What could be causing morning vomiting in a male in his 20s?

Morning Vomiting in a Male in His 20s

The most critical first step is to determine whether this represents cyclic vomiting syndrome (CVS), cannabinoid hyperemesis syndrome (CHS), or another underlying disorder through detailed history of episode pattern, cannabis use, and associated symptoms. 1

Initial Diagnostic Approach

Key Historical Features to Elicit

Pattern Recognition:

• Stereotypical episodes lasting less than 7 days with at least 3 discrete episodes per year (2 in prior 6 months), separated by at least 1 week of baseline health, strongly suggest CVS 1
• Timing of onset: CVS episodes typically begin during night or early morning hours 2
• Associated symptoms: Look for pallor, lethargy, nausea, retching, and abdominal pain occurring together 2
• Return to baseline wellness between episodes is characteristic of CVS, though milder symptoms like occasional nausea may persist 1

Cannabis Use Assessment (Critical):

• Heavy, prolonged use (>4 times weekly, often daily, for >1 year) preceding symptom onset suggests CHS rather than CVS 1
• If cannabis use postdates vomiting onset or is occasional, CHS is unlikely 1
• Hot water bathing behavior provides temporary relief in approximately 48% of CVS patients who don't use cannabis, so this is NOT pathognomonic for CHS 1

Trigger Identification:

• Psychological stress (positive or negative events) triggers 70-80% of CVS episodes 1
• Sleep deprivation, menstrual cycle phases, travel, motion sickness, acute infections, or surgery are common triggers 1
• Prolonged fasting or intense exercise are less common triggers 1

Essential Workup

Basic Laboratory Testing:

• Complete blood count, serum electrolytes and glucose, liver function tests, lipase, and urinalysis to exclude metabolic and structural causes 1, 3
• Consider workup for Addison's disease, hypothyroidism, and hepatic porphyria if clinical suspicion exists, as these can mimic CVS 1

Imaging Considerations:

• One-time esophagogastroduodenoscopy or upper GI imaging to exclude obstructive lesions 1
• If performed soon after an episode, recognize that mild gastritis, erythematous streaking, Mallory-Weiss tears, or esophagitis are epiphenomena of recent vomiting, not causal 1
• Avoid repeated upper GI studies 1
• Do not routinely order gastric emptying scans—few CVS patients have delayed emptying, and results during episodes are uninterpretable, especially with cannabis or opiate use 1
• Brain imaging and neurology referral if any localizing neurologic symptoms present 1

Differential Diagnosis Beyond CVS/CHS

Comorbid Conditions to Screen For:

• Mood disorders (anxiety, depression, panic disorder) present in 50-60% of adult CVS patients 1
• Migraine headaches (20-30% of CVS patients) 1
• Postural orthostatic tachycardia syndrome and other autonomic imbalances 1
• Seizure disorders (approximately 3% of CVS patients) 1

Other Causes in Young Adults:

• Acute gastroenteritis or viral syndromes 3, 4
• Foodborne illness 3
• Acute migraine headaches 3
• Vestibular disturbances 3
• Medication adverse effects 3, 4
• Metabolic abnormalities, endocrine disorders, or toxin exposure 4

Management Strategy

If CVS is Diagnosed

Abortive Therapy (During Prodromal Phase):

• Sumatriptan 50-100 mg orally or 6 mg subcutaneously is first-line abortive therapy 1
• Ondansetron 8 mg sublingual every 4-6 hours during episodes 1
• Earlier intervention during the prodromal phase has higher probability of aborting an episode—patient education on recognizing this phase is imperative 1

Acute Episode Management:

• Sedatives: Lorazepam or alprazolam 0.5-2 mg every 4-6 hours 1
• Alternative antiemetics: Promethazine 12.5-25 mg every 4-6 hours or prochlorperazine 5-10 mg every 6-8 hours 1
• Note: Promethazine peripheral IV administration can cause tissue injury including gangrene 1

Prophylactic Therapy:

• Consider for moderate-severe CVS (≥4 episodes/year, each lasting >2 days, requiring ED visit or hospitalization) 1
• Prophylactic medications can be effective even with ongoing cannabis use 1

Cannabis Cessation Guidance

For Suspected CHS:

• 6 months or at least 3 typical cycle lengths of cannabis cessation required to retrospectively diagnose CHS 1
• If vomiting continues after this cessation period, CHS is ruled out 1
• Avoid stigmatizing patients—offer abortive and prophylactic therapy regardless of ongoing cannabis use uncertainty 1

Lifestyle Modifications

• Help patient identify and develop strategies to eliminate or mitigate triggers 1
• Address sleep deprivation and stress management 1
• Consider referral to neurology, psychiatry, or sleep specialist as indicated 1

Critical Pitfalls to Avoid

• Do not dismiss hot water bathing as diagnostic of CHS—it occurs in CVS without cannabis use 1
• Do not misconstrue excessive water drinking or self-induced vomiting as malingering—these are self-soothing behaviors specific to CVS 1
• Do not order gastric emptying studies routinely or during active episodes 1
• Do not repeat upper endoscopy or imaging without new clinical indication 1
• Do not withhold treatment from patients with ongoing cannabis use while diagnostic uncertainty exists 1