Nausea

Gastrointestinal infection is one of the most common causes of acute nausea and vomiting.[1] Chronic nausea may be the presentation of many gastrointestinal disorders, occasionally as the major symptom, such as gastroesophageal reflux disease, functional dyspepsia, gastritis, biliary reflux, gastroparesis, peptic ulcer, celiac disease, non-celiac gluten sensitivity, Crohn's disease, hepatitis, upper gastrointestinal malignancy, and pancreatic cancer.[1][7] Uncomplicated Helicobacter pylori infection does not cause chronic nausea.[1]

Food poisoning usually causes an abrupt onset of nausea and vomiting one to six hours after ingestion of contaminated food and lasts for one to two days.[8] It is due to toxins produced by bacteria in food.[8]

Many medications can potentially cause nausea.[8] Some of the most frequently associated include cytotoxic chemotherapy regimens for cancer and other diseases, and general anaesthetic agents. An old cure for migraine, ergotamine, is well known to cause devastating nausea in some patients; a person using it for the first time will be prescribed an antiemetic for relief if needed.

Nausea or "morning sickness" is common during early pregnancy but may occasionally continue into the second and third trimesters. In the first trimester nearly 80 % of women have some degree of nausea.[9] Pregnancy should therefore be considered as a possible cause of nausea in any sexually active woman of child-bearing age.[8] While usually it is mild and self-limiting, severe cases known as hyperemesis gravidarum may require treatment.[10]

A number of conditions involving balance such as motion sickness and vertigo can lead to nausea and vomiting.

Dysmenorrhea can cause nausea.[11]

Nausea may be caused by depression, anxiety disorders and eating disorders.[12]

While most causes of nausea are not serious, some serious conditions are associated with nausea. These include pancreatitis, small bowel obstruction, appendicitis, cholecystitis, hepatitis, Addisonian crisis, diabetic ketoacidosis, increased intracranial pressure, spontaneous intracranial hypotension, brain tumors, meningitis, heart attack, rabies[13] carbon monoxide poisoning and many others.[1]

Obstructing disorders

• Gastric outlet obstruction
• Small bowel obstruction
• Colonic obstruction
• Superior mesenteric artery syndrome

Enteric infections

• Viral infection
• Bacterial infection

Inflammatory diseases

• Celiac disease
• Cholecystitis
• Pancreatitis
• Appendicitis
• Hepatitis

Sensorimotor dysfunction

• Gastroparesis
• Intestinal pseudo-obstruction
• Gastroesophageal reflux disease
• Irritable bowel syndrome
• Cyclic vomiting syndrome

Other

• Non-celiac gluten sensitivity
• Biliary colic
• Kidney stone
• Cirrhosis
• Abdominal irradiation[14]

Cardiopulmonary

• Cardiomyopathy
• Myocardial infarction (heart attack)
• Paroxysmal cough

Inner-ear diseases

• Motion sickness
• Labyrinthitis
• Malignancy

Intracerebral disorders

• Malignancy
• Hemorrhage
• Abscess
• Hydrocephalus
• Meningitis
• Encephalitis
• Rabies

Psychiatric illnesses

• Anorexia and bulimia nervosa
• Depression
• Drug withdrawal

Other

• Post-operative vomiting[14]
• Nociception

Drugs

• Chemotherapy
• Antibiotics
• Antiarrhythmics
• Digoxin
• Oral hypoglycemic medications
• Oral contraceptives

Endocrine/metabolic disease

• Pregnancy
• Uremia
• Ketoacidosis
• Thyroid and parathyroid disease
• Adrenal insufficiency

Toxins

• Liver failure
• Alcohol

It has been described that alterations in heart rate can occur as well as the release of vasopressin from the posterior pituitary.[3]

Taking a thorough patient history may reveal important clues to the cause of nausea and vomiting. If the patient's symptoms have an acute onset, then drugs, toxins, and infections are likely. In contrast, a long-standing history of nausea will point towards a chronic illness as the culprit. The timing of nausea and vomiting after eating food is an important factor to pay attention to. Symptoms that occur within an hour of eating may indicate an obstruction proximal to the small intestine, such as gastroparesis or pyloric stenosis. An obstruction further down in the intestine or colon will cause delayed vomiting. An infectious cause of nausea and vomiting such as gastroenteritis may present several hours to days after the food was ingested.[14] The contents of the emesis is a valuable clue towards determining the cause. Bits of fecal matter in the emesis indicate obstruction in the distal intestine or the colon. Emesis that is of a bilious nature (greenish in color) localizes the obstruction to a point past the stomach. Emesis of undigested food points to an obstruction prior to the gastric outlet, such as achalasia or Zenker's diverticulum. If patient experiences reduced abdominal pain after vomiting, then obstruction is a likely etiology. However, vomiting does not relieve the pain brought on by pancreatitis or cholecystitis.[14]

It is important to watch out for signs of dehydration, such as orthostatic hypotension and loss of skin turgor. Auscultation of the abdomen can produce several clues to the cause of nausea and vomiting. A high-pitched tinkling sound indicates possible bowel obstruction, while a splashing "succussion" sound is more indicative of gastric outlet obstruction. Eliciting pain on the abdominal exam when pressing on the patient may indicate an inflammatory process. Signs such as papilledema, visual field losses, or focal neurological deficits are red flag signs for elevated intracranial pressure.[14]

When a history and physical exam are not enough to determine the cause of nausea and vomiting, certain diagnostic tests may prove useful. A chemistry panel would be useful for electrolyte and metabolic abnormalities.[18] Liver function tests and lipase would identify pancreaticobiliary diseases.[18] Abdominal X-rays showing air-fluid levels indicate bowel obstruction, while an X-ray showing air-filled bowel loops are more indicative of ileus. More advanced imaging and procedures may be necessary, such as a CT scan, upper endoscopy, colonoscopy, barium enema, or MRI. Abnormal GI motility can be assessed using specific tests like gastric scintigraphy, wireless motility capsules, and small-intestinal manometry.[14]

Many pharmacologic medications are available for the treatment of nausea. There is no medication that is clearly superior to other medications for all cases of nausea.[20] The choice of antiemetic medication may be based on the situation during which the person experiences nausea. For people with motion sickness and vertigo, antihistamines and anticholinergics such as meclizine and scopolamine are particularly effective.[21] Nausea and vomiting associated with migraine headaches respond best to dopamine antagonists such as metoclopramide, prochlorperazine, and chlorpromazine.[21] In cases of gastroenteritis, serotonin antagonists such as ondansetron were found to suppress nausea and vomiting, as well as reduce the need for IV fluid resuscitation.[21] The combination of pyridoxine and doxylamine is the first line treatment for pregnancy-related nausea and vomiting.[21] Dimenhydrinate is an inexpensive and effective over the counter medication for preventing postoperative nausea and vomiting.[22] Other factors to consider when choosing an antiemetic medication include the person's preference, side-effect profile, and cost.

Nabilone is also indicated for this purpose.

In certain people, cannabinoids may be effective in reducing chemotherapy associated nausea and vomiting.[23][24] Several studies have demonstrated the therapeutic effects of cannabinoids for nausea and vomiting in the advanced stages of illnesses such as cancer and AIDS.[25][26]

In hospital settings topical anti-nausea gels are not indicated because of lack of research backing their efficacy.[27] Topical gels containing lorazepam, diphenhydramine, and haloperidol are sometimes used for nausea but are not equivalent to more established therapies.[27]

Ginger has also been shown to be potentially effective in treating several types of nausea.[28][29]