First, the victims of axonal injury lose consciousness for a few hours; subsequently, they may recover, manifesting a series of neurological symptoms related to the location of the brain lesions, or enter a state of coma or vegetative state, the outcome of which is often fatal.
For the diagnosis of axonal damage, doctors must rely mainly on physical examination and medical history, as instrumental tests such as MRI or CT scan of the brain are unable to detect brain lesions.
At the present time, the victims of axonal damage can only count on symptomatic treatments, as there is still no medical or surgical therapy capable of canceling axon lesions.
What is the Axon?
The axon is the characteristic cellular extension of which neurons are supplied, which serves the latter to spread the nerve signals emitted from or destined for the brain.
Depending on the purpose of the neuron it belongs to, the axon may or may not be covered with a myelin sheath; the axon with the myelin sheath is also called a nerve fiber.
In neurons, the axon joins the so-called body, which is the seat of the cell nucleus, and the so-called dendrites, which are the antennae for the reception of nerve signals from other neurons.
Axonal damage is a serious brain injury, which often results in a state of irreversible coma (90% of cases of coma due to axonal damage are irreversible) or in a vegetative state.
As the term "diffuse" suggests, axonal damage is not a circumscribed brain injury, but affects multiple areas of the brain.
Axonal damage can vary in severity; in fact, depending on the extent of the brain injury, it can be mild, moderate or severe.
Generally speaking, the more severe the axonal damage, the more likely it is that this brain injury will lead to irreversible coma or a vegetative state.
Did you know that ...
The acronym DAI used to indicate axonal damage is the "English acronym of" Diffuse Axonal Injury ", or" diffuse axonal damage ".
Characteristics of Axonal Damage
- Axonal damage is characterized by the rupture of the cytoskeleton of the axons of the cerebral white matter and by a series of secondary changes, such as: interruption of axonal transport, axonal degeneration and stretching, misalignment of the microtubules present in the injured axons and unusual deposition of tau and APP (the accumulation of these proteins is often associated with suffering in the brain; in this regard, think, for example, of Alzheimer's disease);
- White matter lesions, seen in the presence of axonal damage, can vary in size from 1 to 15 millimeters;
- Edema forms in areas of brain injury that characterize axonal damage; this edema is an example of cerebral edema;
- The areas of the brain most prone to diffuse axonal damage are the brain stem, the corpus callosum, the cerebral lobes (in particular the frontal lobe and the temporal lobe), the so-called basal ganglia and the thalamus;
- Histological studies have shown that axonal damage is not immediately following the trauma that causes it, but appears in the hours, if not days, following; from the aforementioned studies, in fact, it emerged that the lesions of the axons are the consequence of a slow succession of biochemical alterations inside the nerve cells involved.
Curiosity
The lesions observed in the presence of axonal damage arise from the abnormal presence of large quantities of calcium ions inside the nerve cells involved; in fact, scholars have observed that these calcium ions trigger enzymes capable of damaging the mitochondria and the cytoskeleton of the neurons in which they are located, causing the lesion of the axons at the end of everything.
lasting a few hours (usually 6 or a little more); after that, the patient goes into a coma or a vegetative state, or he recovers, showing however a series of symptoms that depend on the injured brain area.Possible symptoms of axonal damage in a patient recovering from unconsciousness include:
- Headache;
- Dizziness, balance problems and coordination problems
- Cognitive deficits, such as memory problems, difficulty concentrating and organizing, etc .;
- Recurrent nausea and vomiting
- Permanent sleepiness and fatigue;
- Insomnia;
- Sudden mood swings and personality changes
- Disorientation and confusion;
- Speech problems (ex: difficulty speaking).
It is important to point out to readers that the complete picture of the consequences of axonal damage is visible only a few days after the triggering trauma; this is connected to what was previously stated, regarding the fact that the lesions affecting the axons are the result of a slow succession of biochemical alterations within the nerve cells involved.
Did you know that ...
Milder forms of axonal damage are examples of concussion (or concussion of the brain).
Is Axonal Damage Permanent?
Axonal damage produces permanent injuries; this means that the axons, once damaged, are irremediably out of order.
Therefore, the victims of axonal damage are forced to live with all the problems that can derive from the present brain injuries.
Severity of Axonal Damage and Symptomatology
The symptomatology of axonal damage is all the more articulated and debilitating, the more numerous and severe the brain injuries caused by trauma to the head are.
Complications
If it is severe, the axonal damage can lead to a coma or vegetative state.
As previously reported, 90% of coma cases due to axonal damage are irreversible.
Those few people who manage to recover from a coma following axonal damage typically suffer from profound cognitive deficits.
of corticosteroids, in order to reduce cerebral edema. Consequence of damaging events affecting the axons, cerebral edema requires immediate treatment, as its persistence can further damage the brain.
Treatments such as, for example, speech therapy, physiotherapy and occupational therapy could be included in a rehabilitation program for axonal injury victims.
The rehabilitation program for axonal damage is more likely to have positive implications, the more minor the brain lesions present.
