Nausea is the sensation of discomfort in the stomach accompanied by an urge to vomit. Nausea can be a fleeting sensation or it can be a constant, irritating presence. Short term nausea can be caused by certain odors, motion sickness or fear. Nausea lasting for longer periods of time can be the result of infectious illness, chronic disease, certain conditions or external factors.
Nausea that occurs abruptly is associated with food poisoning, adverse reaction to medication, migraine headaches and inflammation of the pancreas or gall bladder. Pregnancy, gastrointestinal disorders, and metabolic imbalances are conditions in which constant nausea has a gradual onset.
Constant nausea may also be a symptom of brain injury after a trauma, brain tumor or infection of the lining of the brain, or meningitis. Increasing nausea after a head trauma may signify an increase of pressure on the brain.
Constant nausea does not always lead to vomiting. The urge to vomit may occur whether or not there is food or water in the stomach.
In some cases, removal of a noxious agent may alleviate constant nausea; for example, if a medication is determined to be the cause, ceasing the drug may relieve the nausea. In other cases, anti-nausea medication, such as Phenergan and Compazine may be administered.
Constant nausea is not to be considered a normal condition. When it is accompanied by vomiting, there is the risk of additional problems due to dehydration.