Disseminated Mycobacterium avium-intracellulare (MAI) infection is rare in immunocompetent patients. Few cases have been reported in patients who are HIV negative but either immunosuppressed therapeutically or with T Cell abnormality (T cell lymphopenia). Our patient had no evidence of immunosuppression.
A 37 year old African American man presented with swelling of left anterior chest wall and left jaw of 2 months duration, and lower back pain of 2 weeks duration. He previously had fever, night sweats and unintentional weight loss of about 50 Ibs over 6 months period. He denied cough, hemoptysis or chest pain. Seven months earlier, he presented with with fever, hemoptysis, weight loss and a positive PPD (25mm). Even though sputum and BAL were negative for AFB/culture during the previous admission, patient responded clinically to emperical anti-tuberculous therapy and was discharged on same medication. The patient stopped his medication after 2 months and did not follow up at the clinic. PET scan done during the previous admission showed uptake in the right lower lobe, right hilar, mediastinal and supraclavicular lymph nodes but patient refused mediastinoscopy. He is a chronic smoker (3 pack-years). On examination during this admission, his vital signs were stable except for tachycardia (111/min) and temperature of 99.3 F. Pertinent findings on examination included a firm, tender left preauricular swelling (10 × 6 cm), right submandibular and axillary lymphadenopathies and bilateral inguinal lymphadenopathies. In addition, the patient had, a non tender cystic left inframammary chest swelling (15 × 20 cm) and a left paraspinal (L1, L2, and L3) tenderness with no obvious swelling and no focal neurological deficit. Laboratory investigation revealed WBC of 8.6, hematocrit of 33.5, and relative neutrophilia of 81%. Lumbar MRI showed large abscess in left psoas and paravertebral muscle with osteomyelitis in adjacent L1, L2, and L3. HIV test was negative (HIV viral load less than 48, CD4 count of 775). Left anterior chest wall sonogram showed cystic appearing lesion in inframammary location. Based on previous PET scan result and clinical findings, patient had mediastinoscopy with biopsy of lymph nodes, sonogram guided aspiration of anterior chest wall swelling, and biopsy of inguinal lymph nodes. Histology of mediastinal lymph nodes showed caseating granuloma and special stains were positive for AFB. Patient was restarted on anti-tuberculosis therapy, while awaiting culture results. Surprisingly the culture results from BAL and left anterior chest wall aspirate were positive for MAI.
Disseminated MAI primarily occurs in severely immunocompromised patients, such as those with AIDS, a hematologic malignancy, or a history of immunosuppressive therapy. Random cases of lung disease and spondylitis have been reported in HIV negative patients. Few cases of disseminated MAI in HIV negative patients with T cell lymphopenia have been described. In immunocompetent patients, diagnosis of MAI is often difficult until culture results are available as demonstrated in this case. This may delay treatment and lead to further progression of the disease particularly in the absence of risk factors. Disseminated MAI is rare and from our literature reviews, we did not find any simillar presentation in the absence of HIV or some form of immunosuppression.
Although disseminated MAI is rare in immunocompetent patients, high index of suspicion should be maintained in the proper clinical setting.Early institution of therapy and optimization of regimens according to in vitro sensitivity data will lead to decreased morbidity and mortality in all patients with MAI infection.
Kennedy Eneh, No Financial Disclosure Information; No Product/Research Disclosure Information