Should we treat concussion pharmacologically?

The medical management of concussion in sport has traditionally involved close observation and "masterly inactivity". With the use of clinical assessment and neuropsychological testing we have the ability to individualise patient management and determine safe and appropriate return to play strategies. At the present time, the sports physician has no evidence based pharmacological treatment to offer the concussed athlete. The ability to treat concussion with specific drug therapy requires an understanding of the pathophysiological changes that accompany concussive injuries.

PATHOPHYSIOLOGY OF SPORT RELATED CONCUSSION

Concussive brain injury has long been thought to evoke immediate and irreversible damage to the brain. While this may be true in moderate to severe traumatic brain injury, the evidence that this occurs in milder injuries such as concussion is not compelling. Recent experimental evidence suggests that the pathogenesis of axonal dysfunction resulting from head trauma is complex. ¹

In addition, studies of moderate to severe traumatic brain injury have revealed that a cascade of neurochemical, ionic, and metabolic changes occur following experimental brain injury. ² The assumption is that similar changes occur in milder injury although this remains controversial. Most notably, an injury induced ionic flux across the cell membrane due to the release of the excitatory amino acids, has been shown to increase glycolysis that results in a state of metabolic depression due to a decrease in both glucose and oxidative metabolism accompanied by a decrease in cerebral blood flow. ^{2, 3} Each element of this cascade has a different time window that may have important implications in treating concussed individuals.

TREATMENT OPTIONS

There are many pharmacological management options that have been proposed for all grades of brain injury. Readers are referred to some of the larger texts and recent reviews on these topics for more complete discussion..

Table 1 Summary of treatment options

Treatments that are possibly effective	Treatments unlikely to be effective	Treatments that may place the athlete at risk of adverse events
Drugs inhibiting arachidonic acid metabolism	Neurotrophic factors	Free-radical scavengers
Calcium channel antagonists	TRH/TRH analogues	Antioxidants
Corticosteroids	Drugs that modify monoamine function
Hyperbaric oxygen therapy

Corticosteroids

Corticosteroids have been utilised for many years in experimental neurotrauma, initially based upon their ability to stabilise lysosomal membranes and reduce tissue oedema. There are a number of studies...