A Common Complaint with an Unexpected Diagnosis: A Case of Mycobacterium avium Complex Pulmonary Abscesses

Authors

Maryam Fallahi, HCA HealthcareFollow
Mark Cheneler, HCA HealthcareFollow
Qazi Haider, HCA HealthcareFollow
Madhukanth Reddy

Files

Division

North Texas

Hospital

Medical City Weatherford

Specialty

Internal Medicine

Document Type

Poster

Publication Date

2024

Keywords

Mycobacterium avium, pulmonary infections

Disciplines

Bacterial Infections and Mycoses | Internal Medicine | Medicine and Health Sciences | Respiratory Tract Diseases

Abstract

Introduction: Mycobacterial infections are an atypical organism for pulmonary infections. These infections are classically separated in tuberculous (MTB) and nontuberculous (NTM) groups due to their differing pathogenicity and microbiologic therapy regimens. MTB is typically treated with a 4-drug therapy known as RIPE (rifampin, isoniazid, pyrazinamide, and ethambutol) however NTM is typically treated with 3- or 4-drug therapy with a backbone of rifampin, macrolide, and ethambutol. Due to the long courses of therapy required for NTM, stringent diagnostic criteria of clinical, radiologic, and microbiologic findings are required. Despite meeting all 3 criteria for diagnosis, not every patient is a candidate for systemic therapy. Treatment courses often extend to 18 to 24 months as 12 months of negative microbiology are necessary to deem a patient as cured. Here we present a case of Mycobacterium avium complex infection of the right lower lobe complicated by abscess formation. Case presentation: A 61-year-old female with past medical history of pneumonia 8 years prior to evaluation but otherwise no prior pulmonary medical history and no history of immunocompromising conditions present for evaluation of acute cough. She was found to have a right lower lobe pneumonia which was further evaluated with computed tomography (CT) of the chest revealing multiple abscesses in the right lower lobe. Evaluation for fungal infections of Aspergillus, Candida, and histoplasmosis were negative. A sputum acid-fast bacilli (AFB) culture would grow MAC sensitive to aminoglycosides and macrolides. She would be started on 4 drug therapy and has continued to follow-up in the infectious disease clinic. Discussion: Optimal patient selection for treatment remains difficult due to the extended length of treatment and potential for toxicity. With treatment lengths extending beyond 18 months, patient adherence must be taken to consideration. Previous studies have shown peak serum concentrations of antimicrobiologic therapy to frequently be below therapeutic range which is exacerbated by rifampin as a cytochrome P450 inducer. Liposomal amikacin for inhalation has shown potential to improve microbiologic conversion rates and has decreased systemic uptake and toxicity; however, cost remains a limiting factor for more widespread use. More studies are needed to develop optimal treatment regimens for patient compliance and microbiologic cure rates.

Original Publisher

HCA Healthcare Graduate Medical Education

Recommended Citation

Fallahi, Maryam; Cheneler, Mark; Haider, Qazi; and Reddy, Madhukanth, "A Common Complaint with an Unexpected Diagnosis: A Case of Mycobacterium avium Complex Pulmonary Abscesses" (2024). North Texas GME Research Forum 2024. 53.
https://scholarlycommons.hcahealthcare.com/northtexas2024/53