What Is Nausea?
Nausea is the unpleasant feeling of being about to vomit, though it is not always accompanied by vomiting. It is also possible, but uncommon, to have vomiting without nausea. There are numerous disorders that cause nausea and/or vomiting, and they often originate either from the GI tract, the brain, or a system-wide illness, toxin, or medication.
To best treat nausea and prevent serious diseases from progressing, it’s important to determine the underlying cause. It’s often easier to treat symptoms than to discover the underlying cause and begin treatment, but discovering the root issue could rule out serious disorders. In some instances, it might be necessary to see a doctor to address nausea.
- Vomiting: Vomiting is the forceful expulsion of gastric contents. It’s important to distinguish between vomiting and regurgitation, which is explained below.
- Diarrhea: Diarrhea is defined as loose or watery stools that occur at least three times in a 24-hour period. Classifications include acute diarrhea (lasting 14 days or fewer), persistent diarrhea (lasting 14-30 days), or chronic diarrhea (lasting 30 days or more). Additional classifications of diarrhea include invasive diarrhea (AKA dysentery, which is diarrhea containing visible blood or mucus) and watery diarrhea.
- Abdominal pain: Abdominal pain ranges from an obvious sharp stabbing pain or subtle discomfort or fullness. Patients often experience aches, pressure, cramping, or burning.
- Regurgitation: Regurgitation is the return of recently swallowed food back into the mouth. Regurgitation doesn’t involve retching.
- Headaches: When nausea or vomiting are associated with headaches, it may be very serious, requiring immediate medical care. Significant trauma or space-occupying lesions in the brain often cause both headaches and nausea. Space-occupying lesions can be from tumors or other illnesses.
- Dizziness: Dizziness involves feeling faint, woozy, or weak on the feet. Some people mistakenly think dizziness feels like the room is spinning, but that symptom is actually related to vertigo.
What Causes Nausea?
Nausea can have various causes. Looking at the most common causes can help you identify the cause of your nausea and/or vomiting, and whether you should be seen by a doctor.
Infectious Causes (Gastroenteritis)
Gastroenteritis is very common; any patient experiencing nausea and vomiting (accompanied by diarrhea or not) should consider gastroenteritis as the most likely cause. If you are pregnant or have just finished a procedure requiring anesthetics, see below.
If the nausea and vomiting came on suddenly without diarrhea, your nausea and vomiting is likely related to:
- Food poisoning: Derived from toxins produced from staph or other bacteria or chemical irritants that were ingested.
- Viral gastroenteritis: This is a true viral infection of the GI tract. Many viral infections start off with nausea and vomiting symptoms.
- Parasitic infections: Raw fish containing parasites from the anisakis or eustrongylides families can cause intense nausea, vomiting, and belly pain 1-12 hours after ingestion. Symptoms won’t resolve until the parasite has been expelled from the body. Another parasite found in raw olive flounder, called kudoa septempunctata, can cause intense vomiting and diarrhea. Symptoms may occur 3-16 hours after ingestion, but usually resolve within 24 hours.
If significant diarrhea is accompanying nausea and vomiting, the next step is to determine which type of diarrhea you’re experiencing.
- Watery diarrhea: Usually large volume bowel movements with significant abdominal bloating. Watery diarrhea won’t be accompanied with fevers or blood in the stool.
- Norovirus (Norwalk-like virus): This is very common and very infectious. Noroviruses are often seen in outbreaks on cruise ships or inside barracks or school dormitories, where quarters are close and facilities shared.
- Rotavirus as well as many other viruses cause watery diarrhea and nausea/vomiting.
- C. diff Colitis: This is a bacterial infection that often results from antibiotics used to treat unrelated infections. It’s commonly acquired during hospital visits but can rarely be seen in the community.
- Inflammatory diarrhea: This is characterized by fever, severe abdominal pain, and either bloody diarrhea or diarrhea containing mucus. Bacteria commonly cause this type of bacteria more than viruses.
- Salmonella: This is the leading cause of inflammatory diarrhea. It is a bacteria commonly found in poultry, eggs, and milk products (it has also been discovered in fresh produce, meats, nuts and nut products, spices, and animal products). It’s typically related to food that has been left out at warm temperatures, allowing for significant bacterial growth. Once a person has ingested a sufficient amount of bacteria, symptoms typically occur within 8 to 72 hours. Diarrhea, nausea, vomiting, and fever are the classic symptoms of salmonella infection. While this infection can cause bloody stools, it typically isn’t profound amounts of blood. The blood is often detected microscopically during stool tests.
- Campylobacter: Studies have shown that 75% of poultry (namely chicken and turkey) contain campylobacter. Unlike salmonella, small amounts of this bacteria can cause infection. This is a bacteria that forces us to use separate knives and cutting boards when preparing poultry. It’s why you can order your steak to be medium rare, but not your chicken. Diarrhea from campylobacter can contain a significant amount of blood, but can also just be clear liquid diarrhea.
- Bloody diarrhea: Bacteria typically cause bloody diarrhea. E. coli (a specific strain called O157:H7 is found in 31% of patients with bloody diarrhea), shigella (found in 49% of patients), campylobacter (found in 20% of patients), and salmonella (found in 19% of patients).
This form of nausea is familiar to most — and is one of the reasons people dread driving along a winding road or traveling on a boat, plane, or train. This is not considered a disease. In fact, studies have shown that nearly 100% of people can develop motion sickness. Motion sickness can be from real or perceived motion, and is one of the oldest forms of nausea.
Post-Procedure Nausea and Vomiting
Nausea, vomiting, and retching are common post-procedure complications, especially if anesthesia was used, or if the procedure resulted in a significant amount of blood in the stomach. For this diagnosis to be considered, nausea and/or vomiting must have started within 24 hours of the procedure. Sometimes the nausea/vomiting is related to opiates prescribed for recovery.
This cause of nausea and vomiting is related to the brain, while the others mentioned thus far have focused on the GI tract. Vestibular neuritis presents with a rapid and sudden onset of severe vertigo (the sensation that the world is spinning), nausea, vomiting, and unsteady balance.
Nausea and vomiting are common side effects of cancer chemotherapy. Talk to your oncologist if you aren’t receiving or are under-treated with your anti-nausea medication.
Up to 74% of pregnant women suffer from “morning sickness”. About 50% of pregnant women experience vomiting without nausea. Please note that normal nausea and vomiting begins within the first 9 weeks of pregnancy. Any nausea and vomiting that begins after the initial 9 weeks needs to be evaluated by your obstetrician or primary care physician promptly. Also, if at any point when you develop any of the following with your nausea/vomiting: abdominal pain, fevers, significant headaches, diarrhea, neurologic symptoms (ie numbness, tingling, weakness, or loss of sensation) then please see discuss your symptoms with your obstetrician or primary care physician right away. 1% of pregnancies develop hyperemesis gravidarum, which is such severe vomiting that the patient loses 5% of their pre-pregnancy weight. These patients when their urine is tested will show ketones.
Gastroparesis is a syndrome where the stomach is delayed in emptying it’s contents into the small intestine without any mechanical obstruction (ie from the nerves). In addition to nausea and vomiting, gastroparesis causes: early satiety (feeling full early in a meal), belching, bloating, and belly pain. While there are many conditions that have been documented to cause gastroparesis, the majority of cases are caused by diabetes, medications, or post-surgical (see above).
Obstruction of the GI Tract
Whenever there is an actual obstruction of the GI tract — either from a hernia, mass, inflammation from an ulcer, or constipation — the GI tract will distend and reject new food.
Functional Nausea and Vomiting Disorder
There are three separate disorders included in this group:
- Chronic nausea and vomiting syndrome: Bothersome nausea occurs at least 1 day per week or once per week for at least 3 months straight. Self-induced vomiting is not included in this diagnosis.
- Cyclic vomiting syndrome: Typical symptoms include early-morning belly pain, nausea with or without headaches, and recurrent vomiting episodes that peak at eight per hour. These episodes last less than one week and happen at least three times per year, with at least two episodes occurring over 6 months.
- Cannabinoid hyperemesis syndrome: This diagnosis involves the same symptoms as cyclic vomiting syndrome, except CHS involves prolonged and excessive cannabis use.
How To Get Rid of Nausea
Nausea treatment helps you feel better, but don’t forget that it’s crucial to find and treat the underlying causes of nausea. Here, we look at nausea and vomiting treatments. Keep in mind that the medications listed below will, for the most part, not treat underlying causes.
- Zofran (ondansetron): Most common antiemetic.
- Gastroenteritis: In practice, Zofran is most commonly used. While it is inferior to prochlorperazine, it has more favorable side effects. It also comes in a dissolvable form to avoid further upsetting the stomach or forcing expulsion of the medication.
- Postoperative nausea and vomiting: Used for both prevention and treatment of postoperative nausea/vomiting.
- Pregnancy-induced nausea: Guidelines reserve this for more severe cases of pregnancy-induced nausea (ie., hyperemesis gravidarum). Discuss with your obstetrician as they will often prescribe this or a similar medication.
- Phenergan (promethazine)
- Vestibular neuritis
- Dramamine (meclizine): One of the most common antiemetics for motion sickness.
- Motion sickness: This medication can be taken 1 hour before travel and repeated every 24 hours. Meclizine and scopolamine are the predominant treatments.
- Vertigo: A common medication used to treat vertigo.
- Reglan (metoclopramide): This has combined antiemetic and prokinetic properties. Serious and irreversible side effects can occur if this medication is taken over long periods of time. This medication should not be taken for longer than 12 weeks because of the increased risk of side effects. Please discuss with your doctor.
- Gastroparesis: This is a common medication for treatment.
- Chemotherapy-induced nausea and vomiting
- Scopolamine: A common antiemetic for motion sickness.
- Motion sickness: Can be applied as a patch placed behind the ear.
- Cannabinoids (marijuana): This is a topic of frequent debate, often carrying more political and social intensity than other medications. From a research-based perspective, cannabinoids have proved superior in treating chemotherapy-induced nausea compared to placebos. However, cannabinoids were proved inferior to metoclopramide (Reglan). Cannabinoids also have unfavorable side effects (vertigo, drop in blood pressure, and dry mouth) when compared to medications like Zofran. Thus, they are not recommended for conditions such as motion sickness, gastroenteritis, and gastroparesis. Cannabinoids provide a euphoric feeling and mild sedation. The majority of people do not find nausea relief using cannabinoids alone.
When Do I Need to See a Doctor for My Nausea?
It’s best to see the doctor right away if you are looking for immediate relief of your nausea symptoms because the doctor has a lot of anti-nausea medications that he/she can prescribe which typically provides immediate relief.