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Patient Care
Abstract
Introduction: Pancytopenia is a commonly encountered hematologic entity with varying clinical presentations. It results from various disease processes ranging from simple to life-threatening. The most common cause of pancytopenia is megaloblastic anemia, and the most common causes of megaloblastic anemia are deficiencies of vitamin B9 or B12. Thus, folate and B12 deficiency should be high in the differential diagnosis when patients present with pancytopenia. Hemolytic anemia, anemia due to the shortened survival of circulating erythrocytes, often represents a more difficult diagnostic challenge for the clinician. While recognition of ongoing hemolysis is usually rapid and relatively simple, establishing the cause can be more difficult. In the era of routine laboratory testing, especially in high income countries like the United States, more often B12 deficiency presents as nonspecific symptomatic anemia or incidentally discovered mild anemia without symptoms.
Case presentation: A 51-year-old woman with no significant medical history presented to the Emergency Department (ED) referred by her hematologist due to severe macrocytic anemia. She had a three-week history of weakness and dizziness. During a visit to Mexico, she underwent bloodwork which revealed a white blood cell (WBC) count of 2.6, hemoglobin of 7 g/dL, hematocrit of 21%, mean corpuscular volume (MCV) of 93.5 fL, platelet count of 75,000, total bilirubin of 2.1 mg/dL, direct bilirubin of 1 mg/dL, and elevated lactate dehydrogenase (LDH) of 796 U/L. Concerned about these findings, she consulted her primary care physician who referred her to a hematologist. Subsequent laboratory tests prompted referral to the ED. She indicated that her last menstrual period was 1 year ago. Her diet was described as balanced.
Upon admission, the patient's vital signs were stable and unremarkable. The physical examination revealed subconjunctival pallor, while the remainder of the examination was unremarkable. A comprehensive workup showed WBC count 1.91, hemoglobin 5.8 g/dL, hematocrit 16.5%, MCV 115.4 fL, platelets 93,000, total bilirubin 1.7 mg/dL, LDH 6,291 U/L, haptoglobin <10
Further investigation revealed that the patient had a previous episode of severe anemia 10 years prior admission, for which she was discharged with a regimen of cyanocobalamin intramuscular injections monthly. However, she discontinued this treatment after several years due to injection-related pain. Upon reviewing previous medical records, intrinsic factor antibodies were identified.
Discussion: B12 deficiency may result from insufficient intake, gastrointestinal malabsorption, or exposure to exogenous substances. Anemia is the most common presenting laboratory abnormality, generally accompanied by macrocytosis. Pancytopenia may be present in as little as 5% of cases, with hemolysis representing an even rarer manifestation of vitamin B12 deficiency.
Vitamin B12 deficiency may cause pseudo-thrombotic microangiopathy (possibly due to abnormal premature destruction of erythroid progenitors) with non-regenerative macrocytic anemia, elevated lactate dehydrogenase (LDH), and schistocytes on blood smear. This, however, is an atypical presentation of B12 deficiency.
The mechanism of hemolysis in B12 deficiency is likely intramedullary destruction or abortion of erythroid precursors. This patient’s case demonstrates that the evaluation of hemolytic anemia can be extensive, even when the cause and treatment may be relatively straightforward. Although laboratory evaluation quickly revealed ongoing hemolysis, careful history-taking ultimately revealed its cause. This patient’s social situation complicated her case. She was seen by multiple providers in two different countries, with several repeated laboratory tests until appropriate questioning ultimately revealed the patient’s diagnosis of autoimmune pernicious anemia 10 years prior to this hospitalization. Although hemolytic anemia has been previously described as the result of pernicious anemia, such descriptions seem limited to a few case reports.
Presentation Type
Poster
Recommended Citation
Durazo, Yareli; Tran, Victor; Koneru, Sriharsha; and Suarez Parraga, Andres, "Pernicious Anemia Presenting with Pancytopenia and Hemolysis: A Case Report from South Texas" (2024). Research Colloquium. 38.
https://scholarworks.utrgv.edu/colloquium/2024/posters/38
Included in
Pernicious Anemia Presenting with Pancytopenia and Hemolysis: A Case Report from South Texas
Introduction: Pancytopenia is a commonly encountered hematologic entity with varying clinical presentations. It results from various disease processes ranging from simple to life-threatening. The most common cause of pancytopenia is megaloblastic anemia, and the most common causes of megaloblastic anemia are deficiencies of vitamin B9 or B12. Thus, folate and B12 deficiency should be high in the differential diagnosis when patients present with pancytopenia. Hemolytic anemia, anemia due to the shortened survival of circulating erythrocytes, often represents a more difficult diagnostic challenge for the clinician. While recognition of ongoing hemolysis is usually rapid and relatively simple, establishing the cause can be more difficult. In the era of routine laboratory testing, especially in high income countries like the United States, more often B12 deficiency presents as nonspecific symptomatic anemia or incidentally discovered mild anemia without symptoms.
Case presentation: A 51-year-old woman with no significant medical history presented to the Emergency Department (ED) referred by her hematologist due to severe macrocytic anemia. She had a three-week history of weakness and dizziness. During a visit to Mexico, she underwent bloodwork which revealed a white blood cell (WBC) count of 2.6, hemoglobin of 7 g/dL, hematocrit of 21%, mean corpuscular volume (MCV) of 93.5 fL, platelet count of 75,000, total bilirubin of 2.1 mg/dL, direct bilirubin of 1 mg/dL, and elevated lactate dehydrogenase (LDH) of 796 U/L. Concerned about these findings, she consulted her primary care physician who referred her to a hematologist. Subsequent laboratory tests prompted referral to the ED. She indicated that her last menstrual period was 1 year ago. Her diet was described as balanced.
Upon admission, the patient's vital signs were stable and unremarkable. The physical examination revealed subconjunctival pallor, while the remainder of the examination was unremarkable. A comprehensive workup showed WBC count 1.91, hemoglobin 5.8 g/dL, hematocrit 16.5%, MCV 115.4 fL, platelets 93,000, total bilirubin 1.7 mg/dL, LDH 6,291 U/L, haptoglobin <10 >
Further investigation revealed that the patient had a previous episode of severe anemia 10 years prior admission, for which she was discharged with a regimen of cyanocobalamin intramuscular injections monthly. However, she discontinued this treatment after several years due to injection-related pain. Upon reviewing previous medical records, intrinsic factor antibodies were identified.
Discussion: B12 deficiency may result from insufficient intake, gastrointestinal malabsorption, or exposure to exogenous substances. Anemia is the most common presenting laboratory abnormality, generally accompanied by macrocytosis. Pancytopenia may be present in as little as 5% of cases, with hemolysis representing an even rarer manifestation of vitamin B12 deficiency.
Vitamin B12 deficiency may cause pseudo-thrombotic microangiopathy (possibly due to abnormal premature destruction of erythroid progenitors) with non-regenerative macrocytic anemia, elevated lactate dehydrogenase (LDH), and schistocytes on blood smear. This, however, is an atypical presentation of B12 deficiency.
The mechanism of hemolysis in B12 deficiency is likely intramedullary destruction or abortion of erythroid precursors. This patient’s case demonstrates that the evaluation of hemolytic anemia can be extensive, even when the cause and treatment may be relatively straightforward. Although laboratory evaluation quickly revealed ongoing hemolysis, careful history-taking ultimately revealed its cause. This patient’s social situation complicated her case. She was seen by multiple providers in two different countries, with several repeated laboratory tests until appropriate questioning ultimately revealed the patient’s diagnosis of autoimmune pernicious anemia 10 years prior to this hospitalization. Although hemolytic anemia has been previously described as the result of pernicious anemia, such descriptions seem limited to a few case reports.