Page 2504 - Hematology_ Basic Principles and Practice ( PDFDrive )

2236 Part XIII Consultative Hematology

must be considered abnormal until proven otherwise. That some TABLE
palpable spleens may indeed be normal is attested to by the study of 152.5 Causes of Splenomegaly in Children
407
McIntyre and Ebaugh, who found that 3% of healthy college
freshmen have palpable spleens, of which about one-third persist. Disorders of the Blood
“Pretenders” of splenomegaly include the left lobe of the liver, a left Hemolytic anemia: congenital or acquired
upper quadrant tumor such as Wilms tumor or neuroblastoma, the Thalassemia
“wandering spleen,” and the proptotic spleen (seen in children with Sickle cell disease
a depressed diaphragm from obstructive pulmonary disease, such as Leukemia
asthma or bronchiolitis). Osteopetrosis
The most common cause of acute splenomegaly in children, Myelofibrosis, myeloid metaplasia, thrombocythemia
especially young children, is a viral infection. Splenic enlargement in Infections: Acute and Chronic
this setting is mild to moderate and usually transient. When the Viral
history and physical findings suggest a viral etiology, a complete Congenital (e.g., TORCH association)
blood count with differential, platelet count, and reticulocyte count Mononucleosis (e.g., EBV, CMV infection)
should be performed to rule out unsuspected leukemia or hemolytic Virus-associated hemophagocytic syndrome
anemia and to determine whether there is an atypical lymphocytosis. Human immunodeficiency virus
The child should be reevaluated in approximately 4 weeks (or sooner Bacterial
if symptoms persist). If splenomegaly persists beyond 4 to 6 weeks, Sepsis or abscess
the splenic enlargement may be considered chronic. Brucellosis
A list of causes of splenomegaly in children is presented in Table Salmonellosis
408
152.5. Symptoms from splenic enlargement are uncommon, Tularemia
although massive splenomegaly may cause abdominal discomfort Tuberculosis
and early satiety. If the spleen is sufficiently large, there may be Subacute bacterial endocarditis
increased destruction or sequestration of one or more of the formed Syphilis
elements of the blood (hypersplenism). Cytopenias tend to be Lyme disease
mild to moderate, with the platelet count affected the most. An Fungal
approach to the pediatric patient with splenic enlargement is out- Histoplasmosis (disseminated)
lined in the box on Evaluation and Management of Children With Rickettsial
Splenomegaly. Rocky Mountain spotted fever
Cat-scratch disease
Parasitic
Toxoplasmosis
Evaluation and Management of Children With Splenomegaly Malaria
Leishmaniasis (kala-azar)
When evaluating a child with chronic splenomegaly, the clinician must Schistosomiasis
consider all of the possibilities noted in Table 152.5. Clues from the Echinococcosis
history and physical examination may suggest a specific etiology and Hepatic and Portal System Disorders
direct a tailored approach to the diagnostic laboratory evaluation. If, on
the other hand, there is no apparent cause of the enlarged spleen, a Acute or chronic active hepatitis
number of screening laboratory tests should be performed, including a Cirrhosis, hepatic fibrosis, biliary atresia
complete blood count with differential, platelet count, and reticulocyte Portal or splenic venous obstruction (Banti disease)
count; evaluation of the peripheral smear; determination of sedimen- Autoimmune Disease
tation rate; liver function tests; determination of antibody titers to Juvenile rheumatoid arthritis
Epstein-Barr virus, cytomegalovirus, and Toxoplasma spp.; antinuclear Systemic lupus erythematosus
antibody assay; and ultrasound evaluation of the liver, spleen, and
portal system (the last with Doppler flow technique). Further evaluation, Autoimmune lymphoproliferative syndrome (Canale-Smith syndrome)
including bone marrow examination, may be necessary if the screening Neoplasms and Cysts
tests do not reveal the cause of the splenic enlargement. Lymphomas (Hodgkin and non-Hodgkin)
Management of splenomegaly usually is that of the underlying Hemangiomas and lymphangiomas
disease, when such treatment exists. Splenectomy may be indicated Hamartomas
in selected conditions, but the potential benefits from splenectomy Congenital or acquired (posttraumatic) cysts
must be weighed against the risk of postsplenectomy sepsis, a
rapidly progressive bacteremia, most commonly from Streptococcus Storage Diseases and Inborn Errors of Metabolism
pneumoniae, with a mortality rate of approximately 50%. The risk of Lipidoses: Gaucher disease, Niemann-Pick disease, others
postsplenectomy sepsis depends on the age of the patient and the Mucopolysaccharidoses
nature of the underlying disorder. Patients younger than 3 years of Defects in carbohydrate metabolism: galactosemia, fructose intolerance
age and those with a compromised immune or reticuloendothelial Sea-blue histiocyte syndrome
system are most susceptible. When elective splenectomy is indicated, Miscellaneous Disorders
it is advisable to (1) postpone surgery until the patient is at least 5 to
6 years of age; (2) administer pneumococcal, meningococcal, and Histiocytoses
Haemophilus influenzae vaccines (if the patient was not previously Reactive
immunized) at least 1 to 2 weeks before splenectomy; (3) consider use Langerhans cell
of prophylactic penicillin for at least 4 years; and (4) manage significant Malignant
febrile illnesses as possible postsplenectomy sepsis at all times. In Sarcoidosis
addition to the risk of postsplenectomy sepsis, the rare complication Congestive heart failure
of postsplenectomy portal or splenic vein thrombosis must also be Familial Mediterranean fever
considered.
For children younger than 5 years of age with severe symptoms CMV, Cytomegalovirus; EBV, Epstein-Barr virus; TORCH, toxoplasmosis, other
from hemolytic anemia, hemoglobinopathy, or hypersplenism, partial infections, rubella, cytomegalovirus infection, herpes simplex.
splenectomy should be considered. In a number of studies, up to 90%
of the spleen has been removed safely, with a high rate of success
and preservation of splenic function. 409,410 Regrowth of the spleen to
variable degrees has been noted, with occasional need for reoperation.