Multiple Bone Destruction Secondary to Mycobacterium kansasii Pulmonary Disease: A Case Report

Abstract

Mycobacterium kansasii infections predominantly manifest in immunocompromised people and are primarily responsible for lung disease and systemic disseminated infection. Osteopathy is a rare consequence of M. kansasii infection. Here, we present imaging data from a 44-year-old immunocompetent Chinese woman diagnosed with multiple bone destruction, particularly of the spine, secondary to M. kansasii pulmonary disease, which is easily misdiagnosed. The patient underwent an emergency operation after experiencing unexpected incomplete paraplegia during hospitalization, indicating an aggravation of bone destruction. Preoperative sputum testing and next-generation sequencing of DNA and RNA of intraoperative samples confirmed the diagnosis of M. kansasii infection. Treatment with anti-tuberculosis therapy and the subsequent patient response supported our diagnosis. Given the rarity of osteopathy secondary to M. kansasii infection in immunocompetent individuals, our case offers some insight into this diagnosis.

Mycobacterium kansasii is one of the most prevalent species worldwide [1,2], typically found in municipal water [3]; it predominantly affects men and the elderly [4] and has risk factors such as structural lung damage, immunosuppression, and association with certain medications [5]. M. kansasii is primarily responsible for lung disease and systemic disseminated infection in immunocompromised individuals and is rare in immunocompetent people. Osteopathy is a rare sequela of such M. kansasii infections that commonly manifest as osteomyelitis. Only seven such cases involving immunocompetent individuals have been documented in the literature, of which four involving the spine are identical to our case [6,7,8,9,10,11,12]. Here, we describe a rare case of an immunocompetent patient who had a diagnosed systemic M. kansasii infection with spinal involvement and show her imaging performance before (Figure 1) and after (Figure 2) admission.

Although the pathogen development resembles that of tuberculous bacteria, the mechanism of non-tuberculous Mycobacteria (NTM) remains unknown. Patients without HIV infections may be affected by anomalies in the IFN–interleukin-12 (IL-12) axis and T cell + lymphopenia [13,14]. In this case, the patient had reduced T-cell and elevated IFN–autoantibody counts. Given the onset of her symptoms after age 40 and no previous history of recurrent infection, a genetic cause for her disease is less likely. However, patients with NTM infections may require testing for latent immunodeficiency, particularly if they exhibit systemic dissemination and a confirmed M. kansasii infection, as in this case. This patient was previously suspected and misdiagnosed as having lung cancer with bony metastases in the long term because of the resembling imaging performances of the lung and multiple bone lesions and a family history of lymphoma contributing to her father’s death. This misdiagnosis is clinically common if species identification results are not obtained [15,16]. Therefore, clinicians must look for signs of pathogens while diagnosing cancer. Infections by unique pathogens should be considered for people who exhibit symptoms similar to this patient. The cultivation of NTM should be a part of the ongoing research of potential diseases. Moreover, this patient underwent several invasive procedures and biopsies without conclusive proof, which resulted in persistent complaints and unsatisfactory therapeutic outcomes. Disseminated diseases require widespread diagnostic evidence, and thus, clinicians must acquire specimens from all possible lesions in addition to the lungs. Large tissue samples are warranted when repeated puncture cytology specimens fail to provide a definitive diagnosis. In addition to examining the pathology of the lesions, a pathogen examination should be performed to help with the diagnosis.