What is the best course of treatment for a 39-year-old female with a history of gastric sleeve surgery and Vitamin B12 deficiency anemia, presenting with left earache, low-grade fever, vomiting after every meal, and right upper quadrant pain?

Management of Post-Bariatric Surgery Complications with Persistent Vomiting and RUQ Pain

This patient requires urgent imaging (RUQ ultrasound) to evaluate for gallstones/cholecystitis, upper endoscopy to assess for anastomotic stricture or ulcer, and immediate escalation of B12 supplementation given the persistent vomiting and risk of thiamine deficiency. 1

Immediate Priorities

1. Right Upper Quadrant Pain Evaluation

• Order RUQ ultrasound immediately to evaluate for gallstones or cholecystitis, as gallstone formation occurs in 7-39% of post-bariatric patients and is a common cause of RUQ pain 1
• The constant, deep/full quality of pain with daily occurrence raises concern for biliary pathology, which is significantly increased after sleeve gastrectomy 1
• If gallstones are confirmed and symptomatic, cholecystectomy should be considered as it can be performed safely in post-bariatric patients 1

2. Persistent Vomiting Assessment

• Vomiting after every meal for 1 year post-sleeve gastrectomy is NOT normal and requires urgent investigation 1
• While vomiting occurs in 30-60% of patients early post-surgery, persistent vomiting beyond 2-3 weeks indicates a surgical complication such as gastric stenosis, stricture, or ulcer 1
• Order upper endoscopy (EGD) to evaluate for:
  • Gastric stenosis (most common cause of persistent vomiting post-sleeve gastrectomy) 1
  • Gastric ulcers 1
  • Anastomotic complications 1

3. Thiamine Deficiency Prevention - URGENT

• Start thiamine supplementation immediately - when vomiting persists for >2-3 weeks, thiamine supplementation is mandatory to prevent neurological complications including Wernicke's encephalopathy 1
• The combination of persistent vomiting, rapid weight loss post-bariatric surgery, and small thiamine body stores creates extremely high risk 1
• Prescribe thiamine 100 mg PO daily at minimum; consider IV thiamine if neurological symptoms develop 1

Vitamin B12 Deficiency Management

Current Inadequate Supplementation

• The patient's current B12 supplementation is insufficient - standard oral supplementation often fails in post-sleeve gastrectomy patients, especially with persistent vomiting 1
• Sleeve gastrectomy causes B12 malabsorption through reduced gastric acid and intrinsic factor production 2
• Persistent vomiting further impairs absorption and increases deficiency risk 1

Recommended B12 Treatment Protocol

• Switch to intramuscular B12 immediately: 1000 mcg IM weekly for 4-8 weeks, then 1000 mcg IM monthly for life 2, 3
• IM route is superior to oral in post-bariatric patients with malabsorption and vomiting 2, 3
• Alternative if IM not feasible: High-dose oral crystalline B12 at 350-600 mcg daily (though less reliable with ongoing vomiting) 3, 4
• Check homocysteine and methylmalonic acid (MMA) levels to assess functional B12 deficiency, as serum B12 alone may miss up to 50% of metabolically deficient patients 2, 5

Monitoring Requirements

• Recheck B12, MMA, and complete blood count in 4-6 weeks after initiating IM therapy 2
• Monitor potassium in first 48 hours after starting B12 treatment to prevent severe hypokalemia from rapid hematopoiesis 2
• HoloTC and MMA are superior to serum B12 for detecting early deficiency changes 6

Bilateral Otitis Externa Treatment

• Prescribe ofloxacin otic solution: 10 drops (0.5 mL) in each affected ear once daily for 7 days 7
• The low-grade fever (100°F) and bilateral ear canal erythema are consistent with otitis externa 7
• Instruct patient to warm bottle in hand before instillation and maintain position for 5 minutes after drops 7

Additional Nutritional Considerations

Comprehensive Micronutrient Assessment

• Order complete nutritional panel including:
  • Iron studies (ferritin, iron, TIBC) - iron deficiency occurs in 66% of post-bariatric patients within first year 4
  • Folate - deficiency occurs in 15% of patients 4
  • Vitamin D and calcium 1
  • Zinc and copper (zinc deficiency can cause oral symptoms and should be monitored) 8
  • Selenium 9

Lifelong Supplementation Requirements

• All post-sleeve gastrectomy patients require:
  • 1-2 adult multivitamin-plus-mineral supplements daily 1
  • 1200-2400 mg elemental calcium daily 1
  • 3000 IU vitamin D daily (titrated based on levels) 1
  • B12 as outlined above 1, 2
  • Iron supplementation: 65 mg daily for males, 100 mg daily for females 4

Critical Follow-Up Plan

Within 1 Week

• RUQ ultrasound results review 1
• Schedule upper endoscopy if not already completed 1
• Ensure thiamine supplementation started 1
• First IM B12 injection administered 2

Within 2-4 Weeks

• Review endoscopy findings and imaging results 1
• Assess response to thiamine and B12 therapy 2
• Check potassium level 2
• Evaluate vomiting frequency - should be improving if nutritional intervention alone was the issue 1

Within 4-6 Weeks

• Recheck B12, MMA, homocysteine, CBC 2, 6
• Complete nutritional panel results 1
• If vomiting persists despite treatment, surgical consultation for possible revision 1

Common Pitfalls to Avoid

• Do not dismiss persistent vomiting as "normal" post-bariatric surgery - vomiting after every meal at 1 year post-op indicates structural or functional complication 1
• Do not rely on oral B12 supplementation alone in patients with malabsorptive procedures and ongoing vomiting 2, 3
• Do not delay thiamine supplementation when vomiting is persistent - neurological complications can develop rapidly 1
• Do not overlook gallbladder disease - it is extremely common post-bariatric surgery and presents with RUQ pain 1
• Do not use serum B12 alone for diagnosis - functional markers (MMA, homocysteine) are more sensitive 2, 5, 6