A rare presentation of Legionella pneumophila and Mycobacterium intracellulare co-infection masquerading as metastatic lung cancer in a patient with positive anti-interferon gamma antibody.

Adult-onset immunodeficiency (AOID) syndrome due to the presence of anti-interferon gamma antibody (AIGA) is characterized by multiple opportunistic infections. We report a case of a 65-year old healthy woman who suffered from Legionella pneumophila and Mycobacterium intracellulare co-infection with clinical presentation mimicking metastatic lung cancer. She presented with chronic cough and weight loss. Her positron emission tomography scan showed a right upper lobe mass, mediastinal lymphadenopathy and multiple bone lesions. Acid fast bacilli culture of the lung mass and mediastinal lymph node revealed Mycobacterium intracellulare and she improved with prolonged antibiotic. Relapse of disseminated Mycobacterium intracellulare infection occurred 15 months post-treatment and AIGA was positive with functional neutralizing activity on downstream immune pathway. AOID syndrome secondary to AIGA was diagnosed. This case illustrated the importance of high index of suspicion of AOID syndrome and the difficulty of early diagnosis. Further studies on its predictive factors and AIGA-targeted treatment modalities are urgently needed.

Prevalence, risk factors, and recurrence risk of persistent air leak in patients with secondary spontaneous pneumothorax.

Background: Persistent air leak (PAL) is common in secondary spontaneous pneumothorax (SSP), with risk factors only been determined for post-pulmonary resection PAL. Information about its risk factors and long-term outcome is, however, necessary to enable selection of treatment modalities for elderly SSP patients with comorbid conditions. Methods: A retrospective observational study was performed on chest drain-treated SSP patients from 2009 to 2018. The risk factors, long-term recurrent pneumothorax, and mortality rates of those with and without PAL were evaluated. Results: Of 180 non-surgical SSP patients, PAL prevalence for >2 days and >7 days were 81.1% and 43.3%, respectively. Bulla was associated with PAL >7 days (OR: 2.32; P: 0.027) and serum albumin negatively associated (OR: 0.94; P: 0.028). PAL resulted in longer hospitalization in the index episode (P: <0.01). PAL >7 days was associated with a higher pneumothorax recurrence rate in three months (HR: 2.65; P: 0.041), one year (HR: 2.50; P: 0.040) and two-year post-discharge (HR: 2.40; P: 0.029). Patients treated with medical pleurodesis were significantly older (P: <0.01), had higher Charlson Co-morbidity index scores (P: <0.01), and 77.8% of those who had PAL >7 days were considered unfit for surgery. Of these, pneumothorax had not recurred in 69.4% after two years (HR: 0.47; P: 0.044). Conclusion: Bulla was positively associated with PAL over seven days in SSP patients while albumin was negatively associated. PAL over seven days increased future recurrent pneumothorax risks, while elderly SSP patients unfit for surgery had acceptable recurrence rates after medical pleurodesis.