Archive Of Standardized Exam Questions: Folic Acid (Folate) Deficiency

OVERVIEW

This page is dedicated to organizing various examples of standardized exam questions whose answer is folic acid (folate) deficiency. While this may seem a odd practice, it is useful to see multiple examples of how folic acid deficiency will be characterized on standardized exams (namely the boards and the shelf exams). This page is not meant to be used as a tradition question bank (as all of the answers will be the same), however seeing the classic “test” characterization for a disease is quite valuable.

KEY CHARACTERISTICS OF THIS CONDITION (ON EXAMS)

When it comes to standardized exams, each topic has its own “code” marked by key buzzwords, lab findings, clues, etc. If you are well versed in this code you will be able to more quickly identify the condition that is being discussed, and get the right answer on the exam you are taking. Below is the “code” for folic acid deficiency. 

Chief Complaints:

  • Fatigue

Patient History:

  • History of alcohol abuse
  • History of phenytoin usage: a side effect can be this deficiency

Clinical Workup:

  • Megaloblastic anemia:
    • Decreased Hgb/HCT
    • Increased MCV
  • Hyper-segmented neutrophils (on blood smear): neutrophil nuclei can have > 5 lobes.
  • Increased homocysteine: similar to vitamin B12 deficiency this will be elevated.
  • NORMAL methylmalonic acid: in contrast to vitamin B12 deficiency this will be elevated.
QUESTION EXAMPLES

Question # 1

A 30 year old woman, G2P1,  is at 31 weeks gestation. She comes to the clinic because she has been feeling fatigued for the past 2 months. She has also lost 12 pounds during this time period. She currently does not have any prenatal care. She has a history of alcohol abuse. On physical exam she is an ill appearing woman with pallor. Her uterus fundal height is 29 cm. The fetal heart rate is 145 min. Labs are collected, and the results are shown below:

  • Hemoglobin: 5.9 g/dL**
  • Mean corpuscular hemoglobin: 31 pg/cell
  • Mean corpuscular volume: 102 µm³**
  • Leukocyte count: 4500/mm³
  • Reticulocyte count: 0.1%
  • Platelet count: 135,000 mm³
  • Prothrombin time: 13 sec
  •  Bilirubin (total): 0.9 mg/dL
  • ALT: 15 U/L

What is the most likely cause of the patient’s anemia?

Explanation # 1

Fatigue + history of alcohol abuse + anemia + elevated MCV = folic acid deficiency (vitamin B12 deficiency also possible)

Question # 2

A 35 year old female comes to the clinic for a routine visit. Her past medical history is significant for generalized seizures that are controlled with chronic phenytoin therapy. Her seizures are well controlled, and she has been asymptomatic for the past year. She denies smoking or the consumption of any alcohol. Her physical exam is remarkable only for some slight pallor. Labs are collected and shown below.

  • Hemoglobin: 10.5 g/dL ***
  • MCV: 104 fl ***
  • Platelet count: 200,000/mm³
  • Leucocyte count: 7,400/mm³

What is the the patient’s diagnosis?

Explanation # 2

Phenytoin usage + anemia + elevated MCV = folic acid deficiency

Question # 3

A 40 year old male comes to the hospital because he has bloody vomitus and abdominal pain. After learning that his wife was cheating on him 7 months ago, this patient admits to drinking large amounts of whiskey daily to “dull the pain”. Since that time, he has been seen in the ED multiple times for acute alcohol intoxication. His vital signs are currently within normal limits. A physical exam reveals hepatomegaly. A blood smear is performed and shows neutrophils with ~8  nuclear lobes. What diagnosis dos this patient likely have?

Explanation # 3

History of alcohol abuse + hyperhsegmented nuclei = folic acid deficiency

Question # 4

A 50 year old male is brought into the ER after being found unconscious in the street. His clothes smell heavily of alcohol. His vitals are currently within normal limits. A physical exam reveals jaundice and a spider angioma on the right chest. Labs are collected and are shown below:

  • Hemoglobin: 9.9 g/dL ***
  • MCV: 110 µm³ ***
  • Serum ferritin: 220 ng/mL
  • Vitamin B12: 550 pg/mL (N-160-950)

A blod smear shows the presence of neutrophils with hyper-segmented nuclei. What is the likely diagnosis in this patient?

Explanation # 4

History of alcohol abuse + anemia + elevated MCV + hyper-segmented neutrophils = folic acid deficiency 

Question # 5

A 45 year old male is brought to the hospital about half an hour after a tonic-clonic generalized seizure. He has a 4 year history of a seizure disorder that has been treated with phenytoin. The patient also has a long-standing history of alcoholism.  Currently hie is stuporous, and a neurological examination shows no neurological findings. Lab values reveal a hemoglobin concentration of 9.0  g/dl, and a MCV is 108 µm³. What is the likely diagnosis in this patient?

Explanation # 5

History of phenytoin usage + history of alcohol abuse + anemia + elected MCV = folic acid deficiency 

TESTABLE FACTS ABOUT THIS TOPIC (BEYOND ITS IDENTIFICATION)

Many questions on standardized exams go beyond simply recognizing the underlying topic. Often there are specific testable facts regarding some aspect of the topic’s pathophysiology/management/clinical implications that are commonly asked. Some of these are listed below:

Expected Serum Values:

  • Increased homocysteine: similar to vitamin B12 deficiency this will be elevated.
  • NORMAL methylmalonic acid: in contrast to vitamin B12 deficiency this will be elevated.

 

 

Page Updated: 10.21.2016