A 28-year-old woman comes to the physician with fatigue and low energy. She was started on depot medroxyprogesterone acetate injections 6 months ago and relates her symptoms to the therapy and resulting cessation of her menstrual cycles. The patient was diagnosed with diarrhea-predominant irritable bowel syndrome 8 months ago, and continues to have intermittent symptoms of that as well. She also has a history of generalized anxiety disorder. Her current medications include a multivitamin and simethicone for excessive flatulence.
Laboratory results are as follows:

A peripheral smear is shown in the image below:

Which of the following is the best diagnostic test to confirm the diagnosis?

Question

A 28-year-old woman comes to the physician with fatigue and low energy.  She was started on depot medroxyprogesterone acetate injections 6 months ago and relates her symptoms to the therapy and resulting cessation of her menstrual cycles.  The patient was diagnosed with diarrhea-predominant irritable bowel syndrome 8 months ago, and continues to have intermittent symptoms of that as well.  She also has a history of generalized anxiety disorder.  Her current medications include a multivitamin and simethicone for excessive flatulence.
Laboratory results are as follows:

A peripheral smear is shown in the image below:

Which of the following is the best diagnostic test to confirm the diagnosis?

Quizplus · Accepted Answer

11ec193a_9827_699f_853d_59a0cad8599d_MD0002_00 This patient presents with microcytic anemia. The peripheral smear shows microcytic, hypochromic red blood cells consistent with iron deficiency anemia. The differential diagnosis of microcytic anemia includes iron deficiency, thalassemia, and anemia of chronic disease. peripheral smear Iron deficiency is typically caused by blood loss, such as gastrointestinal (GI) or menstrual bleeding. Because the patient is no longer having menstrual cycles, menstrual blood loss is unlikely. The patient also has no symptoms suggesting GI bleeding, although occult GI blood loss is a possibility. Decreased GI absorption of iron can also result in iron deficiency. Celiac disease is a relatively common cause of iron deficiency anemia. The patient was previously diagnosed with irritable bowel syndrome, but her symptoms are actually consistent with a diagnosis of celiac disease. It is not uncommon for patients with celiac disease to be wrongly diagnosed with irritable bowel syndrome given the nonspecific clinical features and subtle findings. The most sensitive and specific serologic test to diagnose celiac disease is anti-tissue transglutaminase antibodies. (Choice A) Anti-glutamic decarboxylase antibodies are frequently found in type 1 diabetes mellitus. (Choice C) A bone marrow biopsy would be indicated if there was suspicion of an underlying hematologic malignancy. This patient has thrombocytosis, which can be found with myeloproliferative neoplasms; however, a reactive thrombocytosis is often found in iron deficiency. (Choice D) A direct antiglobulin (Coombs') test is used to evaluate for autoimmune hemolytic anemia, which often manifests as a normocytic anemia with spherocytes and polychromasia seen on the peripheral smear. (Choice E) Microcytic anemia can be due to thalassemia. However, this patient's mean corpuscular volume is only slightly low and her history is more suggestive of iron deficiency. Furthermore, thrombocytosis is common with iron deficiency but not with thalassemia. Educational objective: Celiac disease is a relatively common cause of iron deficiency anemia due to decreased intestinal iron absorption. The most sensitive and specific serologic test to diagnose celiac disease is anti-tissue transglutaminase antibodies. __________ References: Unawareness of gastrointestinal symptomatology in adult coeliac patients with unexplained iron-deficiency anaemia presentation. (http://www.ncbi.nlm.nih.gov/pubmed/16573794) A controlled, prospective screening study of celiac disease presenting as iron deficiency anemia. (http://www.ncbi.nlm.nih.gov/pubmed/12192198) An excess of prior irritable bowel syndrome diagnoses or treatments in celiac disease: evidence of diagnostic delay. (http://www.ncbi.nlm.nih.gov/pubmed/23697749)

A 28-Year-Old Woman Comes to the Physician with Fatigue and Low