Case Presentation: A 37-year-old female with no medical history presented for lab abnormalities. Initial blood work revealed a hemoglobin of 5.1 g/dL with a MCV and MCH unable to be calculated. Her white blood cell and platelet counts were normal. She denied melena, hematochezia, or other episodes of bleeding other than menorrhagia requiring up to 20 pads/day for 10 days/month. Blood transfusions were initiated and initial workup with iron studies, ferritin, and a transvaginal ultrasound were unrevealing. Upon further history, the patient endorsed paranoid auditory hallucinations for two years. She felt mistrustful of people/family around her. Her brother reported the patient “fell apart” when their parents passed away two years prior. At this time, the patient quit her job and gave up her children. The patient sent peculiar messages to family such as, “Our parents are still alive – where are you hiding them?”. The patient stopped showering routinely as well. Two days after admission, her blood work was remarkable for pancytopenia and normal MCV and MCH levels. Her lactate dehydrogenase was elevated at 2017 U/L, and the haptoglobin was less than 10 mg/dL. A peripheral blood smear did not reveal blasts or evidence of hemolysis, but hypersegmented neutrophils were observed. Interdisciplinary care with psychiatry and hematology was initiated. Nutritional labs were obtained and were notable for a significantly low vitamin B12 level at 56 pg/mL. Daily high-dose cobalamin intramuscular injection was initiated. Her intrinsic factor (IF) antibody then returned positive. She was formally diagnosed with pernicious anemia that would require lifelong cobalamin supplement. After a month of treatment, the patient improved control of internal stimuli with no further episodes of hallucinations and her pancytopenia was resolving.
Discussion: Pernicious anemia (PA) is an autoimmune disorder that causes vitamin B12 deficiency [1]. The symptoms of PA encompass neuropsychiatric, digestive, and hematologic abnormalities. Hematological manifestations of cobalamin deficiency typically inversely correlate with neuropsychiatric impairment [2]. Co-existence of severe hematologic and neuropsychiatric symptoms, as seen in our patient, is atypical. The gold standard of diagnosing PA is based on the detection of IF deficiency [3]. Due to its broad spectrum of clinical presentations, it is challenging to recognize PA. Our patient presented for anemia, and iron deficiency anemia was a top consideration given her menstrual history. Blood-loss anemia can mask megaloblastosis which explained her unknown MCV and MCH at the beginning. It is important to remain broad with your differential diagnosis and fully explore all etiologies of a disease. PA requires parenteral B12 for correction of hematologic abnormalities. With timely intervention, some neuropsychiatric symptoms can be reversed.
Conclusions: PA is a type of megaloblastic anemia due to a lack of IF resulting in vitamin B12 deficiency. It is often insidious to be diagnosed due its wide variety of symptoms and subtle presentations.