There are many different reasons for vomiting. Most people consider dysfunction of the gastrointestinal tract to be one of the main sources of nausea and vomiting, and indeed, many diseases of these organs can cause this symptom. Disorders of the nervous system can also cause vomiting, however. Systemic illnesses or conditions, including pregnancy and endocrinologic disorders, are also causes of vomiting. Since there are so many causes of vomiting, some of which can be linked to serious diseases, patients with this symptom should discuss their condition with a doctor.
Abnormalities of the gastrointestinal tract explain some of the reasons for vomiting. Many infections — including gastritis, food poisoning, gastroenteritis, and colitis — can cause vomiting. Structural abnormalities of the gastrointestinal system, including esophageal strictures, gastric outlet obstruction, small bowel obstruction, and large bowel obstruction are additional causes. Vomiting may also be due to inflammation of certain organs of the gastrointestinal tract, including the gallbladder, the pancreas, or the liver.
Diseases that affect the brain and nervous system of the body can also be reasons for vomiting. For example, it can be caused by having increased pressure inside the brain, either due to a tumor or infection. Classically, this pressure causes projectile vomiting that is most severe early in the morning. Infections of the brain, such as encephalitis or meningitis, can also cause vomiting even if they don’t affect the intracranial pressure. Other neurologic conditions associated with vomiting including inner ear problems, migraines, and motion sickness.
Certain systemic conditions can also be reasons for vomiting. Pregnancy is classically associated with morning sickness, which causes women to have recurrent vomiting, and is thought to be due to the hormonal shifts associated with having a baby. Endocrinologic disorders such as hyperthyroidism and adrenal insufficiency can produce this symptom. Many infections that affect the entire body can result in nausea and vomiting.
Another class of reasons for vomiting is psychiatric disease. Bulimia, for example, is a psychiatric disorder in which patients engage in “purging” behavior, in which they vomit up food after eating it in hopes to control their weight. This is a serious condition that can lead to malnutrition, damage to the esophagus, seizures, and heart problems. Another condition called cyclic vomiting syndrome causes patients to have recurrent episodes of intractable vomiting. These episodes severely limit patients’ ability to go on with their daily activities.
A number of medications can cause nausea and vomiting as side effects, making administration of these drugs another one of the reasons for vomiting. In this category, many people are familiar with chemotherapy regimens used to treat cancer as a type of therapy strongly associated with nausea and vomiting. Other medications, such as antibiotics and pain medications, can also commonly cause this as a side effect.