A 10-year-old girl exhibits the following symptoms: marked hepatomegaly, variceal bleeding, chronic bilateral pulmonary infiltrates, chronic liver disease, hepatic encephalopathy, and only 5% of normal sphingomyelinase activity in peripheral blood leukocytes. What is the most likely diagnosis?

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Quizplus · Accepted Answer

The symptoms and low sphingomyelinase activity are indicative of Niemann-Pick disease type B, which is characterized by hepatomegaly, pulmonary issues, and liver disease due to sphingomyelin accumulation. Niemann-Pick disease (NPD) comprises two distinct but related types of lipid storage disorder, termed type 1 and type 2. In addition, type 1 NPD comprises two subtypes, type 1A (NPA) and type 1B (NPB), both of which result from defects in acid sphingomyelinase. The type 2 forms of NPD lead to accumulations of abnormal LDL-cholesterol. NPA is a disorder that leads to infantile mortality. NPB is variable in phenotype and is diagnosed by the presence of hepatosplenomegaly in childhood and progressive pulmonary infiltration. Pathologic characteristics of the type 1 Niemann-Pick diseases are the accumulation of histiocytic cells that result from sphingomyelin deposition in cells of the monocyte-macrophage system.

A 10-Year-Old Girl Exhibits the Following Symptoms: Marked Hepatomegaly, Variceal