Nausea and vomiting are usually two clinical terms that goes hand in hand. This is because nausea can lead to vomiting and the vice-versa is true. These occur as symptoms for an underlying illness.

Nausea is the sensation or desire to vomit whereas vomiting is the act of forcible emptying of the stomach.

During vomiting, the stomach overcomes pressures that prevent throw-up or return of stomach contents such as food materials and stomach secretions.

When you look at someone vomiting, you realise the abdominal muscles movements due to inward and outward pressures to force the lower portion of the esophagus to open or sphincter at the junction of esophagus and stomach to open. The esophagus is anatomical tube that connects mouth and stomach.

There are many health problems that can prompt you to vomit. The commonest illnesses that force people to vomit include brain illnesses or central causes that are usually signals from the brain. This is why headache, especially in the migraine form, is commonly associated with nausea and vomiting.

Vomiting is one of the commonest symptoms people with brain lesions or tumors or even trauma or even physiological changes such as raised intra-cranial pressure present, especially at early diagnosis of the disease.

Diseases of the stomach such as gastritis, especially acute gastritis, gastro-esophageal reflux prompt patients to vomit so often. 

Ingestion of irritative substance through the mouth can force people to throw-up. These substances can be in form of food, liquid form or even medications. 

Mechanical bowel obstruction is one of the commonest lower gastro-intestinal illnesses that prompt patients to vomit.

Some people are affected by noxious stimulus such as bad smells or abnormal sounds that can cause centrally mediated nausea and vomiting to occur. 

There are also vasovagal events that can bring about significant nausea and vomiting sensations. Such events can rise from a broken bone or the emotional shock of observing a horrible event. 

In a vasovagal episode, the vagus nerve which helps in control of basic body functions such as the heart beat, breathing and blood pressure becomes over-stimulated. Under vasovagal events, the heart beat slows down and blood vessels dilate. This subsequently decreases the blood flow to the brain that can lead to syncope or sudden loss of consciousness and sometimes death.  

People with poorly controlled chronic health problems such as diabetes, hypertension tend to feel nauseated and sometimes can vomit or throw-up.

People with diabetes can develop nausea due to gastro paresis. This condition occurs when the stomach fails to empty properly due to generalised neuropathy or failure of the autonomic nervous system to send proper signals to and from the brain. 

In our daily clinical practice, patients usually present with generalised body weakness, nausea and sometimes vomiting as manifestations of disease complication. 

People with diabetes develop nausea and vomiting when their blood sugars become abnormally high (hyperglycemia) or low blood sugar ( hypoglycemia). Nausea and vomiting in diabetics rise from the disturbance of blood sugar and body insulin balance.

Various illnesses of intra-abdominal organs manifest with nausea and vomiting especially in acute form. Such illnesses may include acute hepatitis, gallbladder disease, pancreatitis,  inflammatory bowel disease,  kidney diseases (for example, kidney stones, infection, kidney failure), some forms of cancer.

Heart attack victims may experience nausea and vomiting as an atypical presentation of angina, especially if the myocardial infarction affects the inferior or lower part of the heart.

Lung infections, for example, pneumonia and bronchitis may also cause nausea and vomiting, especially if the area of lung involved is near the diaphragm, the muscle that separates the chest form the abdomen.

Sepsis, an overwhelming body infection spread through the bloodstream may also be associated with nausea and vomiting. 

Side effects from medications such as anti-cancer dugs are notorious irritants. 

Dr Joseph Kamugishais a resident oncologist at Jerusalem Hospital, Israel