What is the best course of action for an adult patient with diabetes and hypertension, presenting with nausea, vomiting, abdominal pain, low-grade fever, tachycardia, and hypertension, who was recently hospitalized for similar symptoms suspected to be related to gastroparesis or THC syndrome?

Immediate Management of Acute Gastroparesis Exacerbation vs. Cannabinoid Hyperemesis Syndrome

This patient requires immediate differentiation between diabetic gastroparesis exacerbation and cannabinoid hyperemesis syndrome (CHS), followed by aggressive antiemetic therapy with IV metoclopramide 10 mg over 1-2 minutes, while simultaneously screening for cannabis use and assessing for acute complications requiring hospitalization. 1, 2

Critical First Steps: Distinguish Between Two Diagnoses

Screen for Cannabinoid Hyperemesis Syndrome

• Directly ask about cannabis use patterns, as CHS is rising in prevalence and frequently underdiagnosed, with many patients remaining uncertain about the role of cannabis and attributing symptoms to other causes 1
• Look for the pathognomonic feature of compulsive hot water bathing to relieve symptoms, which strongly suggests CHS over gastroparesis 1
• CHS typically presents with cyclical vomiting episodes rather than continuous symptoms, though overlap exists 1
• The differential diagnosis after excluding structural abnormalities includes rumination syndrome, gastroparesis, cyclic vomiting syndrome, and functional chronic nausea and vomiting syndrome 1

Assess for Acute Complications Requiring Immediate Intervention

• Evaluate for life-threatening disorders including acute abdomen, bowel obstruction, mesenteric ischemia, pancreatitis, and myocardial infarction, as these require immediate exclusion in the emergency setting 1
• Check for succussion splash on physical exam (suggestive of delayed gastric emptying or gastric outlet obstruction), digital ulcers and telangiectasia (scleroderma), and ascites or masses (underlying malignancy) 1
• Obtain complete blood count, liver chemistries, and basic metabolic profile if not recently performed 1
• The tachycardia (pulse 109) and hypertension (153/98) may reflect volume depletion, pain, or metabolic derangement requiring correction 1

Immediate Pharmacologic Management

First-Line IV Antiemetic Therapy

Administer IV metoclopramide 10 mg slowly over 1-2 minutes as the first-line treatment for acute vomiting in gastroparesis, providing both prokinetic and antiemetic effects 2

• Metoclopramide is the only FDA-approved medication specifically for diabetic gastroparesis and is indicated for relief of symptoms associated with acute and recurrent diabetic gastric stasis 2, 3
• The FDA label specifies that for severe symptoms of diabetic gastroparesis, therapy should begin with IV or IM metoclopramide injection, with administration up to 10 days potentially required before symptoms subside 2
• Monitor for extrapyramidal side effects and tardive dyskinesia, particularly with prolonged use beyond 12 weeks 4, 2

Alternative or Adjunctive Antiemetic Options

• Ondansetron 4-8 mg IV or granisetron 1 mg can be used as alternative first-line antiemetic therapy, effectively blocking serotonin receptors in the chemoreceptor trigger zone 4
• Prochlorperazine 5-10 mg IV provides alternative dopamine receptor blockade when 5-HT3 antagonists are insufficient 4
• If acute dystonic reactions occur with metoclopramide, inject 50 mg diphenhydramine (Benadryl) intramuscularly and symptoms usually subside 2

Critical Medication Avoidance

Absolutely avoid opioids as they worsen nausea and carry high addiction risk in gastroparesis patients 1

• Do not use GLP-1 receptor agonists if the patient is on them for diabetes, as they further delay gastric emptying and exacerbate symptoms 5, 4
• Avoid synthetic cannabinoids (dronabinol, nabilone) despite approval for chemotherapy-related nausea, as they may slow gastric emptying 4

Glycemic Control Assessment

Optimize glucose control immediately, as hyperglycemia itself causes antral hypomotility, gastric dysrhythmias, and delayed gastric emptying 1

• Diabetic gastroparesis represents a form of neuropathy involving the vagus nerve, occurring in 20-40% of patients with diabetes mellitus, primarily those with long duration of type 1 diabetes with other complications 1
• Poor glycemic control directly contributes to symptom severity and gastric emptying delay 1, 6

Disposition and Follow-Up Planning

If Cannabinoid Hyperemesis Syndrome is Confirmed

• Cannabis cessation is the definitive treatment, with counseling being the mainstay of long-term management 1
• Topical capsaicin (0.1%) cream may improve symptoms acutely by activation of transient receptor potential vanilloid type 1 receptors 1
• Tricyclic antidepressants (amitriptyline 75-100 mg at bedtime) are the mainstay of long-term therapy, starting at 25 mg and titrating weekly 1
• Co-management with psychology or psychiatry may be helpful, as anxiety and depression are very common associated conditions 1

If Gastroparesis Exacerbation is Confirmed

• Continue metoclopramide 5-20 mg three to four times daily after discharge, as it has sustained positive effect in placebo-controlled crossover trials 7
• Consider domperidone 10 mg three times daily as third-line option if metoclopramide fails, though it requires FDA investigational drug application 5, 4
• Dietary modifications including small particle-size, low-fat diet should be reinforced 1, 5
• If symptoms remain refractory after 18 months of appropriate medical therapy, gastric electrical stimulation (GES) may be considered for patients with nausea/vomiting predominant symptoms who are not on opioids and do not have abdominal pain as the predominant symptom 5

Common Pitfalls to Avoid

• Do not assume gastroparesis without screening for cannabis use, as CHS is frequently missed and requires completely different management 1
• Do not delay IV antiemetic therapy while waiting for diagnostic workup, as symptom control is immediately necessary 2
• Do not use metoclopramide in patients with renal impairment (creatinine clearance <40 mL/min) without dose reduction to approximately one-half the recommended dosage 2
• Do not overlook volume status and electrolyte abnormalities from recurrent vomiting, which require correction 1