The national flu epidemic may have you jumpy every time a coworker coughs or sneezes in their cubicle or on the elevator, but at least when you catch the flu, you know you're sick. In other cases, people go to work unaware they're ill. They begin to think occasional aches or pains are normal, given how much stress they're under at work.
Which is why it should be helpful—maybe even life-saving—to put a spotlight on a few under-the-radar medical conditions that may be plaguing workers, potentially stalling or damaging their careers. The following is in no way intended to be a comprehensive look at every malady out there. Just consider this a public service announcement—a reminder that if you're not feeling up to par, don't necessarily blame it on the late-night emails from your frazzled boss.
[Read: 10 Ways to Make Any Job Healthier.]
Medical condition: Abductor spasmodic dysphonia (ABSD)
What it is: It's a neurological voice disorder that affects how one talks. The National Abductor Spasmodic Dysphonia Association estimates 50,000 people in North America have the condition, although it notes on its website that "this number may be somewhat inaccurate due to ongoing misdiagnosis or undiagnosed cases of the disorder." Scott Adams, the creator of the comic strip Dilbert, Robert F. Kennedy, Jr., and Diane Rehm, the popular talk show host on National Public Radio, are among the familiar faces with ABSD.
Warning signs: Are coworkers asking what's wrong with your voice? Marcia Sterling, an attorney in Palo Alto, Calif., says other people noticed her condition before she did. When Sterling would ask for feedback while teaching law students or speaking on panels, she says someone would invariably ask what was the matter with her voice.
Dealing with it in the workplace: Sterling, who left law to write a novel, advises people with ABSD to come clean about their condition. "People 'get it' and tend to be more empathetic if they know what you're going through," which reduces the pressure, she says.
Moreover, it's hard to hide. "Your personality is reflected in your voice," says Sterling, "and what spasmodic dysphonia takes away from you is the ability to express feelings, which is what you need to express your personality."
Medical condition: Sleep apnea
What it is: It's a disorder in which a person stops breathing for a few seconds or longer while sleeping. Several seconds of not breathing may not sound too terrible, but if someone does that, say, every few minutes, it adds up.
Warning signs: Veer Patel, a primary care physician and adjunct instructor at the University of Cincinnati, says, "Sleep apnea is a condition that you don't know you have until you get tested for it. Some of the symptoms include constant headaches and you fall asleep easily in the middle of the day and you don't feel rested, even when you're sleeping for seven or eight hours at night." Patel adds that people who frequently snore and people who are obese are especially susceptible to developing sleep apnea.
Dealing with it in the workplace: Treatment is necessary since it's a condition that can lead to diabetes, heart attacks, and other complications. (Grateful Dead musician Jerry Garcia died in 1995 from a heart attack believed to have stemmed from his sleep apnea.) Sleep apnea sufferers are often prescribed CPAP machines, a mask that pumps air into the person's mouth and nostrils while they sleep. Wearing a mask to bed isn't glamorous, but the machines have likely saved many people from being fired for falling asleep on the job.
Medical condition: Fibromyalgia
What it is: An estimated 6 million people—mostly women ages 20 to 50—are believed to have this condition, in which a person feels pain and tenderness throughout their joints, muscles, tendons, and other soft tissues.
Warning signs: "You first know you have fibromyalgia when you have trouble sleeping and wake up unrefreshed, with aches and pains in your muscles," says Carolyn Dean, a nationally renowned medical doctor and nutritionist based out of Kihei, Hawaii. Other clues include fatigue for no apparent reason or irritable bowel syndrome resulting from anxiety or stress.
Dealing with it in the workplace: There is no widely accepted cure or treatment. Dean prescribes her patients magnesium baths and oral magnesium citrate powder in water and a yeast-, wheat-, dairy-, and sugar-free diet, but consult your doctor for diagnosis and a treatment plan.
Medical condition: Celiac Disease
What it is: Some people can't process gluten. When they eat something with the protein in it, their immune system attacks the gluten and ends up hurting the small intestine in the process—making it hard for the body to absorb important nutrients.
Warning signs: Are you visiting the bathroom a lot or feeling tired frequently? Scott Mann, a graduate student and environmental educator in Harrisburg, Penn., was diagnosed with celiac disease in 2008, a decade after it became routine for him to have to sprint to the bathroom two or three times a day.
Dealing with it in the workplace: You can't manage it well unless you're eating a gluten-free diet, which is why this is a frustrating condition for many people. Mann spent several years working in information technology as a field technician before he learned he had Celiac Disease. "It wasn't all that bad when I worked in a regular office environment," he says. "I'd go down the hallway to the bathroom. But when I was out in the field, it became a problem." However, considering he'd sometimes be behind the stall for a half hour, it was a dilemma throughout his IT career.
Medical condition: Vasovagal Syncope
What it is: It's a condition in which a person's heart rate and blood pressure suddenly drops. The blood flow to the brain is reduced, which causes a brief fainting spell. It isn't life-threatening, but you wouldn't want to pass out while driving.
Warning signs: Fainting a lot? Feel tired and rundown all the time? Last October, Laura Grover, 47, of Raleigh, N.C., and an executive at Quintiles, a contract research firm, was asked by colleagues if she felt OK. Since Grover was used to feeling sick, she waved off her coworkers and went to a meeting. But a few minutes later, she couldn't focus. Her head felt heavy. She was hot and cold simultaneously, nauseous, and her legs shook violently. She then checked into the emergency room. In November, after more episodes and doctor visits, she was diagnosed with vasovagal syncope. She is still working on finding a suitable treatment.
Dealing with it in the workplace: "Be honest, early," says Grover. "It's hard to hide something that can [surface] at work."
[In Pictures: 7 Work Habits That Are Making You Sick.]
Besides, your coworkers may help you. "Standing for a long time can cause an episode, so [my colleagues] help ensure I'm safely seated, even when I'm in a crowded space," says Grover, who adds that many professionals don't seek out a doctor because they assume their medical problems are stress-related. That chain of thinking is arguably a universal trait of human nature. Says Grover: "It seems people want it to be stress."
Corrected on 03/04/2013: A previous version of this story misspelled the names of two medical conditions: Abductor spasmodic dysphonia (ABSD) and Vasovagal Syncope.