Question: Hi,

Initially I had some right sided chest pain which I suspected was related to GERD and wanted to investigate further without doing a gastroscopy.

I was advised for a CT and the report result reads:

There is a cluster of ill-defined nodules in the apical segment of the left lower lobe. There is no evidence of cavitation or calcification. The rest of the lungs are clear. There is no pulmonary consolidation, pneumothorax or pleural effusion.

The airways are patent. Incidental note of the posterior segmental bronchus of the right upper lobe, arising directly from right bronchus intermedius.

There is no mediastinal, hilar or axillary lymphadenopathy. The heart size is within normal limits. There is no pericardial effusion. The visualised upper abdomen is unremarkable.

No rib fracture, rib lesion or chest wall abnormality is detected. No significant bony abnormality is detected.

IMPRESSION

The cluster of ill-defined modules in the apical segment of the left upper lobe is likely inflammatory/infectious. Specifically, TB should be considered.
There is no cavitation or lymphadenopathy.


I had a sore throat roughly a week before doing this CT with low grade fever but initially no sputum production. However, there was sputum produced on the day of this CT scan but previously there was basically none.

I have done some initial tests on sputum for TB. The results were as follows:

28th Nov
Direct smear AFB (ZN Stain)
No Acid-fast bacilli seen

Gram Stain
Pus cells (+++)
Epithelial cells (few)
Gram positive rods (+)

Culture lower respiratory
No growth of pathogen


29th Nov
Smear Acid Fast Bacilli, No AFB seen

Culture, sputum final, No growth of pathogen

Gram Stain Final
White blood cells, Seen (3+)
Epithelial cells, Seen (few)
Gram positive cocci, Seen (1+)


30th Nov
TB Probetec
M. Tuberculosis complex DNA not detected
Nucleic acid amplification test results are preliminary, pending culture results.

METHOD: Strand displacement amplification (ProbeTec DTB Assay)
GENE TESTED: IS6110

COMMENTS:
A negative result does not exclude the possibility of low concentration of MTBC DNA, or MTBC variants that lack the IS6110 gene.

Performance data for smear-negative respiratory (n=83) and non-respiratory (n=422) samples

Respiratory specimens Non-respiratory specimens
ST 14/15 93.3% 31/31 100.0%
SP 68/68 100.0% 389/391 99.5%
PPV 14/14 100.0% 31/34 91.2%
NPV 68/69 98.6% 388/388 100.0%

Performance data for smear-positive (respiratory and non-respiratory) samples (n=55)

ST 46/46 100.0% PPV 46/46 100.0%
SP 9/9 100.0% NPV 9/9 100.0%

Please correlate this result with clinical, radiological and other laboratory findings.


Are there other tests that can be recommended for TB or should these tests be enough? Should I expect further culture results or do these culture results appear final?

Why is the quantiferon Gold test considered of limited value in many parts of the world? Should I have this test?

What could be other causes of the CT scan findings?


Thankyou.

Thanks Dr. Jolanda,

I will consider the simple skin test perhaps as further confirmation. Could you explain why the Quantiferon B test is of limited value in the cases of high incidence of TB? Can it distinguish between active and latent infection?

What sort of other tests can be done to find whether other mycobacteria are infecting the lungs currently? Would the culture of sputum or gram stain normally pick these up and should I also wait a few weeks to see the final culture results to find out if there are other bacteria in the lungs? Or do the culture tests normally specifically only try to culture one type of bacteria?



Thankyou.