Medical Causes of Chronic Vomiting
Chronic vomiting (lasting ≥4 weeks) has diverse etiologies spanning gastrointestinal, metabolic, neurologic, psychiatric, and medication-related causes, requiring systematic evaluation to identify the underlying disorder and guide targeted therapy. 1, 2
Gastrointestinal Causes
Functional and Motility Disorders
- Cyclic Vomiting Syndrome (CVS) presents with stereotypical episodes of acute-onset vomiting lasting <1 week, with at least 3 discrete episodes in the previous year and 2 episodes in the past 6 months, occurring at least 1 week apart, with absence of vomiting between episodes 3, 4
- Gastroparesis causes delayed gastric emptying, though gastric emptying scans should not be ordered routinely in suspected CVS as few patients have delayed emptying and results during episodes are uninterpretable 3
- Chronic nausea and vomiting syndrome can occur with normal gastric emptying 2
Structural and Obstructive Lesions
- Mechanical obstruction from strictures, adhesions, or masses requires exclusion via one-time esophagogastroduodenoscopy or upper gastrointestinal imaging 3
- Mucosal lesions of the upper gastrointestinal tract are among the most common causes of chronic vomiting 5
- Repeated endoscopy or imaging should be avoided once obstruction is excluded 3
Cannabis-Related Causes
Cannabinoid Hyperemesis Syndrome (CHS)
- CHS is considered a subset of CVS when prolonged (>1 year) and heavy cannabis use (≥4 times weekly, often daily) precedes symptom onset 3, 4
- Diagnosis requires 6 months of cannabis cessation or at least 3 typical cycle lengths; continued vomiting after this period rules out CHS 3
- Hot water bathing behavior is reported by 44% of CVS patients and is augmented by cannabis use 4
Cannabinoid Withdrawal Syndrome
- Occurs commonly with cessation of heavy and prolonged cannabis use, with a pooled prevalence of 47% among cannabis users 4
Metabolic and Endocrine Causes
Specific Conditions to Exclude
- Addison's disease (adrenal insufficiency) can mimic CVS and requires specific workup 3
- Hypothyroidism should be evaluated in the differential diagnosis 3
- Hepatic porphyria can present with episodic vomiting similar to CVS 3
- Pregnancy is the most common endocrinologic cause and must be considered in any woman of childbearing age 6
- Various metabolic abnormalities including electrolyte disturbances 6
Neurologic Causes
- Increased intracranial pressure from any etiology typically causes other neurologic signs 6
- Migraine headaches are associated with CVS, with history or family history of migraines being a supportive criterion 4
- Patients with any localizing neurologic symptoms should undergo brain imaging and neurologist referral 3
- Diseases affecting neural control of gut motility 5
Medication and Toxin-Related Causes
- Iatrogenic causes from medications are common and can be resolved by removing the offending agent 6
- Opiates complicate interpretation of gastric emptying studies and affect motility 3
- Medication side effects should always be suspected in chronic vomiting 7
Psychiatric Causes
- Psychogenic disorders are among the most common causes of chronic vomiting 5
- Anxiety and depression are comorbid conditions associated with CVS that require addressing 3
- Psychiatric diagnoses may directly cause nausea and vomiting 6
Infectious Causes
- While gastrointestinal infections are the most common cause of acute nausea and vomiting, chronic infectious etiologies should be considered 7, 6
Initial Diagnostic Workup
Essential Laboratory Testing
- Complete blood count, serum electrolytes and glucose, liver function tests, and lipase should be obtained 3
- Urinalysis is part of the basic workup 3
Imaging Considerations
- One-time esophagogastroduodenoscopy or upper GI imaging effectively excludes obstructive lesions 3
- If endoscopy is performed soon after a CVS episode, recognize epiphenomena of recent vomiting (mild gastritis, erythematous streaking, Mallory-Weiss tear, esophagitis) as not causal 3
Common Pitfalls
- Avoid repeated endoscopy or imaging once structural causes are excluded 3
- Do not routinely order gastric emptying scans in suspected CVS 3
- Cannabis or opiate use invalidates gastric emptying study interpretation 3