Causes of Nausea and Vomiting
Nausea and vomiting can be caused by numerous conditions including gastrointestinal disorders, medications, metabolic abnormalities, and central nervous system disorders, requiring a systematic approach to identify the underlying etiology. 1
Common Causes of Nausea and Vomiting
Gastrointestinal Causes
- Functional dyspepsia (25-40% of cases) 1
- Gastroenteritis or viral syndromes 2
- Constipation (particularly with opioid use) 1
- Gastrointestinal obstruction 3
- Gastroparesis 1
- Gastroesophageal reflux disease 4
- Peptic ulcer disease 4
- Cholecystitis 4
Medication-Related Causes
- Chemotherapy (affects 70-80% of cancer patients) 3, 1
- Opioids (common cause requiring prophylactic management) 1
- Antibiotics and antifungals 3, 1
- Radiosensitizers 3
Metabolic and Endocrine Causes
Central Nervous System Causes
Other Causes
- Radiation therapy 5
- Psychiatric disorders 5, 6
- Toxin exposure 5
- Paraneoplastic syndromes 3
- Cachexia syndrome 3
Temporal Classification of Nausea and Vomiting
Acute Nausea and Vomiting
- Lasts up to 7 days 2
- Often self-limited
- Typically treated symptomatically without extensive evaluation in the absence of alarm symptoms 2
Chronic Nausea and Vomiting
- Persists for 4 weeks or longer 6
- Requires more extensive evaluation
- Often more challenging to treat than acute symptoms 2
Chemotherapy-Related Nausea and Vomiting
- Acute: Initial 24 hours after chemotherapy 3
- Delayed: Later than 24 hours after chemotherapy 3
- Anticipatory: Days to hours before chemotherapy 3
Pathophysiology Insights
Nausea and vomiting involve multiple neuroreceptors including:
- Serotonin (5-HT3) receptors 3
- Dopamine receptors 3, 7
- Corticosteroid receptors 3
- Neurokinin-1 receptors 3
Metoclopramide, a commonly used antiemetic, works by:
- Antagonizing central and peripheral dopamine receptors 7
- Blocking stimulation of the chemoreceptor trigger zone (CTZ) 7
- Increasing gastric motility and accelerating gastric emptying 7
Alarm Signs Requiring Immediate Attention
- Bilious emesis (sign of intestinal obstruction until proven otherwise) 8
- Signs of dehydration 5
- Acidosis from underlying metabolic disorder 5
- Acute abdomen 5
- Significant headache (possible intracranial process) 5
Important Clinical Considerations
- Mechanical obstruction should not be missed, as antiemetics will not resolve the underlying condition 1
- Metoclopramide should be avoided in patients with Parkinson's disease or history of tardive dyskinesia 1
- Drug interactions should be considered when managing nausea and vomiting 1
- In cancer patients, routine assessment of nausea and vomiting symptoms is recommended at every outpatient visit and within 24 hours after inpatient admission 3
Understanding the diverse causes of nausea and vomiting is essential for appropriate diagnosis and management, ultimately improving patient outcomes and quality of life.