L1: AKI Flashcards
Def of AKI
Epidemeology of AKI
Dx Criteria of AKI
S. Cr in AKI
Urine Output in AKI
Staging Cr in AKI
Stage I AKI
Stage II AKI
Stage III AKI
Urinary obstruction must be excluded as a cause of low urine output.
..
The most abnormal parameter is used for classifications.
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Etiology of AKI
Pre-Renal Causes of AKI
Pre-Renal Causes of AKI
- Hypovolemia
Pre-Renal Causes of AKI
- ## Shock
Septic, Cardiogenic or Anaphylactic
Pre-Renal Causes of AKI
- Drugs
Renal Causes of AKI
- Glomerular
- Tubulo-interstitial
- Vascular
Renal Causes of AKI
- Glomerular
Glomerulonephritis (Especially rapidly progressive glomerulonephritis) → Discussed separately.
Renal Causes of AKI
- Interstitial
AIN = Acute Interstitial Nephritis
Renal Causes of AKI
- Tubular
- Ischemic ATN
- Toxic ATN
- Sepsis
Causes of ATN
- Ischemic ATN
- Toxic ATN
- Sepsis
Ischemic ATN
- ALL CAUSES OF PRERENAL DISEASE particularly if SEVERE, PROLONGED & accompanied by hypotension, surgery, and/or sepsis can cause ATN.
Types of Toxic ATN
- Endogenous & Exogenous
Types of Endogenous Nephrotoxins
Protein Endogenous Nephrotoxins
Crystals as endogenous nephrotoxins
Uric acid → in Tumor lysis syndrome.
Types of Exogenous Nephrotoxins
- Drugs
- Toxic Manifestations
- Heavy Metals
- Contrast Agents
Exogenous Nephrotoxins
- Drugs
▪ Antibiotics: Aminoglycosides.
▪ Antifungal: Amphotericin B.
▪ Antiviral: Acyclovir – Cidofovir.
▪ Chemotherapeutic agents: Cisplatin, Methotrexate.
Exogenous Nephrotoxins
- Toxic Ingestions
Ethylene glycol
Exogenous Nephrotoxins
- Heavy Metals
Mercury – Lead – Arsenic
Renal Causes of AKI
- Vascular
Intrinsic renal vascular diseases directly affect both SMALL & LARGE sized blood vessels
within the kidneys.
Vascular Causes of AKI
- Small Blood Vessels
Vascular Causes of AKI
- Large Blood Vessels
① Renal infarction from aortic dissection or renal artery abnormality (such as aneurysm).
② Acute renal vein thrombosis.
Post-Renal Causes of AKI
Pathophysiology Stages of AKI
- Initiating Event (Kidney Injury)
- Oliguric / Anuric (Maintenance)
- Polyuric (Diuretic)
- Recovery
Pathophysiology Stages of AKI
- Initiating Injury
Pathophysiology Stages of AKI
- Oliguric / anuric (Maintainence) Phase
Decreased GFR Mehcanisms in Oliguric / anuric (Maintainence) Phase
◈ Toxins + Ischemia → Necrosis & Sloughing of tubular epithelial cells into tubular lumen → obstruction of tubules → Increased intraluminal pressure.
◈ Back-leak of tubular fluid to renal interstitium.
◈ Excess renin activation → Afferent vasoconstriction.
Complications of Oliguric / anuric (Maintainence) Phase
① Fluid retention → Dilutional hyponatremia.
② Electrolyte retention → Hyperkalemia & Hyperphosphatemia.
③ Ca++: Decreased (May still normal).
④ Increases S. Creatinine, Urea & H+ (Metabolic acidosis).
Duration of Oliguric / anuric (Maintainence) Phase
1–3 weeks
Pathophysiology Stages of AKI
- Polyuric (Diuretic) Phase
Mechanism of Polyuric (Diuretic) Phase
Complications of Polyuric (Diuretic) Phase
① Loss of water (dehydration).
② Loss of electrolytes (hyponatremia, hypokalemia etc…).
Duration of Polyuric (Diuretic) Phase
∼ 2 weeks
Polyuric (Diuretic) Phase is characteristic for which type of AKI?
Ischemic (renal)
Pathophysiology Stages of AKI
- Recovery
Kidney function & urine production normalize
CP of AKI
Symptoms of the cause + ………
CP of AKI
- Volume Status
CP of AKI
- Sodium
CP of AKI
- Potassium
CP of AKI
- Other electrolyres
Increased P & Decreased Ca
CP of AKI
- Metabolic Acidosis
CP of AKI
- Urine Output
Non-oliguric AKI (absence of oliguria) argues against ……
a pre-renal etiology.
….. AKI reveals nothing about the etiology
Oliguric
Anuric AKI Most often seen in …..
shock & complete bilateral urinary tract obstruction.
CP of AKI
- Uremic Manifesfations
Refer to Chronic kidney Disease (CKD)
CP of AKI
- Cardiac Complications
CP of AKI
- Nutritional Symptoms
Steps in Dx of AKI
- Is it AKI or Not?
- What Type?
- Role of Bx?
Dx of AKI
Diffrence Between AKI & CKD
Compare between AKI & CKD in Terms of
- Hx
Compare between AKI & CKD in Terms of
- Renal Size
Compare between AKI & CKD in Terms of
- Hb
Urine Sediment in Pre-Renal AKI
- Normal or near normal.
- Hyaline casts &/or fine granular casts may be seen
Compare between AKI & CKD in Terms of
- Renal Osteodystrophy
Compare between AKI & CKD in Terms of
- Serum Creatinine
Lab Results in Pre-Renal AKI
US in Pre-Renal AKI
Normal
Response to Acute TTT in Pre-Renal AKI
Rapid improvement in renal function
following acute intervention
Urine Sediments in Renal AKI
Labs in Renal AKI
US in Renal AKI
May be enlarged
(Due to inflammation or edema)
Response to Acute TTT in Renal AKI
lack of response to acute intervention
Urine Sediment in Post-renal AKI
May be hematuria & pyuria
Labs in Post-renal AKI
US in Post-renal AKI
Bilateral hydronephrosis
Response to acute TTT in Post-renal AKI
Rapid improvement in renal function following resolution of the obstruction
….. is the preferred test for distinguishing between prerenal disease & intrinsic renal.
FENa+
FENa+ is not utilized during diuretic therapy (as in prerenal conditions can be > 1)
…
Indications of Biopsy in AKI
CI of Bx in AKI
CI of Bx in AKI
- kidney Status
CI of Bx in AKI
- Patient Status
- Most contraindications are relative rather than absolute.
- Clinical circumstances that necessitate urgent renal biopsy may be overridden, EXCEPT FOR uncontrolled bleeding diathesis.
..
- In advanced chronic kidney disease and ultrasound imaging of reduced kidney volume, the renal biopsy is generally contraindicated.
…
Approach to Specifc underling Causes of AKI
- Hemolysis
Approach to Specifc underling Causes of AKI
- Rhabdomyolysis
Approach to Specifc underling Causes of AKI
- Tumor Lysis Syndrome
Managment aspects of AKI
- TTT of Cause
- Supportive
- KRT
Managment aspects of AKI
- TTT of underlying Causes
Managment aspects of AKI
- Supportive Care
Goals of Supportive Care
① Avoid further renal insult & potentially aggravating factors.
② Support adequate kidney perfusion.
③ Ensure early identification & treatment of complications.
Aspects of Supportive Care of AKI
① Medications
② Volume status
③ Electrolytes
④ Acid-base disturbances
⑤ Others (Nutritional support, Contrast agents & Hyperuricemia)
Supportive Care of AKI
- Volume Status
Supportive Care of AKI
- medications
Supportive Care of AKI
- Electrolytes
Supportive Care of AKI
- Electrolytes (Hyperkalemia)
Supportive Care of AKI
- Electrolytes (Hyponatremia)
Supportive Care of AKI
- Electrolytes (hyperphosphatemia)
Supportive Care of AKI
- Electrolytes (Hypocalcemia)
Supportive Care of AKI
- Metabolic Acidosis
When should Treating Metabolic Acidosis by Bicorbonate Avoided? and What is the alternative?
Nutitional Support in AKI
- Protein
Nutitional Support in AKI
- Calories
20 to 30
Nutitional Support in AKI
- Salt & Fluid
Restricted → To correct hypervolemia
Nutitional Support in AKI
- K
Restricted → To correct hyperkalemia
Nutitional Support in AKI
- P
Restricted → To correct hyperphosphatemia
Nutitional Support in AKI
- Ca
Allowed
contrast agents in AKI?
TTT of Hyperuricemia in AKI
Acute treatment is usually not required except in the setting of tumor lysis syndrome.
Indications of KRT in AKI
