@CBS64

The underlying cause for fatigue caused by PCS is most likely not the same from person to person. That being said, different hypothesis have been presented to try and account for the fatigue caused by tbi.

The first hypothesis is disruption/reduction of the hypocretin/orexin neurons in the brain. Orexin is a wake-promoting neuropeptide produced by a small cluster of approximately 30.000 neurons in the brain. Changes in this system could be a cause of fatigue, at least in people with severe tbi [1].

The second hypothesis is, that the reduced ability of glutamate recycling and reuptake in synapses by both astrocytic- and neuronal cells, cause an excitotoxic build up of glutamate in the synapses. This toxic build up of glutamate causes the brain to slow down and require more rest in order to protect itself and clear the synapses [2].

Other hypthesis include disruptions in the brain stem and/or chronic inflammation processes like cytokine production, however research is still ongoing in all of these areas.

[1] Loss of hypocretin (orexin) neurons with traumatic brain injury


[2] http://www.lakartidningen.se/engine.php?articleId=6451 [Swedish article]

-GlassHead