Coughing is a reflex action that is an attempt by the body to expel an irritant from the respiratory tract. The coughing reflex is initiated when an irritant reaches the lower respiratory tract. Irritants such as smoke, food particles, and noxious gases stimulate the pulmonary irritant receptors situated in the lining of the respiratory tract.
In response to this stimulation, the cough reflex initiates intake of a deep breath that is followed by a forceful expulsion of air from the lungs. The irritant can get dislodged and expelled from the respiratory tract due to the high pressure of the coughed out air. However, a single cough may not be successful in expelling the irritant substance.
In such cases, a series of coughs occur till the irritation in the respiratory tract subsides. It is also possible to cough voluntarily. However, voluntary coughs are not as deep or forceful as involuntary coughs.
Like the cough, vomiting is also an involuntary reflex action of the body that attempts to remove an irritant. Unlike cough, however, the vomiting reflex is initiated in response to an irritation in the digestive tract. Vomiting is characterized by a reverse peristalsis of the stomach contents due to strong contractions of the muscles in the stomach and the intestine.
As a result, the contents of the stomach are pushed up into the throat and expelled through the mouth. Vomiting can also be triggered by stimuli such as offensive smells, chemicals, gory visuals, and abnormalities in the blood. All these stimuli are capable of stimulating the vomit centers located in the brain.
Read more on coughing up clear fluid.
Coughing and Vomiting at the Same Time
Coughing and vomiting are both protective reflex mechanisms to expels irritant or toxic substances. However, they are different processes that are controlled by different neural circuits. A cough reflex is an attempt to expel irritants from the respiratory tract, whereas a vomiting reflex is an attempt to expel irritants from the digestive tract.
In some cases, coughing and vomiting may occur together. An irritant that triggers coughing may also be able to trigger vomiting at the same time. It is also possible that one event may trigger the other. Both coughing and vomiting are characterized by a momentary increase in intra-abdominal pressure.
Throat irritation and increased abdominal pressure during coughing may also initiate vomiting, especially if the stomach is full due to a recent meal. Alternatively, vomitus may enter the lower respiratory tract and irritate it, resulting in coughing. During expulsion, both air and vomitus pass through the throat and the mouth.
Coughing that is accompanied by vomiting may appear serious. However, the underlying cause may or may not be serious.
Read more on coughing up phlegm.
Causes of Coughing Up Vomit
Factors that cause severe and uncontrollable coughing can also trigger vomiting. However, in some cases, coughing may expel small food particles that get trapped in the tonsillar tissue. These expelled food particles do not originate from the esophagus, stomach or small intestine.
Vomiting and coughing may also occur together in a person who is gagging. Coughing in these cases is usually a mechanism to clear the throat. A person may also start vomiting shortly after being gagged. However, this does not mean that coughing causes vomiting in these cases. Gagging and vomiting are more likely to occur in people who have problems in swallowing.
The causes of coughing up vomit can be subdivided into two categories: (1) infectious causes, and (2) non-infectious causes.
- Pertussis: Commonly known as the whooping cough, pertussis is a bacterial infection of the respiratory tract. The bacterium, Bordetella pertussis, is the infectious cause of pertussis. The name “whooping cough” derives from the characteristic severe coughing that is seen in pertussis patients. Coughing occurs during the second phase of the disease, and may not be accompanied by any other symptoms.
- Pulmonary tuberculosis: Pulmonary tuberculosis (TB) is caused by infection with the bacterium, Mycobacterium tuberculosis. The lung infection in pulmonary tuberculosis is a serious and chronic condition that can even cause death. The main signs and symptoms of pulmonary tuberculosis include night sweats, weight loss and bloody cough.
- Influenza: Commonly referred to as the flu, influenza is a viral infection of the respiratory tract. Influenza is characterized by a dry cough, which is usually not severe enough to cause vomiting. However, if a person gets viral gastroenteritis along with (or after) influenza, coughing and vomiting may occur simultaneously.
- Acute bronchitis: Acute bronchitis refers to an inflammation of the bronchi. Both bacteria and viruses can cause acute bronchitis. Persistent and productive cough is a characteristic symptom of this condition. Severe coughing may sometimes lead to vomiting. Acute bronchitis is often seen to occur immediately after a flu.
It is important to note that coughing and vomiting can potentially be triggered by any respiratory tract infection.
- Asthma: Asthma is characterized by constriction of airways in response to triggers such as airborne irritants, allergens, cold and stress. The airway constriction in asthma attacks lasts for variable periods of time. Coughing may also occur during an asthma attack. Severe coughing can lead to vomiting in some cases. Asthma is a common respiratory condition in children.
- Bronchiectasis: Bronchiectasis is characterized by an abnormal widening and weakening of the walls of the airways. The most common causes of bronchiectasis are severe infections of the respiratory tract, such as tuberculosis. However, bronchiectasis may also be due to noninfectious causes.
- Post-nasal drip: Post-nasal drip is characterized by a dripping of excess nasal mucus into the back of the throat. The mucus drip into the throat can irritate the throat and trigger coughing. When persistent, coughing may also be able to cause vomiting.
- Chronic obstructive pulmonary disease: Commonly abbreviated as COPD, the chronic obstructive pulmonary disease is characterized by persistent coughing. Tobacco smoking is frequently associated with the irreversible airway damage in chronic obstructive pulmonary disease.
- Gastroesophageal reflux disease: Gastroesophageal reflux disease (commonly abbreviated as GERD) is characterized by a backward flow of the acidic gastric contents into the esophagus and the mouth. The acidic stomach contents can irritate the throat and enter the airways, causing cough. The regurgitated stomach contents are usually not vomited out.
- Iatrogenic causes: Coughing and vomiting may also occur as a side-effect of taking certain medications. These drug-related causes are termed as iatrogenic causes.
- Smoking: Tobacco smoking can irritate the respiratory passages and cause coughing. High levels of nicotine and other substances contained in the tobacco can also cause nausea and vomiting.