Mark Crislip, MD, Infectious Diseases, 11:48PM May 22, 2013
I wish I was half as smart as I like to think I am. Medicine is often about making decisions with the data at hand and sometimes those decisions are wrong. Maybe if I were smarter I would be closer to perfect.
The patient is a new hire as a nursing assistant and part of the evaluation is a PPD. Being from Africa, it is not a surprise that the PPD is a whopping positive, so they send the patient to me.
He has no symptoms of TB, no consumption, no pulmonary complaints. He has no good history of TB exposure but coming from Sub-Saharan Africa it is likely he had multiple unrecognized exposures in his life.
Chest X-ray is interesting. I would have called it normal. Radiology, and this is why we have radiologists, say there is a faint right upper lobe infiltrate. I see it only after reading the radiologists report.
Patient does not have a cough, much less sputum production, and I have to know what is in that right upper lobe. With hesitation I arrange a bronchoscopy.
The specimens are negative on smear and the cultures are negative at three weeks, and the patient is without symptoms and is anxious to start earning an income, so I think, it's not TB, probably not infectious TB given no cavity or cough, so it is OK to return to work. If they had been in the hospital for r/o TB I would have called them good to go.
You know where this is going.
At the start of week five AFB are growing and it is MTB. Expletive deleted.
It is probably early reactivation TB and he is mostly controlling it. A repeat CXR shows the infiltrate is a tich worse, a slightly nodular smudge, like a Messier object.
He is still completely without symptoms and off work.
Active TB remains difficult to diagnose with alacrity, even after 400 years of infecting humans. Can't even trust a negative chest x-ray to rule out the disease:
"The rate of normal CXR among persons with culture-confirmed pulmonary TB was high. Respiratory specimen cultures should be obtained in TB suspects with a normal CXR, particularly HIV-infected persons."
Oh well. Live and learn. At least no harm done.
"If I had all the answers, I'd run for God." Max Klinger
Int J Tuberc Lung Dis. 2008 Apr;12(4):397-403. Normal chest radiography in pulmonary tuberculosis: implications for obtaining respiratory specimen cultures.