What are the typical causes of nausea?

Typical Causes of Nausea

Nausea arises from a diverse array of gastrointestinal, neurologic, metabolic, infectious, and medication-related etiologies, with the specific cause heavily dependent on whether symptoms are acute (≤7 days) or chronic (≥4 weeks) and the patient population involved.

Acute Nausea (≤7 Days)

In the absence of alarm symptoms, acute nausea is most commonly caused by self-limited viral gastroenteritis, foodborne illness, medication adverse effects, acute migraine, vestibular disturbances, or early pregnancy 1, 2.

Most Common Acute Causes:

• Viral gastroenteritis and other viral syndromes - typically presents with sudden onset, mild fever, diarrhea, and short duration 1
• Foodborne illness - consider timing relative to food ingestion 1
• Medication adverse effects - particularly with recent medication initiation 2
• Acute migraine headaches 1
• Vestibular disturbances (motion sickness, labyrinthitis) 1
• Early pregnancy - always check pregnancy status in reproductive-age women 2

Other Acute Causes to Consider:

• Surgical anesthesia and post-operative state 2
• Acute metabolic abnormalities (hypercalcemia, electrolyte disturbances) 3
• Toxin exposure 2
• Acute intracranial processes (if headache or neurologic signs present) 2

Chronic Nausea (≥4 Weeks)

Chronic nausea has a broader differential diagnosis requiring systematic evaluation, with gastrointestinal causes (particularly gastroparesis and functional dyspepsia) being most common, followed by medication effects, metabolic disorders, and psychiatric conditions 4.

Gastrointestinal Causes:

Gastroparesis and Dysmotility:

• Gastroparesis (delayed gastric emptying) - occurs in 20-40% of diabetic patients and 25-40% of functional dyspepsia patients 3
• Diabetic gastroparesis - represents vagal neuropathy, primarily in long-duration type 1 diabetes with other complications 3
• Idiopathic gastroparesis - may follow viral infection 3
• Medication-induced dysmotility - particularly opioids and anticholinergic agents 3

Obstructive Causes:

• Malignant bowel obstruction - common in advanced colorectal and ovarian cancer 3
• Gastric outlet obstruction 3
• Constipation and fecal impaction 3, 5

Mucosal Disease:

• Gastroesophageal reflux disease (GERD) - most common cause of recurrent vomiting in children 6
• Gastritis and peptic ulcer disease 5
• Gastric malignancies (in patients with risk factors) 4

Neurologic Causes:

• Brain metastases 3, 5
• Increased intracranial pressure (from tumor, trauma, or hydrocephalus) 3
• Vestibular disorders 4
• Cyclic vomiting syndrome 4

Metabolic and Endocrine Causes:

• Hypercalcemia 3, 5
• Electrolyte abnormalities 5
• Diabetes mellitus (both as cause of gastroparesis and via hyperglycemia-induced dysmotility) 3
• Adrenocortical disorders 3
• Thyroid disorders 2

Infectious Causes:

• Systemic infections (sepsis, pneumonia, otitis media, meningitis) 3
• Enteritis 3

Medication and Toxin-Related:

• Chemotherapy and radiation therapy - 70-80% of cancer patients on chemotherapy experience nausea/vomiting 3
• Opioid-induced nausea 3
• Anticholinergic medications 3
• Other medication adverse effects 3
• Toxic agents 3

Psychiatric Causes:

• Anxiety disorders - strongest risk factor for nausea in community samples (OR 3.42) 7
• Depression - also increases risk (OR 1.47) 7
• Functional disorders - 80-90% lifetime prevalence of anxiety/depression in functional GI disorder patients 7

Special Population Considerations

Infants and Neonates:

• Gastroesophageal reflux (GER) - most common cause, particularly in first weeks of life, often related to overfeeding 3
• Congenital GI abnormalities (malrotation with/without volvulus, atresia, annular pancreas, Hirschsprung disease) - consider when bilious emesis or forceful vomiting present in first week of life 3
• Hypertrophic pyloric stenosis - presents outside newborn period with projectile vomiting 3, 6
• Intussusception - unusual in first 3 months, presents with crampy pain and bloody stools 3
• Metabolic disorders (phenylketonuria, hyperammonemia, maple syrup urine disease, galactosemia) 3

Cancer Patients (Not Receiving Chemotherapy):

• Disease involving GI tract or abdomen 3
• Malignant bowel obstruction 3
• Brain metastases 3
• Metabolic abnormalities (hypercalcemia) 3

Critical Pitfalls to Avoid

• Bilious vomiting in infants/children represents a surgical emergency (malrotation with volvulus) until proven otherwise 6
• Do not dismiss chronic nausea as purely functional without excluding gastroparesis (requires gastric emptying study), malignancy (requires endoscopy if risk factors present), and metabolic causes 3, 4
• Always consider anxiety and depression as primary or contributing factors, particularly when other causes are not identified - anxiety carries the highest risk (OR 3.42) 7
• Medication review is essential - opioids, anticholinergics, and many other medications commonly cause nausea 3
• In cancer patients, distinguish between chemotherapy-induced nausea (requires specific antiemetic protocols) and other causes requiring different management 5