The term “nausea” refers to a feeling of impending vomiting. However, nausea may or may not be followed by actual vomiting. There are many causes of nausea. Frequent regurgitation, lack of appetite, abdominal pain, changes in urination, changes in bowel movements, dizziness and fainting are often associated with feelings of nausea. For effective treatment, the underlying cause of nausea needs to be identified.
In some cases, the feelings of nausea are temporary, and go away on their own. However, in other cases, nausea may occur chronically or over a long period of time. In such chronic cases, the feelings of nausea may either be constant or intermittent. Constant feelings of nausea may also persist during sleep. Intermittent episodes of intense nausea may get triggered by factors such as motion, stress, hunger and intake of certain foods. Vomiting may also be triggered during these intense episodes of nausea. The nature of the trigger factors vary on a case-to-case basis.
Causes of Chronic Nausea
There are many different causes of chronic nausea. It can be due to a host of digestive, hormonal, systemic and even psychological conditions. Various substances, including certain pharmaceutical drugs, may also be responsible for persistent nausea.
Gastrointestinal causes constitute the most common triggers of nausea in both males and females. Vomiting usually tends to occur along with nausea in these conditions. Other accompanying signs and symptoms include excessive belching, abdominal bloating and diarrhea. The feelings of nausea tend to intensify when food is consumed. In some cases, hunger may also aggravate the feelings of nausea.
- Gastroesophageal reflux disorder (GERD): Gastroesophageal reflux disorder is characterized by a regurgitation of stomach acid and other contents into the esophagus and the pharynx.
- Gastritis: Gastritis refers to inflammation of the gastric mucosa.
- Indigestion: Also known as non-ulcer dyspepsia, indigestion is characterized by a burning pain in the upper part of the abdomen.
- Gastroenteritis: Also known as stomach flu, gastroenteritis refers to an infection of the intestine that causes abdominal cramps, vomiting, fever, and diarrhea.
- Peptic ulcer: Peptic ulcer (also known as stomach ulcer) refers to sores that form in the mucosal lining of the stomach, esophagus and the small intestine. These sores or ulcers are caused by the action of the bacteria, Helicobacter pylori, and the stomach acid.
- Food poisoning: Food poisoning is caused by consumption of foods contaminated with pathogenic microbes.
- Obstruction of gastrointestinal tract: Nausea and projectile vomiting are common in cases of gastrointestinal obstruction.
- Intolerance to certain foods: Certain individuals are sensitive to certain food products (such as diary). Consumption of such foods can lead to nausea and other symptoms.
- Hiatal hernia: Hiatal hernia refers to a condition in which the upper region of the stomach pushes through the diaphragm and enters the thoracic cavity.
- Pancreatitis: Pancreatitis refers to an inflammation of the pancreas that lies behind the lower half of the stomach. Abdominal pain may be associated with nausea in this condition.
- Hepatitis: Hepatitis refers to inflammation of the liver. Jaundice is a common symptom.
- Gallstones: Gallstones refer to the formation of hardened deposits of cholesterol and other substances within the gallbladder.
Read more on signs of burst appendix.
Nausea in girls and women may occur due to hormonal causes. Nausea in these cases may either be episodic or constant. The hormonal changes responsible for feelings of nausea in women may either be natural (such as the hormonal changes during menstrual cycles and pregnancy) or drug-induced (such as use of hormonal contraceptives).
- Pregnancy: Pregnancy is a natural condition that is commonly associated with chronic nausea in women, especially during early morning hours.
- Prementrual syndrome (PMS): Hormonal changes caused by the events of a menstrual cycle may cause nausea, fatigue and irritability in some women.
- Drugs: Use of hormonal contraceptives, fertility enhancing drugs, and hormone replacement therapy is also associated with chronic nausea symptoms in some women.
Read more on pregnancy nausea.
Central nervous system causes
Injury or diseases of the central nervous system may also cause chronic feelings of nausea. These feelings of nausea are commonly accompanied by symptoms such as headache, dizziness, difficulty in concentrating, impaired memory and other cognitive disabilities. Immediate medical attention must be sought if these symptoms appear along with nausea.
- Head injury: Head trauma caused by a violent impact to the head frequently results in nausea.
- Intracranial hemorrhage: Intracranial hemorrhage refers to bleeding inside the skull. The bleeding may either occur around the brain or within the brain.
- Increased intracranial pressure: Increased pressure inside the brain and the cerebrospinal fluid may also cause nausea.
- Central nervous system infections: Infections of the central nervous system, such as encephalitis and meningitis, may also be accompanied by chronic nausea.
- Migraine: The intense headaches in migraine are often accompanied by nausea and hypersensitivity to light and sound.
Toxins, poisons, and drugs
A variety of toxins, poisons, and drugs may cause nausea. In fact, nausea is a common side-effect of many medications such as antibiotics and non-steroidal anti-inflammatory drugs (commonly abbreviated as NSAIDs). Nausea caused by these substances may either be due to irritation of the gastric mucosa (technically known as gastritis) or stimulation of the chemoreceptor trigger zone (abbreviated as CTZ). Nausea caused by toxins, poisons and drugs usually resolves once the offending substance is flushed out or discontinued.
- Toxins: Toxins released by certain microbes can cause nausea along with other symptoms.
- Poisons: Poisoning due to heavy metals, pesticides and insecticides can also result in nausea.
- Drugs: Certain drugs cause nausea as a common side effect. Nausea is a well known side effect of chemotherapy. In addition, narcotics abuse, nicotine replacement therapy, and excessive alcohol intake are also associated with nausea.
Chronic nausea may also be caused by a variety of systemic diseases such as kidney failure, liver failure and diabetes. The symptom of nausea may also be caused by severe pain. In addition to physical conditions, psychogenic factors such as depression and anxiety may also be accompanied by nausea. In terms of psychogenic nausea, the sensation may be due to some limbic stimulation of the nausea centers an is not an imagined sensation.