Splenomegaly

Matthew J. Ryan

INTRODUCTION

Splenomegaly may be evident in benign viral infections, serious systemic infections, hematologic diseases, neoplastic conditions, and metabolic disorders. The terms “splenomegaly” and “hypersplenism” are not interchangeable. Splenomegaly refers to an enlarged spleen, whereas hypersplenism refers to a hyperfunctioning spleen that results in a reduction in the number of circulating blood cells. Hypersplenism is usually associated with splenomegaly, but not always.

A palpable spleen tip is not necessarily pathologic. Approximately 3% of older adolescents and adults have palpable spleens. A palpable spleen is detected in most premature infants and up to 30% of term infants. By adulthood, the normal spleen, which is located beneath the 9th and 11th ribs, reaches dimensions of 12 cm long, 7 cm wide, and 3 cm thick. Normal spleens are soft, located at the mid-clavicular line, nontender and often only palpable on deep inspiration. Splenic tenderness or a spleen edge >2 cm below the costal margin is always abnormal. A normal-size spleen being pushed down by hyperinflated lungs may cause apparent splenomegaly.

HINT: Percussion can be used to evaluate splenic size. To delineate the lower “tip,” the examiner starts in the area of tympany in the left anterior axillary line of the mid-abdomen and percusses upward toward the splenic dullness. The upper border is defined by starting in the left midaxillary line of the midthorax and percussing downward toward the splenic dullness. Proper abdominal exam on a relaxed abdomen is critical to palpate an enlarged spleen. Begin in the left lower quadrant (an enlarged spleen may be missed by beginning in the left upper quadrant). Stand on the patient’s right side and use the right hand to palpate while supporting the rib cage with the left hand.

DIFFERENTIAL DIAGNOSIS LIST

Infectious Causes

Viral Infection

Adenovirus
Mononucleosis (Epstein-Barr virus [EBV] infection)
Cytomegalovirus (CMV) infection
Coxsackievirus
HIV
Rubella
Herpes
Hepatitis A, B, C

Bacterial Infection

Pneumonia
Sepsis
Endocarditis
Brucellosis
Tularemia
Splenic abscess
Cat-scratch disease—Bartonella sp.
Tuberculosis
Syphilis
Leptospirosis
Rocky Mountain spotted fever (RMSF)—Rickettsia rickettsii
Salmonella infection
Streptococcal infection
Ehrlichiosis

Other Infections

Malaria
Toxoplasmosis
Babesiosis
Histoplasmosis
Coccidioidomycosis
Schistosomiasis
Trypanosomiasis

Neoplastic Causes

Leukemia
Lymphoma
Lymphosarcoma
Hamartoma
Metastatic disease (neuroblastoma)

Traumatic Causes

Laceration
Hematoma
Traumatic cyst

Metabolic or Genetic Causes

Lipid Metabolism Defects

Gaucher disease
Niemann-Pick disease
Gangliosidoses
Mucolipidoses
Metachromatic leukodystrophy
Wolman disease

Mucopolysaccharidoses

Hurler syndrome
Hunter syndrome

Hematologic Causes

Red Blood Cell (RBC) Membrane Defects

Hereditary spherocytosis
Hereditary elliptocytosis
Hereditary stomatocytosis

RBC Enzyme Defects

Glucose-6-phosphate dehydrogenase (G6PD) deficiency
Pyruvate kinase deficiency

Hemoglobin Defects

Sickle cell disease (SCD)
Thalassemia

Extrinsic Hemolytic Anemias

Autoimmune hemolytic anemia
Erythroblastosis fetalis

Congestive Causes

Congestive heart failure
Constrictive pericarditis
Chronic liver disease with portal hypertension
Perisplenic anatomic obstructions
Splenic vein thrombosis
Splenic artery aneurysm
Cavernous transformation of the portal vein

Miscellaneous Causes

Serum sickness
Splenic hemangioma
Chronic granulomatous disease
Juvenile rheumatoid arthritis (JRA)
Systemic lupus erythematosus (SLE)
Autoimmune hepatitis

Histiocytic Disorders

Langerhans cell histiocytosis
Hemophagocytic lymphohistiocytosis
Malignant histiocytic disorders
Beckwith-Wiedemann syndrome
Amyloidosis
Sarcoidosis
Congenital splenic cyst

DIFFERENTIAL DIAGNOSIS DISCUSSION

Benign Infection

Many benign infections, especially upper respiratory tract infections, can be associated with mild, transient splenomegaly. Adenovirus, coxsackievirus, and Streptococcus are commonly involved organisms.

Epstein-Barr Virus Infection (Infectious Mononucleosis)

Infectious mononucleosis is discussed in Chapter 50, “Lymphadenopathy.” Of note, splenomegaly may persist for several months after resolution of mononucleosis. The splenomegaly should be resolved before the athlete returns to contact sports.

Cytomegalovirus Infection

Epidemiology

CMV is ubiquitous, and most people are infected with the virus by adulthood. The source is body fluids, including blood, urine, breast milk, saliva, and feces. Transmission of CMV is both horizontal (person to person) and vertical (mother to child). CMV is the most common congenital viral infection.

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