emeses

Emesis is the act of vomiting, a reflex that expels gastric contents through the mouth. The plural emeses is used in medical writing to refer to multiple vomiting episodes; in clinical practice, clinicians often describe vomiting as "episodes of emesis" or simply "vomiting." The term derives from Greek emesis (vomiting) via Latin.

Physiology: Vomiting is coordinated in the brainstem, primarily by the vomiting center in the medulla, with input from the chemoreceptor trigger zone and afferent signals from the gastrointestinal tract, the vestibular system, and higher brain centers. Activation produces reverse peristalsis, closure of the glottis, and coordinated abdominal and diaphragmatic contractions.

Causes and presentation: Emeses have numerous etiologies, including infectious gastroenteritis, pregnancy (hyperemesis), motion sickness, postoperative nausea, cytotoxic chemotherapy and other emetogenic drugs, alcohol, migraines, metabolic disorders, intracranial disease, and mechanical obstruction. Clinically, emesis may occur with or without nausea and can lead to dehydration and electrolyte disturbances. Hematemesis indicates possible upper gastrointestinal bleeding or mucosal injury; bilious emesis may suggest an intestinal obstruction proximal to the duodenum.

Evaluation and management: Evaluation aims to identify the cause and assess severity. Management includes fluid and electrolyte replacement, treating the underlying condition, and antiemetic therapy. Common agents include 5-HT3 receptor antagonists (ondansetron), dopamine antagonists (metoclopramide, prochlorperazine), and NK1 receptor antagonists (aprepitant). Therapy is tailored to the patient, pregnancy status, and contraindications. Severe or persistent emeses may require hospitalization.

See also: nausea, retching, regurgitation, hyperemesis gravidarum, cyclic vomiting syndrome. Etymology: from Greek emesis; emeses as plural form.