Kidneys
• Location
• Structure
- Location • Retroperitoneal area - Structure • Cortex • Medulla • Nephron - Receives 20% to 25% of cardiac output - Performs numerous functions
Fluids and electrolytes; waste
• Glomerular filtration rate (GFR)
• Hormonal control
- Glomerular filtration rate (GFR) • Result of pressure gradient • 80 to 125 mL/min • Reabsorption • Secretion - Hormonal control • Aldosterone • Antidiuretichormone
Acid Base Balance
Kidney blood pressure regulation
* Renin-angiotensin-aldosterone
The term used to describe accumulation of nitrogenous wastes is: A. Anuria B. Azotemia C. Oliguria D. Uremic syndrome
B. Azotemia
Acute kidney injury
AKI Causes
Prerenal Etiology
- Diminished blood flow; hypoperfusion of the kidney • Volume depletion • Vasodilation • Decreased cardiac output - Can progress to intrarenal damage
Intrarenal Etiology
• Kidney tissue affected directly
• Glomerular, vascular, and/or hematological
problem
Intrarenal Etiology
-Acute tubular necrosis (ATN)
• Ischemia • Nephro toxic agents - Antibiotics - Nonsteroidal antiinflammatory drugs (NSAIDs) • Contrast-induced • Rhabdomyolysis
Postrenal Etiology
Pathophysiology Summary
• Prerenal:
• Renal:
• Postrenal:
A treatment for postrenal etiology of AKI is: A. Diuretic administration B. Fluid administration C. Nephrectomy D. Ureteral stent placement
D. Ureteral stent placement
Course of AKI
-Initiation Phase
Course of AKI
- Maintenance phase (oliguric/anuric)
- Maintenance phase (oliguric/anuric) • BUN and creatinine increase daily • Oliguria is common • Urine output less than 400 mL/day • Fluidoverload,electrolyte imbalances, and acidosis • Renal replacement therapy required
Course of AKI
-Recovery phase
Assessment Patient History
- Predisposing factors
- Disease states • Hypertension • Diabetes • Immunological disease • Hereditary disorders - Hypotensive episodes - Exposure to nephrotoxic agents
Clinical Presentation of AKI
Physical findings of AKI
- The patient’s general appearance is assessed for:
• Signs of uremia (malaise, fatigue, disorientation, and
drowsiness)
• Color and texture of skin
• Bruising, petechiae, and edema
• Current and admission body weight and intake and output
• Dehydration/fluid overload
Laboratory tests for AKI
• Serum creatinine
• Serum BUN
- Affected by catabolism, bleeding, and dehydration
• BUN:creatinine ratio
- Normal 10:1 to 20:1
- More than 20:1, suspect nonrenal causes of Laboratory abnormalities
- Urine creatinine clearance
• Estimate of GFR
• 24-hour urine; specific collection protocol
• Normal 84 to 138 mL/min
• Can calculate an estimated value with serum lab values (Cockcroft and Gault formula)
Laboratory Findings
Urine tests for AKI
Diagnostic studies for AKI
- Noninvasive tests
- Noninvasive tests • X-ray of kidneys, ureter, and bladder (KUB) - Size, shape, and position of kidneys - Calculi, cysts, and tumors • Renal ultrasound - Size of kidneys - Obstruction • MRI
Diagnostic Studies
- Invasive tests (5)