Physiology of death by decapitation
Decapitation is quickly fatal to humans and most animals. Unconsciousness occurs within 10 seconds without circulating oxygenated blood (brain ischemia). Cell death and irreversible brain damage occurs after 3–6 minutes with no oxygen, due to excitotoxicity. Some anecdotes suggest more extended persistence of human consciousness after decapitation, but most doctors consider this unlikely and consider such accounts to be misapprehensions of reflexive twitching rather than deliberate movement, since deprivation of oxygen must cause nearly immediate coma and death ("[Consciousness is] probably lost within 2–3 seconds, due to a rapid fall of intracranial perfusion of blood").A laboratory study testing for humane methods of euthanasia in awake animals used EEG monitoring to measure the time duration following decapitation for rats to become fully unconscious, unable to perceive distress and pain. It was estimated that this point was reached within 3–4 seconds, correlating closely with results found in other studies on rodents (2.7 seconds, and 3–6 seconds). The same study also suggested that the massive wave which can be recorded by EEG monitoring approximately one minute after decapitation ultimately reflects brain death.
Prognosis
If left untreated, more serious complications could result, including birth defects in pregnancy, increased risk of a miscarriage, bone mineral loss and, in extreme cases, death. Graves disease is often accompanied by an increase in heart rate, which may lead to further heart complications, including loss of the normal heart rhythm (atrial fibrillation), which may lead to stroke. If the eyes are proptotic (bulging) enough that the lids do not close completely at night, dryness will occur – with the risk of a secondary corneal infection, which could lead to blindness. Pressure on the optic nerve behind the globe can lead to visual field defects and vision loss, as well. Prolonged untreated hyperthyroidism can lead to bone loss, which may resolve when treated. Epidemiology
Graves disease occurs in about 0.5% of people. Graves disease data has shown that the lifetime risk for women is around 3% and 0.5% for men. It occurs about 7.5 times more often in women than in men and often starts between the ages of 40 and 60. It is the most common cause of hyperthyroidism in the United States (about 50 to 80% of cases). History
Graves disease owes its name to the Irish doctor Robert James Graves, who described a case of goiter with exophthalmos in 1835. Medical eponyms are often styled nonpossessively; thus Graves disease and Graves disease are variant stylings of the same term. The German Karl Adolph von Basedow independently reported the same constellation of symptoms in 1840.