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).       

Motion Sickness

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.     

Vestibular Neuritis

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. 

Chemotherapy

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.

Pregnancy

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

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.