Unit 5: Renal/Musculoskeletal/Burns Acute Kidney Injury and Renal
Function Examination: In-Depth Exploration of AKI Definitions and
Criteria, Creatinine and GFR Alterations, Urine Output Metrics, Phases
of AKI (Onset, Oliguria, and Beyond), Causes of Post-Renal AKI (BPH,
Bladder and Prostate Cancer, Calculi Formation, Spinal Cord Disease),
Toxemia of Pregnancy, Malignant Hypertension, Prerenal Ischemia,
Renal Function Assessment, Oliguria Management, Anuria
Identification, Renal Failure Progression, Kidney Function Monitoring,
Fluid Balance in Renal Patients, and Advanced Nephrology Practices
Exam Questions Verified and Provided with Complete A+ Graded
Rationales Latest Updated 2026
What is AKI?
Acute kidney injury is the rapid loss of renal function
What is the RIFLE classification for staging AKI?
Risk: Cr inc. x 1.5 OR GFR dec. 25%; urine output <0.5 mL/kg/hr for 6 hrs.
Injury: Cr inc. x 3 OR GFR dec. 50%; urine output <0.5 mL/kg/hr for 12 hr.
Failure: Cr inc. x 3 OR GFR dec. 75%; urine output <0.3 mL/kg/hr for 24 hr (oliguria) OR anuria
for 12 hr.
Loss: persistent acute kidney failure. Complete loss of kidney function >4 weeks.
,End-Stage Renal Disease: complete loss of kidney function >3 mo
What are the types of AKI?
–Prerenal (hypoperfusion of kidney)
–Intrarenal (actual damage to glomeruli or kidney tubules)
–Postrenal (urinary obstruction that impedes forward flow)
What are some causes of pre-renal AKI?
-Hypovolemia (dehydration, hemorrhage, burns)
-Dec. cardiac output (HF, MI)
-Dec. peripheral vascular resistance (anaphylaxis, septic shock)
-Dec. renovascular blood flow (embolism, renal artery thrombosis)
What are some causes of intra-renal AKI?
-Nephrotoxic injury (drugs, contrast media, severe crush injury)
-Interstitial nephritis (allergies, infections)
-Other causes: toxemia of pregnancy, malignant HTN, prolonged prerenal ischemia
, What are some causes of post-renal AKI?
-BPH
-Bladder cancer
-Calculi formation
-Spinal cord disease
-Prostate cancer
What is the first phase of AKI?
•Onset or initiation- initial insult, onset of event
What is the second phase of AKI?
•Oliguria- urine output <400ml/24 hrs, accompanied by increase in serum concentration of
substances usually excreted by kidneys
What is the third phase of AKI?
•Diuresis- gradual increase in urine output, daily urine output 1-3L per day (due to osmotic
diuresis) signals that filtration has started to recover, kidneys has recovered ability to excrete
wastes but not to concentrate the urine, observe closely for hyponatremia, hypokalemia,
dehydration
Function Examination: In-Depth Exploration of AKI Definitions and
Criteria, Creatinine and GFR Alterations, Urine Output Metrics, Phases
of AKI (Onset, Oliguria, and Beyond), Causes of Post-Renal AKI (BPH,
Bladder and Prostate Cancer, Calculi Formation, Spinal Cord Disease),
Toxemia of Pregnancy, Malignant Hypertension, Prerenal Ischemia,
Renal Function Assessment, Oliguria Management, Anuria
Identification, Renal Failure Progression, Kidney Function Monitoring,
Fluid Balance in Renal Patients, and Advanced Nephrology Practices
Exam Questions Verified and Provided with Complete A+ Graded
Rationales Latest Updated 2026
What is AKI?
Acute kidney injury is the rapid loss of renal function
What is the RIFLE classification for staging AKI?
Risk: Cr inc. x 1.5 OR GFR dec. 25%; urine output <0.5 mL/kg/hr for 6 hrs.
Injury: Cr inc. x 3 OR GFR dec. 50%; urine output <0.5 mL/kg/hr for 12 hr.
Failure: Cr inc. x 3 OR GFR dec. 75%; urine output <0.3 mL/kg/hr for 24 hr (oliguria) OR anuria
for 12 hr.
Loss: persistent acute kidney failure. Complete loss of kidney function >4 weeks.
,End-Stage Renal Disease: complete loss of kidney function >3 mo
What are the types of AKI?
–Prerenal (hypoperfusion of kidney)
–Intrarenal (actual damage to glomeruli or kidney tubules)
–Postrenal (urinary obstruction that impedes forward flow)
What are some causes of pre-renal AKI?
-Hypovolemia (dehydration, hemorrhage, burns)
-Dec. cardiac output (HF, MI)
-Dec. peripheral vascular resistance (anaphylaxis, septic shock)
-Dec. renovascular blood flow (embolism, renal artery thrombosis)
What are some causes of intra-renal AKI?
-Nephrotoxic injury (drugs, contrast media, severe crush injury)
-Interstitial nephritis (allergies, infections)
-Other causes: toxemia of pregnancy, malignant HTN, prolonged prerenal ischemia
, What are some causes of post-renal AKI?
-BPH
-Bladder cancer
-Calculi formation
-Spinal cord disease
-Prostate cancer
What is the first phase of AKI?
•Onset or initiation- initial insult, onset of event
What is the second phase of AKI?
•Oliguria- urine output <400ml/24 hrs, accompanied by increase in serum concentration of
substances usually excreted by kidneys
What is the third phase of AKI?
•Diuresis- gradual increase in urine output, daily urine output 1-3L per day (due to osmotic
diuresis) signals that filtration has started to recover, kidneys has recovered ability to excrete
wastes but not to concentrate the urine, observe closely for hyponatremia, hypokalemia,
dehydration
