What is the appropriate evaluation and management for a patient with chronic vomiting?

Chronic Vomiting: Evaluation and Management

Initial Diagnostic Workup

Begin with basic laboratory studies including complete blood count, serum electrolytes, glucose, liver function tests, lipase, and urinalysis, followed by one-time esophagogastroduodenoscopy to exclude obstructive lesions. 1

• Prolonged vomiting causes hypokalemia, hypochloremia, and metabolic alkalosis that must be corrected immediately. 1
• Check for hypercalcemia, hypothyroidism, and adrenal insufficiency if clinically indicated. 1
• Perform gastric emptying scintigraphy (2-4 hour study) only if gastroparesis is specifically suspected based on postprandial symptom worsening. 1, 2
• Avoid repeated endoscopy or imaging studies unless new symptoms develop. 1

Critical First Step: Cannabis Screening

Screen all patients for cannabis use patterns before proceeding with any diagnosis, as use >4 times weekly for >1 year suggests cannabinoid hyperemesis syndrome (CHS) rather than cyclic vomiting syndrome (CVS). 1, 3

• Hot water bathing occurs in 71% of CHS patients but also in 48% of CVS patients without cannabis exposure, so this behavior alone does not confirm CHS. 3
• CHS requires 6 months of cannabis cessation (or at least 3 typical cycle lengths) to retrospectively diagnose. 1
• If cannabis use criteria are met, change the working diagnosis from CVS to CHS—definitive treatment requires cessation of cannabis use. 3

Determining the Pattern: CVS vs Continuous Symptoms

Cyclic Vomiting Syndrome should be strongly suspected if the patient has stereotypical episodes of acute-onset vomiting lasting <7 days, at least 3 discrete episodes in the past year (with 2 occurring in the prior 6 months), and episodes separated by at least 1 week of baseline health. 1, 3

• Approximately 65% of CVS patients experience prodromal symptoms including impending sense of doom, panic, fatigue, mental fog, restlessness, anxiety, headache, bowel urgency, diaphoresis, or flushing. 1, 3
• Each patient exhibits a highly stereotyped pattern—identical timing, duration, and associated symptoms that repeat with every episode. 3
• Most episodes occur in early morning hours. 3
• Abdominal pain is present in most CVS patients and should not exclude the diagnosis. 3
• Episodic patterns suggest CVS, while continuous symptoms suggest chronic nausea vomiting syndrome. 2

Severity Classification for CVS

Classify CVS severity to determine treatment intensity:

• Mild CVS: <4 episodes/year, each lasting <2 days, no ED visits or hospitalizations—requires abortive therapy only. 3
• Moderate-severe CVS: ≥4 episodes/year, lasting >2 days, requiring ED visits or hospitalizations—requires both prophylactic and abortive therapy. 3

Treatment Approach for Moderate-Severe CVS

Initiate amitriptyline as first-line prophylactic therapy, starting 25 mg at bedtime and titrating to 75-150 mg nightly (1-1.5 mg/kg). 1, 3

• Response rate to amitriptyline is 67-75%. 1, 3
• Obtain baseline ECG due to QTc prolongation risk. 1, 3
• Titrate slowly by 10-25 mg every 2 weeks to optimize tolerability. 3
• Administer at night to reduce daytime sedation and anticholinergic effects (dry mouth, blurred vision, constipation, weight gain). 3

Second-Line Prophylactic Options

• Topiramate: Start 25 mg daily, titrate to 100-150 mg daily in divided doses; monitor electrolytes and renal function twice yearly. 3
• Levetiracetam: Start 500 mg twice daily, titrate to 1000-2000 mg daily in divided doses; monitor CBC. 3
• Zonisamide: Start 100 mg daily, titrate to 200-400 mg daily; monitor electrolytes and renal function twice yearly. 3

Abortive Therapy Education

Educate patients to recognize their stereotypical prodromal symptoms and take abortive medications immediately—the probability of successfully aborting an episode is highest when medications are taken at the onset of prodromal symptoms. 1, 3

• Standard abortive regimen: Sumatriptan 20 mg intranasal spray + ondansetron 8 mg sublingual. 1, 3
• Sumatriptan can be repeated once after 2 hours, maximum 2 doses per 24 hours. 3
• Ondansetron can be given every 4-6 hours during the episode. 3
• Administer sumatriptan in a head-forward position to optimize medication contact with anterior nasal receptors. 3

Additional Abortive Agents

• Promethazine: 12.5-25 mg oral/rectal every 4-6 hours. 3
• Prochlorperazine: 5-10 mg every 6-8 hours or 25 mg suppository every 12 hours. 3
• Sedatives (alprazolam, lorazepam, diphenhydramine) can truncate episodes but use with caution in patients with substance abuse risk. 3

Emergency Department Management

For patients presenting in active emetic phase:

• Place patient immediately in a quiet, dark room to minimize sensory stimulation. 3
• Aggressive IV fluid replacement with dextrose-containing fluids for rehydration and metabolic support. 3
• Ondansetron 8 mg IV every 4-6 hours as first-line antiemetic. 3
• IV ketorolac 15-30 mg every 6 hours (maximum 5 days, daily maximum 120 mg) as first-line non-narcotic analgesia for severe abdominal pain. 3
• Droperidol or haloperidol for refractory cases. 3
• IV benzodiazepines for sedation. 3

Essential Lifestyle Modifications

All patients require:

• Regular sleep schedule, avoiding sleep deprivation. 1, 3
• Avoiding prolonged fasting. 1, 3
• Stress management techniques—stress is a trigger in 70-80% of CVS patients, including positive stressors like birthdays and vacations. 3
• Identifying and avoiding individual triggers (hormonal fluctuations, travel, motion sickness, acute infections, surgery, intense exercise). 3

Comorbidity Management

Screen for anxiety, depression, and panic disorder, as these are present in 50-60% of CVS patients, and treating underlying anxiety can decrease CVS episode frequency. 1, 3

• Migraine headaches occur in 20-30% of CVS patients. 3
• Postural orthostatic tachycardia syndrome (POTS) is observed in a substantial subgroup. 3
• Co-management with a psychologist or psychiatrist may be helpful for patients with lack of response to standard therapies or extensive psychiatric comorbidity. 4

Cannabinoid Hyperemesis Syndrome Management

For confirmed CHS (cannabis use >4 times weekly for >1 year):

• Counseling to achieve marijuana cessation is the mainstay of long-term therapy. 4
• Tricyclic antidepressants (amitriptyline 75-100 mg at bedtime, starting at 25 mg and titrating weekly) for long-term management. 4
• Topical capsaicin (0.1%) cream may improve symptoms by activation of transient receptor potential vanilloid type 1 receptors. 4
• Do not stigmatize patients using cannabis—offer treatment regardless of ongoing use while encouraging cessation. 1
• Combining evidence-based psychosocial interventions and pharmacology may be necessary for successful long-term management. 4

Critical Pitfalls to Avoid

Never use opioids in CVS or CHS patients because they worsen nausea and have a high potential for addiction. 4, 1, 3

• Never use antiemetics if mechanical bowel obstruction is suspected. 1
• Monitor for QTc prolongation with ondansetron, especially in patients with electrolyte abnormalities, congestive heart failure, or bradyarrhythmias. 1
• Provide thiamin supplementation to prevent Wernicke's encephalopathy in patients with persistent vomiting. 1
• Missing the prodromal window dramatically drops abortive therapy effectiveness. 3
• Do not misinterpret self-soothing behaviors (excessive water intake, self-induced vomiting) as malingering—these are characteristic coping mechanisms in CVS. 3
• Do not use abdominal pain as an exclusion criterion for CVS. 3
• Exercise caution with ketorolac in high-risk patients (over 60 years, compromised fluid status, nephrotoxic chemotherapy, history of peptic ulcer disease, significant alcohol use). 3

Special Populations

Coalescent CVS

• A distinct subgroup experiences progressively longer and more frequent episodes, eventually leading to daily nausea and vomiting with few asymptomatic days. 3
• Manage with prophylactic therapy comparable to moderate-severe CVS (amitriptyline). 3
• A thorough history typically reveals years of episodic nausea/vomiting preceding the coalescent phase. 3

Pregnancy

• In women of childbearing age, perform urine pregnancy testing to exclude pregnancy-related nausea. 3
• Nausea and vomiting of pregnancy affects up to 90% of pregnant women and is usually self-limited. 5