Tuesday, June 27, 2006

AFB


This 83 y/o man with no COPD, no TOB Hx was referred to us by his PCP for 2-3 days of cough and low-grade fevers at home. He had had a cold the week before with some rhinorrhea and then developed low-grade fevers (~100) at home with scant purulent sputum and dyspnea as well as malaise. No night sweats, chills, weight loss or hemoptysis.
His exam was only remarkable for B/L ronchi, worse on the right. On admission, he had the fairly benign CxR above; WBC ~9K with a left shift and no other biochemical abnormalities. He had minimal hypoxemia and was started on ABTx for a purulent tracheobronchitis with dyspnea in an 83 y/o patient. He had a great clinical response within the first 24 hours and was D/C'ed home off O2 in 2 days.
His sputum smears were non-contributory but 2 weeks later I got a call from our lab that he was growing AFB in his sputum Cx.
Would you assume it is TB or would you favor a non-TB mycobacteria? Clinically he was doing great at this time and had finished his ABTx (doxycycline). What would you do next?

8 comments - CLICK HERE to read & add your own!:

Jennings said...

With his clinical improvemement, negative smear and negative CXR, I would wait for the cx to establish the identification - I agree it is likely to be non-TB mycobacteria. I assume he doesn't have a PPD? Does he have any risk factors for TB?

Baleeiro said...

No known exposures. We did place a PPD after the Cx started growing and it was very positive.

Jennings said...

I think you are obligated to assume this is active TB until proven otherwise (especially if the positive PPD is not old and that he wasn't treated for latent TB in the past).
Perhaps it is not radiographically apparent, or perhaps a CT would more readily identify the disease that is too small to be seen on plain film, but I think treatment pending official ID is in order. There should NOT be cross-reactivity (i.e. a positive PPD should not represent the non-TB mycobacterias) so she was exposed; I would treat for active TB and then if the sputum shows non-TB, I would switch to INH for latent TB.

Jennings said...

I think you are obligated to assume this is active TB until proven otherwise (especially if the positive PPD is not old and that he wasn't treated for latent TB in the past).
Perhaps it is not radiographically apparent, or perhaps a CT would more readily identify the disease that is too small to be seen on plain film, but I think treatment pending official ID is in order. There should NOT be cross-reactivity (i.e. a positive PPD should not represent the non-TB mycobacterias) so she was exposed; I would treat for active TB and then if the sputum shows non-TB, I would switch to INH for latent TB.

Jennings said...

On the other hand, since he is improved, that could be a contaminant at well. Doing nothing and waiting for the sputum identification would also be reasonable. If negative, you could just treat for latent TB.

Jeff H said...

If not for the + PPD, I would have said, without a doubt, that you should wait for the final ID. With the positive PPD, we have to believe that the patient has TB, or has latent TB. In either case, it may be unrelated to the tracheobronchitis. If the patient is now asymptomatic, given the unremarkable CXR, I still think it is reasonable to wait for a final ID. If it is non-TB, the patient should be treated for latent-TB. The other option (equally defensible) is to start 4 drugs and, it it turns out to be non-TB, scale back to treatment of latent-TB.

I think that the only clearly WRONG thing to do in this situation is to start treating for latent TB before a definitive ID of the AFB+ but.

Jeff H said...

bug, that is.

zolt said...

How much was the ppd reading?
ppd more than 20 mm has no differential other than myco.tb!