Coughing and vomiting are two different process, with coughing involving the respiratory tract while vomiting originates in the digestive tract. However, it is possible for one to trigger or cause the other. Sometimes the same irritant that causes the coughing can also lead to vomiting, and while separate processes it may occur at the same time. Most people are concerned when coughing leads to vomiting and it is understandably an uncomfortable and at times scary experience. However, it may not always be as serious as it seems.
Coughing vs Vomiting
Coughing and vomiting can both be seen as protective mechanisms to expel irritants from the respiratory tract and digestive tract respectively. It is important to understand why and how these mechanisms occur before delving further into the possible causes.
Why do we cough?
The cough reflex as it is known arises when an irritant enters the lower respiratory tract. Pulmonary irritant receptors in the respiratory lining are stimulated by irritants such as noxious gases, smoke and food particles. A deep breath is then followed by a forceful expulsion of the air in the lungs. The high pressure of the expelled air should remove the irritant from the respiratory tract and into the environment. However, this does not always work effectively and there may be repeated coughing until the irritant is removed. Coughing can also be voluntarily initiated but it is usually not as deep and forceful.
Why do we vomit?
The vomiting process is similar to the cough reflex in many respects but it arises from the digestive tract. Vomiting occurs when there is irritation of the digestive tract although it can even be triggered by other stimuli, like an offensive smell or gory scene. Sometimes chemicals or abnormalities in the blood can also trigger vomiting. The reason is that the triggers may stimulate the vomit centers in the brain which then causes the stomach and intestinal muscles to push its contents in a backward direction (reverse peristalsis), up into the throat and out through the mouth.
Coughing and Vomiting Together
Some of the key aspects in both coughing and vomiting is that the pressure within the abdomen may momentarily increase. Coughed up air and vomitus both have to pass through the throat and then is expelled out of the mouth. Coughing can irritate the throat and along with the increase in abdominal pressure it can initiate vomiting. Often this is more likely to occur if coughing occurs immediately after eating particularly after ingesting a large meal.
Causes of Coughing Up Vomit
Coughing can push out mucus and air from the respiratory tract but the expelled air cannot draw out the digested food in the digestive tract. Sometimes when coughing, the process of vomiting is initiated. The intestinal contents are then pushed out at the same time and it may seem like the vomitus. Therefore the causes of coughing up vomit is essentially the same as causes of severe uncontrollable coughing. Sometimes small particles of food that may get trapped in the tonsillar tissue may be expelled during coughing. These small particles, often looking like tiny white specks, are not originating from the esophagus, stomach or small intestines despite looking like its digested.
It is important to differentiate between gagging and coughing. Sometimes a person may gag and the vomit shortly thereafter. This can occur for a number of reasons. Even though we may cough after gagging in order to clear the throat, in these cases the coughing usually does not cause the vomiting that may follow. People with conditions where there is a problem swallowing are more likely to experience this type of gagging and vomiting. It is also important to understand that vomitus can sometimes enter the lower airways (aspiration) and this can trigger profuse coughing.
Any respiratory tract infection that leads to coughing could also lead to vomiting. These are some of the infectious conditions where it may be seen.
- Pertussis (whooping cough) is a respiratory tract infection caused by the bacterium Bordetella pertussis. Severe coughing is a symptom of the second phase of the disease even when there are no other symptoms.
- Pulmonary tuberculosis is a lung infection caused by Mycobacterium tuberculosis. It is a serious chronic lung disease that can lead to death. Weight loss, night sweats and a bloody cough are some of the other symptoms.
- Influenza (flu) is a viral infection that may cause a dry cough. Usually it is not severe enough to trigger vomiting. However, viral gastroenteritis may sometimes occur with or soon after the flu and vomiting is a common symptom of gastroenteritis.
- Acute bronchitis is a common respiratory tract infection that involves the bronchi and is caused by viruses or bacteria. It often arises with or immediately after the flu. The persistent productive cough can sometimes lead to vomiting in severe cases.
There are many non-infectious conditions that can cause coughing and vomiting. These are some of the more common conditions.
- Asthma is a common airway disease particularly in children. The airways may constrict for variable periods of time in response to certain triggers like allergens, airborne irritants, stress and cold. Coughing may sometimes be prominent which can lead to vomiting.
- Bronchiectasis is an abnormal widening and weakening of the airway walls. Although many non-infectious conditions can cause it, bronchiectasis is often caused by severe respiratory tract infections like tuberculosis.
- Post nasal drip is a nasal condition where excessive nasal mucus drips down to the back of the throat. It may then trigger coughing due to the throat irritation. Usually it is a shallow cough but persistent coughing can sometimes trigger vomiting.
- Chronic obstructive pulmonary disease (COPD) is an irreversible airway disease often associated with tobacco smoking. Persistent coughing is a major symptom in chronic bronchitis.
- Gastroesophageal reflux disease (GERD) is where the acidic stomach contents flow backwards into the esophagus and sometimes reaches the mouth. It can cause coughing when it irritates the throat or enters the airways. Usually the contents are regurgitated and not vomited out.
- Iatrogenic causes refer to pharmaceutical drugs that may cause certain conditions. Some medication may cause coughing and vomiting as a side effect.
- Tobacco smoking especially when in excess over a short time period can cause coughing due to the irritation to the airways. The high levels of nicotine and other chemicals in the bloodstream may cause nausea which could lead to vomiting.