Primary and Secondary TB

Find out how TB can cause primary disease (soon after your first infection) or secondary disease (months/years after your first infection). Rishi is a pediatric infectious disease physician and works at Khan Academy.

These videos do not provide medical advice and are for informational purposes only. The videos are not intended to be a substitute for professional medical advice, diagnosis or treatment. Always seek the advice of a qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read or seen in any Khan Academy video.

[Parentstock]

10minutes video = two hours of book reading. Amazing work 🙌

[serialreader]

No where on earth could you find a better explicative video than this one !

[nooralhoda]

the best video i saw to understand primary and secondary tb infection, i've past a whole day to understand it from other sources until i found this easy and organized explanation, thanks a lot!🎩🎩🎩

[MiaZaheeyaSofea]

he explains in all his videos humorously haha! love it, made my revisions more fun. thank you

[kevinc]

Wife works at a kidney dialysis center...she tested positive a week ago go chest x-rays today ...follow up tomorrow to find out what they found....this is crazy she is always happy always helping people and always kind.

[heyhaylie]

Khan Academy is the best! And the different colors that he uses just makes it fantastic!!!! Thanksss soo much!

[basicslime]

You are amazing you just saved my pathology exam thank you so much.

[doconboard]

Awesome.. This is the first time i am able to understand this topic With such a clarity..thanks 😊

[MiaZaheeyaSofea]

he explains them videos so humurously..haha! love it makes me revision more fun

[xiaoleiqu]

I hope you are my professor. This is so helpful.

[callumweeks]

Sahhh good to have this visual on the different prgressions of the disease. Excellent compliment to my path lecturer's cytokine detail.

[eyeofthetiger]

thats so awesome, so simplified!!! TY TY TY TY

[HafizahHoshni]

Simply excellent. Very grateful for clear, concise and well presented video. Thank you for the great channel. 9/8/2018 😊

[nat]

really useful for revision, thanks for this

[HZuckermann]

Cheesy Death! I like it, some of the youtube tutorials I've watched made by other people are so bland but you've got an interesting tone and you add a bit of humour - much more memorable! Thank you, keep up the great work.

[longtran]

The video sound is pretty good, beyond my imagination

[sumrar]

Excellent, thank you for explaining it so clearly!

[railzip]

Perfect!!! I have to write a paper on this

[Strawberry-cuwr]

I cant seem to watch other videos on bio cos urs are the best

[hraza]

Thank you. How do I tell the difference between primary and secondary infection in a vignette, if they dont give the location of the lesion in the lung? I only knew child for primary and adult for secondary, but I had one question where there was an adult and i had to choose the answer for primary.

Also why does Secondary TB affect the upper lobe and not the bottom? I heard two reasons, which is correct? One is that the upper lobe has higher V/Q so more vent RELATIVE to perfusion, and the other reason was that the TB is trying to run away from the now developed immune system by going to the area of least perfusion, and doesnt care about ventilation by this point(otherwise it wudve gone to the bottom)