Acute kidney injury: Difference between revisions
From IDWiki
m (Text replacement - "Clinical Presentation" to "Clinical Manifestations") |
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β | == |
+ | ==Definition== |
β | * |
+ | *An inability of the kidneys to maintain body homeostasis, usually defined by an acute increase in creatinine |
β | == |
+ | ==AKIN Stage== |
+ | {| class="wikitable" |
||
β | {| |
||
β | ! |
+ | !Stage |
β | ! |
+ | !Serum creatinine |
β | ! |
+ | !Or, urine output |
|- |
|- |
||
β | | |
+ | |1 |
β | | |
+ | |Creatinine increase β₯26.5 umol/L or 1.5-2 times baseline |
β | | |
+ | |<0.5ml/kg/h for 6h |
|- |
|- |
||
β | | |
+ | |2 |
β | | |
+ | |Creatinine increase 2-3 times baseline |
β | | |
+ | |<0.5ml/kg/h for 12h |
|- |
|- |
||
β | | |
+ | |3 |
β | | |
+ | |Creatinine increase >3 times baseline, or creatinine β₯354 umol/L increased by at least 44 umol/L, or need for dialysis |
β | | |
+ | |<0.3ml/kg/h for 24h |
|} |
|} |
||
β | == |
+ | ==Differential Diagnosis== |
β | * |
+ | *Pre-renal: decreased renal perfusion |
β | ** |
+ | **Hypovolemia |
β | ** |
+ | **Blood loss |
β | ** |
+ | **Shock |
β | ** |
+ | **Sepsis |
β | ** |
+ | **Heart failure |
β | ** |
+ | **Vomiting and diarrhea |
β | * |
+ | *Renal/intrinsic |
β | ** |
+ | **Glomerulonephritis (GN): glomerular damage |
β | *** |
+ | ***Primary |
β | **** |
+ | ****Minimal change (in children) |
β | **** |
+ | ****Membranous (in adults) |
β | **** |
+ | ****Focal sclerosing (in HIV patients) |
β | *** |
+ | ***Secondary |
β | **** |
+ | ****Focal sclerosing or diffuse (in diabetic patients) |
β | **** |
+ | ****Lupus, multiple myeloma, and amyloidosis |
β | ** |
+ | **Acute tubular necrosis (ATN): tubular damage |
β | *** |
+ | ***Ischemia from prerenal disease |
β | *** |
+ | ***Toxins |
β | *** |
+ | ***Drugs |
β | **** |
+ | ****Aminoglycosides |
β | **** |
+ | ****Amphotericin |
β | **** |
+ | ****Cisplatin |
β | *** |
+ | ***Pigments: hemoglobin, myoglobin |
β | *** |
+ | ***Proteins: immunoglobulin light chains (e.g. multiple myeloma) |
β | *** |
+ | ***Crystals |
β | **** |
+ | ****Uric acid |
β | **** |
+ | ****Acyclovir |
β | **** |
+ | ****Methotrexate |
β | **** |
+ | ****Indinavir |
β | **** |
+ | ****Oral NaPO4 |
β | *** |
+ | ***Contrast-induced |
β | ** |
+ | **Acute interstitial nephritis (AIN): interstitial damage |
β | *** |
+ | ***Allergic |
β | **** |
+ | ****Antibiotics: beta-lactams, sulfas |
β | **** |
+ | ****NSAIDs |
β | **** |
+ | ****PPIs |
β | *** |
+ | ***Infective |
β | **** |
+ | ****Pyelonephritis |
β | **** |
+ | ****Legionellosis |
β | *** |
+ | ***Infiltration |
β | **** |
+ | ****Sarcoidosis |
β | **** |
+ | ****Lymphoma |
β | **** |
+ | ****Leukemia |
β | *** |
+ | ***Autoimmune |
β | **** |
+ | ****SjΓΆgren's syndrome |
β | **** |
+ | ****TINU syndrome |
β | **** |
+ | ****IgG4 disease |
β | **** |
+ | ****Systemic lupus erythematosis (SLE) |
β | *** |
+ | ***Small vessel disease |
β | **** |
+ | ****Cholesterol emboli |
β | **** |
+ | ****Thrombotic microangiopathy |
β | ***** |
+ | *****HUS/TTP |
β | ***** |
+ | *****DIC |
β | ***** |
+ | *****Preeclampsia |
β | ***** |
+ | *****Anti-phospholipid syndrome (APS) |
β | ***** |
+ | *****Malignant hypertension |
β | ***** |
+ | *****Scleroderma renal crisis |
β | * |
+ | *Post-renal (obstructive) |
β | ** |
+ | **Bladder neck |
β | *** |
+ | ***BPH or prostate cancer (in men) |
β | *** |
+ | ***Cervical cancer (in women) |
β | ** |
+ | **Neurogenic bladder |
β | *** |
+ | ***Anticholinergics |
β | ** |
+ | **Ureteral (bilateral) |
β | *** |
+ | ***Malignancy |
β | *** |
+ | ***LAN |
β | *** |
+ | ***Retroperitoneal fibrosis |
β | *** |
+ | ***Nephrolithiasis |
β | == |
+ | ==Clinical Manifestations== |
β | === |
+ | ===Clinical clues of etiology=== |
+ | {| class="wikitable" |
||
β | {| |
||
β | ! |
+ | !Type |
β | ! |
+ | !History |
β | ! |
+ | !Examination |
|- |
|- |
||
β | | |
+ | |Prerenal |
β | | |
+ | |Volume loss (e.g. vomiting, diarrhea, diuretics, hemorrhage, burns)<br />Thirst and reduced fluid intake<br />Heart failure or cirrhosis |
β | | |
+ | |Weight loss, orthostatic hypotension and tachycardiac, poor skin turgor, signs of heart failure or liver failure |
|- |
|- |
||
β | | |
+ | |Intrinsic renal |
| |
| |
||
| |
| |
||
|- |
|- |
||
β | | |
+ | |ATN |
β | | |
+ | |History of nephrotoxic medications, hypotension, trauma or myalgias suggestion rhabdo, CT contrast |
β | | |
+ | |Muscle tenderness, compartment syndrome, volume status |
|- |
|- |
||
β | | |
+ | |GN |
β | | |
+ | |Lupus, systemic sclerosis, rash, arthritis, uveitis, weight loss, fatigue, HCV infection, HIV infection, hematuria, foamy urine, cough, sinusitis, hemoptysis |
β | | |
+ | |Periorbital, sacral, and lower-extremity edema; rash; oral or nasal ulcers |
|- |
|- |
||
β | | |
+ | |AIN |
β | | |
+ | |Medication use (antiiotics, PPIs), rash, arthralgias, fever, infection |
β | | |
+ | |Fever, drug rash |
|- |
|- |
||
β | | |
+ | |Vascular |
β | | |
+ | |Nephrotic syndrome, trauma, flank pain, anticoagulation, vascular surgery |
β | | |
+ | |Livedo reticularis, fundoscopy showing malignant hypertension, abdominal bruits |
|- |
|- |
||
β | | |
+ | |Post-renal |
β | | |
+ | |Urinary urgency or hesitancy, gross hematuria, polyuria, stones, medications, cancer |
β | | |
+ | |Bladder distension, pelvic mass, prostate enlargement |
|} |
|} |
||
'''Source:''' Rahman M, Shad F, and Smith MC. [https://www.aafp.org/afp/2012/1001/p631.html Acute kidney injury: A guide to diagnosis and management]. ''Am Fam Physician''. 2012;86(7):631-639. |
'''Source:''' Rahman M, Shad F, and Smith MC. [https://www.aafp.org/afp/2012/1001/p631.html Acute kidney injury: A guide to diagnosis and management]. ''Am Fam Physician''. 2012;86(7):631-639. |
||
β | == |
+ | ==Investigations== |
β | * |
+ | *Laboratory |
β | ** |
+ | **Urinalysis and microscopy |
β | *** |
+ | ***Granular casts (from heme), suggesting ATN |
β | *** |
+ | ***Red blood cell casts, suggesting GN |
β | ** |
+ | **Urine sodium |
β | *** |
+ | ***<10mmol/L suggests pre-renal, unless diuresed |
β | ** |
+ | **Urea to creatinine ratio |
β | *** |
+ | ***Increased ratio suggests pre-renal cause |
β | ** |
+ | **Extended electrolytes |
β | * |
+ | *Renal ultrasound, for possible obstruction |
β | === |
+ | ===Fractional excretion of sodium (FENa)=== |
β | $FENa = \frac{U_{Na} \div U_{Cr}}{S_{Na} \div S_{Cr}} = \frac{U_{Na} \times S_{Cr}}{S_{Na} \times U_{Cr}}$ |
+ | <nowiki>$FENa = \frac{U_{Na} \div U_{Cr}}{S_{Na} \div S_{Cr}} = \frac{U_{Na} \times S_{Cr}}{S_{Na} \times U_{Cr}}$</nowiki> |
+ | {| class="wikitable" |
||
β | {| |
||
β | ! |
+ | !FENa |
β | ! |
+ | !Etiology |
|- |
|- |
||
β | | |
+ | |<1% |
β | | |
+ | |Pre-renal |
|- |
|- |
||
β | | |
+ | |1 to 4%<br /> >2% |
β | | |
+ | |Intrinsic renal<br /> Acute tubular necrosis (ATN) |
|- |
|- |
||
β | | |
+ | |>4% |
β | | |
+ | |Post-obstructive |
|} |
|} |
||
β | == |
+ | ==Management== |
β | * |
+ | *Treatment depends on etiology |
β | ** |
+ | **Prerenal: Fluid challenge |
β | ** |
+ | **Renal: Stop nephrotoxic medications |
β | ** |
+ | **Post-renal: Nephrostomy tubes |
β | * |
+ | *Dialysis if |
β | ** |
+ | **Acidosis |
β | ** |
+ | **Electrolyte imbalance (K+) |
β | ** |
+ | **Intoxication (drugs, alcohols) |
β | ** |
+ | **Overloaded fluid (heart failure) |
β | ** |
+ | **Uremia (pericarditis, neurological symptoms) |
β | == |
+ | ==Prognosis== |
β | * |
+ | *Increased risk of developing CKD with |
β | ** |
+ | **Increasing age |
β | ** |
+ | **Female sex |
β | ** |
+ | **AKIN stage |
β | ** |
+ | **Absolute increase in serum creatinine |
β | ** |
+ | **Albuminuria |
[[Category:Nephrology]] |
[[Category:Nephrology]] |
Revision as of 17:19, 10 August 2020
Definition
- An inability of the kidneys to maintain body homeostasis, usually defined by an acute increase in creatinine
AKIN Stage
Stage | Serum creatinine | Or, urine output |
---|---|---|
1 | Creatinine increase β₯26.5 umol/L or 1.5-2 times baseline | <0.5ml/kg/h for 6h |
2 | Creatinine increase 2-3 times baseline | <0.5ml/kg/h for 12h |
3 | Creatinine increase >3 times baseline, or creatinine β₯354 umol/L increased by at least 44 umol/L, or need for dialysis | <0.3ml/kg/h for 24h |
Differential Diagnosis
- Pre-renal: decreased renal perfusion
- Hypovolemia
- Blood loss
- Shock
- Sepsis
- Heart failure
- Vomiting and diarrhea
- Renal/intrinsic
- Glomerulonephritis (GN): glomerular damage
- Primary
- Minimal change (in children)
- Membranous (in adults)
- Focal sclerosing (in HIV patients)
- Secondary
- Focal sclerosing or diffuse (in diabetic patients)
- Lupus, multiple myeloma, and amyloidosis
- Primary
- Acute tubular necrosis (ATN): tubular damage
- Ischemia from prerenal disease
- Toxins
- Drugs
- Aminoglycosides
- Amphotericin
- Cisplatin
- Pigments: hemoglobin, myoglobin
- Proteins: immunoglobulin light chains (e.g. multiple myeloma)
- Crystals
- Uric acid
- Acyclovir
- Methotrexate
- Indinavir
- Oral NaPO4
- Contrast-induced
- Acute interstitial nephritis (AIN): interstitial damage
- Allergic
- Antibiotics: beta-lactams, sulfas
- NSAIDs
- PPIs
- Infective
- Pyelonephritis
- Legionellosis
- Infiltration
- Sarcoidosis
- Lymphoma
- Leukemia
- Autoimmune
- SjΓΆgren's syndrome
- TINU syndrome
- IgG4 disease
- Systemic lupus erythematosis (SLE)
- Small vessel disease
- Cholesterol emboli
- Thrombotic microangiopathy
- HUS/TTP
- DIC
- Preeclampsia
- Anti-phospholipid syndrome (APS)
- Malignant hypertension
- Scleroderma renal crisis
- Allergic
- Glomerulonephritis (GN): glomerular damage
- Post-renal (obstructive)
- Bladder neck
- BPH or prostate cancer (in men)
- Cervical cancer (in women)
- Neurogenic bladder
- Anticholinergics
- Ureteral (bilateral)
- Malignancy
- LAN
- Retroperitoneal fibrosis
- Nephrolithiasis
- Bladder neck
Clinical Manifestations
Clinical clues of etiology
Type | History | Examination |
---|---|---|
Prerenal | Volume loss (e.g. vomiting, diarrhea, diuretics, hemorrhage, burns) Thirst and reduced fluid intake Heart failure or cirrhosis |
Weight loss, orthostatic hypotension and tachycardiac, poor skin turgor, signs of heart failure or liver failure |
Intrinsic renal | ||
ATN | History of nephrotoxic medications, hypotension, trauma or myalgias suggestion rhabdo, CT contrast | Muscle tenderness, compartment syndrome, volume status |
GN | Lupus, systemic sclerosis, rash, arthritis, uveitis, weight loss, fatigue, HCV infection, HIV infection, hematuria, foamy urine, cough, sinusitis, hemoptysis | Periorbital, sacral, and lower-extremity edema; rash; oral or nasal ulcers |
AIN | Medication use (antiiotics, PPIs), rash, arthralgias, fever, infection | Fever, drug rash |
Vascular | Nephrotic syndrome, trauma, flank pain, anticoagulation, vascular surgery | Livedo reticularis, fundoscopy showing malignant hypertension, abdominal bruits |
Post-renal | Urinary urgency or hesitancy, gross hematuria, polyuria, stones, medications, cancer | Bladder distension, pelvic mass, prostate enlargement |
Source: Rahman M, Shad F, and Smith MC. Acute kidney injury: A guide to diagnosis and management. Am Fam Physician. 2012;86(7):631-639.
Investigations
- Laboratory
- Urinalysis and microscopy
- Granular casts (from heme), suggesting ATN
- Red blood cell casts, suggesting GN
- Urine sodium
- <10mmol/L suggests pre-renal, unless diuresed
- Urea to creatinine ratio
- Increased ratio suggests pre-renal cause
- Extended electrolytes
- Urinalysis and microscopy
- Renal ultrasound, for possible obstruction
Fractional excretion of sodium (FENa)
$FENa = \frac{U_{Na} \div U_{Cr}}{S_{Na} \div S_{Cr}} = \frac{U_{Na} \times S_{Cr}}{S_{Na} \times U_{Cr}}$
FENa | Etiology |
---|---|
<1% | Pre-renal |
1 to 4% >2% |
Intrinsic renal Acute tubular necrosis (ATN) |
>4% | Post-obstructive |
Management
- Treatment depends on etiology
- Prerenal: Fluid challenge
- Renal: Stop nephrotoxic medications
- Post-renal: Nephrostomy tubes
- Dialysis if
- Acidosis
- Electrolyte imbalance (K+)
- Intoxication (drugs, alcohols)
- Overloaded fluid (heart failure)
- Uremia (pericarditis, neurological symptoms)
Prognosis
- Increased risk of developing CKD with
- Increasing age
- Female sex
- AKIN stage
- Absolute increase in serum creatinine
- Albuminuria