Mycobacterium avium complex infection-related immune reconstitution inflammatory syndrome of the central nervous system in an HIV-infected patient: Case report and review

Difficulty in diagnosing intracranial infection caused by Mycobacterium avium in an AIDS patient: case report and review of the literature

BACKGROUND

Mycobacterium avium complex (MAC) is an uncommon clinical pathogen, especially in the central nervous system (CNS), and carries a poor prognosis. MAC infections commonly present as immune reconstitution disease (IRD) in HIV patients. Herein, we report a case of intracranial infection caused by MAC in an AIDS patient without disseminated MAC (DMAC) and immune reconstitution inflammatory syndrome (IRIS).

CASE PRESENTATION

A 31-year-old HIV-positive male presented us with progressively worsening CNS symptoms, and neuroimaging revealed ring-enhancing lesions. The intracranial lesions worsened after the empirical therapy for toxoplasma encephalitis and fungal infection. Due to the rapid progression of the disease, the patient died. Mycobacterium avium was the only pathogen in brain tissue after cultures and molecular biology tests.

CONCLUSION

MAC infection in CNS is challenging to diagnose in HIV patients. Our findings emphasize that obtaining tissue samples and applying molecular biology methods is essential to help diagnose the patient as soon as possible to receive adequate treatment.

Neurological manifestations of nontuberculous mycobacteria in adults: case series and review of the literature

Introduction

Nontuberculous mycobacteria (NTM) mediated infections are important to consider in cases with neuroinflammatory presentations. We aimed to characterize cases of NTM with neurological manifestations at the National Institutes of Health (NIH) Clinical Center and review the relevant literature.

Materials and methods

Between January 1995 and December 2020, six cases were identified. Records were reviewed for demographic, clinical, and radiological characteristics. A MEDLINE search found previously reported cases. Data were extracted, followed by statistical analysis to compare two groups [cases with slow-growing mycobacteria (SGM) vs. those with rapidly growing mycobacteria (RGM)] and evaluate for predictors of survival. NIH cases were evaluated for clinical and radiological characteristics. Cases from the literature were reviewed to determine the differences between SGM and RGM cases and to identify predictors of survival.

Results

Six cases from NIH were identified (age 41 ± 13, 83% male). Five cases were caused by SGM [Mycobacterium avium complex (MAC) n = 4; Mycobacterium haemophilum n = 1] and one due to RGM (Mycobacterium abscessus). Underlying immune disorders were identified only in the SGM cases [genetic (n = 2), HIV (n = 1), sarcoidosis (n = 1), and anti-interferon-gamma antibodies (n = 1)]. All cases were diagnosed using tissue analysis. A literature review found 81 reports on 125 cases (SGM n = 85, RGM n = 38, non-identified n = 2). No immune disorder was reported in 26 cases (21%). Within SGM cases, the most common underlying disease was HIV infection (n = 55, 65%), and seizures and focal lesions were more common. In RGM cases, the most common underlying condition was neurosurgical intervention or implants (55%), and headaches and meningeal signs were common. Tissue-based diagnosis was used more for SGM than RGM (39% vs. 13%, p = 0.04). Survival rates were similar in both groups (48% SGM and 55% in RGM). Factors associated with better survival were a solitary CNS lesion (OR 5.9, p = 0.01) and a diagnosis made by CSF sampling only (OR 9.9, p = 0.04).

Discussion

NTM infections cause diverse neurological manifestations, with some distinctions between SGM and RGM infections. Tissue sampling may be necessary to establish the diagnosis, and an effort should be made to identify an underlying immune disorder.

Metagenomic next-generation sequencing assistance in identifying Mycobacterium avium meningoencephalitis: A case report and literature review

Nontuberculous mycobacteria associated intracranial infection is a rare disease that mainly occurs in HIV-infected patients. The disease has a poor prognosis. The authors report a case of non-tuberculous mycobacterial meningoencephalitis in a non-AIDS patient, but long history of poorly controlled type 2 diabetes mellitus. A 55-year-old, right-handed, male patient presented with an 8-day history of fever, episodes of severe headache with signs of meningeal irritation. MRI showed hyperintensities/contrast enhancement in the visual pathways, basal ganglia sellar region and leptomeninges. No etiological diagnosis was reached until metagenomic next-generation sequencing (mNGS) was used, showing the presence of Mycobacterium avium. The patient was cured with aggressive antimycobacterial therapy. The authors discuss the clinical manifestations and drug therapy of nontuberculous mycobacteria-related intracranial infections by reviewing relevant literature. As meningoencephalitis by Mycobacterium avium has a high mortality an early diagnosis and appropriate therapeutic interventions are warranted. For this reason, the use of mNGS can be helpful to avoid therapeutic delay.

Epidemiology, clinical presentation, and predictors of outcome in nontuberculous mycobacterial central nervous system infection: a systematic review

BACKGROUND

CNS manifestations represent an emerging facet of NTM infection with significant mortality. Due to protean presentation and low index of suspicion, many cases are often treated erroneously as tubercular meningitis or fungal infections.

OBJECTIVES

Literature on NTM CNS disease is scarce, with most available data on pulmonary disease. This systematic review aimed to evaluate the epidemiology, clinical presentation, diagnostic modalities, and predictors of outcome in CNS NTM infection.

METHODS

The literature search was performed in major electronic databases (PubMed, Google Scholar, and Scopus) using keywords "CNS," "Central nervous system," "brain abscess," "meningitis," "spinal," "Nontuberculous mycobacteria," "NTM". All cases of CNS NTM infection reported between January 1980 and December 2022 were included.

RESULTS

A total of 77 studies (112 cases) were included in the final analysis. The mean age of all patients was 38 years, with most patients male (62.5%). Mycobacterium avium complex (MAC) was the most common aetiology, followed by M. fortuitum and M. abscessus (34.8%, 21.4% and 15.2%, respectively). The disseminated disease was found in 33% of cases. HIV (33.9%) and neurosurgical hardware (22.3%) were the common risk factors. Intracranial abscess (36.6%) and leptomeningeal enhancement (28%) were the most prevalent findings in neuroimaging. The overall case fatality rate was 37.5%. On multivariate analysis, male gender (adjusted OR 2.4, 95% CI 1.2-7.9) and HIV (adjusted OR 3.7, 95% CI 1.8-6.1) were the independent predictors of mortality). M. fortuitum infection was significantly associated with increased survival (adjusted OR 0.18, 95% CI (0.08-0.45), p value 0.012).

CONCLUSIONS

Current evidence shows the emerging role of rapid-grower NTM in CNS disease. Male gender and HIV positivity were associated with significant mortality, while M fortuitum carries favourable outcomes.

Epidural intracranial abscesses and multiple bone metastases caused by disseminated Mycobacterium avium complex infection: illustrative case

BACKGROUND

Mycobacterium avium complex (MAC) generally causes localized pulmonary infections in immunocompromised hosts, but rarely in other organs and tissues, which is called disseminated MAC infection.

OBSERVATIONS

The authors herein present a 48-year-old male patient with disseminated MAC infectious lesions in the lungs and on the cranial, vertebral, femoral, and pelvic bones, a normal CD4 count, and immunopositivity for the interferon-ɤ (IFN-ɤ) neutralization antibody. Cranial lesions were multiple osteolytic lesions associated with abscesses in the cranial bones. The patient initially received conservative treatment with multiple antibiotics; however, cranial lesions worsened. Therefore, multiple cranial lesions were removed via osteoplastic craniectomy and the postoperative course was uneventful. Pathological findings revealed MAC infection. The patient was discharged without recurrence or complications.

LESSONS

Multiple cranial MAC dissemination with immunopositivity for the IFN-ɤ antibody is rare. The authors herein present the clinical course of a rare surgical case of MAC dissemination with a literature review.

Immune Reconstitution Inflammatory Syndrome Induced by Mycobacterium avium Complex Infection Presenting as Chronic Inflammatory Demyelinating Polyneuropathy in a Young AIDS Patient

Antiretroviral therapy (ART) can restore protective immune responses against opportunistic infections (OIs) and reduce mortality in patients with human immunodeficiency virus (HIV) infections. Some patients treated with ART may develop immune reconstitution inflammatory syndrome (IRIS). Mycobacterium avium complex (MAC)-related IRIS most commonly presents as lymphadenitis, soft-tissue abscesses, and deteriorating lung infiltrates. However, neurological presentations of IRIS induced by MAC have been rarely described. We report the case of a 31-year-old man with an HIV infection. He developed productive cough and chronic inflammatory demyelinating polyneuropathy (CIDP) three months after the initiation of ART. He experienced an excellent virological and immunological response. Sputum culture grew MAC. The patient was diagnosed with MAC-related IRIS presenting as CIDP, based on his history and laboratory, radiologic, and electrophysiological findings. Results: Neurological symptoms improved after plasmapheresis and intravenous immunoglobulin (IVIG) treatment. To our knowledge, this is the first reported case of CIDP due to MAC-related IRIS. Clinicians should consider MAC-related IRIS in the differential diagnosis of CIDP in patients with HIV infections following the initiation of ART.

Infectious Myelopathies

In the setting of both globalization and increasing use of immunosuppressive therapy, infectious myelopathies are an important cause of morbidity worldwide. Clinical spinal cord syndromes related to infection are varied, including transverse myelitis, acute flaccid paralysis related to anterior horn cell involvement, spinal cord compression, chronic spastic paraparesis, and myeloradiculitis. Causative pathogens include viruses, parasites, pyogenic and atypical bacteria, and fungi. The epidemiology, clinical characteristics, diagnosis, and treatment of selected organisms will be discussed in this article.

Large abscess formed in the abdominal wall by Mycobacterium avium complex: A case of unmasking immune reconstitution inflammatory syndrome

Immune reconstitution inflammatory syndrome (IRIS) is a clinical entity with a broad presentation that is complicated in patients with acquired immunodeficiency syndrome after initiating antiretroviral therapy. A 51-year-old Japanese man was diagnosed with disseminated Mycobacterium avium complex (MAC) infection presenting as unmasking IRIS, which formed a large abscess in the patient's abdominal wall. MAC-IRIS commonly involves the lymph nodes, bone marrow, and gastrointestinal tract. To our knowledge, this is the first case report of an abdominal wall abscess caused by MAC-IRIS.

Brain and Spinal Epidural Abscess

PURPOSE OF REVIEW

Brain abscesses and spinal epidural abscesses are serious, potentially life-threatening infections of the central nervous system. This article outlines the clinical presentation, evaluation, and management of brain abscesses and spinal epidural abscesses, with a specific focus on bacterial infections.

RECENT FINDINGS

The overall incidence of brain abscesses has declined, in part because of fewer brain abscesses associated with otogenic infections. However, emerging patient populations at high risk for brain abscess include those with a history of penetrating head trauma, neurosurgery, or immunodeficiency. Improved mortality rates for brain abscess are attributable to modern diagnostic imaging, stereotactic-guided aspiration, and newer antimicrobials that readily penetrate into the central nervous system and abscesses. Brain MRI is more sensitive than CT for brain abscess, particularly in the early stages, but CT remains more widely available and can adequately identify potential abscesses and confirm response to treatment. With the advent of minimally invasive neurosurgical techniques, surgical excision is often employed only for posterior fossa, multiloculated, or superficial well-circumscribed abscesses. In select clinical scenarios, conservative medical management may be a safe alternative to a combined surgical and medical approach. Unlike brain abscess, the incidence of spinal epidural abscess is on the rise and has been attributed to higher prevalence of predisposing factors, including spinal procedures and instrumentation.

SUMMARY

Successful diagnosis and management of brain abscess and spinal epidural abscess requires a collaborative approach among neurologists, neurosurgeons, radiologists, and infectious disease physicians. The foundation of management of brain abscess includes surgical intervention for diagnostic purposes if a pathogen has not been identified or for decompression of larger abscesses or those with mass effect and significant surrounding edema; appropriate dosing and adequate duration of an antimicrobial regimen tailored to the presumptive source of infection and available culture data, and eradication of the primary source of infection. For spinal epidural abscesses, neurologic status at the time of presentation is directly related to outcomes, underscoring the importance of prompt recognition and intervention.

Isolated Cerebellar Spindle Cell Pseudotumor Caused by Mycobacterium Avium-Intracellulare Complex in a Patient without AIDS

BACKGROUND

Spindle cell pseudotumors are formed by histiocytes in response to infection by Mycobacterium avium-intracellulare complex (MAC) and are rare in patients without AIDS.

CASE DESCRIPTION

A 66-year-old man presented with neck pain, ataxia, and a history of sarcoidosis. A cerebellar lesion was identified on magnetic resonance imaging and surgically excised. Histopathology revealed this to be a spindle cell pseudotumor and MAC was isolated by bacterial culture of cerebrospinal fluid. Hematology revealed cluster of differentiation 4 lymphocytopenia but human immunodeficiency virus serology was negative. The patient was commenced on antimicrobial treatment that included a macrolide and remained well at 1 year follow-up.

CONCLUSIONS

This rare presentation of isolated intracranial MAC was treated with surgical excision and antimicrobials with a good outcome.

Management of the immune reconstitution inflammatory syndrome

The immune reconstitution inflammatory syndrome (IRIS) is a frequent early complication of antiretroviral therapy (ART) in patients with advanced HIV. Because there is no confirmatory diagnostic test, the diagnosis is based on clinical presentation and exclusion of alternative causes for deterioration, such as antimicrobial drug resistance. Opportunistic infection treatment should be optimized. Mild cases may require symptomatic therapy alone or nonsteroidal anti-inflammatory drugs. Corticosteroids have been used to treat more severe cases of IRIS associated with mycobacterial and fungal infections. There is evidence from a randomized controlled trial that prednisone reduces morbidity and improves symptoms in paradoxical tuberculosis (TB)-IRIS. Neurological TB-IRIS is potentially life-threatening; high-dose corticosteroids are indicated and ART interruption should be considered if level of consciousness is depressed. When considering corticosteroid treatment clinicians should be aware of their side effects and only use them when the diagnosis of IRIS is certain. In viral forms of IRIS corticosteroids are generally avoided.