Disseminated Mycobacterium kansasii disease in complete DiGeorge syndrome.

Abstract

Complete DiGeorge syndrome (cDGS) describes a subset of patients with DiGeorge syndrome that have thymic aplasia, and thus are at risk for severe opportunistic infections. Patients with cDGS and mycobacterial infection have not previously been described. We present this case to illustrate that patients with cDGS are at risk for nontuberculous mycobacterial infections and to discuss further antimicrobial prophylaxis prior to thymic transplantation. A 13-month old male was identified as T cell deficient by the T cell receptor excision circle (TREC) assay on newborn screening, and was subsequently confirmed to have cDGS. He presented with fever and cough, and was treated for chronic aspiration pneumonia as well as Pneumocystis jirovecii infection without significant improvement. It was only after biopsy of mediastinal lymph nodes seen on CT that the diagnosis of disseminated Mycobacterium kansasii was made. We reviewed the literature regarding atypical mycobacterial infections and prophylaxis used in other immunocompromised patients, as well as the current data regarding cDGS detection through TREC newborn screening. Multiple cases of cDGS have been diagnosed via TREC newborn screening, however this is the first patient with cDGS and disseminated mycobacterial infection to be reported in literature. Thymic transplantation is the definitive treatment of choice for cDGS. Prophylaxis with either clarithromycin or azithromycin has been shown to reduce mycobacterial infections in children with advanced human immunodeficiency virus infection. Children with cDGS should receive thymic transplantion as soon as possible, but prior to this are at risk for nontuberculous mycobacterial infections. Severe, opportunistic infections may require invasive testing for diagnosis in patients with cDGS. Antimicrobial prophylaxis should be considered to prevent disseminated mycobacterial infection in these patients.