Abstract Background Hereditary hemorrhagic telangiectasia (HHT) is a rare autosomal dominant vascular disorder characterized by recurrent epistaxis, mucocutaneous telangiectasias, and visceral arteriovenous malformations. Chronic bleeding often results in iron-deficiency anemia and transfusion dependence. Transfusion thresholds are typically set at hemoglobin 7 g/dL, with values 5 g/dL considered life-threatening. Survival below 3 g/dL is exceptionally rare. We report a patient with HHT who maintained full-time employment and functional capacity at hemoglobin near 2 g/dL, highlighting remarkable physiologic adaptation. Case Presentation A 62-year-old man with known HHT presented with generalized malaise. He reported frequent hospitalizations for epistaxis and anemia, receiving transfusions every 4-6 weeks. Despite hemoglobin 2 g/dL, he performed occupational duties with fatigue only when hemoglobin dropped below 2.5 g/dL. He denied dyspnea, chest pain, syncope, or neurologic symptoms. On examination, he was alert, conversant, and hemodynamically stable, with pallor and mucocutaneous telangiectasias. Laboratory evaluation revealed hemoglobin 1.9 g/dL, hematocrit 7%, MCV 86 fL, low-normal reticulocytes, and ferritin 1500 ng/mL. Peripheral smear showed basophilic stippling without hemolysis. Chest radiograph was normal. He received four units of packed red blood cells, increasing hemoglobin to 7.4 g/dL, and was discharged on outpatient iron chelation therapy. Discussion This case illustrates extraordinary tolerance to profound chronic anemia. Gradual hemoglobin decline enabled compensatory mechanisms including increased cardiac output, plasma volume expansion, and enhanced tissue oxygen extraction. Oxygen content at hemoglobin 2 g/dL would be approximately one-third of normal, yet the patient remained functional, underscoring remarkable physiologic adaptation. Clinically, this challenges rigid transfusion thresholds and highlights the importance of symptom-guided, individualized management. Pulmonary and critical care clinicians should recognize such adaptation, balancing transfusion needs against risks of iron overload, alloimmunization, and infection. This case demonstrates that chronic anemia may allow preservation of organ function far below conventional hemoglobin thresholds. This abstract is funded by: None
Torre et al. (Fri,) studied this question.