Nausea is an unpleasant feeling that is usually experienced before vomiting. Constant or persistent nausea is characterized by feeling nauseous for more than 24 hours. Although nausea and vomiting often come together, vomiting may occur without feeling nauseous and nausea can occur without vomiting.
Nausea and vomiting are usually controlled by areas in the brain and gut. The brain's vomiting center responds to different signals, which include:
- Noxious smells
- Toxic substances in the blood
- High adrenaline levels (e.g., in a fight or flight situation)
- Pregnancy hormones
- Signals from balance organs
Possible Causes for Constant Nausea
Constant or persistent nausea can have a number of potential causes, and they include:
Around 3 in every 4 pregnant women tend to experience nausea during early pregnancy or in the first 12 weeks of pregnancy. Nausea during this time is called morning sickness. Although morning sickness commonly occurs during the first trimester, nausea and/or vomiting may also return later in pregnancy. It is usually a result of the pressure the baby puts on the mother's tummy or gastritis in some cases.
There are also women who experience a severe form of nausea and vomiting called hyperemesis gravidarum, which may continue during pregnancy. It has been estimated that around 1 in every 100 pregnant women experience hyperemesis gravidarum in their pregnancy.
2. Side Effect of Medications
Medications, whether they are over-the-counter or prescribed, can have certain side effects. An example would be chemotherapy drugs, which can upset the stomach and contribute to nausea and vomiting.
If you are taking new medications, make sure to carefully read their labels for more information about their potential side effects. Asking your doctor and reading medication information can help reduce your risk of experiencing medication-induced nausea.
The following are medications that are commonly known for causing nausea:
- Opiates (morphine and codeine)
- Nonsteroidal anti-inflammatory drugs (NSAIDs)
- Certain antibiotics (erythromycin and metronidazole)
- Certain antidepressants
- Hormonal contraceptives
- Iron supplements
3. Gastrointestinal Infections
Viral and bacterial infections that affect the stomach can cause nausea. Food poisoning is caused by the ingestion of food-borne bacteria, which often cause nausea and vomiting. Aside from nausea and/or vomiting, diarrhea may also occur in gastrointestinal infections.
People with gastrointestinal infections often recover within two days. However, those who are infected with rotavirus and giardia may experience longer symptoms of nausea, vomiting, diarrhea, and flatulence for a week or more.
4. Excessive Alcohol Consumption
Alcohol abuse or excessive intake of alcohol may lead to stomach and liver inflammation, which can cause nausea and vomiting. These symptoms are usually caused by a direct chemical effect on a person's brain.
5. Stomach Problems
- Gastroesophageal reflux disease (GERD): People experience GERD or acid reflux when the contents of their stomach come back up their esophagus when they eat. This condition can irritate the esophagus and cause heartburn along with other symptoms, such as nausea.
- Stomach ulcers: Also called as gastric ulcers, are usually seen in people with gastric cancer and severe liver disease. Stomach ulcers can cause nausea, food intolerance, and severe pain.
- Gastroparesis: This condition is caused by a delay in stomach emptying and inadequate food grinding. The most common symptoms of gastroparesis are stomach pain, nausea, and vomiting. People who have Parkinson's disease, diabetes, and those who have had bariatric surgery (weight loss surgery) are more prone to developing gastroparesis.
6. Neurological and Psychological Conditions
- Migraine headache
- Symptoms of meningitis (severe headache, stiff neck, and light sensitivity)
- Brain injury or swelling
- Brain tumor
- Bulimia nervosa and other eating disorders
7. Seasickness or Motion Sickness
Seasickness, also called motion sickness, is the sensation people get when the motion they sense with their inner ear is not the same as the motion they visualize.
Most cases of motion sickness happen when people travel by boat, airplane, train, or car. Other people experience motion sickness in amusement park rides, such as a rollercoaster ride. At first, a person with motion sickness develops a feeling of uneasiness and sweating along with dizziness. These sensations are then followed by nausea, vomiting, or both.
When to Seek Medical Help
If your nausea is accompanied by symptoms of a heart attack, seek immediate medical attention. The most common symptoms of a heart attack are crushing chest pain, pain in the left arm, jaw pain, intense headache, or sweating.
Immediate medical attention is also required if your nausea is accompanied by difficulty breathing, confusion, stiff neck, and a severe headache. You should also seek medical help right away if you are dehydrated or think you may have consumed a poisonous substance.
See your doctor if you have severe nausea, making you unable to drink or eat anything for 12 hours or longer. A doctor's visit is also recommended if your nausea does not improve even after taking over-the-counter remedies within 24 hours.
Treatment usually depends on the cause of nausea. Some of the common treatment methods include:
- When you are in a vehicle, try to sit in the front seat instead of sitting at the rear seat to help relieve motion sickness.
- Take medications to help relieve motion sickness. These medications may be an antihistamine, a scopolamine patch, or dimenhydrinate (Dramamine).
- Taking medications for the treatment of any underlying causes of nausea.
- Pain relievers for intense headaches or migraine headaches.
- Acid reducers for gastroesophageal reflux disease (GERD).
- Keeping yourself well-hydrated to avoid being dehydrated after nausea subsides.
- When reintroducing food, the BRAT diet may be beneficial until you feel better. The BRAT diet consists of bananas, rice, applesauce, and toast.
The onset of nausea can be prevented by avoiding the things that trigger it. Some of its common triggers are:
- Air and sea travel
- Certain odors (cooking smells and strong perfume)
- Flickering lights (common triggering factor of migraine headaches)
Motion sickness can also be prevented by taking an anti-nausea medication, such as scopolamine, before air, land, or sea travel. Another way to help reduce the symptoms of nausea is to change your eating habits, such as eating small frequent meals. After meals, avoiding any intense physical activity may help as well.
Eat foods that are less likely to induce nausea, such as broth, gelatin, toast, cereals, and crackers. Avoid consuming foods that are greasy, spicy, and high in fat.