<unk>  and vomiting may have a number of causes in people with cancer. While more than one cause may exist in the same person stimulating symptoms via more than one pathway, the actual cause of<unk>  and vomiting may be unknown in some people. The underlying causes of<unk>  and vomiting may in some cases not be directly related to the cancer. The causes may be categorized as disease-related and treatment-related. The stimuli which lead to emesis are received and processed in the brain. It is thought that a number of loosely organized neuronal networks within the medulla oblongata probably interact to coordinate the emetic reflex. Some of the brain stem nuclei which have been identified as important in the coordination of the emetic reflex include the parvicellular reticular formation, the Bötzinger complex and the nucleus tractus solitarii. The nuclei coordinating emesis had formerly been referred to as the vomiting complex, but it is no longer thought to represent a single anatomical structure. Efferent outputs which transmit the information from the brain leading to the motoric response of retching and vomiting include vagal efferents to the esophagus, stomach and intestine as well as spinal somatomotor neurones to the abdominal muscles and phrenic motor neurones (C3–C5) to the diaphragm. Autonomic efferents also supply the heart and airways (vagus), salivary glands (chorda tympani) and skin and are responsible for many of the prodromal signs such as salivation and skin pallor.<unk>  and vomiting may be initiated by various stimuli, through different neuronal pathways. A stimulus may act on more than one pathway. Stimuli and pathways include: * Toxic substances in the gastrointestinal tract: toxic substances (including drugs which are used in the treatment of cancer) in the lumen of the gastrointestinal tract stimulate vagal afferent nerves in the gut mucosa which communicate to the nucleus tractus solitarii and the area postrema to initiate vomiting and<unk> . A number of receptors on the terminal ends of the vagal afferent nerves have been identified as being involved in this process, including the 5-hydroxytryptamine3 (5-HT3), neurokinin-1, and cholecystokinin-1 receptors. Various local mediators located in enterochromaffin cells of the gut mucosa play a role in stimulating these receptors. Of these 5-hydroxytryptamine seems to play the dominating role. This pathway has been postulated to be the mechanism by which some anti-cancer drugs such as cisplatin induce emesis. * Toxic substances in the blood: toxic substances which have been absorbed into the blood (including cytostatics) or endogenous toxic (waste) material released by body or cancer cells into the blood can be detected directly in the area postrema of the brain and trigger the emetic reflex. The area postrema is a structure located on the floor of the fourth ventricle around which the blood-brain barrier is permeable, thus allowing for the detection of humoral or pharmacological stimuli in the blood or cerebrospinal fluid. This structure contains receptors which form a chemoreceptor trigger zone. Some of the receptors and neurotransmitters involved in the regulation of this emetic pathway include dopamine type D2, serotonin types 2–4 (5HT2–4), histamine type 1(H1), and acetylcholine (muscarinic receptors type 1 to 5, M1–5). Some other receptors such as substance P, cannabinoid type 1 (CB1) and the endogenous opioids may also be involved. * Pathological conditions of the gastrointestinal tract: diseases and pathological conditions of the GIT may also lead to<unk>  and vomiting through direct or indirect stimulation of the above named pathways. Such conditions may include malignant bowel obstruction, hypertrophic pyloric stenosis and gastritis. Pathological conditions in other organs which are linked to the above named emetic pathways may also lead to<unk>  and vomiting, such as the myocardial infarction (through stimulation of cardiac vagal afferents) and kidney failure. * Stimulation of the central nervous system: certain stimuli of the central nervous system may induce the emetic reflex. These include fear, anticipation, brain trauma and increased intra-cranial pressure. Of particular relevance to cancer patients in this regard are the stimuli of fear and anticipation. Evidence suggests that cancer patients may develop the side effects of<unk>  and vomiting in anticipation of chemotherapy. In some patients, re-exposure to cues such as smell, sounds or sight associated with the clinic or previous treatment may evoke anticipatory<unk>  and vomiting. * Pathological conditions of the vestibular system: a disturbance of the vestibular system such as in motion sickness or Meniere's disease can induce the emetic reflex. Such disturbances of the vestibular system could also be cancer related such as in cerebral or vestibular secondaries (metastasis), or cancer treatment related such as the use of opioids.
Cancer and nausea
symptoms of Peptic ulcer disease
Diabetes and pregnancy
Old age and driving
symptoms of Gastrointestinal bleeding
symptoms of Pancreatitis
symptoms of Diverticulitis
Cancer signs and symptoms