Mycobacterium Avium Complex Treatment Research Articles

Hypercalcemia: A Metabolic Complication of an AIDS-Defining Illness

Abstract Background: Hypercalcemia may result from the activation of macrophages in granulomatous diseases with increased production of 1,25 dihydroxyvitamin D/calcitriol. Its occurrence in patients with human immunodeficiency virus-1 (HIV-1) infection may be atypical and signal major changes in immune status. We report on a patient with acquired immunodeficiency syndrome (AIDS) presenting with new-onset hypercalcemia after months of treatment for mycobacterium avium complex (MAC) infection and normal calcitriol levels. Clinical Case: A 37-year-old man on treatment for HIV-1 and disseminated MAC infection presented to the hospital 6 months after initial diagnosis with worsening headache, cough, and abdominal pain. On arrival he was afebrile and without palpable lymphadenopathy. He was found to have a high serum calcium (13.4 mg/dL, n 8.6–10.6 mg/dL) and acute kidney injury (AKI) (creatinine 4 mg/dL, n 0.6–1.25 mg/dL). His CD4 count had increased from 24 at time of diagnosis to 162 cells/μL (n 410–1,590 cells/μL); his HIV viral load was undetectable. Workup for hypercalcemia revealed an elevated phosphorus (5.2 mg/dL, n 2.5–5.0 mg/dL), low 25-OH vitamin D level (<13 ng/mL, n 25–80 ng/dL), low PTH (4.8 pg/mL, n 12–88 pg/mL), and calcitriol level of 31.4 pg/mL, n 19.9–73.3 pg/mL). Additional tests, including serum electrophoresis, thyroid stimulating hormone, and parathyroid hormone-related peptide levels, were unremarkable. The patient was diagnosed with hypercalcemia secondary to dysregulated calcitriol production in the setting of disseminated MAC and possible immune reconstitution. Hypercalcemia resolved with hydration and prednisone 20 mg daily. Patient was discharged with an 8-day prednisone taper, but readmitted to the hospital 3 weeks later with recurrent hypercalcemia (13.8 mg/dL) and AKI. Urine calcium was found to be elevated (484 mg/24 hours, n100-300 mg/24 hours) and repeat calcitriol was 53.6 pg/ml. Patient was restarted on prednisone 40 mg daily with normalization of calcium within 5 days (calcium 10.3 mg/dL). Conclusion: Hypercalcemia due to increased calcitriol production in the setting of MAC infection, an AIDS-defining illness, may occur months after initiation of effective antibiotic and antiviral therapy and could represent a manifestation of immune reconstitution. The deleterious effects of excess calcitriol may be present even in patients with chronic vitamin D deficiency and a calcitriol level that inappropriately remains within the normal range.

An unusual cause of stridor

A 12-month-old infant was referred with a 6-week history of recurrent admissions with worsening stridor. On each previous admission, the stridor responded well, but transiently, to oral dexamethasone. At this...

A Substitution Gone Horribly Wrong

SESSION TITLE: Lung Infections 1 SESSION TYPE: Affiliate Case Report Slide PRESENTED ON: Sunday, October 29, 2017 at 10:45 AM - 12:00 PM INTRODUCTION: Mycobacterium abscessus is the most common and pathogenic species of the rapidly-growing Mycobacteria. Although much is known about the etiology and associations of this species, literature is lacking in regards to development of a M. abscessus infection during treatment for Mycobacterium Avium Complex (MAC). Below is a case of M. abscessus substitution that occurred during prolonged treatment for Mycobacterium Avian Intracellulare (MAI) infection. CASE PRESENTATION: The patient is an 81-year-old man who was on prolonged course of ethambutol, azithromycin, and rifampin for a pulmonary MAI infection. The initial CT scan of the chest showed extensive bronchiectasis and AFB cultures resulted 4+ MAI. After several antibiotic courses over a period of 40 months, the patient began having frequent pulmonary decompensations requiring hospitalization associated with failure to thrive and 30 lb. weight loss. The patient tested positive for multidrug resistant M. abscessus despite being on treatment for MAC. This organism was found to be only susceptible to tigecycline, amikacin, and linezolid. The patient has been started on this regimen and his symptoms are now better controlled. DISCUSSION: MAC is the most common form of nontuberculous mycobacteria responsible for disease and it requires long-term multidrug treatment. M. abscessus complex is a group of rapidly growing, multidrug-resistant NTM species that are ubiquitous in soil and water, which renders it exceedingly difficult to treat. There are only very rare reports documenting development of M. abscessus during long-term antibiotic therapy for MAC, deemed the microbial substitution phenomenon. CONCLUSIONS: In this patient, M. abscessus developed during the long-term multidrug treatment for MAI. This is likely due to the microbial substitution phenomenon. This phenomenon calls into question the efficacy of our current treatment for MAI infections in that it may not be as aggressive as it needs to be to prevent subsequent M. abscessus infections. Reference #1: Tsunoda Y, Sekine A, Sumazaki Y, et al. Mycobacterium Abscessus Pulmonary Disease: Important Pathogen Involved in Microbial Substitution During the Treatment of Non-Abscessus Mycobacterial Disease. Kekkaku. 2016;91(4):469-73. Reference #2: Nei T, Saitoh T, Morimoto K, et al. Microbial substitution of Mycobacterium avium-intracellulare to Mycobacterium abscessus during clinical course. J Infect Chemother. 2007;13(5):343-5. DISCLOSURE: The following authors have nothing to disclose: Rahim Wooley, Allen Blaivas No Product/Research Disclosure Information