which they said that the site most affected by primary tuberculosis was the lower/middle lung . I found it a bit strange since I saw in a few sources(including sketchy and other textbooks ) that M tuberculosis site of predilection was the apex of the lung due to the high V/Q relation . Maybe I’m making confusion with concepts. Any help with it will be greatly appreciated
Primary TB : ghon foci in lower lungs. Reactivation: cavitary lesion in Upper lungs particularly apex
thanks a lot ! Makes sense , sketchy says that the primary site for cavitations is the apex and progression of this secondary disease can affect middle, lower lobes
I’m using sketchy too. I’m pretty sure it says primary tb is in middle/lower lung (in the sketch, it’s located in the left, where you see the holes in cactus is in the middle).
And reactivation is in the upper lobe (in the sketch, it’s located in the right, with holes in cactus in upper portion)
Usually It is the secondary TB that presents with symptoms or disseminated. Primary Tb affects the lower lobes mostly.
Primary infection goes with the aspiration way … middle or lower
Reactivation choose to be in a more ventilated less perfused area which is the apex …
Think “1ry is obligated to go with the inspired air direction… but reactivation can choose best ventilated area “obligate aerobe” & least perfused “less immunity”which is the apex”.