The medical abbreviation N/V describes the closely linked symptoms of Nausea and Vomiting, which are frequently documented together in healthcare settings. While often grouped, they are two distinct physical experiences that serve as generalized warning signals. Nausea is a subjective feeling, whereas vomiting is an objective, motor action.
Defining Nausea
Nausea is the unpleasant, wave-like sensation often felt in the throat, mouth, or stomach, creating a strong desire to vomit. This sensation is a neurological signal mediated by afferent nerve pathways, such as the vagus nerve, which relay information from the gastrointestinal tract to the brainstem. Physiologically, nausea is often accompanied by decreased propulsive movements of the stomach, known as gastric motility. This feeling acts as a defense mechanism, signaling a potential threat, such as an ingested toxin or systemic imbalance.
Defining Vomiting (Emesis)
Vomiting, also referred to as emesis, is the active, forceful expulsion of the contents of the stomach, and sometimes the small intestine, through the mouth. This process is a complex, coordinated protective reflex controlled by a central pattern generator in the brainstem. The physical act begins with a deep breath and the closure of the glottis to protect the lungs from aspiration. The reflex requires the relaxation of the lower esophageal sphincter, which normally keeps stomach contents contained. Expulsion is achieved through the coordinated contraction of the diaphragm and the abdominal wall muscles, which drastically increases intra-abdominal pressure, forcing the stomach contents upward and out.
Common Triggers of N/V
Nausea and vomiting can be initiated by a wide array of stimuli that feed into the brain’s emetic center. Gastrointestinal issues are common sources, including infectious gastroenteritis, food poisoning, and mechanical irritation or distension of the stomach and intestines. These triggers activate chemoreceptors and mechanoreceptors in the gut lining, sending signals via the vagal nerve to the brain.
Other causes are systemic and neurological, such as motion sickness, which stimulates the vestibular system of the inner ear. Certain medications, notably chemotherapy agents and opioids, can cause N/V by stimulating the chemoreceptor trigger zone (CTZ). Because the CTZ is located outside the blood-brain barrier, it is sensitive to circulating toxins or chemicals in the bloodstream.
When N/V Requires Medical Attention
While N/V is often temporary, certain accompanying symptoms suggest a more serious underlying health issue that warrants prompt medical evaluation. Signs of severe dehydration, such as excessive thirst, lack of urination, dry mouth, or dizziness when standing, require attention. Dehydration can rapidly become severe when a person is unable to keep down even small sips of fluid.
The presence of blood in the expelled contents is a serious indicator, whether it is bright red or has a dark, granular “coffee ground” appearance. Other concerning indicators include vomiting that lasts longer than 24 to 48 hours, or N/V accompanied by a high fever, severe abdominal pain, confusion, or a stiff neck. These signs suggest complications ranging from internal bleeding to neurological infection.