Nausea-Vomiting; Causes, Symptom, Diagnosis, Treatment

Nausea-Vomiting is a sensation of unease and discomfort in the upper stomach with an involuntary urge to vomit. It may precede vomiting, but a person can have nausea without vomiting. When prolonged, it is a debilitating symptom. Nausea is a non-specific symptom, which means that it has many possible causes. Some common causes of nausea are motion sickness, dizziness, migraine, fainting, low blood sugar, gastroenteritis (stomach infection) or food poisoning. Nausea is a side effect of many medications including chemotherapy, or morning sickness in early pregnancy. Nausea may also be caused by anxiety, disgust, and depression

Nausea and vomiting interrupt the intrinsic motor activity of the gastrointestinal tract. With nausea, the normal tone of the fundus and body of the stomach is lost, and pyloric sphincter pressure decreases. Alkaline duodenal contents reflux freely into the distal stomach and may produce vomiting due to local irritation. Retching increases intra-abdominal pressure and promotes duodenogastric and gastroesophageal reflux by simultaneous contraction of the muscles of inspiration, the abdominal wall muscles, and the diaphragm. Vomiting usually occurs at end inspiration when intra-abdominal pressure is highest. The diaphragm abruptly relaxes, and abdominal pressure is suddenly transmitted to the chest. The cardio of the stomach herniates through the diaphragm into the thorax, and stomach contents are projected via the esophagus into the pharynx. Aboral peristalsis has not been demonstrated in humans and is not required to explain the vomiting process.

Pathophysiology of Nausea-Vomiting

Research on nausea and vomiting has relied on using animal models to mimic the anatomy and neuropharmacologic features of the human body. The physiologic mechanism of nausea is a complex process that has yet to be fully elucidated. There are four general pathways that are activated by specific triggers in the human body that go on to create the sensation of nausea and vomiting.

• Central nervous system (CNS): Stimuli can affect areas of the CNS including the cerebral cortex and the limbic system. These areas are activated by elevated intracranial pressure, irritation of the meninges (i.e. blood or infection), and extreme emotional triggers such as anxiety.
• Chemoreceptor trigger zone (CTZ): The CTZ is located in the area postrema in the floor of the fourth ventricle within the brain. This area is outside the blood-brain barrier and is therefore readily exposed to substances circulating through the blood and cerebral spinal fluid. Common triggers of the CTZ include metabolic abnormalities, toxins, and medications. Activation of the CTZ is mediated by dopamine (D2) receptors, serotonin (5HT3) receptors, and neurokinin receptors (NK1).
• Vestibular system: This system is activated by disturbances to the vestibular apparatus in the inner ear. These include movements that cause motion sickness and dizziness. This pathway is triggered via histamine (H1) receptors and acetylcholine (ACh) receptors.
• Peripheral Pathways: These pathways are triggered via chemoreceptors and mechanoreceptors in the gastrointestinal tract, as well as other organs such as the heart and kidneys. Common activators of these pathways include toxins present in the gastrointestinal lumen and distension of the gastrointestinal lumen from blockage or dysmotility of the bowels. Signals from these pathways travel via multiple neural tracts including the vagus, glossopharyngeal, splanchnic, and sympathetic nerves.

Causes Nausea-Vomiting

Nausea and vomiting are not diseases, but they are symptoms of many conditions such as

• Acute gastritis (direct irritation of the stomach lining)
• Central causes in which signals from the vomiting center in the brain cause nausea and vomiting
• Other illnesses not due to stomach problems, for example, brain tumors, pancreatitis, and appendicitis
• Medications, medical treatments, and illicit or illegal drugs, drug or alcohol overdose
• Mechanical obstruction of the bowel
• Motion sickness or seasickness
• Early stages of pregnancy (nausea occurs in approximately 50%-90% of all pregnancies; vomiting in 25%-55%)
• Medication-induced vomiting
• Intense pain
• Emotional stress (such as fear)
• Gallbladder disease
• Food poisoning
• Infections (such as the “stomach flu”)
• Overeating
• A reaction to certain smells or odors
• Heart attack
• Concussion or brain injury
• Brain tumor
• Ulcers
• Some forms of cancer
• Bulimia or other psychological illnesses
• Gastroparesis or slow stomach emptying (a condition that can be seen in people with diabetes)
• Ingestion of toxins or excessive amounts of alcohol

Other possible causes of nausea and vomiting include

• Acute liver failure
• Alcohol use disorder (Alcoholism)
• Anaphylaxis (in children)
• Anorexia nervosa
• Appendicitis
• Benign paroxysmal positional vertigo (BPPV)
• Brain tumor
• Bulimia nervosa
• Cholecystitis (gallbladder inflammation)
• Crohn’s disease (a type of inflammatory bowel disease)
• Cyclic vomiting syndrome
• Depression (major depressive disorder)
• Diabetic ketoacidosis (high levels of blood acids called ketones)
• Dizziness
• Ear infection (middle ear)
• Enlarged spleen (splenomegaly)
• Fever
• Food poisoning
• Gallstones
• Gastroesophageal reflux disease (GERD)
• Generalized anxiety disorder
• Heart attack
• Heart failure
• Hepatitis (liver inflammation)
• A hiatal hernia
• Hydrocephalus (a congenital brain abnormality)
• Hyperparathyroidism (overactive parathyroid)
• Hyperthyroidism (overactive thyroid)
• Hypoparathyroidism (underactive parathyroid)
• Intestinal ischemia
• Intracranial hematoma (blood vessel ruptures with bleeding in or around the brain)
• Intussusception (in children)
• Irritable bowel syndrome
• Medications (including aspirin, nonsteroidal anti-inflammatories, oral contraceptives, digitalis, narcotics and antibiotics)
• Meniere’s disease
• Meningitis (inflammation of the membranes and fluid surrounding your brain and spinal cord)
• Milk allergy
• Pancreatic cancer
• Pancreatitis (pancreas inflammation)
• Peptic ulcer
• Pseudotumor cerebri (increased pressure inside the skull), also known as idiopathic intracranial hypertension
• Pyloric stenosis (in infants)
• Radiation therapy
• Severe pain
• Toxin ingestion

Sign Symptom of Nausea-Vomiting

• A headache
• Lightheadedness
• Dizziness
• A general feeling of being sick to one’s stomach
• The muscular ring between the esophagus and stomach (esophageal sphincter) relaxes.
• The abdominal muscles and diaphragm contract.
• The windpipe (larynx) closes.
• The lower portion of the stomach contracts.
• Stomach Cramps
• Abdominal Pain
• Diarrhea
• Vertigo
• weakness,

Other symptoms, which cause nausea after eating that indicate an underlying condition:

Condition	Additional symptoms
Food poisoning	vomiting diarrhea stomach pain fatigue loss of appetite fever aches
Stomach flu	vomiting diarrhea head and muscle aches fever loss of appetite weight loss
Food intolerance	vomiting diarrhea stomach pain cramps bloating or gas heartburn
Food allergy	vomiting diarrhea stomach pain skin rashes swelling – typically on the face or throat dizziness shortness of breath hay fever-like symptoms, such as sneezing
GERD	heartburn a sore throat bad breath bloating or gas difficulty swallowing a chronic cough
Gallbladder disease	vomiting diarrhea fever pain, typically in upper-right abdomen jaundice pale stools
Irritable bowel syndrome	diarrhea constipation stomach pain
Mesenteric ischemia	vomiting diarrhea fever bloating or gas stomach pain
Acute pancreatitis	pain in upper left or middle of the abdomen, often through to the back vomiting fever abdominal pain after eating

Diagnosis of Nausea-Vomiting

• Blood tests (to check electrolytes and blood cell count)
• Urinalysis (to check for dehydration and infection)
• X-rays or CT scans may be helpful depending on the doctor’s clinical suspicion of the cause of nausea and vomiting
• Ultrasound
• A CT scan of the head may be ordered if there is a new onset headache or head trauma associated with nausea and vomiting.

Treatment of Nausea-Vomiting

Nausea does not always require treatment, but sometimes treatment is helpful. There are several things you can do on your own to help, including:

• Drink beverages that settle the stomach, such as ginger ale or chamomile tea.
• Avoid caffeinated colas, coffees, and teas.
• Drink clear liquids to avoid dehydration (if vomiting is associated with nausea).
• Eat small, frequent meals to allow the stomach to digest foods gradually.
• Eat foods that are bland and simple for your stomach to digests, such as crackers or unbuttered bread, rice, chicken soup, and bananas.
• Avoid spicy foods and fried foods.

Some over-the-counter medications can help to relieve nausea, including:

• Chewable or liquid antacids, bismuth sub-salicylate (Pepto-Bismol) or a solution of glucose, fructose and phosphoric acid (Emetrol). These medicines help by coating the stomach lining and neutralizing stomach acid.
• Dimenhydrinate (Dramamine) or meclizine hydrochloride (Bonine, Dramamine II). These medications are helpful for treating or preventing motion sickness and are thought to block receptors in the brain that trigger vomiting.

The most commonly prescribed anti-nausea and anti-vomiting medications include (but are not limited to)

• prochlorperazine
• ondansetron 
• promethazine
• metoclopramide
• trimethobenzamide
• hydroxyzine 

Home or Natural Remedies

• Avoiding foods and smells that trigger your nausea.
• Keeping soda crackers by your bed and eating a couple before getting up. Allow some time for digestion, and rise slowly once you are ready.
• Eating smaller meals more frequently throughout the day instead of three big meals.
• Drinking less water/fluids with your meals, and instead,d drink them between meals.
• Eatingdriery, plain foods such as white rice, dry toast, or a plain baked potato instead of richer, creamier foods.
• Sucking on hard candy.
• Keeping rooms well ventilated or having a fan close by for easier breathing. If neither of these are possible, take time to go outside to get some fresh air.
• Getting plenty of rest; Listen to your body when you are feeling fatigued, and try lying down.
• Sniffing ginger or lemons, or drinking ginger ale or lemonade, which can help ease the feeling of nausea.
• Talking with your healthcare provider about the prenatal vitamins you are taking; having too much iron may cause nausea, and switching to a different vitamin could help.
• Asking your healthcare provider about taking a vitamin B-6 supplement, which has proven to help reduce nausea and vomiting.

References

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• https://www.ncbi.nlm.nih.gov/pubmed/18321441
• https://www.ncbi.nlm.nih.gov/pubmed/29545633
• https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4699282/
• https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4699282/
• https://www.ncbi.nlm.nih.gov/pubmed/29545633
• https://www.ncbi.nlm.nih.gov/pubmed/17885699
• https://www.ncbi.nlm.nih.gov/pubmed/21174569
• https://www.ncbi.nlm.nih.gov/pubmed/21174569
• https://www.webmd.com/digestive-disorders/digestive-diseases-nausea-vomiting
• https://www.healthline.com/health/nausea-and-vomiting
• https://emj.bmj.com/content/22/3/200
• https://books.google.com/books/about/Postoperative_Nausea_and_Vomiting.html?id=YjrzCwAAQBAJ
• https://en.wikipedia.org/wiki/Chemotherapy-induced_nausea_and_vomiting
• https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=fc9c0ba9-3525-4fb4-a625-ef7dbe2ce4fe

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