A2 Answers

A2: B12 Deficiency

A 62-year-old man with a several-week history of fatigue, loss of appetite, and feeling feverish presented at the hospital with severe pallor and signs of left and right ventricular failure. Neurologic examination disclosed poor short-term memory and decreased sense of vibration in the legs.

An electrocardiogram showed changes consistent with the presence of cardiac ischemia. The hemoglobin level was 3.7 g per deciliter, with a mean corpuscular volume of 108 μm3, a white-cell count of 3200 per cubic millimeter, and a platelet count of 57,000 per cubic millimeter.



You review this slide of his peripheral smear. Comment on it and what it could mean. What are the possible diagnoses? Name three. B12, folate, and nonmegaloblastic anemia.

Hypersegemented neutrophils, megalocytes, basophilic stippling (thalassemia, anemia of chronic disease, iron deficiency, and lead poisnoning= baste the tail)


You look through the chart and you note that the patient had a severe history of Crohn's disease. 10 years ago he had a portion of his colon resected.

After you discover the previous surgery, what type of nutritional deficit are you most concerned about? B12 Deficiency
What do you think is the most likely diagnosis? Megaloblastic Anemia
What type of diet puts patients most at risk for this disease? Why is that the case? Vegan Diet. No animal products.
What is significant for the amount of time since this patient’s colon resection? What part of the colon do you think was resected? It takes 6-9 years for B12 stores in our live to run out. Folate stores run out in a month. HIs terminal ileum was most likely resected due to his history of Crohn’s disease.

What two specific lab tests/values will be elevated in this patient? Serum homocysteine and methylmalonic acid


Which of the following will administration of folate correct in this patient: (select the most correct answer(s). More than one is possible)
-Correct both B12 and folate deficiency completely?
-Correct Folate deficiency
-Correct B12 deficiency
-Correct the hematologic aspect of B12 deficiency
-Correct the neurologic aspect of B12 deficiency
-Neither correct B12 or folate deficiency completely

Name at 5 reasons for B12 deficiency?

Pure vegan diet, malnutrition, decreased intrinsic factor, gastric acid, intestinal reabsorption, pregnancy/lactation

(D latum, pancreatic insufficiency)

What is the most common reason for B12 deficiecy?

Pernicious anemia

What is the most common cause of folate deficiency?

Decreased intake -malnutrition, infants/elsderly, chronic alcholhilcs, goat milk
Malabsorption-celiac disease, bacterial overgrowth
Drug inhibition- 5 flurorouracil, methotrexate, bactrim, phenytoin, ocp, alchohol
Increased utilization- pregnancy/lactation, dissmeinated malignancy, severe hemolytic anemia
What other lab test could you order to differentiate between folate versus B12 deficiency?

Methylmalonic acid

What 5 factors are required in Cobalamin absorption from the diet?

Intrinsic factor, salivary gland enzymes, r binder,pancreatic proteases, b 12

What medications for GERD can cause a B12 deficiency? PPI’s


What other cell types are associated with a B12 deficiency? A histologic image is provided below as a clue.



small intestine epithelial cells

The image below is taken from the patient above? What abnormalities do you notice and what is this condition called?

Subacute combined degeneration thoracic cervical cord. note the pale areas of demylination in the posterior columns and the lateral cortical spinal tracts

Name some positive physical exam findings for this condition? (Things that you definitely checked because you learned this condition so well during 2nd year)

Rhomberg
MMSE (dementia)
Ataxia
Vibratory sensation and joint sense


(Clinical Vignette adapted from CaseFiles Internal Medicine).