Hiccups are annoying, especially when they just won't quit. If they last more than two days, nonstop hiccups may occasionally be a sign of a medical problem, as they were for one 68-year-old man.

In an extremely rare and highly unusual case, constant hiccups turned out to be the man's only symptom of a heart attack. Cases like this are so few and far between that it was last known to occur more than 50 years ago.

The gentleman went to the emergency room because he had been hiccuping every 4 to 6 seconds for four days. No matter what he tried, his hiccups hadn't let up, according to the case study in the January issue of the American Journal of Emergency Medicine.

The man had no other health complaints. His blood pressure was a little high and doctors did a chest X-ray to look for a possible tumor, but found none. So they gave him a muscle relaxant and another drug known to ease "singultus," the medical term for hiccups.

Neither of the drugs helped the hiccups, but doctors assured him they would go away on their own.

Two days later, he was back in the emergency room still hiccuping. Since he was an older man with several risk factors for heart disease -- diabetes, smoking, and high blood pressure -- he was given an electrocardiogram (EKG), that showed several heart rhythm abnormalities. Blood tests revealed a high level of a protein released when the heart muscle has recently been damaged, confirming his diagnosis of a small heart attack.

There had been little reason for doctors to suspect a heart attack since the patient had no chest pain, no difficulty breathing, no discomfort, and no nausea, dizziness, or sweating -- just constant hiccups. But as soon he was put on heart medications, his hiccups were gone.

Dr. Joshua Davenport, an emergency physician at St. Luke's-Roosevelt Hospital in New York City and the case study's lead author says he honestly doesn't know why the man had none of the traditional heart attack warning signs. "But many people, especially diabetics, can have unusual presentations for heart problems," he explains.

Davenport is quick to point out that hiccups are not typically caused by something severe like a heart attack without a person having other concerning symptoms. "Our case was an exception and very rare," he admits.

As for why a heart problem might have triggered hiccups, Davenport says that when the heart is not getting enough oxygen because less blood is flowing through a diseased artery, this can irritate the nerves of the diaphragm, the breathing muscle underneath the heart.

Hiccups are caused by a spasmodic contraction of the diaphragm, typically on the left side, says Dr. David Johnson, a professor of medicine at Eastern Virginia Medical School in Norfolk. The more common reasons why nerves running to the diaphragm get irritated and cause hiccups are a distended stomach, drinking alcohol or lots of soda, chewing gum or smoking, explains Johnson, a past president of the American College of Gastroenterology.

From time to time, he'll see cases of nonstop hiccups that may be triggered by acid reflux. Ongoing hiccups can also be due to a tumor in the head, neck, or lungs, or infections in the brain or ear, because nerves that go to the diaphragm may begin in the brain or neck.
The good news is that most hiccups don't last long and are easy to treat. His favorite remedy? A spoonful of sugar.

What's the worst case of hiccups you've ever had? What'd you do to get rid of them? Tell us on Facebook.

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That sinking feeling in your gut? Don’t worry: it’s probably appropriate for our times. It may be due to your foundering finances, your slippery hold on employment, or the sudden realization that you love “Glee” just a bit too much.

For the medical record, however, a nagging anticipation that something wicked this way comes is a listed warning sign for at least eight illnesses or conditions.

Heart attacks, aortic dissections, adrenal gland tumors, some seizures and severe allergic reactions all share one clairvoyant-sounding symptom: “an impending sense of doom.”

One form of epileptic seizure may offer the best case study to explain this amorphous, dark disquiet, this brand of bad-health ESP. That’s because these seizures – abrupt surges of electricity activity within the brain – occur in a lower, middle swath known to fuel this apocalyptic vibe.

“The temporal lobe involves the emotional circuitry of the brain,” says Dr. David Ko, chief of neurology and director of the EEG Lab at the Los Angeles County + USC Medical Center. “Some patients with temporal lobe epilepsy get this psychic or emotional component.

“They get this panicky feeling that something really bad is going to happen,” says Ko, who co-authored a recent article, that touched on this eerie symptom. “Some people have describe it as being like an impending sense of doom.”

Such seizures are not sparked by actual stimuli. And, he adds, they are far different from panic attacks – anxiety disorders that include feelings of approaching calamity but which typically peak after 10 to 20 minutes. Seizures sparked by temporal lobe epilepsy “have a discrete beginning and end, one or two minutes,” Ko says.

But why would heart attacks or instances of abrupt bleeding into and along the wall of the aorta (the main artery pushing blood out of the heart) lead to this same Doomsday sensation?

“If you’re having any chest pain, you get very anxious. The circulatory system is part of the (brain’s) emotional system,” Ko explains. “If you think you are having a heart attack, the heart starts racing, your blood pressure goes up.”

This sends neurotransmitters – chemical messengers -- surging toward receptors in the temporal lobe, igniting a vague but an urgent alarm: “Uh oh….”

Allergic reactions – including those caused by certain foods or wildlife stings – can similarly set off the body’s “fight or flight” neural-response, and light up those same communication pathways.

At least one famous work of literary fiction tapped into this irrational feeling of looming disaster, Ko notes. In his famous book, “The Idiot,” 19th century Russian writer Fyodor Dostoyevsky created a main character who suffers from epileptic seizures.

“That character had that sense of doom,” Ko says. “Dostoyevsky is a well known person who had epilepsy. He wrote about his symptoms. And obviously, his work is very dramatic and (the general mood of his tales) is not a pleasant one.”

 Bill Briggs is a frequent contributor to msnbc.com and author of “The Third Miracle.”

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