Imaging features of Mycobacterium avium-intracellulare complex (MAC) in children with AIDS

A rare case of disseminated Mycobacterium avium complex with colitis in a renal transplant recipient

Mycobacterium avium complex (MAC) colitis is a rare complication of immunosuppression in solid organ transplant (SOT) recipients. Here, we describe a case of disseminated MAC infection with colitis following renal transplantation. Despite common pathways of immunosuppression, SOT recipients and human immunodeficiency virus (HIV)-infected patients differ in their typical presentations of MAC infection. Intestinal infections have been more commonly reported in HIV-infected patients than in SOT recipients. The explanation for this difference may be related to HIV's targeted effects on the CD4⁺ T-cell reservoir in gut-associated lymphoid tissue.

BCGitis and BCGosis in children with primary immunodeficiency - imaging characteristics

BACKGROUND

When administered to an immune-compromised patient, BCG (Bacille Calmette-Guérin) can cause disseminated and life-threatening infections.

OBJECTIVE

To describe the imaging findings in children with primary immunodeficiency and BCG-related infections.

MATERIALS AND METHODS

We reviewed the imaging findings of children with primary immunodeficiency treated at a children's hospital during 2012-2014 with localized or disseminated BCG infection. Imaging modalities included US, CT and radiography.

RESULTS

Nine children with primary immunodeficiency had clinical signs of post-vaccination BCGitis; seven of these children showed disseminated disease and two showed only regional lesions with characteristic ipsilateral lymphadenopathy. Overall, lymphadenopathy was the most prevalent feature (n = 8) and characteristically appeared as a ring-enhancing hypodense (CT) or hypoechoic (US) lesion. Visceral involvement with multiple abscesses appeared in the spleen (n = 2), liver (n = 1) and bones (n = 1). All lesions regressed following appropriate anti-tuberculosis treatment.

CONCLUSION

BCG infection needs to be considered in children with typical findings and with suspected primary immunodeficiency.

The chest X-ray features of chronic respiratory disease in HIV-infected children--a review

Several features of human immunodeficiency virus (HIV) infection contribute to the development of chronic respiratory disease in children. These include the frequency and severity of acute chest infections, as well as the increased risk of pulmonary tuberculosis, aspiration, cardiovascular disease, lymphocytic interstitial pneumonitis or pulmonary neoplasia. The chest radiograph (CXR) remains the most accessible investigation for respiratory disease and plays an important role in the baseline assessment and follow-up. This review focuses on the CXR abnormalities of HIV-related chronic respiratory disease in children. The most commonly documented chronic CXR abnormalities are homogeneous opacification and pulmonary nodules, with pulmonary tuberculosis and lymphocytic interstitial pneumonitis the leading respective causes. Deficiencies in radiographic reporting methodology and relative paucity of radiographic data contribute to current limitations in knowledge and understanding of this field. The review highlights the need for standardised terminology and systematic reporting methodology in future studies. Prospective research on the natural history of lymphocytic interstitial pneumonitis, response to anti-tuberculous therapy, the impact of anti-retroviral therapy and HIV-associated bronchiectasis are needed.

Depression of local cell-mediated immunity and histological characteristics of disseminated AIDS-related Mycobacterium avium infection after the initiation of antiretroviral therapy

OBJECTIVE

The aim of the present study was to examine the immunohistological characteristics of disseminated Mycobacterium avium infection after the initiation of antiretroviral therapy (ART) for acquired immunodeficiency syndrome (AIDS).

METHODS

We histologically investigated five autopsied AIDS patients with systemic M. avium infection.

RESULTS

The inflammatory cell composition in the affected tissues was assessed using immunohistochemistry. The celiac lymph nodes and intestinal canal were the most commonly involved organs in the AIDS cases. The most common histological feature was unstructured aggregation of histiocytes. Immunohistochemistry revealed depression of CD4(+), CD8(+) and CD57(+) cells in the gut lamina propria and mesenteric lymph nodes.

CONCLUSION

These findings suggest that local cell-mediated immunity is depressed in affected tissues and that the primary histological feature is poor organization of granulomas in mycobacterial lesions, despite the administration of adequate ART.

Pulmonary infections in HIV-positive children

Infection of the lungs and airways by viral, bacterial, fungal and protozoal agents, often producing atypical radiographic features, is common in children with human immunodeficiency virus (HIV) infection. Conventional chest radiography and chest CT remain the most useful imaging modalities for evaluation of the immunocompromised patient presenting with a suspected pulmonary infection. In this review the radiological features of acute lung infections in this population are discussed.

Comparative radiological features of disseminated disease due to Mycobacterium tuberculosis vs non-tuberculosis mycobacteria among AIDS patients in Brazil

Background

Disseminated mycobacterial disease is an important cause of morbidity and mortality in patients with HIV-infection. Nonspecific clinical presentation makes the diagnosis difficult and sometimes neglected.

Methods

We conducted a retrospective cohort study to compare the presentation of disseminated Mycobacterial tuberculosis (MTB) and non-tuberculous Mycobacterial (NTM) disease in HIV-positive patients from 1996 to 2006 in Brazil.

Results

Tuberculosis (TB) was diagnosed in 65 patients (67.7%) and NTM in 31 (32.3%) patients. Patients with NTM had lower CD4 T cells counts (median 13.0 cells/mm³ versus 42.0 cells/mm³, P = 0.002). Patients with tuberculosis had significantly more positive acid-fast smears (48.0% vs 13.6%, P = 0.01). On chest X-ray, miliary infiltrate was only seen in patients with MTB (28.1% vs. 0.0%, P = 0.01). Pleural effusion was more common in patients with MTB (45.6% vs. 13.0%, P = 0.01). Abdominal adenopathy (73.1% vs. 33.3%, P = 0.003) and splenic hypoechoic nodules (38.5% vs. 0.0%, P = 0.002) were more common in patients with TB.

Conclusion

Miliary pulmonary pattern on X-ray, pleural effusion, abdominal adenopathy, and splenic hypoechoic nodules were imaging findings associated with the diagnosis of tuberculosis in HIV-infected patients. Recognition of these imaging features will help to distinguish TB from NTM in AIDS patients with fever of unknown origin due to disseminated mycobacterial disease.

Bile duct-duodenal fistula caused by AIDS/HIV-associated tuberculosis

Allthough infrequent, digestive fistulae in HIV/AIDS patients have been reported throughout the digestive tract from the esophagus to the anus, with predominance of esophageal fistulae. AIDS/HIV-associated opportunistic infections may invade the digestive system and lead to fistula formation. Tuberculosis is the most common infection associated with these esophageal fistulae. We report here one case of bile duct-duodenal fistula in a female AIDS patient with associated abdominal Mycobacterium tuberculosis infection compromising lymphnodes of the hepatic pedicle where the fistula was found. According to the reviewed literature, this is the third case of bile duct-duodenal fistula associated with abdominal tuberculosis in AIDS patient, and the first where both the fistula and the tuberculosis infection were diagnosed at laparotomy for acute abdomen. Whether the AIDS patient with abdominal pain needs or not a laparotomy to treat an infectious disease is often a difficult matter for the surgeon to decide, as most of the times appropriate medical treatment will bring more benefit.