Related Experiment Video
Updated: Sep 3, 2025

Continuous Manual Exchange Transfusion for Patients with Sickle Cell Disease: An Efficient Method to Avoid Iron Overload
Published on: March 14, 2017
Severe Hemolytic Anemia due to Vitamin B12 Deficiency in Six Months
1University of Massachusetts Medical School, Worcester, MA 01655, USA.
Abstract:
Gastric bypass is a common cause of vitamin B12 deficiency. It can lead to patients presenting with symptoms of anemia. The body has significant reserves of vitamin B12 and loses vitamin B12 slowly. The following case is of a patient who underwent a gastric bypass five years ago and whose hemoglobin (Hgb) dropped from 12.2 g/dL to 4.4 g/dL over six months due to questionable adherence to vitamin supplements. Further work-up showed hemolytic anemia and thrombocytopenia due to a very low vitamin B12 level of 47 pg/mL, with his blood counts improving with vitamin B12 supplementation. The case points to the importance of thinking about vitamin deficiency as a cause of hemolysis to avoid unnecessary procedures.
Related Concept Videos
Vitamins
Disorders of Erythrocytes
Erythrocyte disorders can be broadly categorized into two main types: anemic and polycythemic conditions.
A low oxygen-carrying capacity of the blood due to the loss, lower production, or destruction of erythrocytes is termed anemia. Hemorrhagic anemia, for example, occurs when bleeding from an external wound or internal ulcer reduces erythrocyte counts.
On the other...
Disorders of Hemostasis
Thromboembolic Disorders
Two factors primarily cause thromboembolic conditions.
Blood Transfusion and Agglutination
History
The history of blood transfusion dates back to the 17th century, when early attempts were made in animals. In 1818 James Blundell, a British doctor, performed the first successful human blood transfusion. Later in 1900, Karl...
Hemoglobin
When all four heme groups are bound to oxygen, the resulting molecule is called oxyhemoglobin. As a result, arterial blood...
Immunodeficiency Diseases
There are three main causes of immunodeficiency...

