Hepatomegaly



Hepatomegaly


Christina Bales



INTRODUCTION

Hepatomegaly is an important physical examination finding, which may reflect intrinsic liver disease or a wide array of systemic diseases. Determination of liver size may be achieved with a combination of techniques, including palpation, percussion, and auscultation. Among these, palpation is the most common approach. It is accomplished by applying gentle manual pressure to the right lower abdominal wall and advancing superiorly until the inferior border of the liver is appreciated with the fingertips. Extension of the liver below the xiphoid process and/or below the right costal margin in the midclavicular line by more than 3 cm in neonates or more than 2 cm in older children may suggest hepatomegaly. However, several pitfalls in this technique must be considered. Increased lung expansion, accumulation of air or liquid in the pleural or subdiaphragmatic space, and a narrow chest cavity (e.g., scoliosis or pectus excavatum) may all result in inferior displacement of the liver without actual hepatic enlargement. Presence of the Riedel lobe, a normal anatomic variant in which the right lobe of the liver extends far below the right costal margin, may also confound the examination. Thus, determination of the liver span is recommended. The span is measured by ascertaining the upper border via chest wall percussion and the lower border via one or more of the three aforementioned techniques. Auscultation is performed by placing the stethoscope below the xiphoid and “scratching” superiorly from the right lower quadrant until the lower edge of the liver causes a change in the transmitted sound. In neonates, the normal liver span is 4.5 to 5 cm. By 12 years of age, it measures 7 to 8 cm in boys and 6 to 7 cm in girls.

The differential diagnosis for pediatric hepatomegaly is expansive and is best organized by considering six broad mechanisms of liver enlargement (all beginning with the letter “I” for ease of recall): Infection, Inflammation (noninfectious), Inappropriate accumulation of fat, Infiltration, I mpaired outflow of blood or bile, and Inborn errors of metabolism resulting in abnormal cellular storage:


DIFFERENTIAL DIAGNOSIS LIST


Infection (Infectious Hepatitis)



  • Viral Infections



    • Hepatitis A to E


    • Epstein-Barr virus (EBV) (infectious mononucleosis)


    • Cytomegalovirus (CMV)



    • Herpesvirus


    • Varicella


    • Enterovirus


    • Adenovirus


    • Rubella


    • HIV


  • Bacterial Infections (± sepsis or abscess)



    • Bartonella henselae (“cat-scratch” disease)


    • Salmonella typhi


    • Streptococcus


    • Staphylococcus


    • Tularemia


    • Brucellosis


    • Listeria monocytogenes


    • Actinomycosis


    • Ehrlichiosis


    • Tuberculosis


  • Spirochete Infections



    • Treponema pallidum (syphilis)


    • Borrelia burgdorferi (Lyme disease)


    • Leptospirosis


  • Rickettsial Infections



    • Rickettsia rickettsii (Rocky Mountain spotted fever)


    • Coxiella burnetii (Q fever)


  • Fungal Infections



    • Aspergillus


    • Histoplasmosis


    • Coccidioidomycosis


    • Candidiasis


  • Parasite/Amoeba Infections



    • Entamoeba histolytica


    • Toxocariasis


    • Schistosomiasis


    • Clonorchis sinensis


    • Leishmaniasis


    • Plasmodium falciparum (Malaria)


Inflammation (Noninfectious Hepatitis)



  • Autoimmune hepatitis (AIH)


  • Primary sclerosing cholangitis


  • Juvenile idiopathic arthritis (JIA)


  • Systemic lupus erythematosus


  • Radiation


  • Giant cell hepatitis (neonatal)


  • Toxins



    • Organic (e.g., Amanita phalloides mushroom)


  • Drugs (e.g., acetaminophen overdose)


  • Alcohol


Inappropriate Accumulation of Fat



  • Obesity (nonalcoholic fatty liver disease (NAFLD) or nonalcoholic steatohepatitis (NASH))


  • Diabetes mellitus


  • Ethanol (chronic use)


  • Drugs (e.g., corticosteroids, valproic acid)


  • Parenteral nutrition (PN)


  • Protein malnutrition (kwashiorkor)


  • Celiac disease


  • Reye syndrome


Infiltration (Tumors and Other Cellular Infiltrates)



  • Tumors



    • Hepatoblastoma


    • Hepatocellular carcinoma


    • Hemangioma


    • Hemangioendothelioma


    • Metastasis (e.g., neuroblastoma)


  • Cellular Infiltrates



    • Extramedullary hematopoiesis (e.g., in sickle-cell disease)


    • Leukemia


    • Lymphoma


    • Langerhans cell histiocytosis (LCH)


    • Hemophagocytic lymphohistiocytosis (HLH)


    • Malignant histiocytosis


Impaired Outflow of Blood



  • Veno-occlusive disease (VOD)


  • Budd-Chiari syndrome


  • Congenital hepatic vein web/stenosis



  • Congestive heart failure


  • Constrictive pericarditis


  • Bile (extrahepatic cholestasis)



    • Biliary atresia


    • Choledochal cyst


    • Choledocholithiasis


    • Biliary ascariasis


  • Bile (intrahepatic cholestasis)



    • PFIC


    • Alagille syndrome


    • Nonsyndromic bile duct paucity


    • Cystic fibrosis


Inborn Errors of Metabolism of Lipids and Sphingolipids



  • Niemann-Pick disease


  • Gaucher disease


  • Wolman disease


  • Cholesteryl ester storage disease


  • Mucolipidoses


  • Fatty acid oxidation disorders


  • Proteins



    • Tyrosinemia


    • α-1 Antitrypsin deficiency


  • Carbohydrates



    • Mucopolysaccharidoses (e.g., Hunter, Hurler)


    • GM1 Gangliosidosis


    • Glycogen storage disease


    • Hereditary fructose intolerance


    • Galactosemia


    • Peroxisomes (e.g., Zellweger syndrome)


  • Metals



    • Iron (primary and secondary hemochromatosis)


    • Copper (Wilson disease)


DIFFERENTIAL DIAGNOSIS DISCUSSION


Viral Infection

It is not uncommon for children with viral syndromes to have modest hepatomegaly with mild elevations in transaminase levels. In most cases, the course is benign, and only observation for resolution of the infection is required. Certain hepatotropic viruses (listed above) may cause a more significant acute hepatitis, associated with tender hepatomegaly, jaundice, and marked elevations in liver transaminases. In rare cases, these findings may herald the onset of fulminant liver failure, and close observation with monitoring of liver synthetic parameters, including prothrombin time/international normalized ratio (PT/INR), albumin, and glucose levels, is warranted. Viral hepatitis is discussed in further detail in Chapter 45, “Jaundice.”


Infectious Mononucleosis

Infectious mononucleosis is discussed in Chapter 50, “Lymphadenopathy.”


CMV Infection

CMV Infection is discussed in Chapter 73, “Splenomegaly.”


HIV Infection

HIV-related cholangiopathy, typically associated with CMV, Microsporidia or Cryptosporidia superinfection, is the most common hepatic manifestation of advanced HIV infection. Patients may present with abdominal pain, diarrhea, icterus or jaundice, and hepatomegaly. Widespread implementation of HAART therapy has reduced the incidence of this complication. The course of chronic
HBV and HCV infection may be more severe in the setting of HIV coinfection. HIV infection is discussed in further detail in Chapter 70, “Sexually Transmitted Diseases.”


Liver Abscess


Etiology

In the United States and other developed countries, pediatric liver abscess is a rare phenomenon, primarily caused by bacteria. Staphylococcus, anaerobes, and gram-negative rods are the predominant culprits. Parasitic agents, including Entamoeba histolytica and Echinococcus granulosa, predominate in underdeveloped nations, where liver abscess is more common. Risk factors for liver abscess in the pediatric population include:



  • Immunodeficiency (e.g., chronic granulomatous disease, history of bone marrow transplant)


  • Congenital biliary obstruction (e.g., biliary atresia, choledochal cyst)


  • Inadvertent portal vein cannulation with umbilical vein catheterization of the neonate


  • Liver transplantation


  • Inflammatory bowel disease


Clinical Features

Patients may present with fever, pain/tenderness in right upper quadrant, anorexia, nausea, vomiting, and, occasionally, jaundice. Signs can be subtle, particularly in the immunocompromised patient, and a high index of suspicion may be required.


Evaluation

The white blood cell count, alanine aminotransferase (ALT), aspartate aminotrans-ferase (AST), and alkaline phosphatase levels are usually increased. Blood cultures identify a bacterial organism in 50% of cases. Amebic infection can be diagnosed with indirect hemagglutination (90% sensitivity) or IgG enzyme immunoassay (99% sensitive). Ultrasound, computed tomography (CT), and magnetic resonance imaging (MRI) are useful imaging modalities.



Treatment

Initial therapy involves empiric broad-spectrum intravenous antibiotic therapy. A typical regimen includes triple therapy with ampicillin, a β-lactamase inhibitor, and metronidazole. CT- or ultrasound-guided percutaneous aspiration with or without drain placement is generally advocated for abscesses ≥5 cm in diameter. Open surgical drainage is indicated in cases of spontaneous abscess rupture or failed percutaneous drainage.


Autoimmune Hepatitis


Etiology

Autoimmune hepatitis is a progressive inflammatory disease that is likely caused by dysregulated immune reactions to host liver antigens. Genetic and environmental factors have been implicated.



Clinical Features

Autoimmune hepatitis is more prevalent in female patients. A personal history or family history of other autoimmune disease may be elicited. The clinical presentation may mimic acute viral hepatitis. A subset of these patients will develop progression to acute liver failure within weeks of initial manifestations. The presentation may also be more insidious. In these cases, vague constitutional symptoms, such as fatigue, anorexia, and headache, predominate with or without relapsing icterus/jaundice. Approximately 10% of patients remain asymptomatic until signs of portal hypertension evolve. Given the highly varied presentation, AIH should be considered in the differential diagnosis of both acute and chronic hepatitis, as well as more advanced cirrhosis.


Evaluation

Physical examination may reveal signs of acute hepatitis, including fever, icterus/jaundice, and tender hepatomegaly, or stigmata of chronic liver disease, including splenomegaly, ascites, dilated abdominal wall veins, spider nevi, and palmar erythema. In addition to transaminase elevation with or without conjugated hyperbilirubinemia, laboratory studies often reveal an elevated globulin fraction (i.e., total protein to albumin ratio). Levels of autoantibodies, including antinuclear, antismooth muscle, and anti-liver-kidney-microsomal antibodies, may be elevated. Liver biopsy is necessary to establish the diagnosis, and classically reveals interface hepatitis with plasma cell involvement. The PT/INR and albumin level should be evaluated in all patients to ensure preservation of liver synthetic function.

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Sep 14, 2016 | Posted by in PEDIATRICS | Comments Off on Hepatomegaly

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