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
- Bone Marrow Bx: Niemann-Pick cell
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
References
