What causes nausea?

Common Causes of Nausea

Nausea can be caused by multiple conditions including gastrointestinal disorders, medication side effects, chemotherapy, radiation therapy, hypercalcemia, constipation, bowel obstruction, and opioid use. 1 Understanding these causes is essential for effective management and improving patient quality of life.

Gastrointestinal Causes

• Gastritis/GERD: Treatable with proton pump inhibitors or H2 receptor antagonists 1
• Gastric outlet obstruction: May benefit from corticosteroids, endoscopic stenting, or G-tube decompression 1
• Bowel obstruction: May require surgical intervention or palliative management with medications like olanzapine 1
• Constipation: Common cause of nausea, especially in patients on opioids 1
• Gastroenteritis: Common cause of acute nausea and vomiting 2

Medication-Related Causes

• Opioid-induced nausea: Affects many patients on pain management 1
• Chemotherapy-induced nausea: Major impact on quality of life 1
• Other medications: Common culprits include:
  • Digoxin
  • Phenytoin
  • Carbamazepine
  • Tricyclic antidepressants 1
  • Medications with anticholinergic properties 2

Metabolic/Systemic Causes

• Hypercalcemia: Can trigger nausea and requires specific treatment 1
• Pregnancy: Early pregnancy is a common cause of nausea 2
• CNS pathology: Brain metastases or other neurological disorders 1, 2

Other Notable Causes

• Anxiety disorders: Strongest risk factor for nausea in community studies (OR 3.42) 3
• Depression: Also increases risk of nausea (OR 1.47) 3
• Vestibular disturbances: Motion sickness and other vestibular disorders 2
• Radiation therapy: Common side effect of treatment 1

Diagnostic Approach

When evaluating nausea:

1. Determine if acute (≤7 days) or chronic (≥4 weeks) 2, 4
2. Assess for alarm symptoms requiring urgent evaluation
3. Review medication list thoroughly
4. Consider timing of symptoms in relation to meals
5. Evaluate for associated symptoms that may suggest specific causes

Management Considerations

Management should target the underlying cause:

• Gastritis/GERD: Proton pump inhibitors, H2 receptor antagonists 1
• Medication-induced: Consider dose reduction, medication change, or prophylactic antiemetics 1
• Opioid-induced: Prophylactic antiemetics, opioid rotation if persistent 1
• Nonspecific nausea:
  • Dopamine receptor antagonists (prochlorperazine, haloperidol, metoclopramide, olanzapine)
  • Benzodiazepines for anxiety-related nausea 1
  • Metoclopramide has the strongest evidence for non-chemotherapy related nausea 1

Pitfalls to Avoid

• Failing to check medication side effects as a potential cause
• Overlooking constipation as a common and treatable cause of nausea
• Not considering anxiety and depression, which are significant risk factors
• Focusing only on gastrointestinal causes when the etiology may be neurological, metabolic, or psychiatric
• Using multiple antiemetic medications without targeting the specific cause

The prevalence of nausea in the community is approximately 12%, making it a common symptom that significantly impacts quality of life 3. Proper identification of the underlying cause is essential for effective management and symptom relief.