Does Fluoroquinolone Use Affect Tuberculosis Diagnosis?

Q: Does Fluoroquinolone Use Affect Tuberculosis Diagnosis?

Hello： Based on your description, I will prioritize considering a fungal infection. <br>If the culture results from the second hospital show no tuberculosis, I will be less concerned about tuberculosis. <br>Since the sputum smear is negative, there is no need to wear a mask conti

Does the use of fluoroquinolones affect the diagnosis of pulmonary tuberculosis?

Hello Dr.
Yang, I am a pharmacist.
My boyfriend (who is the same age as me) previously went to the emergency room due to a fever, and an X-ray revealed lesions in his lungs.
The doctor prescribed fluoroquinolones (FQ) for him, and after taking them for 12 days, it was found that the lesions had not completely resolved on the X-ray.
He was then scheduled for a CT scan and sputum analysis (at this point, he had no cough or sputum production, which initially included red sputum).
The sputum smear and culture results were negative, but the CT scan indicated a cavitary lesion in his right upper lung.
I feel a bit uneasy because I have read articles suggesting that FQ can lead to misdiagnosis and delayed diagnosis, so I advised him to seek a second opinion at another hospital.
At the second hospital, he underwent bronchoscopy (40 days after stopping FQ), and they informed him that the smear for tuberculosis was negative, but he would need to wait for the culture results.
However, the smear also indicated a fungal infection.

I would like to ask Dr.
Yang if the smear culture results from the second hospital are reliable? Is it possible that the prior use of FQ led to a false negative result in the smear? He has recently attended a funeral and is very anxious about potentially infecting others present.
Additionally, does he need to wear a mask at all times after the lung cavitation? Will it heal? Is it true, as stated in online articles, that he is at a higher risk of being infected by other pathogens or developing lung cancer? Is the fungal infection necessarily related to tuberculosis, or could it be a simple fungal infection? Thank you for your patience in reading and answering my questions.

Wang Dada, 30~39 year old female. Ask Date: 2024/04/13

Dr. Yang Wenda reply Pulmonology

Hello: Based on your description, I will prioritize considering a fungal infection.
If the culture results from the second hospital show no tuberculosis, I will be less concerned about tuberculosis.
Since the sputum smear is negative, there is no need to wear a mask continuously, as it may cause unnecessary worry among others! The cytology of the bronchial washings did not reveal any malignant cells, so lung cancer is not a concern for now.
Regular imaging follow-ups will be conducted to monitor any changes in the lesions in the future!

Reply Date: 2024/04/13

More Info

Fluoroquinolones (FQs) are a class of antibiotics commonly used to treat various bacterial infections, including respiratory tract infections. However, their use can complicate the diagnosis of tuberculosis (TB), particularly in cases where TB is suspected but not yet confirmed.
In your boyfriend's case, the initial use of FQs for a suspected lung infection may have masked the presence of TB. This is because FQs can suppress the growth of certain bacteria, potentially leading to false-negative results in sputum smear tests and cultures for Mycobacterium tuberculosis. The antibiotics may reduce the bacterial load, making it more difficult to detect TB in laboratory tests. Therefore, it is plausible that the initial negative sputum smear and culture results could have been influenced by the prior administration of FQs.

The fact that your boyfriend underwent a bronchoscopy after stopping the FQ treatment is significant. Bronchoscopy allows for more direct sampling of lung tissue and secretions, which can provide a clearer picture of the underlying pathology. The negative smear for TB bacilli is reassuring, but it is essential to wait for the culture results, as they can take several weeks to confirm or rule out TB. Cultures are more sensitive than smears and can detect lower levels of bacteria.

Regarding the presence of a cavitary lesion (the "hole" in the lung), this can occur in various pulmonary conditions, including TB and fungal infections. The presence of a cavity does not automatically indicate active TB, especially if the cultures are negative. However, it does warrant careful monitoring and follow-up, as cavitary lesions can be associated with an increased risk of secondary infections, including fungal infections like aspergillosis, which could explain the positive culture for fungi.

As for your concerns about transmission, if your boyfriend is confirmed to be free of TB, the risk of transmission to others is significantly reduced. However, if there is any uncertainty, wearing a mask is a prudent measure to prevent potential spread, especially in crowded or enclosed spaces.
Cavities in the lung can heal over time, but the healing process depends on the underlying cause of the cavity. If it is due to an infection that is being treated effectively, the cavity may close up. However, if there is ongoing infection or other complications, it may not heal properly.
Regarding the risk of lung cancer or other infections, it is essential to understand that while cavitary lesions can be associated with an increased risk of certain complications, this does not mean that your boyfriend will inevitably develop these conditions. Regular follow-up with a healthcare provider is crucial to monitor his lung health and address any concerns.

Finally, regarding the relationship between fungal infections and TB, it is possible for someone to have a fungal infection without having TB. Fungal infections can occur independently, particularly in individuals with compromised immune systems or underlying lung conditions.
In summary, the use of fluoroquinolones can complicate the diagnosis of tuberculosis, and while your boyfriend's initial tests were negative, the subsequent bronchoscopy and culture results will provide more clarity. It is essential to maintain open communication with healthcare providers and follow their recommendations for monitoring and treatment.

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