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1. Alpha-1 antitrypsin deficiency
The patient was diagnosed with alpha-1 antitrypsin (AAT-1) deficiency. Although there are reports of second-hand smoke causing lung disease, the presentation is classic for alpha-1 antitrypsin deficiency other than the patient is presenting somewhat later in life than usual. Topamax does not cause emphysema.
In AAT-1 deficiency circulating levels of AAT-1 are reduced due to an inherited deficiency usually seen in patients of Northern European origin. AAT-1 normally binds elastase released by neutrophils in the lung preventing tissue breakdown and emphysema. The obvious treatment is to replace circulating AAT-1 by infusion. However, when this was first proposed in the early 1980's it was dismissed as foolish and impractical. However, time has shown that AAT-1 replacement results in a reduction in the rate of decline of FEV1. However, the rate of decline varies between patients and AAT-1 replacement is quite expensive (usually over $80,000/year) and will not reverse severe emphysema. Lung transplant or lung volume reduction surgery can be performed on those with more severe emphysema.
Our patient had an AAT-1 level of 27.7 mg/dL (normal 150-350) and was phenotyped as ZZ rather than the normal MM. She is currently receiving alpha-1 replacement therapy and doing well.
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