Niemann-Pick Disease

Epidemiology:

  • Predisposed Group: Ashkenazi jews (for type A only)

Physiology

  • Inheritance: autosomal recessive
  • Lysosomal Storage Disease: sphingomyelinase deficiency (in types A and B only) with sphingomyelin and cholesterol deposition
    • Deficiency of sphingomyelinase: accumulation of sphingomyelin in reticuloendothelial system, CNS, and lung
    • Pulmonary Hypertension: due to capillary occlusion

Pathologic Patterns

  • Desquamative interstitial pneumonia (DIP)

Diagnosis

  • Sphingomyelinase: deficient
    • Diagnostic
  • Bone Marrow Bx: Niemann-Pick cell
    • Sea-blue histiocytes

Clinical Variants

  • Type A Niemann-Pick Disease
    • Epidemiology: onset shortly after birth -> rapidly fatal
    • Clinical
      • Hepatosplenomegaly
      • Failure to thrive
      • Neurologic impairment
      • Retinal cherry-red spots: rare
  • Type B Niemann-Pick Disease
    • Epidemiology: onset in teens-20’s -> relatively benign form
    • Clinical
      • Hepatosplenomegaly
      • Hematologic Involvement: platelet dysfunction, coagulopathy
      • Pulmonary Involvement: usually asymptomatic
        • Interstitial Lung Disease (see ILD-Etiology, [[ILD-Etiology]]): usually asymptomatic
        • CXR/Chest CT: interstitial lung disease with diffuse nodular infiltrates
        • PFT’s: mild restriction with decreased DLCO
        • OLB: foamy alveolar macrophages
        • Pulmonary Hypertension (see Pulmonary Hypertension, [[Pulmonary Hypertension]]): only one reported case
      • Usually no neurologic impairment, but can manifest cerebellar ataxia
      • Brownish skin
  • Type C Niemann-Pick Disease
    • Epidemiology: onset in childhood
    • Clinical
      • Progressive neurologic deterioration
      • Retinal cherry-red spots

Treatment

  • xxx

References

  • xxx