What is the best approach to manage a patient with chronic abdominal pain, gastrointestinal symptoms, and severe back pain, who also uses cannabis daily?

Assessment Approach for Patient with Chronic Abdominal Pain, GI Symptoms, and Severe Back Pain

Immediate Priority: Cannabis Hyperemesis Syndrome Evaluation

The most critical first step is to strongly advise complete cannabis cessation for at least one week, as cannabis hyperemesis syndrome (CHS) is a leading differential diagnosis given daily cannabis use since August and the constellation of epigastric pain, nausea, poor appetite, and weight loss. 1

History - Cannabis-Specific Details

• Document exact frequency and duration of cannabis use (CHS typically requires >1 year of use at >4 times weekly, though this patient's recent onset warrants investigation) 1
• Ask specifically about compulsive hot shower/bath use for symptom relief—this is pathognomonic for CHS 1
• Assess for cyclic pattern of symptoms (≥3 episodes annually) 1
• Document THC concentration/potency of products used (concentrates up to 70% THC have longer clearance times and higher risk) 2, 3
• Inquire about any prior symptom-free periods and their correlation with cannabis abstinence 1

History - Red Flag Symptoms for Serious Pathology

• Constitutional symptoms: fever, night sweats, unintentional weight loss (already present—concerning) 4
• Alarm features: hematemesis, melena, hematochezia, progressive dysphagia 4
• Neurological red flags for back pain: saddle anesthesia, urinary retention/incontinence, progressive bilateral leg weakness, fecal incontinence 4
• Timing and character of pain: constant severe pain unrelieved by position changes suggests serious pathology 4
• Early satiety and post-prandial fullness (already present—concerning for gastric outlet obstruction or malignancy) 4

History - Functional vs. Inflammatory Pain Characteristics

• Relationship of pain to meals, bowel movements, and stress 4
• Pain that awakens patient from sleep suggests organic disease 4
• Detailed bowel habit changes: frequency, consistency, urgency, nocturnal diarrhea 4
• Previous response to empiric therapies (PPIs, antispasmodics) 4

History - Psychosocial Risk Factors for Chronic Pain

• Early life adversity, trauma, discrimination experiences, poverty 4
• Pre-existing anxiety, depression, catastrophizing behaviors 4
• Social support availability and pain-reinforcing factors (disability claims, substance misuse history) 4
• Cannabis use disorder symptoms: irritability with missed doses (already present), failed quit attempts, continued use despite harm 5

Investigations - Prioritized by Urgency

Immediate/Urgent (Within Days)

• Abdominal ultrasound (already ordered): evaluate for cholelithiasis, hepatobiliary pathology, pancreatic masses, abdominal aortic aneurysm 6
• Upper endoscopy with biopsy: essential given progressive weight loss, early satiety, and epigastric pain to exclude malignancy, peptic ulcer disease, gastric outlet obstruction 4
• CT abdomen/pelvis with IV contrast: if ultrasound non-diagnostic and symptoms persist, to evaluate for pancreatic pathology, lymphadenopathy, occult malignancy 4
• Fecal calprotectin or lactoferrin: to exclude inflammatory bowel disease given variable bowel habits and elevated CRP 4

Secondary Investigations (If Initial Workup Negative)

• Gastric emptying study: if early satiety and post-prandial fullness persist after cannabis cessation, to evaluate for gastroparesis 4
• Small intestinal bacterial overgrowth (SIBO) breath testing: if bloating and variable bowel habits persist, particularly given cannabis-induced gut dysmotility 4
• Esophagogastroduodenoscopy (EGD) with gastric biopsies: if not already performed, to exclude eosinophilic gastroenteritis, H. pylori, fungal overgrowth 4

Back Pain Investigations

• MRI lumbar and thoracic spine: X-ray is insufficient given severity and new right mid-back extension; MRI needed to exclude epidural abscess, metastatic disease, discitis, spinal stenosis 4
• Inflammatory markers: ESR in addition to CRP (already mildly elevated at 9) to assess for inflammatory/infectious etiology 4
• Consider bone scan or PET-CT: if weight loss and back pain suggest possible malignancy with spinal metastases 4

Laboratory Work - Additional Tests

• Repeat comprehensive metabolic panel: monitor mildly elevated ALT (45), assess for hepatobiliary disease progression 4
• Lipase/amylase: to exclude chronic pancreatitis given epigastric pain and cannabis use 4
• Celiac serology (tissue transglutaminase IgA with total IgA): if diarrhea-predominant symptoms and weight loss 4
• Stool studies: C. difficile, ova and parasites, Giardia antigen if diarrhea persists 4

Critical Clinical Decision Points

Cannabis Cessation Trial (MUST DO FIRST)

• Mandate complete cannabis abstinence for minimum 7 days, ideally 2 weeks 1, 2
• Withdrawal symptoms (irritability, anxiety, restlessness) typically peak at 24-72 hours and resolve within 1-2 weeks 2, 7
• Provide supportive management: no specific pharmacotherapy recommended, but symptomatic treatment for agitation/insomnia acceptable 7
• If GI symptoms resolve with cessation, diagnosis is CHS and definitive treatment is permanent abstinence 1
• Complete resolution typically requires abstinence for 6 months or duration equal to 3 typical symptom cycles 1

Urgent Gastroenterology Referral Indications (ALREADY MET)

• Progressive unintentional weight loss (>5% body weight) 4
• Persistent epigastric pain with early satiety 4
• Age >30 with new-onset symptoms and alarm features 4
• Do not wait for outpatient appointment—consider ED evaluation if symptoms worsen or no improvement within 3-5 days 4

Pain Management Approach

• Avoid opioids entirely: risk of narcotic bowel syndrome, cannabis use disorder comorbidity, and worsening nausea 4, 1
• Trial NSAIDs (ibuprofen 400-600mg TID or naproxen 500mg BID) for back pain if no contraindications 4
• Consider low-dose tricyclic antidepressant (amitriptyline 25mg at bedtime, titrate to 75-100mg): addresses both chronic pain and functional GI symptoms 4, 1
• Topical capsaicin 0.1% to abdomen: may provide relief if CHS confirmed 1

Multidisciplinary Referrals

• Psychology/psychiatry: assess for anxiety, depression, catastrophizing, and provide cognitive behavioral therapy or gut-directed hypnotherapy if functional component identified 4
• Chronic pain team: if pain becomes centrally-mediated or persists despite treatment of underlying causes 4
• Addiction medicine: for cannabis use disorder management if patient unable to maintain abstinence 7, 5

Common Pitfalls to Avoid

• Do not dismiss symptoms as purely functional without excluding serious pathology first—weight loss and progressive symptoms warrant thorough investigation 4
• Do not continue cannabis use during diagnostic workup—it confounds the clinical picture and delays diagnosis of CHS 1
• Do not prescribe opioids for chronic abdominal pain—risk of narcotic bowel syndrome and addiction outweighs benefits 4
• Do not order repetitive low-yield investigations—once organic disease excluded, focus shifts to functional management 4
• Do not delay endoscopy in setting of alarm features—weight loss with epigastric pain requires direct visualization 4