Dehydration and Prerenal Acute Kidney Injury

Yes, dehydration is a classic cause of prerenal acute kidney injury (AKI) due to reduced renal perfusion from volume depletion. 1

Mechanism of Dehydration-Induced Prerenal AKI

Dehydration leads to decreased intravascular volume, causing reduced renal perfusion and subsequent prerenal AKI 1
In dehydration, blood urea nitrogen (BUN) rises disproportionately to creatinine due to enhanced reabsorption of urea in the proximal tubule, resulting in an increased BUN-to-creatinine ratio 1
Unlike creatinine, 40-50% of filtered urea is reabsorbed in the proximal tubule, paralleling sodium and water reabsorption, which increases significantly during dehydration 1
The kidney attempts to preserve intravascular volume through various mechanisms, but these compensatory mechanisms may be insufficient in severe dehydration 2

Disproportionate rise in BUN compared to creatinine (elevated BUN-to-creatinine ratio) 1
Mild elevation in creatinine that typically resolves with rehydration 1
Absence of other markers of intrinsic kidney injury (such as proteinuria, hematuria, or abnormal urinary sediment) 1
Clinical signs of dehydration (poor skin turgor, dry mucous membranes, orthostatic hypotension) 1

Advanced age 1, 3
Preexisting renal impairment 4, 3
Use of medications that affect renal function:
- Renin-angiotensin-aldosterone system (RAAS) inhibitors 3
- Diuretics 3
- Non-steroidal anti-inflammatory drugs (NSAIDs) 3
Heart failure or atherosclerosis 3
Exposure to heat stress 5, 6
Large tumor burden (in cancer patients) 4

Prompt rehydration is the cornerstone of treatment 3
Intravenous or oral fluid replacement based on severity of dehydration 1
Temporary discontinuation of RAAS inhibitors, diuretics, or NSAIDs may be necessary 3
Correction of electrolyte abnormalities, particularly hyperkalaemia if present 3
Monitoring of urine output during rehydration as an indicator of improving renal perfusion 1
Reassessment of kidney function after adequate rehydration to confirm resolution 1

Maintaining adequate hydration, particularly during hot weather or physical exertion 5, 6
Consumption of electrolyte solutions during periods of increased risk 5
Monitoring kidney function in high-risk patients during periods of illness that may cause dehydration 3
Temporary adjustment of medications that affect renal function during acute illness with risk of dehydration 3
Regular monitoring of serum creatinine and potassium in patients with chronic kidney disease using RAAS inhibitors who are at risk of dehydration 3

Persistent elevation of kidney function markers after adequate rehydration suggests underlying intrinsic kidney disease that requires further investigation 1
Recurrent episodes of dehydration-induced AKI may contribute to the development of chronic kidney disease through several mechanisms 2
Even well-hydrated individuals may develop AKI during extreme heat stress or strenuous exercise, suggesting other factors beyond dehydration may contribute 5, 6
Maintaining optimal fluid status (euvolemia) is critical in reducing the incidence of AKI 7