Mana Surge
Betrayed by their own magic, death is far too common in younger mages. Mana surges are deadly to those who cannot release or control their mana and has taken the lives of many. The rapid exhaustion and immediate reclaiming of mana, via potions or other methods, begins a shutdown of magical containment and focus, the threshold weakening greatly with each attempt. Unless immediate precautions are taken, it can severely injure or kill the caster.
Due to the lack of knowing better, lack of control, or the disbelief of wieldable power, less experienced mages are usually the casualties reported. Thus, young mages, especially those starting training, should be monitored carefully when given potions, and taught at length of the dangers of surges.
In short, and in relation to the Mana Pool - Or 'Soul', as many refer to it as - It is a rapid flush of all of the mana in the Mana pool. It does not result in the 'breaking' of the Mana Pool Ceiling; Someone who has gone through a Mana Surge doesn't have a shattered mana pool, or soul, and a Heretic can still go through a Mana Surge, while having their soul "shattered".
Symptoms
Symptoms vary greatly depending on many differing factors; the skill of the mage, type of magic, number of potions used, etc. The most common, however, were migraines, moderate to intense general pain (usually in the main casting focus - Hands, feet, arms, etc), fatigue, dizziness, and aggression. Physical symptoms according to elemental magic type are as follows, but are not limited to:
*Heat: Sweating, overheating, heat in extremities, burns around focus area
*Frost: Chills, trembling, frost around focus area, frostbite in extremities
*Earth: Stiffness in joints, sinking into the ground, feet petrified in earth
*Electricity: tingling under the skin, muscle spasms, shaking, static shock, full electrocution
*Air: Shortness of breath, wind gusts, bubbling under the skin, air in blood
The other types of magic are harder to symptom, due to their more abstract concepts. The Elemental category is particularly dangerous and deadly, and are of a physical variety. The Restoration category, for example, is mostly harmless as far as the expulsion of magic goes, and is much more concerning in the physiological and medical sense. The Entropic category, on the other hand, is horrifying in comparison to the previous examples; that while it provides the ability to speak to another through telepathy and other mental abilities, the class also allows the teachings of Necromancy and Debilitation.
Prevention
While the obvious answer is denying the immediate use of potions that enhance or 'refill' the mana pool, but it is a crude and ham-fisted method - if the most effective. For the individual teachers and their personal proteges, on the other hand, knowing the symptoms and being aware of your student's personality can give insight to personal changes that lead to potion addiction and Mana Surge - and in turn, teaching your student to recognize these things as well, as well as keeping an open communication between the both of you, is essential as well.
Cure
If caught early enough, the recovery is quite simple. First, the mana must be fully drained from the apprentice. To do this, the mage in effect must actively cast until their mana is depleted. Without actively casting, the mana is trapped in the extremities and builds until it seeps through slowly and painfully.
With gentle and slow healing or a long period of bed rest, any other pain can dissipate on its own. Injuries sustained by the mana surges must be dealt with immediately, especially those of Elemental types - especially that of air mages. Air bubbles within the blood can be immediately life-threatening, as well as a solidifying of the blood and other organs from earth magic, and elemental effects cause the most deaths.
For lesser effects such as frostbite or burns, healing magic can be used on the affected mage. Casting is disuaded until both teacher and student are sure that no lingering effects remain.
~Colborn Vesk, Head of Tower of Tempest Atheneum