Alpha-1-Antritrypsin deficiency
Clinical Signs:
Alpha-1-antitrypsin deficiency causes panacinar (pan-uh-sin-are) emphysema is responsible for 2% of all cases of emphysema in the US. Typically the patients are middle age. Other clinical symptoms are neonatal cholestasis (look it up), hepatitis, liver cirrhosis, and ulcerative panniculitis (look it up).
Etiology:
Mendelian inheritance consistent with deficiency gene. The gene for Alpha-1-antitrypsin is present on chromosome 14 and expressed in the hepatocyte and in the mononuclear phagocyte. Two Parental alleles, (all ells) Z type and S type, are codominantly expressed. Therefore phenotypes, null-null, ZZ, and SZ, are responsible for emphysema
Pathophysiology:
Inhibited proteases of leukocytic origin probably are partly responsible for the damage to the lung in the absence of the major protease(pro-tee-aze) inhibitor.
Pathology:
Pan lobular emphysema
Imaging:
Radiographically, severe emphysematous changes are present predominantly in the lower lobes. There may be increased vascularity of the upper lobes. Evidence of pulmonary hypertension and right ventricular enlargement is often present. The plain chest x-ray may not be particularly abnormal in the early stages.
On CT the increased involvement of the lower lobe is more apparent, and bullous change is not common. Bronchial wall thickening and dilatation (Arrowheads) are, however, quite common findings on high-resolution CT as are the areas of low attenuation that correlate with the presence of emphysema (Arrows).
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