What is the cause of severe anemia (low hemoglobin) with no apparent source of bleeding in a patient?

From the Guidelines

The primary cause of severe anemia with no apparent source of bleeding in a patient is most commonly gastrointestinal blood loss or malabsorption, and therefore, examination of both the upper and lower gastrointestinal tract is crucial. According to the guidelines for the management of iron deficiency anaemia by the British Society of Gastroenterology 1, in the absence of overt blood loss or any obvious cause, all patients should have upper gastrointestinal endoscopy, including small bowel biopsy, and colonoscopy or barium enema to exclude gastrointestinal malignancy. Key considerations in the diagnostic workup include:

• Obtaining a complete blood count, coagulation profile, and type and cross-match for potential transfusion
• Performing abdominal and pelvic ultrasound to check for internal bleeding
• Considering CT scan of abdomen/pelvis if ultrasound is inconclusive
• Conducting upper and lower endoscopy to rule out gastrointestinal bleeding Additionally, it is essential to check medication history for anticoagulants or NSAIDs, assess for symptoms of occult bleeding (melena, hematuria), and consider rare causes like hemolysis or bone marrow failure if bleeding source remains unidentified. A more recent study on the management and prevention of anemia in adult critical care patients 1 highlights the importance of addressing anemia promptly, as it is associated with increased morbidity and mortality in critical care patients. However, the most critical step in managing a patient with severe anemia and no visible bleeding source is to initiate immediate diagnostic workup while simultaneously stabilizing the patient, which may involve administering intravenous fluids and considering blood transfusion if hemoglobin is critically low.

From the Research

Causes of Severe Anemia

• Severe anemia with no apparent source of bleeding in a patient can be caused by various factors, including internal bleeding, such as gastrointestinal bleeding 2, 3
• Gastrointestinal bleeding can be caused by conditions such as gastric ulcers, which can lead to episodes of melena, as seen in a case report of a 71-year-old male trauma patient who declined blood transfusion 4
• Other potential causes of severe anemia include trauma, surgery, or medical conditions that affect the blood's ability to carry oxygen

Diagnosis and Management

• Diagnosis of severe anemia typically involves hemodynamic assessment and resuscitation, as well as laboratory tests to determine the underlying cause of the anemia 2, 3
• Management of severe anemia may involve blood transfusions, although this may not be an option for patients who decline blood transfusion due to religious or personal beliefs 4, 5
• Alternative management strategies for patients who decline blood transfusion include crystalloid fluid resuscitation, bleeding control, vasopressor support, erythropoietin administration, and supplementation with iron, folic acid, and vitamin B12 4, 5

Treatment Options

• Treatment options for severe anemia depend on the underlying cause and may include endoscopic hemostasis for gastrointestinal bleeding, as well as supportive care such as oxygen therapy and mechanical ventilation 4, 2, 3
• In some cases, patients with severe anemia may require intensive care unit (ICU) admission and close monitoring of their hemodynamic status 3
• The use of blood products, such as plasma and factor VIIa, may also be considered in certain cases, particularly in patients with severe bleeding or trauma 6