Page 2610 - Hematology_ Basic Principles and Practice ( PDFDrive )

Chapter 160 The Spleen and Its Disorders 2323

SPLENECTOMY
TABLE Causes of Splenomegaly
160.3 Indications and Timing
Primary
Process Pathogenesis Examples Splenectomy should be performed for clinical indications rather
Anatomic Developmental Cysts, pseudocysts, hamartomas, than for specific diagnoses. In many instances, removal of the spleen
abnormalities peliosis, hemangiomas will improve the condition of patients with hemolytic anemia due
to intrinsic disorders of erythrocyte membranes and enzyme disor-
Hematologic Hemolysis Intrinsic (membrane, enzyme, ders, and of those with chronic conditions, such as storage diseases
hemoglobin disorders), extrinsic and portal hypertension. Specific clinical indices that require inter-
(immune)
Extramedullary Myeloproliferative diseases/ vention should be identified, and parameters that can be used to
identify clinical improvement (usually an increase in peripheral
hematopoiesis myelodysplasias, myelofibrosis, blood cell counts, growth, or energy level) should be determined
osteopetrosis
before the procedure is performed. For patients with inherited
Infectious Bacteria Acute and chronic systemic erythrocyte membrane or enzyme disorders, such as hereditary
infection, abscesses, subacute spherocytosis or pyruvate kinase deficiency, marked reticulocytosis
bacterial endocarditis indicating significant metabolic energy required for erythropoiesis,
Mycobacteria Miliary tuberculosis somatic growth failure, or lack of exercise tolerance would be
Spirochetes Syphilis, Lyme disease, leptospirosis potential indications for splenectomy. Avoidance of formation of
Viruses Epstein-Barr virus; cytomegalovirus; gallstones, formerly often considered an indication for splenectomy
human immunodeficiency virus; when a diagnosis of hereditary spherocytosis was made, is less
hepatitis A, B, C important today because minimally invasive surgical procedures
Rickettsia Rocky Mountain spotted fever, Q have improved the management of cholelithiasis. Patients with
fever, typhus storage disorders such as Gaucher disease often develop spleno-
Fungi Disseminated candidiasis, megaly and hypersplenism, and subsequent cytopenias requiring
histoplasmosis, South American intervention. As new therapies are developed, such as eliglustat for
blastomycosis Gaucher disease and ruxolitinib for primary myelofibrosis, these
Parasites Malaria, babesiosis, toxoplasmosis, patients experience a significant reduction in spleen size and increase
Toxocara canis, Toxocara cati, in quality of life, which may mitigate the need for splenectomy. 18,19
leishmaniasis, schistosomiasis, The clinical benefit to be obtained from splenectomy should at least
trypanosomiasis balance, and preferably outweigh, the potential long-term risks of
Immunologic Collagen vascular Felty syndrome, systemic lupus postsplenectomy septicemia, an increased risk for thrombosis, and
diseases erythematosus, mixed connective the shift of storage cells from the spleen to other organs, such as the
tissue disorder, systemic bone marrow, where they may do more harm in the absence of the
vasculitis, Sjögren syndrome, spleen. Not all patients with hemolytic anemias require splenec-
systemic mastocytosis tomy. If such patients develop an aplastic crisis due to parvovirus
Immunodeficiency Common variable immunodeficiency B19 infection while their spleens are intact, they may require a
Immune/ Graft-versus-host disease, serum transfusion. Many patients with mild chronic hemolysis and well-
inflammatory sickness, large granular compensated anemia may be better off with their spleens remaining
lymphocyte lymphocytosis, intact. Patients with ITP should undergo surgical splenectomy
Weber-Christian panniculitis when the risks of bleeding or of medical therapies (such as long-
term corticosteroids or the anti-CD20 monoclonal antibody ritux-
Neoplastic Primary Lymphomas, leukemias imab) are such that the benefits of splenectomy exceed the risks.
malignancies
Metastatic Breast, lung, skin, colon The introduction of thrombopoietin mimetics for treatment of
chronic ITP has further delayed or eliminated the need for splenec-
malignancies
tomy in many patients. The indications for splenectomy are differ-
Infiltrative Storage diseases Gaucher disease, Niemann-Pick ent in adults than in children, and are affected by the presence of
disease, GM 1 gangliosidosis, underlying disorders, such as systemic lupus erythematosus and
glycogen storage disease type IV, HIV. In an attempt to avoid immunologic consequences of a total
Tangier disease, Wolman disease, splenectomy, several centers are performing partial splenectomies for
mucopolysaccharidoses, hereditary spherocytosis, although in some cases a second procedure
hyperchylomicronemia types I is later required. 20
and IV Splenectomy for sickle cell disease is usually performed for splenic
Congestive Portal Intrahepatic cirrhosis, extrahepatic sequestration that is severe, persistent, or recurrent. In some sickle
hypertension cirrhosis (Budd-Chiari syndrome) syndromes, the spleen does not autoinfarct in childhood, and persis-
Systemic Congestive heart failure tent splenomegaly may increase the degree of anemia. The risk for
Local Splenic vein thrombosis subsequent development of gallstones should be considered in
patients with hemoglobinopathies and other hemolytic anemias so
that cholecystectomy can be performed simultaneously, if deemed
indicated. 21
overload causes hemosiderosis of both the spleen and the liver, so that The timing of splenectomy (when it is to be performed) should
portal hypertension may develop and further increase splenic pathol- again be chosen to minimize risks and maximize benefits. Immunity
ogy. Hypersplenism increases the transfusion requirement in patients to carbohydrate antigens, such as those in the cell walls of encapsu-
who are already transfusion dependent. lated organisms such as Streptococcus pneumoniae, Neisseria meningiti-
Interestingly, spleen status at the time of allogeneic hematopoietic dis, and Haemophilus influenzae type b, develops over the first 2–3
stem cell transplantation affects outcomes. Patients with splenomegaly years of life. When splenectomy can be delayed until the patient is
have delayed engraftment while those with prior splenectomy have at least 2 and preferably more than 5 years of age, specific immunity
17
early engraftment and no difference in mortality. The increased risk and response to administered polysaccharide vaccines will improve
in infection may be mitigated by the high-intensity setting in which host defenses and lessen the risk for postsplenectomy sepsis. When
stem cell transplantation occurs. patients have a disease, such as Gaucher disease, or hemolytic anemia