Nausea is a subjective sensation of impending vomiting or profound gastrointestinal discomfort, often accompanied by autonomic signs such as hypersalivation, diaphoresis, tachycardia, pallor, and tachypnea. It frequently occurs with anorexia and vomiting and is a common symptom in gastrointestinal, metabolic, endocrine, infectious, neurological, cardiac, and drug-related disorders. Nausea is also common in early pregnancy, with additional triggers including pain, anxiety, alcohol intake, overeating, or ingestion of unpleasant substances.

Pathophysiology

Nausea arises from complex interactions between the central nervous system, the gastrointestinal tract, and the autonomic nervous system. Key mechanisms include:

1. Gastrointestinal stimuli: Stretch receptors, chemoreceptors, and visceral afferents in the stomach and intestines signal the vomiting center in the medulla.

2. Central nervous system activation: The chemoreceptor trigger zone (CTZ) in the area postrema responds to circulating toxins, drugs, and metabolic disturbances.

3. Vestibular input: Disorders of the inner ear (e.g., labyrinthitis, Ménière’s disease) stimulate the vomiting center via the vestibular nuclei.

4. Autonomic response: Sympathetic and parasympathetic activation produces pallor, diaphoresis, tachycardia, hypersalivation, and tachypnea.

5. Hormonal and metabolic influences: Pregnancy hormones, adrenal insufficiency, metabolic acidosis, and electrolyte imbalances can trigger nausea through direct CNS or gastrointestinal effects.

Emergency interventions

• Assess airway, breathing, and circulation in patients with severe nausea and vomiting.

• Monitor vital signs for hypotension, tachycardia, and dehydration.

• Correct fluid and electrolyte imbalances using IV fluids when necessary.

• Administer antiemetics such as ondansetron, metoclopramide, or promethazine.

• Prepare for diagnostic evaluation (e.g., imaging, labs) in acute or unexplained cases.

• Elevate the head of the bed or position the patient side-lying to prevent aspiration.

History and physical examination

• Obtain detailed medical history focusing on GI, endocrine, metabolic, infectious, and neurological disorders.

• Ask about drug use, alcohol consumption, pregnancy, and exposure to toxins or surgery.

• Clarify onset, duration, frequency, triggers, and relief factors for nausea.

• Evaluate associated symptoms: vomiting (color, volume), abdominal pain, anorexia, weight loss, bloating, belching, bowel habit changes, or diarrhea.

• Physical exam: Inspect skin and mucosa for jaundice, bruising, pallor, spider angiomas.

• Abdominal exam: Inspect, auscultate, palpate, and percuss for tenderness, rigidity, organomegaly, and bowel sounds.

• Assess neurological and systemic signs as relevant.

Medical causes

Other Causes

• Medications: Antineoplastics, opioids, ferrous sulfate, levodopa, potassium, estrogens, antibiotics, NSAIDs.

• Herbal remedies: Ginkgo biloba, St. John’s wort.

• Radiation & surgery: Postoperative or radiotherapy-induced nausea.

Special considerations

• Evaluate fluid, electrolyte, and acid-base status.

• Maintain fresh air in patient’s room and remove emesis promptly.

• Keep patient upright or side-lying to prevent aspiration.

• Administer pain relief promptly; consider parenteral or suppository routes.

• Monitor for gastric retention if antiemetics are used; insert nasogastric tube as required.

• Prepare for diagnostic procedures: CT scan, ultrasound, endoscopy, colonoscopy.

• Consult nutritionist for metabolic demands and parenteral nutrition if needed.

Patient counseling

• Discuss triggers and avoidance strategies.

• Advise on hydration and nutrition.

• Explain medications, procedures, and monitoring.

• Encourage early reporting of persistent or worsening symptoms.

Pediatric pointers

• Common in children as stomachache or post-overeating symptom.

• May result from infection, GI disorders, or psychological stress.

• Monitor hydration and signs of electrolyte imbalance.

Geriatric pointers

• Contributing factors: tooth loss, reduced saliva, decreased gastric motility, diminished taste/smell.

• Monitor for dehydration, electrolyte disturbances, and drug interactions.

References

1. Berkowitz, C. D. (2012). Berkowitz’s Pediatrics: A Primary Care Approach (4th ed.). USA: American Academy of Pediatrics.

2. Buttaro, T. M., Tybulski, J., Bailey, P. P., & Sandberg-Cook, J. (2008). Primary Care: A Collaborative Practice (pp. 444–447). St. Louis, MO: Mosby Elsevier.

3. Colyar, M. R. (2003). Well-Child Assessment for Primary Care Providers. Philadelphia, PA: F.A. Davis.

4. Lehne, R. A. (2010). Pharmacology for Nursing Care (7th ed.). St. Louis, MO: Saunders Elsevier.

5. McCance, K. L., Huether, S. E., Brashers, V. L., & Rote, N. S. (2010). Pathophysiology: The Biologic Basis for Disease in Adults and Children. Maryland Heights, MO: Mosby Elsevier.

6. Sommers, M. S., & Brunner, L. S. (2012). Pocket Diseases. Philadelphia, PA: F.A. Davis.