Kidney Dysfunction After Traumatic Brain Injury: Pathophysiology and General Management.

Area of Science:

• Nephrology
• Neurology
• Critical Care Medicine

Background:

• Traumatic brain injury (TBI) is a leading cause of death and disability, frequently requiring intensive care unit (ICU) admission.
• A significant subset of TBI patients develop acute kidney injury (AKI), with a smaller proportion requiring kidney replacement therapy (KRT).
• Existing clinical trials specifically for TBI with AKI are limited, necessitating a review of general principles.

Purpose of the Study:

• To provide an overview of the epidemiology and pathophysiology of AKI in ICU patients with TBI.
• To discuss the interplay between TBI management strategies and kidney function.
• To highlight therapeutic targets and potential risks for AKI in this population.

Main Methods:

• Review of current literature on TBI, AKI, and their management in the ICU setting.
• Analysis of the effects of common TBI treatments on renal function.
• Discussion of hemodynamic management and fluid resuscitation strategies.

Main Results:

• Osmotic agents like mannitol and hypertonic saline, used for intracranial pressure (ICP) reduction, are associated with increased AKI risk, potentially higher with mannitol.
• Hemodynamic management, including fluid choice (avoiding hypotonic solutions) and vasopressors, is crucial for maintaining cerebral perfusion pressure (CPP) and kidney perfusion.
• Continuous KRT is recommended for TBI patients needing renal support, with careful monitoring to avoid rapid osmolar shifts that could worsen intracranial hypertension.

Conclusions:

• Preventing secondary brain injury through ICP and CPP management is paramount in severe TBI.
• Careful selection of fluids and osmotic agents is necessary to mitigate AKI risk in TBI patients.
• Close ICP and CPP monitoring is essential, particularly during KRT initiation in TBI patients.