Which of the following is the most likely consequence of this treatment decision?

A 34-year-old female presents with fatigue and malaise of 2 months duration. On questioning, the patient has also admits some tingling in her feet. Laboratory results indicate that this patient has a macrocytic, megaloblastic anemia. The physician thinks the patient may have a folate deficiency, and chooses to treat her with intravenous folate alone. Which of the following is the most likely consequence of this treatment decision?

1.Induction of corneal neovascularization
2.Masked signs of neural damage
3.Night blindness
4.Pellagra
5.Premature alopecia

Solution

The two most common causes of megaloblastic anemia are vitamin deficiencies, especially folate and vitamin B12 (cobalmin). Folate deficiency is common in nutritionally deprived people and occasionally in pregnant women. B12 deficiency is classically associated with pernicious anemia, though may also result from a shortened bowel or Crohn’s disease (B12 is uptaken in the ileum).

This patient likely has pernicious anemia and a B12 deficiency. While folate is indicated in such patients, intravenous vitamin B12 is required to correct underlying neurological problems. B12 deficiency can produce neurological disturbances such as optic neuropathy, subacute combined neurodegeneration, parasthesias and abnormal myelination. While administration of folate alone would moderately correct the anemia, it would mask underlying neurological pathologies.

Clinically, anyone with megaloblastic anemia suspected to be caused by a B-vitamin deficiency should receive both B12 and folate to prevent this problem.