Introduction to a How I Treat series on consultative hematology for inpatients

Patients admitted to the hospital may have preexisting hematologic conditions, or they may develop hematologic complications during the course of hospitalization. Bleeding, clotting, and/or hematologic cell line abnormalities affect patients with diverse diagnoses, and optimal evaluation and management involve input from specialists of many disciplines. The How I Treat series in this issue of Blood includes articles written by experts in hematology and transfusion medicine, with a focus on case-based examples that cross specialties and highlight considerations for diagnosis and treatment.

This series includes 4 articles, listed below, that address key hematologic issues encountered in hospitalized patients.

• Bethany Samuelson Bannow and Barbara A. Konkle, “How I approach bleeding in hospitalized patients”

• Imo J. Akpan and Beverley J. Hunt, “How I approach the prevention and treatment of thrombotic complications in hospitalized patients”

• Jeffrey L. Carson and Gary M. Brittenham, “How I treat anemia with red blood cell transfusion and iron”

• Rebecca L. Zon and Nancy Berliner, “How I manage inpatient consultations for quantitative neutrophil abnormalities in adults”

Excessive bleeding is frequently encountered in hospitalized patients and may be due to common or uncommon problems. The initial assessment needs to ascertain whether bleeding symptoms represent something new, indicating an acquired process, or whether the patient has a prior history of bleeding. Samuelson Bannow and Konkle present cases that address the evaluation and management of bleeding related to severe liver disease in an acutely ill patient in the perioperative setting, acute bleeding upon presentation to the emergency department due to a factor VIII inhibitor, and evaluation and management of a patient with peripartum hemorrhage. These cases emphasize the critical role played by the clinical laboratory in support of rapid evaluation of the patient (with testing driven by the bleeding history), to facilitate initiation of the optimal therapeutic intervention(s).

At the opposite end of the clinical spectrum, thrombotic complications are also frequently encountered in hospitalized patients. Admission to the hospital is recognized as one of the strongest risk factors for venous thromboembolism, underscoring the importance of risk-assessment and appropriate use of thromboprophylaxis. In addition, many patients are already on antithrombotic therapy for a variety of reasons at the time of admission to the hospital. Akpan and Hunt review their approach to the prevention and treatment of thromboembolic complications in hospitalized patients in their contribution to this How I Treat series. Topics covered include prevention of hospital-associated thrombosis, management of bleeding complications in hospitalized patients on anticoagulant therapy, perioperative issues, thrombotic complications associated with vascular access for extracorporeal membrane oxygenation, and peripartum management of patients with inherited antithrombin deficiency. The contributions of the hematologist in the assessment and management of hospitalized patients with thrombotic complications cannot be overemphasized.

Although multiple trials have shown the safety of restrictive red blood cell transfusion thresholds, hemoglobin thresholds for transfusion in some patient populations (including those with cardiovascular disease and chronic anemia) are not as clear. Further, few transfusion-focused studies have considered the importance of diagnosing and managing iron-restricted erythropoiesis as an approach to conserving red blood cells and minimizing transfusion complications. The article in this series, jointly written by Carson (a transfusion clinical trial expert) and Brittenham (an iron expert), presents a refreshing and practical look at issues surrounding red blood cell transfusion therapy and the diagnosis and treatment of iron-restricted anemia. After reading the cases, readers may approach their next patient with anemia differently.

Zon and Berliner complete this series with a review addressing quantitative neutrophil abnormalities in hospitalized patients. Although some patients with abnormal neutrophil counts have inherited defects, most hospitalized patients with neutropenia or neutrophilia have a variety of acquired disorders. Using patient presentations, the authors provide a logical framework for approaching these patients that uses current and prior laboratory findings, key aspects of the history and clinical presentation, and responses to interventions to identify the cause of the abnormal neutrophil count. Treatment options, including when granulocyte colony-stimulating factor or filgrastim should be considered for hospitalized patients with neutropenia, are reviewed. A subset of these patients require further workup, including additional laboratory testing and/or obtaining a bone marrow aspirate and biopsy.

Platelet transfusions are frequently ordered to prevent or treat bleeding in hospitalized patients, but may not lead to the desired clinical outcome. Although an article on platelets is not included in this How I Treat series, we guide the interested reader to the recent article by Stanworth and Shah.¹ As in the articles in this series, illustrative case examples are used to encourage us to think beyond the platelet count and take a more risk-adapted approach in the decision to transfuse or not to transfuse patients with thrombocytopenia.

This How I Treat series highlights hematologic issues that clinicians frequently encounter in hospitalized patients. With expert opinions on complex issues, the series provides food for thought regarding diagnostic and therapeutic approaches; we hope you enjoy these articles.