bluedusk
Forum Elite
Topics: 35
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is anyone certain whether alveolar-arterial gradient is decreased in restrictive lung disease?
one interp. is that restrict. and obstruc. mainly affect filling changes (not a-a gradient), while it takes a vent or perfusion defect to affect a-a gradient.
however, it seems to me that restrictive disease (for example, a pneumoconiosis) could affect gas diffusion, and therefore also a-a gradient.
anyone know the "board" answer for this?
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| Malaysian
Forum Guru
Topics: 28
Posts: 778
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In my opinion I'm more for the former statement.I guess the only way the restrictive lung disease can cause an increase in the gradient is if the disease is widespread and involves most of the lung.
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| bluedusk
Forum Elite
Topics: 35
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i found the answer! it's in goljan's textbook (i love this man). actually, it's a little amazing how this isn't addressed more firmly in his lectures.
so, you DO get an increased a-a in both restrictive and obstructive disease. in restrictive because of diffusion abnormalities, and in obstructive because of the increased dead space (and shunting) from air not getting to the alveoli past blocked terminal bronchioles.
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| bluedusk
Forum Elite
Topics: 35
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that should be, for obstructive lung disease, increased ventilation defects and therefore shunting. apologies.
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