Quinolone duration for Legionella if myasthenia present?

I had spoken to you about a very sick patient with severe Legionella pneumonia. He had renal failure from severe rhabdomyolysis, intubated, and in septic shock. Thank you so much for your help. He finally walked out the hospital. I have a question about another severe Legionella pneumonia patient. This patient has cavitary Legionella pneumonia but has myasthenia gravis. I have him on Avelox and Zithro.


As you know the Avelox is already worsening his myasthenia. He was very sick with a big consolidation and abscess now extubated doing well only on Avelox and Zithro. I do not think I can give anything else. I am planning on giving him 6 weeks of above regimen while I watch closely for respiratory compromise. Do you have any ideas? Thank you so very much for your help.


Congratulations on your successful therapy for a patient with shock, rhabdomyolysis, and renal failure. These are all risk factors for high mortality, so your patient was fortunate that you were his physician.

With respect to 6 weeks of therapy with the quinolone in face of a history of myasthenia gravis: If this patient has no other immunosuppressive risk factor including corticosteroids, 6 weeks of antibiotic therapy is likely unnecessary. If his myasthenia gravis is worsening on therapy and his pneumonia is under control, the quinolone might be discontinued. Azithromyin has been used successfully as monotherapy for many patients, as you know. And, if combination therapy is used for severely-ill patients, the advantage of combination therapy will be in the first few days of therapy.

So, you have the option of discontinuing the moxifloxacin now and using azithromycin only. Total duration might be 14 days if he is afebrile and clinically improving. The chest radiograph gives an indication of severity of illness at onset, but radiographic resolution cannot be used as a prognostic sign.