Causes of nausea and vomiting:

 

Common causes of nausea and vomiting includes:

 

​​​ 1. Drugs (opioid, antibiotics,iron, NSAIDs and digoxin)

 

 2. Toxic (cancer treatment)

 

 3. Metabolic (hypercalcaemia, renal impairment)

 

4. GI (intestinal obstruction and gastric stasis)

 

 5. Anxiety and fear

 

 

 

 

 Toxic

 

Cancer treatments such as chemotherapy and radiotherapy may damage or irritate mucosal lining of the GI tract to cause release of various neurotransmitters. Although no single mediator is responsible for directly causing vomiting, it should be noted that the GI tract contains 80% of 5-hydroxytryptamine (also known as serotonin) within the body.

 

It therefore has been postulated that 5-HT is released upon damage from enterochromaffin cells of GI tract. This stimulates the vagal and splachnic nerve to carry impulse to the area postrema of the brain resulting in emesis. 

 

Other theories regarding the cause of vomiting include taste alteration which occurs during cancer treatment. It is suggested that the perception of taste inhibits activities which is undesirable during ingestion of food such as nausea, pain and vomiting. However during cancer treatment, taste may be impaired and as a result  there is a lack of inhibition of those activities, therefore nausea and vomiting may be experienced by patients.

 

 

 

Metabolic

 

 Renal impairment, liver failure or hypercalcaemia causes the accumlation of toxins and emotogenic substances within the plasma. This circulates around the body and due to the location of the CTZ being outisde of blood brain barrier,it is exposed to toxins and this results in the activation of the CTZ which subsequently activates the VC.