Appendix D: Sample Responses to Case Questions

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114: VITAMIN B₁₂ DEFICIENCY: LIKE HOT PIZZA TO THE TONGUE LEVEL II

CASE SUMMARY

A 45-year-old woman presents with complaints of tongue pain, fatigue, paresthesias, anorexia, and early satiety. These complaints have been bothering her over the course of months to years, but she has recently noticed increased tongue swelling and pain. The physical exam and laboratory tests reveal findings consistent with vitamin B₁₂ deficiency, including low hemoglobin, hematocrit, and vitamin B₁₂ levels; elevated MCV and MCH; a low-grade fever; mild tachycardia; mild splenomegaly; and decreased pinprick, vibratory, and temperature sensations in the lower extremities. The peripheral blood smear showed abnormalities commonly seen in vitamin B₁₂ deficiency. Additionally, she is taking both metformin and omeprazole, which are potential causes of vitamin B₁₂ deficiency. Several options for replacement of vitamin B₁₂ are available, and intramuscular (IM), deep subcutaneous (SC), and oral replacement are all potential options for this patient.

QUESTIONS

Collect Information

1.a. What subjective and objective information indicates the presence of vitamin B₁₂ deficiency?

• Complaints of fatigue and lethargy¹

• (+) red, smooth, swollen, sore tongue with loss of papillae (atrophic glossitis)²

• (+) tingling and numbness in feet (paresthesias) and decreased pinprick, vibratory, and temperature sensations in both lower extremities²

• Decreased hemoglobin, hematocrit, and RBC count

• Decreased serum vitamin B₁₂ level

• Elevated MCV and MCH levels¹

• Low-reticulocyte count in the presence of anemia

• Mild splenomegaly

• Persistent low-grade fever

• Mild tachycardia¹

• Anorexia and early satiety

• Mild thrombocytopenia^1–3

• Peripheral blood smear containing macro-ovalocytosis, hypersegmented granulocytes, large platelets, and macrocytic red blood cells with megaloblastic changes^1–3

1.b. What additional information is needed to fully assess this patient’s vitamin B₁₂ deficiency?

• The main causes of cobalamin deficiency are pernicious anemia, insufficient nutritional vitamin B₁₂ intake, ileal disease and/or resection, and food-cobalamin malabsorption usually caused by atrophic gastritis. This form of gastritis is usually caused by Helicobacter pylori infection or long-term antacid use. Other causes include chronic alcoholism, gastric reconstruction surgery, or chronic pancreatic disease.^1–3

• Information about the patient’s diet would be extremely valuable. Vitamin B₁₂ deficiency is much more common in vegetarians and vegans due to their lack of intake of meat, fish, and dairy products.¹

• Knowing the length of time she has been taking her chronic medications would be valuable to determine whether the metformin and/or omeprazole could be playing a role in her vitamin B₁₂ deficiency.

• Currently, any vitamin B₁₂ level <150 pmol/L or <200 pg/mL is considered deficient. However, sensitivity and specificity lack with vitamin B₁₂ serum ...