109: The Reckoning
Jamie and the Highlanders sneak into Fort William to rescue Claire from the clutches of Black Jack, ready to fight with blades, fists and unloaded pistols. Given the price already on Jamie’s head, Ned Gowan has warned the men that they must inflict no fatal injuries tonight. Our Highlanders know how to fight, of course, and rise to the challenge.
The Redcoats are knocked on the head and fall one, by one, by one.
Ultimately, Jamie finally knocks out Black Jack with a non-fatal blow to the head. (And the audience groans, knowning what is to come).
What exactly is happening when someone is knocked out?
Weighing in at approximately three pounds, the brain resides in the protective shell of the skull. Additional protection is provided by layers of tough membranes called meninges covering the brain as well as cerebrospinal fluid in which the brain essentially floats. Within the brain are billions of nerve cells, called neurons. These cells are specialized to allow the gathering and transmission of electrochemical signals. Some travel short distances within the brain, others might travel as far from the tip of the finger all the way up the arm. Some neurons control muscle contractions, some are for sensation and others are messengers between neurons.
Mild traumatic brain injury (TBI) or concussion, is a traumatically induced disruption of brain function as a result of an external force. This trauma causes loss of consciousness, alteration of mental state for up to 24 hours, and post-traumatic amnesia for up to 1 day.
A direct blow to the head sets the brain tissue in motion within the skull, squeezing, stretching and sometimes tearing neurons in the brain. This leads to varying degrees of abnormality in how the brain processes information.
Loss of consciousness in these injuries is thought to be due to brain edema (swelling). The brain’s auto-regulatory mechanisms counteract this to protect against massive swelling by limiting blood flow. The effect of the limited blood flow is accumulation of lactic acid and changes in metabolism at the cellular level in the brain lasting weeks and making the brain vulnerable to further injury during this time.
Symptoms of mild TBI, or concussion, are many:
Loss of consciousness
Altered mental state for up to 24 hours
Tinnitus (ringing in the ears)
Sensitivity to sound
Symptoms can last months in some cases.
In mild TBI, imaging of the brain with MRI and CT will not show abnormalities but the stretching and swelling of the neurons has a significant impact on the brain’s neurologic circuits. A brain still healing from a concussion is vulnerable to further trauma. When a second concussion occurs before the first concussion has fully healed, patients are at risk for rapid and severe brain swelling with catastrophic results – Second Impact Syndrome. After the first concussion, the brain is still healing and has not yet regained its ability to auto-regulate intracranial pressure and blood flow pressure within the brain. Remember that the brain is encased within the protective skull so there is minimal room for swelling to occur. The massive swelling of the brain in second impact syndrome is rapid can lead to death within minutes.
The awareness of Second Impact Syndrome has led to strict policies and training, particularly in youth sports, regarding return to play after concussion, though the primary way to avoid this will but more research into avoiding first concussions. It is likely that we will see protective headgear for soccer players in the coming decades.
Another sequelae of repeated concussions is Chronic Traumatic Encephalopathy (CTE). Athletes and others who have received repeated blows to the head and concussions may manifest memory loss, mood and behavioral disturbances and progress to dementia decades after the trauma. Some may further develop Chronic Traumatic Encephalomyopathy (CTEM), a disease similar to ALS or Lou Gehrig’s disease causing profound weakness and muscle atrophy. Many former NFL players have been identified on autopsy as suffering from CTE or CTEM, as sadly there is currently no definitive test to diagnose the condition in the living. As science advances and we come to be able to identify and diagnose this earlier, it may mean significant policy changes in the future for sports and activities where the risk of head injury is high.
Great advances have been made in the understanding of brain injury in recent decades, leading to heightened awareness of concussion and protective devices for sport. A far cry from tricorn hats which would have offered no protection from head injury!