Antineutrophil cytoplasmic antibodies in infective endocarditis: a case report and systematic review of the literature

Kidney Failure in Pauci-immune Crescentic Glomerulonephritis: Rationale for Immunosuppression to Improve Kidney Outcome

PURPOSE OF REVIEW

Pauci-immune crescentic glomerulonephritis is the hallmark finding in ANCA-associated vasculitis (AAV) when the kidneys are affected. The rationale for immunosuppression in AAV is based on the underlying autoimmune nature of the disease. Overall remission rates, kidney outcomes, and the burden of disease have greatly improved since the discovery of various immunosuppressive therapies, but relapses remain common, and a significant proportion of patients continue to progress to end-stage kidney disease. Here, we review the role of immunosuppressive therapies for the treatment of pauci-immune crescentic glomerulonephritis.

RECENT FINDINGS

Besides the recognized role of B and T cells in the pathogenies of AAV, the focus on the contribution of inflammatory cytokines, neutrophil extracellular traps (NETs), and the complement system allowed the discovery of new therapies. Specifically, the C5a receptor blocker (avacopan) has been approved as a glucocorticoid-sparing agent. Additionally, based on observational data, more clinicians are now using combination therapies during the induction phase. There is also an evolving understanding of the role of plasma exchange in removing ANCA antibodies. Furthermore, the recent development of risk score systems provides physicians with valuable prognostic information that can influence decisions on immunosuppression, although future validation from larger cohorts is needed. The over-activation of various immune pathways plays a significant role in the pathogenesis of pauci-immune crescentic glomerulonephritis in AAV. Immunosuppression is, therefore, an important strategy to halt disease progression and improve overall outcomes. Relapse prevention while minimizing adverse events of immunosuppression is a major long-term goal in AAV management.

Approach to the Atypical Wound

The heterogeneity of atypical wounds can present diagnostic and therapeutic challenges; however, as the prevalence of atypical wounds grows worldwide, prompt and accurate management is increasingly an essential skill for dermatologists. Addressing the underlying cause of an atypical wound is critical for successful outcomes. An integrated approach with a focus on pain management and patient engagement is recommended to facilitate enduring wound closure. Advances in treatment, in addition to further research and clinical training, are necessary to address the expanding burden of atypical wounds.

ANCA-associated vasculitis presenting with isolated neurological manifestations in a patient with cocaine abuse: a case report and literature review

Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is a group of rare conditions predominantly affecting small vessels of skin, musculoskeletal, pulmonary, renal, and rarely central and peripheral nervous systems. Isolated neurological manifestations of AAV are uncommon and challenging to diagnose. Cocaine has been reported as a potential trigger for the development of AAV. There are only a few case reports of isolated neurological involvement in cocaine-induced AAV with poorly characterized histopathological features. We present a unique case of AAV with isolated neurological manifestations presenting with multiple cranial neuropathies, leptomeningeal enhancement on imaging and histopathologic evidence of small-vessel vasculitis in the leptomeninges and brain and extensive dural fibrosis in a patient with cocaine abuse. The patient's progressive neurological deficits were controlled after starting immunosuppression with rituximab and prednisone. We also reviewed the literature to provide the diagnostic overview of AAV and evaluate intervention options. To our knowledge, this is the first case of AAV with isolated neurological manifestations and histopathologic evidence of small-vessel vasculitis in a patient with cocaine abuse. Patients with multiple cranial neuropathies and meningeal involvement should be screened for AAV, especially if they have a history of cocaine abuse.

Clinicopathological differences between Bartonella and other bacterial endocarditis-related glomerulonephritis - our experience and a pooled analysis

Background

Although Staphylococcus aureus is the leading cause of acute infective endocarditis (IE) in adults, Bartonella spp. has concomitantly emerged as the leading cause of "blood culture-negative IE" (BCNE). Pre-disposing factors, clinical presentation and kidney biopsy findings in Bartonella IE-associated glomerulonephritis (GN) show subtle differences and some unique features relative to other bacterial infection-related GNs. We highlight these features along with key diagnostic clues and management approach in Bartonella IE-associated GN.

Methods

We conducted a pooled analysis of 89 cases of Bartonella IE-associated GN (54 published case reports and case series; 18 published conference abstracts identified using an English literature search of several commonly used literature search modalities); and four unpublished cases from our institution.

Results

Bartonella henselae and Bartonella quintana are the most commonly implicated species causing IE in humans. Subacute presentation, affecting damaged native and/or prosthetic heart valves, high titer anti-neutrophil cytoplasmic antibodies (ANCA), mainly proteinase-3 (PR-3) specificity, fastidious nature and lack of positive blood cultures of these Gram-negative bacilli, a higher frequency of focal glomerular crescents compared to other bacterial infection-related GNs are some of the salient features of Bartonella IE-associated GN. C3-dominant, but frequent C1q and IgM immunofluorescence staining is seen on biopsy. A "full-house" immunofluorescence staining pattern is also described but can be seen in IE -associated GN due to other bacteria as well. Non-specific generalized symptoms, cytopenia, heart failure and other organ damage due to embolic phenomena are the highlights on clinical presentation needing a multi-disciplinary approach for management. Awareness of the updated modified Duke criteria for IE, a high index of suspicion for underlying infection despite negative microbiologic cultures, history of exposure to animals, particularly infected cats, and use of send-out serologic tests for Bartonella spp. early in the course of management can help in early diagnosis and initiation of appropriate treatment.

Conclusion

Diagnosis of IE-associated GN can be challenging particularly with BCNE. The number of Bartonella IE-associated GN cases in a single institution tends to be less than IE due to gram positive cocci, however Bartonella is currently the leading cause of BCNE. We provide a much-needed discussion on this topic.

Rheumatic masqueraders: mimics of primary vasculitis - a case-based review

INTRODUCTION

Vasculitis conditions are often serious and sometimes fatal diseases, therefore it is paramount to diagnose correctly and treat appropriately. Mimics of primary vasculitis can include either non-inflammatory syndromes or secondary vasculitis where the underlying etiology of the vasculitis is being driven by infection, malignancy, drug-effect or other.

AREAS COVERED

This review comprises six individual cases of vasculitis mimics. Each case is presented and the clinical, radiographic, and histological features that distinguish the case from primary vasculitis are highlighted. Key mimics in large, medium and small vessel vasculitis are outlined.

EXPERT OPINION

The diagnosis of vasculitis requires a comprehensive assessment of clinical, radiographic, and histologic features. Clinicians should be familiar with mimics of primary vasculitis conditions. In the case of non-inflammatory mimics, it is important to differentiate from primary vasculitides in order to avoid unnecessary and potentially harmful immunosuppression. For cases of secondary vasculitis, identification of the correct etiologic cause is critical because treatment of the underlying stimulus is necessary for successful management and outcomes.

Hemophagocytic Lymphohistiocytosis and Anti-neutrophil Cytoplasmic Antibody-associated Vasculitis Possibly Caused by Enterococcus faecalis Infective Endocarditis

Infection can induce hemophagocytic lymphohistiocytosis (HLH) and anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV). We herein report a 52-year-old man who had HLH and AAV simultaneously, possibly caused by Enterococcus faecalis infective endocarditis. The HLH diagnosis was based on the HLH-2004 criteria. AAV was diagnosed based on a positive result for proteinase-3 ANCA and necrotizing vasculitis of the small vessels on a skin biopsy. He eventually died and was sent for autopsy after combination treatment of valve replacement, antibiotics, and immunosuppressants, including corticosteroids. This case involved a challenging diagnosis and treatment of HLH with various complications in an adult.

Autoimmunity and Infection in Glomerular Disease

The ongoing glomerular damage of infections is not limited to the most widely known form of post-streptococcal glomerulonephritis, which is today less common in the Western world; other forms of glomerulonephritis are associated with several bacterial, viral and parasitic pathogens. The mechanisms responsible range from the direct damage of glomerular cells to the formation and deposition of immunocomplexes to molecular mimicry to the secretion of superantigens. Similarly, in the course of glomerular disease, infections are more frequent than in the general population due to the loss of immunoglobulins in urine and the immunosuppressive agents used to treat the autoimmune disease that decrease the activity of the immune system. Recognizing this two-way link, understanding its pathogenetic mechanism, and identifying the most appropriate therapeutic choice are essential for the personalized management of patients. In this continuously developing field, this short review summarizes the current state of the art as support for physicians, who are increasingly involved in managing patients with glomerular disease and infections.

"Let the Cat Out of the Heart": Clinical Characteristics of Patients Presenting With Blood Culture-Negative Endocarditis Due to Bartonella Species

Patients with blood culture-negative endocarditis due to Bartonella infection frequently presented with fever, cytopenias, kidney failure, and positive PR3-ANCA. Bartonella IgG titers were variable. Patients commonly underwent surgery with overall low mortality.

Infections and systemic vasculitis

Infections and systemic vasculitis (SV) are characterized by mutual influence, which increases the risk of occurrence, aggravates the course and outcome of the disease. The review considers the issues related to both the trigger role of infections in the development of SV and comorbid infections (CI) that complicate the course of the disease. Recognition of the infectious etiology of SV is of great importance, since it requires a comprehensive examination and, if necessary, early and complete etiotropic treatment. Since SV per se and the use of both induction and maintenance immunosuppressive therapy are significant risk factors for secondary CIs, special attention should be paid to the prevention of the latter, including vaccination, primarily against influenza and pneumococcal infections.