
  • Membrano-Proliferative Glomerulonephritis Type 2
  • Membranous Glomerulonephritis
  • Mesangio-Proliferative Glomerulonephritis
  • Minimal Change Disease
  • Osmotic Nephrosis

Etiology: Post-Renal

Ureteral Obstruction

Bladder Neck Obstruction

Urethral Obstruction

Multifactorial Etiologies


Urinalysis (see Urinalysis, [[Urinalysis]])

Urine Microscopy

Serum Creatinine

Biomarkers for the Early Detection of Acute Kidney Injury

Neutrophil Gelatinase-Associated Lipocalin (NGAL)

Serum or Urinary Cystatin C

Kidney Injury Molecule-1 (KIM-1)

Urinary IL-18

Fractional Excretion of Sodium (FENa) (see xxx)

Fractional Excretion of Urea (FE Urea) (see xxx)

Urinary Uric Acid:Urinary Creatinine Ratio

Urine Osm

Diagnostic Volume Challenge

Renal Biopsy

Prevention of Acute Kidney Injury (AKI)

Prevention of Contrast Nephropathy

Prevention of Alcoholic Hepatitis-Associated AKI

Prevention of End-Stage Liver Disease-Associated AKI in Setting of SBP

Prevention of ESLD-Associated AKI in Setting of Large-Volume Paracentesis

Prevention of ESLD-Associated AKI

Maintenance of Renal Perfusion

Management of Hyperglycemia

Fenoldopam (see Fenoldopam, [[Fenoldopam]])

Clinical Manifestations

Neurologic Manifestations

Renal Manifestations

Other Manifestations




Optimization of Nutrition

Renal Replacement Therapy (RRT)

Atial Natriuretic Peptide (ANP) (Experimental)

Erythropoetic Agents (Experimental)

Renal Tubule Assist Device (Experimental)

Hemofiltration for Sepsis (Experimental)

Stem Cells (Experimental)




Contrast Nephropathy