Frequency of abdominal CT findings in AIDS patients with M. avium complex bacteraemia

CT findings of Talaromyces marneffei infection among HIV patients with lymphadenopathy

Background

Talaromyces marneffei (T. marneffei) is an opportunistic fungal pathogen commonly found in human immunodeficiency virus (HIV) patients that often infects lymph nodes. Knowledge about the computed tomography (CT) characteristics of T. marneffei lymphadenopathy in HIV patients is limited. The aim of this study was to investigate the clinical and CT characteristics of T. marneffei lymphadenopathy to improve its diagnosis and promote recognition of this type of infection in radiology.

Methods

Between February 2019 and June 2021, we retrospectively reviewed the clinical features and CT characteristics of T. marneffei lymphadenopathy in 21 HIV patients.

Results

The clinical symptoms of T. marneffei infection are non-specific. Anemia (100%), fever (85.7%) and cough and sputum production (76.2%) were the most frequent symptoms. Multiple lymphadenopathies, mainly in the mediastinum (76.2%) and mesentery (82.4%), can be fused (14.3%) and necrotic (52.4%), with slight (41.7%) and moderate enhancement (58.3%) that is heterogeneous. In addition to involving the lymph nodes, the lesions involved the lungs (81.0%), liver and spleen (42.9%), and small intestine (14.3%).

Conclusions

T. marneffei is prone to affecting lymph nodes and extranodal organs in HIV patients. Although the clinical manifestations of T. marneffei infection are not specific, the possibility of T. marneffei infection should be considered if CT findings indicate multiple lesion sites.

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.

Coexistent Pseudogout and Mycobacterium avium-intracellulare Septic Arthritis in a Patient with HIV and ESRD

Pseudogout is a crystal-induced arthropathy characterized by the deposition of calcium pyrophosphate dihydrate (CPPD) crystals in synovial fluid, menisci, or articular cartilage. Although not very common, this entity can be seen in patients with chronic kidney disease (CKD). Septic arthritis due to Mycobacterium avium-intracellulare (MAI) is a rare entity that can affect immunocompromised patients such as those with acquired immunodeficiency syndrome (AIDS) or those who are on immunosuppressive drugs. Here, we describe a 51-year-old female who presented with fever, right knee pain, swelling, warmth, and decreased range of motion for several days. The initial assessment was consistent with pseudogout, with negative bacterial and fungal cultures. However, due to high white blood cell (WBC) count in the synovial fluid analysis, she was empirically started on intravenous (IV) vancomycin and piperacillin-tazobactam and discharged on IV vancomycin and cefepime, while acid-fast bacilli (AFB) culture was still in process. Seventeen days later, AFB culture grew Mycobacterium avium-intracellulare (MAI), and she was readmitted for relevant management. This case illustrates that septic arthritis due to MAI should be considered in the differential diagnosis of septic arthritis in immunocompromised patients.

Review article: the aetiology, investigation and management of diarrhoea in the HIV-positive patient

BACKGROUND

Diarrhoea is a common presentation throughout the course of HIV disease.

AIM

To review the literature relating to aetiology, investigation and management of diarrhoea in the HIV-infected adult.

METHODS

The PubMed database was searched using major subject headings 'AIDS' or 'HIV' and 'diarrhoea' or 'intestinal parasite'. The search was limited to adults and to studies with >10 patients.

RESULTS

Diarrhoea affects 40-80% of HIV-infected adults untreated with antiretroviral therapy (ART). First-line investigation is by stool microbiology. Reported yield varies with geography and methodology. Molecular and immunological methods and special stains have improved diagnostic yield. Endoscopy is diagnostic in 30-70% of cases of pathogen-negative diarrhoea and evidence supports flexible sigmoidoscopy as a first line screening procedure (80-95% sensitive for CMV colitis), followed by colonoscopy and terminal ileoscopy. Radiology is useful to assess severity, distribution, complications and to diagnose HIV-related malignancies. Side effects and compliance with ART are important considerations in assessment. There is a good evidence base for many specific therapies, but optimal treatment of cryptosporidiosis is unclear and only limited data support symptomatic treatments.

CONCLUSIONS

The immunological response to HIV infection and Antiretroviral therapy remains incompletely understood. Antiretroviral therapy regimens need to be optimised to suppress HIV while minimising side effects. Effective agents for management of cryptosporidiosis are lacking. There is an urgent need for enhanced regional diagnostic facilities in countries with a high prevalence of HIV. The ongoing roll-out of Antiretroviral therapy in low-resource settings will continue to change the aetiology and management of this problem, necessitating ongoing surveillance and study.

Mesenteric lymph nodes seen at imaging: causes and significance

With the advent of multidetector computed tomography, routine evaluation of mesenteric lymph nodes is now possible. For the first time, normal mesenteric nodes may be reliably identified noninvasively. Because of the increasing volume of cross-sectional imaging examinations being performed, lymph nodes in the mesentery are being detected with increasing frequency. This is often an unsuspected finding. Although the detected lymph nodes may be normal, there is a large number of disease processes that may lead to mesenteric lymphadenopathy. The most common causes of mesenteric lymphadenopathy are neoplastic, inflammatory, and infectious processes. Many of these causes may also result in lymphadenopathy elsewhere in the body. It is important to recognize mesenteric lymphadenopathy in patients with a history of a primary carcinoma because the lymphadenopathy affects the staging of the disease, which in turn will affect further management. In addition, mesenteric lymphadenopathy may be the only indicator of an underlying inflammatory or infectious process causing abdominal pain. The distribution of the lymph nodes may indicate the exact nature of the underlying disease process, and the correct treatment may then be instituted. Besides neoplastic, inflammatory, and infectious processes, many other disease processes may occasionally result in mesenteric lymphadenopathy.

Mesenteric neoplasms: CT appearances of primary and secondary tumors and differential diagnosis

Computed tomography (CT) remains the optimal imaging modality for diagnosing tumors in the mesentery. Although primary neoplasms arising from the mesenchymal tissues of the mesentery are rare, the small bowel mesentery is a major avenue for the dissemination of tumor within the peritoneal cavity. Tumors spread to the mesentery by four major routes: (a) direct extension, commonly seen with carcinoid tumor of the small intestine as well as intraabdominal cancers such as pancreatic and colon cancer; (b) lymphatic dissemination of lymphoma and some epithelial malignancies; (c) hematogenic spread resulting in embolic metastases to the small intestinal wall, usually seen in melanoma and breast cancer; and (d) seeding through the peritoneum from ovarian and gastrointestinal malignancies as well as some lymphomas. Although percutaneous imaging-guided or surgical biopsy is often necessary to guide management, analysis of CT features along with the clinical history may be useful in differentiating mesenteric tumors from infectious, inflammatory, or vascular processes affecting the mesentery. The article presents the characteristic appearances of primary and secondary mesenteric neoplasms at CT and offers a rational approach to the differential diagnosis of mesenteric masses depicted at CT.

Gastrointestinal infections in the immunocompromised host

Infectious diseases of the gastrointestinal tract continue to be an important source of morbidity and mortality. Viruses, bacteria, fungi, and protozoa that infect normal hosts also infect the gastrointestinal tract in immunocompromised hosts. Disease caused by these pathogens may be more severe and more difficult to treat in immunocompromised hosts. In addition, pathogens that rarely cause disease in normal hosts cause significant disease in immunosuppressed hosts. Diagnostic decisions need to take into account expected pathogens and response to therapy. Treatment decisions must be based on the findings of diagnostic procedures; expected pathogens; and recent data suggesting that highly active antiretroviral therapy, with its ability to reconstitute immune function, is an essential component of treatment. This review summarizes the most important developments made in the pathogenesis, clinical presentation, diagnosis, and treatment of gastrointestinal infections in immunocompromised hosts in the past year.