ABSTRACT
Despite modernization of trauma care, the majority of headinjured patients are initially managed by emergency medical services that do not have specialized training in the pathophysiology and treatment of head injury. It is for this reason that the traditional division into primary and secondary brain damage remains useful; primary brain damage occurs at the time of impact, produces its clinical effect almost immediately and is refractory to most treatment. By contrast, secondary brain damage occurs at some time after the primary impact and is largely preventable and treatable. The clinician’s role, therefore, is to recognize and document the primary brain damage, then to prevent and treat secondary brain damage. Recent research has shown that, although primary brain damage has been regarded as irreversible, changes in ultrastructure, the blood-brain barrier and neuronal function may progress over time and may provide some potential for treatment (Povlishock 1992, 1995; Maxwell, 1995). Changes may evolve over hours or even days (Reilly, 2001). Understanding this concept prepares the non-specialist clinician for the main challenge in head injury management: the prevention and treatment of secondary damage. It is therefore essential that all the causes and consequences of secondary brain damage are known and understood. In an ideal world, no secondary brain damage would occur! Also, this concept paves the way for understanding how neuroprotective strategies (hemodynamic and pharmacological) may limit secondary brain damage.
