Overview
This lecture covers acute kidney injury (AKI), including its causes, phases, lab abnormalities, treatments, and essential nursing interventions.
Causes of Acute Kidney Injury
- AKI is a sudden, typically reversible loss of kidney function.
- Prerenal AKI is caused by decreased blood flow to kidneys (e.g., sepsis, shock, hypovolemia, vascular obstruction).
- Intrarenal AKI results from direct kidney damage (e.g., trauma, hypoxia, toxins, medications like gentamicin).
- Postrenal AKI is due to mechanical urine outflow obstruction (e.g., stones, tumors, BPH).
Phases of Acute Kidney Injury
- Onset phase: kidney injury occurs from one of the above causes.
- Oliguria phase: urine output drops below 400 mL/day; fluid overload, edema, and hypertension can occur.
- Diuresis phase: urine output increases (up to 5L/day); lab values start to improve.
- Recovery phase: normalization of creatinine, BUN, and GFR occurs; some patients may not fully recover.
Lab Abnormalities in AKI
- Hyperkalemia (increased potassium) can cause cardiac dysrhythmias.
- Hyponatremia (decreased sodium) can cause seizures.
- Hypercalcemia and hypermagnesemia are present.
- Metabolic acidosis and anemia (due to decreased erythropoietin) are common.
- Creatinine and BUN levels are increased.
Treatment and Nursing Care
- Treat underlying causes (e.g., dehydration, obstruction).
- Use diuretics to reduce fluid, medications (e.g., calcium gluconate) to lower potassium, and antihypertensives as needed.
- Dialysis may be required for severe cases.
- Implement seizure precautions and monitor I&Os and daily weight.
- Restrict intake of potassium, sodium, phosphate, and magnesium.
Key Terms & Definitions
- AKI (Acute Kidney Injury) — sudden, reversible loss of kidney function.
- Prerenal AKI — kidney injury from reduced blood flow.
- Intrarenal AKI — injury from direct kidney damage.
- Postrenal AKI — injury from urine flow obstruction.
- Oliguria — urine output less than 400 mL/day.
- Diuresis — increased urine output phase in AKI.
- BUN (Blood Urea Nitrogen) — waste product used to assess kidney function.
- GFR (Glomerular Filtration Rate) — measurement of kidney filtering capacity.
- Erythropoietin — hormone from kidneys stimulating red blood cell production.
Action Items / Next Steps
- Review chronic kidney disease in the upcoming lecture.
- Study the phases and lab changes of AKI for exams.
- Restrict dietary potassium, sodium, phosphate, and magnesium for AKI patients.