Disseminated Mycobacterium avium complex infection in an immunocompetent pregnant woman

The development and validation of a diagnostic scoring system to differentiate pulmonary tuberculosis from non-tuberculosis pulmonary infections in HIV-infected patients with severe immune suppression

Background

It remains challenging to differentiate tuberculosis (TB) from non-TB pulmonary infections in HIV-infected patients. Herein, we developed a scoring system aimed to rapidly determine the likelihood of TB or non-TB pathology in HIV-infected patients presenting with pulmonary infections.

Methods

We collected and collated data of hospitalized HIV-infected patients with pulmonary infections, followed by univariate and multivariate data analyses to determine risk variables that were significantly different between HIV/TB patients and HIV/non-TB patients. Subsequently, a regression coefficient was calculated for each variable, and a score was assigned to each variable in line with its regression coefficient. The sum of the scores for each variable in our scoring model was used to predict the likelihood of TB or non-TB pulmonary infection in each patient. Finally, we tested the diagnostic accuracy of the scoring system in our retrospective cohort, as well as in a prospective cohort.

Results

A total of 598 HIV-infected patients were enrolled in our retrospective cohort, among whom 288 had TB and 310 had non-TB pulmonary infections. Eight variables, including fever, highest body temperature, erythrocyte sedimentation rate (ESR), cervical lymphadenopathy, hilar and/or mediastinum lymphadenopathy, pulmonary cavitation, pleural effusion, and miliary nodules, were found to be mathematically significantly different via univariate analysis and multivariate logistic regression analysis. After regression coefficient calculation followed by score assignment, a receiver operating characteristic (ROC) curve was plotted, and the area under the curve (AUC) was calculated to be 0.902. When the total score for a patient is > 12, the sensitivity and specificity for TB prediction using our scoring system were 76.4% and 87.7% respectively in the retrospective cohort, and its diagnostic accuracy was 82.7% in the prospective cohort.

Conclusions

Our results demonstrate that our proposed diagnostic scoring system could be helpful in differentiating pulmonary TB from non-TB pulmonary infections in HIV-infected patients.

Sarcoidosis with marked necrosis in enlarged lymph nodes mimics mycobacterial infection: a case report

Background

Sarcoidosis is pathologically characterized by the formation of non-necrotizing epithelioid cell granulomas. However, pathological findings of patients with sarcoidosis have rarely revealed necrosis. We report here on a patient with sarcoidosis which needed to be distinguished from infectious disease because of marked necrosis in the lymph nodes.

Case presentation

A 46-year-old Japanese woman was referred to our hospital due to a dry cough and appetite loss. A chest X-ray and computed tomography revealed markedly enlarged mediastinal and hilar lymph nodes and hepatosplenomegaly. Surgical biopsy of these lymph nodes was performed in order to make a diagnosis. Pathological findings revealed epithelioid cell granuloma with marked necrosis that suggested infectious etiology such as mycobacterial and fungal infections. In addition to the pathological findings, immunoglobulin A (IgA) antibody for Mycobacterium avium complex (MAC), enlargement of lymph nodes and hepatosplenomegaly indicated disseminated MAC, while sarcoidosis was considered as another important differential diagnosis according to elevated angiotensin-converting enzyme, soluble interleukin-2 receptor and uveitis. While waiting for the results of the cultures of acid-fast bacilli, the symptoms of cough and consumption had worsened, and initiation of therapy was required before the confirmed diagnosis. The therapy for MAC was initiated because it was feared that immunosuppressive therapy containing corticosteroid for sarcoidosis could worsen the patient’s condition if MAC infection was the main etiology. However, the treatment for MAC was not effective, and it was clarified that no acid-fast bacilli were cultured in the liquid culture medium, so the diagnosis was corrected to sarcoidosis after reconsideration of clinical and pathological findings. Prednisolone (30 mg/day) was administered orally, and the patient’s symptoms and radiological findings improved.

Conclusion

Sarcoidosis must be considered even if pathological findings reveal marked necrosis, because rare cases of sarcoidosis exhibit extensive necrosis in lymph nodes. It is extremely important to carefully examine the clinical and pathological findings through discussion with the examining pathologist to reach the correct diagnosis.

Clinical Characteristics and Etiologies of Miliary Nodules in the US: A Single-Center Study

BACKGROUND

Miliary nodules have been typically described as a radiological manifestation of disseminated tuberculosis. However, miliary nodules are known to occur in a wide variety of conditions. The primary objective of the study was to identify clinical characteristics and etiologies of miliary nodules within our institution.

METHODS

Using International Classification of Diseases, Ninth and Tenth Revision codes, electronic medical records were used to retrospectively identify 53 patients who fulfilled criteria of miliary nodules over the last 10 years. Demographic and clinical data were extracted for all the patients in this cross-sectional study.

RESULTS

The diagnosis of tuberculosis was made in 15 (28.3%) patients, sarcoidosis in 12 (22.6%), silicosis in 7 (13.2%), extrathoracic malignancy in 5 (9.4%), and histoplasmosis in 4 (7.6%) patients. Four of 9 HIV patients had histoplasmosis. There was 1 case each of hypersensitivity pneumonitis, Pneumocystis jiroveci pneumonia, Mycobacterium-avium complex, Epstein-Barr virus pneumonia, cryptococcosis, aspergillosis, and primary lung cancer. Sputum was positive for acid fast bacilli in 4 cases (28%), and bronchoscopy had a 57% successful yield in miliary tuberculosis.

CONCLUSION

Our study is the largest single-center data review evaluating the etiology of miliary nodules within the United States; most of the data exist in case reports.

Mycobacterium smegmatis But Not Mycobacterium avium subsp. hominissuis Causes Increased Expression of the Long Non-Coding RNA MEG3 in THP-1-Derived Human Macrophages and Associated Decrease of TGF-β

Pathogenic mycobacteria are able to persist intracellularly in macrophages, whereas non-pathogenic mycobacteria are effectively combated and eliminated after their phagocytosis. It is known that TGF-β plays an important role in this context. Infection with pathogenic mycobacteria such as Mycobacterium tuberculosis or M. avium leads to production of active TGF-β, which blocks the ability of IFN-γ and TNF-α to inhibit intracellular replication. On the other hand, it is known that the long non-coding RNA (lncRNA) maternally expressed 3 (MEG3) is involved in the regulation of TGF-β. In this study, we show how the infection of THP-1-derived human macrophages with the saprophytic M. smegmatis but not with the facultatively pathogenic M. avium subsp. hominissuis leads to increased MEG3 expression. This is associated with the downregulation of DNA methyltransferases (DNMT) 1 and 3b, which are known to regulate MEG3 expression via promoter hypermethylation. Consequently, we observe a significant downregulation of TGF-β in M. smegmatis-infected macrophages but not in M. avium subsp. hominissuis pointing to lncRNAs as novel mediators of host cell response during mycobacterial infections.

Invasive Nontuberculous Mycobacterial Infections among Cardiothoracic Surgical Patients Exposed to Heater-Cooler Devices1

Invasive nontuberculous mycobacteria (NTM) infections may result from a previously unrecognized source of transmission, heater–cooler devices (HCDs) used during cardiac surgery. In July 2015, the Pennsylvania Department of Health notified the Centers for Disease Control and Prevention (CDC) about a cluster of NTM infections among cardiothoracic surgical patients at 1 hospital. We conducted a case–control study to identify exposures causing infection, examining 11 case-patients and 48 control-patients. Eight (73%) case-patients had a clinical specimen identified as Mycobacterium avium complex (MAC). HCD exposure was associated with increased odds of invasive NTM infection; laboratory testing identified patient isolates and HCD samples as closely related strains of M. chimaera, a MAC species. This investigation confirmed a large US outbreak of invasive MAC infections in a previously unaffected patient population and suggested transmission occurred by aerosolization from HCDs. Recommendations have been issued for enhanced surveillance to identify potential infections associated with HCDs and measures to mitigate transmission risk.

Disseminated tuberculosis in pregnancy unknown to doctors in Western Europe case presentation: 'part of the routine study in infertility'

Tuberculosis in pregnancy is possibly increasing in Western Europe due to a higher incidence in immigrant women from endemic regions. Common in recent immigrants. Diagnosis during pregnancy is delayed because the disease is more frequently extra-pulmonary with few symptoms and western doctors are no longer familiar with signs and symptoms of tuberculosis. We report the case of a 28-year-old woman presenting in the 13th week of pregnancy with vaginal bleeding, respiratory symptoms including persistent coughing and fever since 1 month. Diagnosis was delayed because of doubts on taking x-rays during pregnancy, and only 6 days after admission chest x-ray and blood-cultures led to diagnose miliary tuberculosis. Despite tuberculostatic medication expulsion of an infected fetus and placenta occurred. Histological examination of the placenta confirmed tuberculosis in the placental tissue.

Disseminated Mycobacterium intracellulare Infection in an Immunocompetent Host

Disseminated Mycobacterium avium complex (MAC) infection can occur in immunocompromised patients, and rarely in immunocompetent subjects. Due to the extensive distribution of the disease, clinical presentation of disseminated MAC may mimic malignancies, and thorough examinations are required in order to make accurate diagnosis. We report a case of disseminated Mycobacterium intracellulare disease in an immunocompetent patient, which involved the lung, lymph nodes, spleen, and multiple bones. F-18 fluorodeoxyglucose positron-emission tomography imaging showed multiple hypermetabolic lesions, which are suggestive of typical hematogenous metastasis. However, there was no evidence of malignancy in serial biopsies, and M. intracellulare was repeatedly cultured from respiratory specimens and bones. Herein, we should know that disseminated infection can occur in the immunocompetent subjects, and it can mimic malignancies.

Mycobacterium avium-avium-associated typhlitis mimicking appendicitis in an immunocompetent host

Mycobacterium avium-intracellulare complex (MAC) primarily causes respiratory infection in patients with underlying lung disease or disseminated disease in immunocompromised patients. We report a unique case of MAC disease in the terminal ileum of a healthy patient, mimicking appendicitis. This case emphasizes the need to further explore MAC pathogenesis in immunocompetent hosts.