Nausea and vomiting are insistent characters. Pain may be ignored, or resolved with rest and some pills, an itch resisted, and fatigue overcome with caffeine and commitment. But when stomach contents are considering an unscheduled departure, your complete attention is diverted.
Nausea is the unpleasant sensation that vomiting is imminent, although the threatened call down the great white telephone may never occur. The word comes from the Greek nausia, meaning seasickness, rather appropriate for pilots because nausea may be an unhappy traveling companion. It might be said this is a symptom that comes in waves!
Everyone has experienced it, and nausea is a symptom, not a disease, so causes must be sought. For aviators that is doubly important; the underlying condition may render flying unsafe, and some medicines used to keep the food down can impair those faculties needed to keep the shiny side up.
Vomiting is coordinated by brain networks receiving messages from the gut; inner ear balance apparatus; brain centres responding to sights, smells, and emotions; and circulating blood chemicals.
Hence an impressive variety of insults can push the body’s “eject” button.
The first is one every GA pilot should know: “My carbon monoxide detector won’t stop beeping. It’s giving me a headache, dizziness, and nausea.” So, if you are feeling sick on board, and you do not have a detector, apply the oxygen mask and land!
Most commonly, nausea accompanies something relatively mundane. Gastroenteritis and food poisoning are familiar offenders, often bringing abdominal cramps, vomiting, and diarrhea along for the ride. Indigestion, reflux, overeating, and excessive alcohol can also leave the stomach distinctly disgruntled, as can consuming disagreeable food. For instance, people intolerant to lactose, the sugar found in milk, may inadvertently consume it in a sauce, causing nausea.
Medicines commonly cause queasiness. Antibiotics, opioid painkillers, antidepressants, diabetes and weight-loss drugs, and cancer treatments can all provoke nausea. If symptoms appear shortly after starting a new medication, consider that before blaming last night’s shrimp. The GLP-1 drugs that I described last year in these pages cause weight loss by a variety of mechanisms including slowing down gut emptying, so nausea is a frequent side effect, managed by eating smaller, more frequent meals.
Nausea can accompany any headache and sometimes dominates migraine attacks. However, if a headache is unremitting and returns every morning, accompanied by nausea and possibly eased by standing up, the cause may be something more sinister like a brain tumor.
As pilots know, the inner ear deserves special mention. It has a complex vestibular system that tells the brain where our body is and how it is moving. Of course, we all experienced the inner ear in all its splendor during instrument training—truly one cannot, and should not, fly by the seat of our pants! Disorders such as labyrinthitis or Ménière’s disease can generate dizziness and nausea because the brain receives conflicting information about what the body is doing. If nausea, together with impaired balance, tinnitus (ringing noise), and loss of hearing occur, acoustic neuroma, a very treatable tumor of the nerve supplying the ear, may be the culprit.
Pregnancy famously causes nausea, especially early on, although “morning sickness” was clearly named by somebody who never experienced it; symptoms can occur at any hour.
Stress, fear, and anxiety can also provoke an upset stomach. Often dismissively titled psychosomatic, implying a degree of craziness, it isn’t an imaginary illness; the brain and gut communicate through neural and hormonal pathways and the symptoms are real. Remember awaiting an important result, preparing to give a speech, or entering an ILS in deteriorating weather? Those symptoms you experience are very real. Even if you didn’t listen to the forecast, your stomach did. When I was but a lad, a group of us consumed a bottle of whisky—the next 24 hours were utterly miserable and even now just seeing that brand of spirit makes me “sick to my stomach”—a very real, psychosomatic experience.
Occasionally nausea is the calling card of something much more serious. Appendicitis, gallstones, pancreatitis, bowel obstruction, and kidney stones can all produce it, usually accompanied by pain. Severe infection can cause nausea, as can metabolic disturbances including very high or low blood glucose.
Neurological causes include concussion; raised pressure within the skull, such as from a brain tumor; meningitis, and, occasionally, stroke.
Heart attack does not invariably present as a Hollywood clutch-the-chest event. Nausea, sweating, breathlessness, and upper abdominal discomfort can occur, sometimes with surprisingly little chest pain.
Sudden nausea associated with chest pressure, significant breathlessness, collapse, a severe new headache, neurological symptoms, or intense abdominal pain deserves urgent medical assessment, not antacid and optimism.
Persistent or recurrent unexplained nausea also needs investigation, particularly when accompanied by weight loss, difficulty swallowing, blood in vomit, altered bowel habit, or persistent abdominal discomfort.
Motion sickness is an obvious one for pilots. Your eyes, inner ears, and sensory receptors normally provide the brain with a coherent picture of movement. Motion sickness develops when those signals disagree. In turbulence, while concentrating on an instrument panel is the classic scenario. The vestibular apparatus says, “We’re moving.” Your eyes, focused inside the cockpit, reply, “No we’re not.” The brain dislikes contradictions and throws up its hands—“I am sick of this!”
Symptoms often begin with pallor, yawning, sweating, salivation, and a vague abdominal unease before progressing to nausea and sometimes vomiting. Once established, it can seriously degrade concentration and decision-making. It also makes cleaning the aircraft afterwards rather unpleasant.
Passengers are usually more susceptible than aviators because pilots anticipate the aircraft movements and have external visual references. New students may experience airsickness and then adapt with repeated exposure. If symptoms begin in flight, look toward a stable distant horizon, keep head movements to a minimum, increase ventilation, and, if practical, transfer control while you recover. Avoid reading or staring downward unnecessarily.
Before flight, being rested, hydrated, and neither ravenously hungry nor stuffed with a gigantic greasy breakfast helps. Ginger may reduce nausea for some people and has the considerable advantage of not turning your brain into Jell-O.
For uncomplicated nausea, treatment is often wonderfully unsophisticated. Take small, frequent sips of cold water rather than gulping a pint. Dehydration makes matters worse; if vomiting (or diarrhea) is significant, fluids containing electrolytes may help replace both water and salts.
Eat small meals when able. Bland foods are often better tolerated than fatty, spicy, or strongly scented dishes. Fresh air can help. Ginger or peppermint tea works for some people, but lying flat immediately after eating is generally unhelpful if reflux is contributing.
Persistent nausea should be treated according to its cause: acid suppression for reflux, migraine therapy for migraine, treatment of infection when appropriate, correction of metabolic problems, and so forth.
There are multiple antiemetic drugs including ondansetron, prochlorperazine, metoclopramide, promethazine, and others. Scopolamine patches and antihistamines such as meclizine are widely used for motion sickness. But most motion-sickness and anti-nausea medications act on the central nervous system, causing sleepiness, dizziness, blurred vision, slowed reactions, or impaired judgment, not characteristics desirable in a pilot.
If you are painting the porcelain due to gastroenteritis, suppressing nausea and vomiting does not magically make you fit to fly. You may still be dehydrated, weak, distracted, and several thousand feet away from the nearest bathroom.
Current FAA guidance specifically warns that gastrointestinal illness can cause dehydration, cramps, and pain that may worsen with altitude. Some apparently innocuous over-the-counter preparations can also cause dizziness or drowsiness.
And motion sickness itself appears on FAA Form 8500-8 medical history as “motion sickness requiring medication.” A pilot reporting it should expect the AME to ask about frequency, severity, whether it occurred in an aircraft, and whether medication was necessary.
So don’t conceal recurrent airsickness, but don’t assume an isolated episode condemns your flying career either. Motion sickness frequently improves with habituation, and your AME can help distinguish an occasional physiological response from a transient or persistent vestibular problem.
The simplest rule is one we have discussed many times in these pages: IMSAFE: Illness? Medication? Stress? Alcohol? Fatigue? Emotion/Eating? Nausea manages to tick an impressive number of those boxes.
If you wake on flying day feeling decidedly green, ask why. Did you eat something questionable? Start a new drug? Drink too much last night? Are you dizzy? Feverish? Dehydrated? Developing abdominal pain? Could this be a migraine? Is it recurring for no obvious reason? And if you need medication merely to feel well enough to fly, that fact itself should make you reconsider launching.
Never experiment with a new anti-nausea or motion-sickness medication before flying. Discuss medications with your AME, because the pill your family doctor reasonably recommends for a passenger may be completely inappropriate for a pilot.
Nausea is usually transient and harmless, but it is one of the body’s most effective warning lights. Sometimes it means nothing more sinister than turbulent air or a dodgy oyster. Occasionally it signals significant disease. I recall a patient who had an obstructing colon cancer that he said was symptom free until he presented with a massively distended abdomen and three days of constipation. Oh, and six weeks of unremitting nausea and ten days of tossing cookies!
Either way, while your stomach may not hold an FAA medical certificate, it retains an extremely effective veto over the day’s flight. When it starts voting “no,” listen, and fly well!
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