Nausea and Vomiting

Key considerations: Bowel obstruction, DKA, Acute coronary syndrome (atypical)

Cannot miss

history: Duration, frequency, character of emesis (bloody, bilious, non-bilious); Abdominal pain, diarrhea, fever (gastroenteritis); Last menstrual period — pregnancy; Medications: new meds, chemotherapy, opioids; Dietary history: sick contacts, undercooked food; Headache, visual changes (increased ICP); Vertigo, hearing changes (vestibular); History of diabetes (DKA), prior surgeries (obstruction); exam: Vital signs: dehydration markers (tachycardia, orthostatic, dry mucous membranes); Abdominal: distension, tenderness, bowel sounds, peritoneal signs; Neurological: mental status, papilledema, focal deficits; Skin turgor, mucous membrane moisture (hydration assessment); labs: BMP: electrolytes (hypokalemia, hyponatremia, metabolic alkalosis from vomiting); CBC: WBC (infection); Lipase (pancreatitis); LFTs (hepatitis, biliary); HCG (pregnancy); Urinalysis (UTI, DKA ketonuria); Blood glucose (DKA, hypoglycemia); Lactate if sepsis concern; imaging: CT abdomen: obstruction, mass, pancreatitis; KUB: air-fluid levels (obstruction); CT head: if neurological symptoms (increased ICP); bedside: Point-of-care glucose; Pregnancy test; Ultrasound: gallbladder if RUQ pain, bladder for retention

immediate: IV access and fluid resuscitation with normal saline; Antiemetics: ondansetron 4mg IV/ODT; Correct electrolytes: potassium, magnesium; NPO if surgical cause suspected; general: Treat underlying cause; Ondansetron 4mg IV/ODT q6h PRN; Metoclopramide 10mg IV if gastroparesis; Rehydration: IV fluids until able to tolerate PO; Dextrose-containing fluids if unable to eat; specific: diagnosis: Gastroenteritis; steps: IV fluids for dehydration; Ondansetron for symptom relief; Trial of oral fluids before discharge; Most viral — antibiotics not indicated unless bacterial suspected; diagnosis: Bowel Obstruction; steps: NPO, nasogastric tube decompression; IV fluid resuscitation; CT abdomen with contrast; Surgery consult; diagnosis: DKA; steps: Aggressive IV fluids (NS 1L/hr initially); Insulin drip 0.1 units/kg/hr; Potassium replacement (replace before insulin if K <3.3); Follow anion gap, glucose, potassium closely; diagnosis: Hyperemesis Gravidarum; steps: IV fluids with dextrose; Ondansetron or metoclopramide; Thiamine 100mg IV (prolonged vomiting depletes thiamine); OB follow-up

admit: Inability to tolerate PO after treatment; Surgical cause (obstruction, appendicitis); Severe electrolyte abnormalities; DKA; Intractable vomiting with dehydration; discharge: Tolerating PO fluids after treatment; Electrolytes corrected or stable; Clear etiology identified and treated; Return precautions: inability to keep fluids down, blood in emesis, severe pain, fever; consults: Surgery: obstruction, appendicitis; GI: refractory vomiting, cyclic vomiting syndrome; OB/GYN: hyperemesis gravidarum

Vomiting + headache = think increased ICP — always ask about neurological symptoms
Metabolic alkalosis with hypokalemia is classic for prolonged vomiting — replace K aggressively
Bilious vomiting means the obstruction is distal to the ampulla of Vater — get CT
Cyclic vomiting syndrome: often associated with cannabis use (cannabinoid hyperemesis) — hot showers provide relief
Pregnancy test in ALL women of reproductive age with nausea/vomiting — hyperemesis and ectopic pregnancy both present this way

ACEP Clinical Policy: Nausea and Vomiting 2021, UpToDate. Last reviewed: 2024-11-01