Hiccups--spasms of the diaphragm leading to audibly irregular breathing--are not life threatening. Hiccups typically occur in limited episodes, going away by themselves or addressed through minor self-administered treatments. Humans and other mammals hiccup throughout life and even in utero. There seems to be no reason for it, and until recently no known cause. There are now many proposed causes for hiccups, several or all of which may be genuine--it may be an effect with numerous causes. Drinking alcohol or carbonated beverages can cause hiccups, as can exhaustion, dehydration, and sudden changes in temperature. Though these infrequent, brief episodes can be a source of annoyance, there is usually no cause for concern.
Causes of Concern
It is misleading to say that one might "die of hiccups." Hiccups are occasionally a symptom of life-threatening conditions, but are never, in themselves, the cause of death. Stories of people who have died of hiccups, such as that of Pope Pius XII, are either unsupported by evidence or entirely apocryphal. Pius XII, for example, died of a stroke. If you experience any of the following hiccup episodes, it may be the result of a more serious condition, which in turn may be life threatening. A bout of hiccups is defined as having hiccups on and off for up to 48 hours. Persistent hiccups last more than 48 hours. Persistent hiccups become intractable hiccups when they last for two months or more. Persistent and intractable hiccups are sometimes present with traumatic conditions. Death is rarely associated with hiccups, but intractable hiccups can be a symptom of potentially fatal conditions.
Potential Causes of Persistent Hiccups
Though hiccups become less common with age, episodes of persistent or intractable hiccups become more common. Essentially, any condition that can affect the regulation of breathing, or conditions that impact the upper digestive system, can provoke or be provoked by hiccups. This is because intractable hiccups are usually caused by an irritation of the nerves of the chest. Chronic GERD (common heartburn), laryngitis, thyroid enlargement, tumors, chest and ear infections, and hiatal hernia can trigger persistent hiccups. As hiccups have long been associated with alcohol consumption, late-stage alcoholics can develop hiccups that persist for days.
Intractable Hiccups Without Known Cause
Though persistent or intractable hiccups can be a signal that there is an underlying toxic condition, there have been several cases of individuals who had intractable hiccups and no other health problems whatsoever. The BBC reports that the current Guinness record for longest bout of hiccups was 68 years--held by a hog farmer with no other complaints.