|Description||Neuropathic effects in the brain stem cause loss of consciousness and sometimes death. Significantly harder to cure|
|DNA cost||21, 8(Neurax Worm)|
|Previous symptom||Paralysis, Systemic Infection, Aphasia(Neurax Worm)|
|Next symptom||Total Organ Failure, Brain Haemorrhage(Neurax Worm), Acute Encephalitis(Necroa Virus)|
Coma is a tier 4 symptom. It is also available in the Simian Flu, Neurax Worm, Black Death and the Necroa Virus DLCs. It has neuropathic effects in the brain stem, which causes loss of consciousness and death. In the Black Death scenario, it is already evolved at the start of the game.
Of all the standard symptoms that specifically make the plague harder to cure (Coma, Paralysis, and Insanity), Coma has the largest effect of all of them (+24%). This symptom has a low lethality rate compared to other tier 4 symptoms, meaning it is usually used to slow cure progress rather than to kill rapidly.
In Necroa Virus, Coma, along with Fever weren't lethal. They do have other effect. While Coma in Necroa Virus decrease infectivity, Fever slows research speed.
If you got Sympto-Stasis then in Nano-Virus mode, this, along with Insomnia, Paranoia and Paralysis won't cost any DNA, which means it's free to upgrade!
In real life Edit
A coma is a deep state of prolonged unconsciousness in which a person cannot be awakened; fails to respond normally to painful stimuli, light, or sound; lacks a normal wake-sleep cycle; and does not initiate voluntary actions. Coma patients exhibit a complete absence of wakefulness and are unable to consciously feel, speak or move. Comas can be derived by natural causes, or can be medically induced.
Many types of problems can cause coma. Forty percent of comatose states result from drug poisoning. Certain drug use under certain conditions can damage or weaken the synaptic functioning in the ascending reticular activating system(ARAS) and keep the system from properly functioning to arouse the brain. Secondary effects of drugs, which include abnormal heart rate and blood pressure, as well as abnormal breathing and sweating, may also indirectly harm the functioning of the ARAS and lead to a coma. Given that drug poisoning is the cause for a large portion of patients in a coma, hospitals first test all comatose patients by observing pupil size and eye movement, through the vestibular-ocular reflex. (see Diagnosis below).
The second most common cause of coma, which makes up about 25% of cases, is lack of oxygen, generally resulting from cardiac arrest. The Central Nervous System (CNS) requires a great deal of oxygen for its neurons. Oxygen deprivation in the brain, also known as hypoxia, causes sodium and calcium from outside of the neurons to decrease and intracellular calcium to increase, which harms neuron communication. Lack of oxygen in the brain also causes ATP exhaustion and cellular breakdown from cytoskeleton damage and nitric oxide production.
Twenty percent of comatose states result from the side effects of a stroke. During a stroke, blood flow to part of the brain is restricted or blocked. An ischemic stroke, brain hemorrhage, or tumor may cause restriction of blood flow. Lack of blood to cells in the brain prevent oxygen from getting to the neurons, and consequently causes cells to become disrupted and die. As brain cells die, brain tissue continues to deteriorate, which may affect the functioning of the ARAS.
The remaining 15% of comatose cases result from trauma, excessive blood loss, malnutrition, hypothermia, hyperthermia, abnormal glucose levels, and many other biological disorders. Furthermore, studies show that 1 out of 8 patients with traumatic brain injury experience a comatose state.