Bartonella Endocarditis and Pauci-Immune Glomerulonephritis: A Case Report and Review of the Literature

ANCA-Negative Pauci-Immune Glomerulonephritis Associated with Bartonella Endocarditis

Kidney complications can occur due to infective endocarditis, one of which is glomerulonephritis. Most often, an immune complex or complement-mediated glomerulonephritis is seen on kidney biopsy. In a minor subset of cases, pauci-immune glomerulonephritis may be present. Most often, such patients will demonstrate the presence of antineutrophil cytoplasmic antibodies (ANCA) on serologic testing. A growing number of cases of ANCA-associated glomerulonephritis due to Bartonella endocarditis have been reported. This type of endocarditis can present diagnostic difficulties given that these patients are often culture negative. Herein, we report a challenging case of ANCA-negative pauci-immune glomerulonephritis showing florid crescents on biopsy that was associated with Bartonella endocarditis.

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.

Hydralazine use can be associated with IgM-dominated immune complex-mediated glomerulonephritis

CONTEXT

IgM-dominant immune complex-mediated glomerulonephritis (IgM-dominant ICMGN) is a rare renal entity, characterized by a membranoproliferative pattern by light microscopy, dominant IgM staining by immunofluorescent staining, and subendothelial deposits by electron microscopy. This study was to investigate if some of IgM-ICMGN were associated with autoimmune disorders induced by hydralazine.

DESIGN

Seven IgM-dominant ICMGN cases were identified over 8 years. Their pathologic phenotypes and clinical scenarios were analyzed in detail.

RESULTS

Patients' ages ranged from 47 to 87 years old with 5 women and two men. Six of seven patients had drug-induced autoimmune phenomenon (hydralazine-induced positive ANCA and ANA). All of them had renal dysfunction and some proteinuria. Most pathologic features showed a membranoproliferative pattern of glomerulonephritis with dominant IgM deposits at subendothelial spaces. IgM nephropathy (a variant of focal segmental glomerulosclerosis), chronic thrombotic microangiopathy, and cryoglobulinemic glomerulopathy were ruled out in the cases.

CONCLUSION

The hydralazine-induced autoimmune phenomenon can be seen in IgM-dominant ICMGN, which should be classified as a subtype of membranoproliferative glomerulonephritis.

Uncommon pathogens causing infective endocarditis

Infective endocarditis is caused by a wide range of aetiological agents. The microbiology, epidemiology, and treatment of this disease have changed considerably in the last two decades. Staphylococci and streptococci are known to be the classical causative agents; however, blood culture-negative endocarditis caused by fastidious and slow-growing organisms is now common. The list of uncommon pathogens causing endocarditis has expanded in recent years. This is a narrative literature review of the aetiological agents of endocarditis that are rarely encountered in clinical practice, their epidemiology, the characteristics of these pathogens, the clinical presentations of the cases, and their management.

Epidemiology and treatment of invasive Bartonella spp. infections in the United States

OBJECTIVES

Bartonella spp., renowned for cat-scratch disease, has limited reports of dissemination. Tissue and blood cultures have limitations in detecting this fastidious pathogen. Molecular testing (polymerase chain reaction, PCR) and cell-free DNA have provided an avenue for diagnoses. This retrospective observational multicenter study describes the incidence of disseminated Bartonella spp. and treatment-related outcomes.

METHODS

Inclusion criteria were diagnosis of bartonellosis via diagnosis code, serology testing of blood, polymerase chain reaction (PCR) of blood, 16/18S tests of blood or tissue, cultures of blood or tissue, or cell-free DNA of blood or tissue from January 1, 2014, through September 1, 2021. Exclusions were patients who did not receive treatment, insufficient data on treatment course, absence of dissemination, or retinitis as dissemination.

RESULTS

Patients were primarily male (n = 25, 61.0%), white (n = 28, 68.3%), with mean age of 50 years (SD 14.4), and mean Charlson comorbidity index of 3.5 (SD 2.1). Diagnosis was primarily by serology (n = 34, 82.9%), with Bartonella henselae (n = 40, 97.6%) as the causative pathogen. Treatment was principally doxycycline with rifampin (n = 17, 41.5%). Treatment failure occurred in 16 (39.0%) patients, due to escalation of therapy during treatment (n = 5, 31.3%) or discontinuation of therapy due to an adverse event or tolerability (n = 5, 31.3%).

CONCLUSIONS

In conclusion, this is the largest United States-based cohort of disseminated Bartonella spp. infections to date with a reported 39% treatment failure. This adds to literature supporting obtaining multiple diagnostic tests when Bartonella is suspected and describes treatment options.

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.

Bartonella henselae infection-mediated shunt nephritis

Serum anti-neutrophil cytoplasmic antibody (ANCA) positivity with membranoproliferative pattern on renal biopsy can be due to ANCA-associated vasculitis as well as chronic indolent infections. We present the case of an adolescent boy with congenital heart disease and history of cardiac surgery who presented with severe acute kidney injury requiring hemodialysis. Renal biopsy showed membranoproliferative glomerulonephritis with full-house immunofluorescence pattern. Low serum complements, PR3 ANCA positivity and elevated Bartonella immunoglobulin titers suggested a diagnosis of infective endocarditis-associated glomerulonephritis. Cardiac shunt revision and antibiotic therapy lead to improvement in kidney function. Chronic infections lead to formation of immune complexes that may cause deposit within the renal parenchyma and induce production of ANCA. The distinction of ANCA-associated vasculitis and chronic infections causing acute kidney injury is important in determining therapeutic management. While rare in the pediatric population, we highlight the importance in considering indolent infections in patients with acute glomerulonephritis and ANCA positivity, especially with risk factors.

Understanding Bartonella-Associated Infective Endocarditis: Examining Heart Valve and Vegetation Appearance and the Role of Neutrophilic Leukocytes

BACKGROUND

The endocardium and cardiac valves undergo severe impact during infective endocarditis (IE), and the formation of vegetation places IE patients at a heightened risk of embolic complications and mortality. The relevant literature indicates that 50% of IE cases exhibit structurally normal cardiac valves, with no preceding history of heart valve disease. Gram-positive cocci emerge as the predominant causative microorganisms in IE, while Gram-negative Bartonella spp., persisting in the endothelium, follow pathogenic pathways distinct from those of typical IE-causing agents. Employing clinical as well as advanced microbiological and molecular assays facilitated the identification of causative pathogens, and various morphological methods were applied to evaluate heart valve damage, shedding light on the role of neutrophilic leukocytes in host defense. In this research, the immunohistochemical analysis of neutrophilic leukocyte activation markers such as myeloperoxidase, neutrophil elastase, calprotectin, and histone H3, was performed. A distinct difference in the expression patterns of these markers was observed when comparing Bartonella spp.-caused and non-Bartonella spp.-caused IE. The markers exhibited significantly higher expression in non-Bartonella spp.-caused IE compared to Bartonella spp.-caused IE, and they were more prevalent in vegetation than in the valvular leaflets. Notably, the expression of these markers in all IE cases significantly differed from that in control samples. Furthermore, we advocated the use of 16S rRNA Next-Generation Sequencing on excised heart valves as an effective diagnostic tool for IE, particularly in cases where blood cultures yielded negative results. The compelling results achieved in this study regarding the enigmatic nature of Bartonella spp. IE's pathophysiology contribute significantly to our understanding of the peculiarities of inflammation and immune responses.

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.

Vasculitis Mimics and Other Related Conditions

The approach to diagnosis of primary systemic vasculitis can be challenging, often requiring consideration of important secondary causes of vasculitis and non-inflammatory mimics. An atypical pattern of vascular involvement and/or atypical features of primary vasculitis (eg, cytopenia, lymphadenopathy) should prompt a more thorough investigation into other diseases. Herein, we review selected mimics organized by the size of blood vessels typically affected.

Bartonella henselae Infective Endocarditis: A Rare Cause of Pauci-Immune Necrotizing Glomerulonephritis-A Case Report

Rationale

Bartonella sp. are the most common causes of culture-negative infective endocarditis (IE) cases in the United States. Although, infection-related glomerulonephritis can frequently mimic primary vasculitis due to pauci-immune pattern, majority of previously reported cases of Bartonella henselae-associated glomerulonephritis have immune-complex deposits on immunofluorescence. We present a rare case of B henselae IE-related pauci-immune necrotizing glomerulonephritis. Timely recognition of this atypical presentation led to appropriately directed medical therapy.

Presenting concerns of the patient

A 33-year-old Caucasian male with a history of human immunodeficiency virus (HIV) on highly active antiretroviral therapy (HAART), alcohol abuse, previous subarachnoid hemorrhage (SAH), and recent wisdom tooth extraction (on amoxicillin) was transferred from an outside hospital for further evaluation of severe headache. He was diagnosed with an SAH and right anterior cerebral artery mycotic aneurysm. The serum creatinine at the outside hospital was 292 umol/L (3.3 mg/dL) with a previously normal baseline around 2 years ago. The serum creatinine at our institution was 256 umol/L (3.0 mg/dL). The urinalysis demonstrated +100 protein, +3 blood and 29 red blood cells/high power field. The urine protein creatinine ratio (UPC) was 1.7 g/g. Serologic evaluation was positive for a low C4 10.2 mg/dL, elevated rheumatoid factor 40 IU/mL and an elevated proteinase 3 (PR-3) antineutrophilic cytoplasmic antibodies (ANCA Ab) 4.0 U/mL. A transesophageal echocardiogram (TEE) showed echo densities on both mitral and aortic valve. Blood cultures were negative. Further serologic evaluation was positive for B henselae IgG titer of 1:2560 (normal <1:320) with a negative IgM titer.

Diagnoses

A percutaneous kidney biopsy revealed pauci-immune necrotizing glomerulonephritis, with 14/16 glomeruli globally sclerotic, and 2 glomeruli with active segmental necrotizing lesions. There was no evidence of immune-complex deposition on immunofluorescence or electron microscopy. Clinical findings were consistent with B henselae IE associated mycotic aneurysm and necrotizing glomerulonephritis.

Intervention

Empiric treatment for an active glomerulonephritis with immunosuppressive agents was deferred on admission, given concern for an underlying infectious process and mycotic aneurysms in an HIV-positive patient. He received antibiotic treatment with doxycycline and ceftriaxone with gentamicin for synergy. Despite this, the mitral and aortic valve regurgitation worsened, and he developed congestive heart failure requiring aortic valve replacement and mitral valve repair. The explanted aortic valve was positive for B henselae by polymerase chain reaction (PCR) confirming the diagnosis of B henselae IE.

Outcomes

Immunosuppression was deferred due to timely identification of an atypical presentation of B henselae-associated ANCA antibodies-positive, pauci-immune necrotizing glomerulonephritis. A course of antibiotic treatment resulted in improved renal functions along with undetectable B henselae and PR3 Ab titers. The serum creatinine decreased to 176 umol/L (2 mg/dL) and remained stable 12 months after discharge.

Teaching points

B henselae IE should be suspected in patients with pauci-immune necrotizing glomerulonephritis and culture-negative IE. This is imperative for optimal decision making in the management of such patients. Having high clinical suspicion can avoid unnecessary and potentially deleterious use of immunosuppressive agents.

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

Infective endocarditis (IE) may be misdiagnosed as ANCA-associated vasculitis (AAV), especially when antineutrophil cytoplasmic antibodies (ANCA) are detected. Distinguishing IE from AAV is crucial to guide therapy. However, little is known about ANCA positivity in IE patients. We present a case report and systematic review of the literature on patients with ANCA-positive IE, aiming to provide a comprehensive overview of this entity and to aid clinicians in their decisions when encountering a similar case. A systematic review of papers on original cases of ANCA-positive IE without a previous diagnosis of AAV was conducted on PubMed in accordance with PRISMA-IPD guidelines. A predefined set of clinical, laboratory, and kidney biopsy findings was extracted for each patient and presented as a narrative and quantitative synthesis. A total of 74 reports describing 181 patients with ANCA-positive IE were included (a total of 182 cases including our own case). ANCA positivity was found in 18-43% of patients with IE. Patients usually presented with subacute IE (73%) and had positive cytoplasmic ANCA-staining or anti-proteinase-3 antibodies (79%). Kidney function was impaired in 72%; kidney biopsy findings were suggestive of immune complexes in 59%, while showing pauci-immune glomerulonephritis in 37%. All were treated with antibiotics; 39% of patients also received immunosuppressants. During follow-up, 69% of patients became ANCA-negative and no diagnosis of systemic vasculitis was reported. This study reviewed the largest series of patients with ANCA-positive IE thus far and shows the overlap in clinical manifestations between IE and AAV. We therefore emphasize that clinicians should be alert to the possibility of an underlying infection when treating a patient with suspected AAV, even when reassured by ANCA positivity. Key Points • This systematic review describes - to our knowledge - the largest series of patients with ANCA-positive infective endocarditis (IE) thus far (N=182), and shows a high degree of overlap in clinical manifestations between IE and ANCA-associated vasculitis (AAV). • ANCA positivity was found in 18-43% of patients with infective endocarditis. Of patients with ANCA-positive IE, the majority (79%) showed cytoplasmic ANCA-staining or anti-PR3-antibodies. We emphasize that clinicians should be alert to the possibility of an underlying infection when treating a patient with suspected AAV, even when reassured by ANCA positivity. • In patients with IE and ANCA-associated symptoms such as acute kidney injury, an important clinical challenge is the initiation of immunosuppressive therapy. All patients with data in this series received antibiotics; 39% also received immunosuppressive therapy. In many of these patients, ANCA-associated symptoms resolved or stabilized after infection was treated. ANCA titers became negative in 69% , and a diagnosis of AAV was made in none of the cases. We therefore recommend that (empiric) antibiotic treatment remains the therapeutic cornerstone for ANCA-positive IE patients, while a watchful wait-and-see approach with respect to immunosuppression is advised.

A "cat"-astrophic case of Bartonella infective endocarditis causing secondary cryoglobulinemia: a case report

Background

Culture-negative infective endocarditis (IE) constitutes approximately 10% of all cases of IE. Bartonella endocarditis is a common cause of culture-negative endocarditis and is associated with a high mortality rate. To date, no cases of Bartonella IE has been reported in association with cryoglobulinemia in the UK. We present a unique case of Bartonella IE causing secondary cryoglobulinemia in a young female.

Case presentation

A 17-year-old female with a background of pulmonary atresia and ventricular septal defect repaired with a cardiac conduit at the age of 4, presented with a one-year history of weight loss (from 53 to 39 kg) and poor appetite. She subsequently developed a vasculitic rash and haematoproteinuria with decline in renal function, requiring urgent hospital admission. Initial blood tests showed a near normal creatinine, but a raised cystatin C. Renal biopsy showed focal necrotizing glomerulonephritis with no acute tubular necrosis or chronic change. Subsequent blood tests supported a diagnosis of cryoglobulinaemic vasculitis (high rheumatoid factor, low complement, polyclonal gammopathy, Type 3 cryoglobulin). A weak positive PR3 meant there was some uncertainty about whether this could be a primary ANCA-associated vasculitis (AAV). Initial workup for an infectious cause, including multiple blood cultures, were negative. However, an echocardiogram showed definite vegetations on her surgical conduit. The patient did not respond to empirical antimicrobials and so was referred for surgical revision of her conduit. Tissue samples obtained intra-operatively demonstrated Bartonella species. With targeted antimicrobials post-operatively, she improved with resolution of immunologic abnormalities and at last review had a normal renal profile. On reviewing her social history, she had adopted several stray cats in the preceding year; and thus, the cause of the Bartonella infection was identified.

Conclusion

This is the first reported case of Bartonella endocarditis causing secondary cryoglobulinemia reported in the UK. The key learning points from this case include that Bartonella endocarditis can present as a cryoglobulinaemic vasculitis and should be considered in any differential when the cause of cryoglobulinaemia is not clear and to enquire about relevant exposures especially when culture-negative endocarditis is suspected.

Renal autoimmunity: The role of bacterial and viral infections, an extensive review

Autoimmunity is a process by which the loss of self-tolerance results in an immune attack against the body own tissues and organs. For autoimmunity to occur, various elements serving as triggers were described by which infections are considered one of the leading factors. In turn, renal involvement in autoimmune diseases, whether by an organ-specific attack, or as part of a systemic disease process, is well known. As bacterial and viral infections are considered to be common triggers for autoimmunity in general, we aimed to study their association with renal autoimmunity in particular. We performed an extensive search of the recent and relevant medical literature regarding renal autoimmunity syndromes such as infection-associated glomerulonephritis and vasculitis, associated with bacterial and viral infections. By utilizing PubMed and Google Scholar search engines, over 200 articles and case reports were reviewed. Among other mechanisms, direct infection of the renal parenchyma, molecular mimicry, induction of B-cells or secretion of superantigens, bacterial and viral pathogens were found to correlate with the development of renal autoimmunity. Nevertheless, this was not true for all pathogens, as some mimic autoimmune diseases and others show a surprisingly protective effect. The exact immunopathogenesis is yet to be determined, however. For conclusion, bacterial and viral infections are linked to renal autoimmunity by both direct damage and as mediators of systemic diseases. Further research particularly on the immunopathogenetic mechanisms of renal autoimmunity associated with infections is required.

A case of Bartonella henselae native valve endocarditis presenting with crescentic glomerulonephritis

Bartonella endocarditis is often an elusive diagnosis, usually derived from evaluating multiple laboratory tests and assessment of presenting symptoms. Herein we describe a case of Bartonella henselae native mitral valve endocarditis with an initial presentation of volume overload and renal failure. The Bartonella organism is tedious to isolate from culture medium, causing most diagnoses to be delayed. Due to the destructive nature of B. henselae endocarditis, the need for rapid identification remains prudent. This therefore creates an opportunity for Next Generation Sequencing (NGS) to be used. We further summarize the varied presentations that may be associated with B. henselae endocarditis, and hope that this will heighten the clinicians' awareness of this entity when presented with acute onset renal failure and culture negative vegetations.

Bartonella Endocarditis Presenting as Recurrent Cerebral Mycotic Aneurysm

Bartonella henselae is a known cause of culture-negative endocarditis, which can be difficult to diagnose without a high clinical suspicion as specific diagnostic testing is required. 

We report the case of a 48-year-old male who presented with altered sensorium. A CT of the head showed left-hemispheric intracranial hemorrhage (ICH) likely secondary to ruptured left posterior cerebral artery (PCA) fusiform aneurysm seen on catheter cerebral angiogram, which was treated with endovascular embolization. The patient had a significant history of mitral valve prolapse; however, a transthoracic echocardiogram (TTE) was negative for any vegetation. Blood cultures were also negative. A year later, he presented with another ICH in the PCA territory and was found to have a new left distal PCA aneurysm, which was again treated with endovascular embolization. During that hospitalization, an echocardiogram showed myxomatous changes in the mitral valve with severe mitral regurgitation; however, blood cultures were negative. Further queries about the patient’s social history revealed that his spouse had been a cat owner in 2018, which prompted Bartonella henselae testing. The blood work showed elevated immunoglobulin G (IgG) titers for which he was placed on antibiotics. A follow-up catheter angiogram detected a new distal middle cerebral artery (MCA) M4 branch aneurysm treated with surgical clipping. The aneurysm tested positive for Bartonella henselae on polymerase chain reaction (PCR) testing. The patient subsequently underwent successful mitral valve replacement, which also was positive for Bartonella henselae on PCR testing; however, the Warthin-Starry stain was negative.

This case demonstrates how a comprehensive history along with persistent evaluation for the underlying etiology of cerebral aneurysms can lead to the diagnosis of Bartonella henselae endocarditis. Cerebral mycotic aneurysms are known complications of endocarditis; however, the underlying infection can be difficult to diagnose. Recognition of this culture-negative endocarditis is critical for the appropriate treatment and management of patients to prevent morbidity and mortality.

Bartonella and Coxiella infections presenting as systemic vasculitis: case series and review of literature

OBJECTIVES

Coxiella and Bartonella sp. display particular tropism for endothelial or endocardial tissues and an abnormal host response to infections with induced autoimmunity. We aimed, through a case series combined with a comprehensive literature review, to outline characteristics of Coxiella and Bartonella infections presenting as systemic vasculitis.

METHODS

We retrospectively included cases of definite Coxiella and Bartonella infections presenting with vasculitis features and performed a comprehensive literature review.

RESULTS

Six cases of Bartonella infections were added to 18 cases from literature review. Causative pathogens were mainly B. henselae. Bartonella infection mimicked anti-neutrophil cytoplasmic antibodies (ANCA)-associated vasculitis in 83% with PR3-ANCA and presented as cryoglobulinemic vasculitis in 8%. Glomerulonephritis was present in 92%, and 88% had endocarditis. Complement fractions were low in 82% and rheumatoid factor positive in 85%. Kidney biopsies showed cell proliferation, mostly crescentic, with pauci-immune glomerulonephritis in 29%. Outcome was favorable, with the use of antibiotics alone in one third. Five cases of Coxiella infections were added to 16 from literature review. Sixteen had small-vessel vasculitides, mainly cryoglobulinemia vasculitis in 75%. One patient had polyarteritis nodosa-like vasculitis and four large-vessel vasculitis. Outcome was good except for one death. A highly sensitive next generation sequencing analysis on 3 Coxiella and 2 Bartonella-related vasculitides biopsies did not find any bacterial DNA.

CONCLUSION

Coxiella and Bartonella are both able to induce vasculitis but display distinct vasculitis features. Bartonella mimics PR3-ANCA-associated vasculitis in the setting of endocarditis, whereas Coxiella may induce vasculitis involving all vessel sizes.

Clinical and Echocardiographic Characteristics of Bartonella Infective Endocarditis: An 8-Year Single-Centre Experience in the United States

BACKGROUND

Infective endocarditis due to Bartonella species is rare. The clinical and echocardiographic characteristics are not well defined. We aimed to investigate the clinical and echocardiographic findings of Bartonella endocarditis in the contemporary era.

METHODS

The infective endocarditis (IE) registry and echocardiographic database at our institution were retrospectively analysed to evaluate the clinical and echocardiographic features of Bartonella endocarditis.

RESULTS

Between January 2008 and December 2015, there were 11 patients with Bartonella IE (0.84% among a total of 1,308 cases of definite IE): median age 54 (30-69) years, all male, 9 Caucasian, 10 had a history of cat exposure, 10 had a pre-existing valvulopathy including 6 patients with a prosthetic valve with prosthesis age range between 3 to 5 years and 1 patient with implantable cardioverter defibrillator (ICD). Bartonella henselae was responsible for all the cases. Echocardiographic evidence of IE was found in 6 of 11 patients on transthoracic echocardiography (TTE), and 6 of 8 on transoesophageal echocardiography (TEE). Bartonella IE was associated with significant valvular destruction and dysfunction on echocardiography. Nine (9) patients were managed surgically with excellent outcomes, including two patients who failed initial medical therapy. Two (2) patients who were managed medically had progression of valvular dysfunction. At a median follow-up of 6 months, there were no deaths attributable to IE or other cardiovascular causes.

CONCLUSION

In a contemporary single-centre cohort in the United States, Bartonella IE remains rare, but should be considered when pathogen could not be identified in patients with suspected IE, especially those with prosthetic valves or bicuspid aortic valve (BAV). The vast majority of patients with Bartonella IE were managed surgically with excellent outcomes.

Bartonella-Associated Endocarditis with Severe Active Crescentic Glomerulonephritis and Acute Renal Failure

We report a case of severe acute kidney failure due to crescentic glomerulonephritis who presented initially with culture-negative endocarditis with vegetations on the aortic valve. Anti-nuclear and anti-phospholipid antibodies were positive with initially negative anti-neutrophil cytoplasmic antibodies (ANCAs). Kidney biopsy revealed severe acute crescentic glomerulonephritis with mesangial immune complex deposition. PR3-ANCA subsequently become positive, and the patient developed worsening kidney failure requiring hemodialysis. This case illustrates that Bartonella can present as culture-negative endocarditis with severe crescentic glomerulonephritis with positive PR-3 ANCAs and can mimic ANCA-associated crescentic glomerulonephritis.

Mimics of vasculitis

While prompt diagnosis of vasculitis is important, recognition of vasculitis mimics is equally essential. As in the case of vasculitis, an approach to mimics based on the anatomic size of vessels can be useful. Infections can mimic vasculitis of any vessel size, including the formation of aneurysms and induction of ANCAs. Genetic disorders and vasculopathies are important considerations in large and medium vessel vasculitis. Cholesterol emboli, thrombotic conditions and calciphylaxis typically affect the medium and small vessels and, like vasculitis, can cause cutaneous, renal and CNS manifestations. Reversible cerebral vasoconstriction syndrome is important to distinguish from primary angiitis of the CNS. As an incorrect diagnosis of vasculitis can result in harmful consequences, it is imperative that the evaluation of suspected vasculitis includes consideration of mimics. We discuss the above mimics and outline a systematic and practical approach for differentiating vasculitis from its mimics.

Clinical Manifestations Associated with Bartonella henselae Infection in a Tropical Region

Bartonella henselae is a zoonotic Gram-negative Bacillus associated with self-limited regional lymphadenopathy. In recent decades, an expanding spectrum of clinical manifestations has been described, in part, due to improved diagnostics. However, updated epidemiological data are sparse. We retrospectively reviewed the clinical features of 31 patients with B. henselae infection over 15 years from 2005 to 2019, in the tropical Top End of Australia. Our annual disease incidence of 1.3 cases per 100,000 population is lower than that in the national database surveillances in the United States, but the hospitalization incidence of 0.9 per 100,000 population in our region is higher than those reported in the literature, with an average length of stay of 9 days. Patients were more commonly male, aboriginal, and aged less than 14 years (median age: 7 years), living in a rural setting with presentation during our monsoon season. The disease spectrum included lymph node disease (74%), organ peliosis, endocarditis, cutaneous lesions, parapharyngeal abscess, parotitis, and neurologic and ocular syndromes. Lymph node disease was far commoner in children than the more serious systemic B. henselae infections associated with adults (P = 0.074). Although no deaths were reported, significant morbidities were observed. Two endocarditis cases presented with glomerulonephritis, and hematological and neurological features mimicking vasculitis, and consequently received immunosuppressants. One case was only diagnosed after representation with serial embolic strokes. Given the heterogeneity of disease manifestations with nonspecific symptoms and significant consequences, a timely and accurate diagnosis is needed to avoid unnecessary treatments or interventions.

Diagnostic Abilities for Determining the Level of Blood Cryoglobulins in the Choice of Tactics for Operations on the Small Intestine

The study of the incidence of cryoglobulinemia is relevant in patients with an intestinal anastomotic leak. This study aims to determine a laboratory marker of the risk of small intestine anastomotic leak. The study was based on 96 patients who were subjected to resections of segments of the small intestine with the formation of intestinal anastomoses at the State Institution “Zaytsev V.T. Institute of General and Urgent Surgery of National Academy of Medical Sciences of Ukraine”. Of all the operated patients, there were 55.2% women and 44.8% men. Of the 96 patients examined, cryoglobulinemia was detected in the majority – 62.5% of patients, of which 4 were later proved to have inactive hepatitis C; the remaining 38.5% had no cryoglobulinemia. According to the existing theory of the autoimmune mechanism of postoperative surgical complications formation, the revealed decrease in the level of cryoglobulins on the second day could be related to their fixation in the microcirculatory bed and the development of immunocomplex inflammation. While the increase in the content of cryoglobulins in serum on the third day can be caused by their entry into the circulatory bed from deposition or fixation sites and the development of a secondary immune response. In patients with intestinal anastomosis failure after resection of intestinal segments, cryoglobulinemia rates increased more than 80 mg/l; this indicator could be used as a marker of postoperative complications.

Antineutrophil cytoplasmic antibody-positive infective endocarditis complicated by acute kidney injury: a case report and literature review

Patients with infective endocarditis (IE) may present with multisystem disturbances resembling autoimmune diseases, such as antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV). The kidneys are susceptible to damage in IE and AAV, which is a source of diagnostic ambiguity. Therefore, distinguishing infection from an inflammatory process is pivotal for guiding appropriate therapy. We report a 22-year-old man with IE characterized by ANCA positivity and complicated by acute kidney injury. A renal biopsy showed crescentic nephritis with tubulointerstitial lesions. However, transthoracic echocardiography and blood culture provided evidence of IE, and AAV was ruled out. Surgical intervention and antibiotic treatments were successful. We summarized previously reported cases of ANCA-positive IE that had renal biopsy data. We found that ANCA-positive IE can involve multiple organs. The representative renal pathology was crescentic nephritis, focal segmental glomerulonephritis, mesangial cell proliferation, tubular injury, and interstitial oedema. Immunofluorescence showed predominate C3 deposits. Electron microscopy showed electron-dense deposits in the subendothelial or mesangial areas. Eight patients received immunosuppressive therapy with excellent results. Repeated testing for bacterial pathogens and multiple renal biopsies may be useful for diagnosing ANCA-positive IE. With ANCA-positive IE, immunosuppressive therapy along with antibiotic treatments may be beneficial for recovery of renal function.

Diagnostic and treatment challenge of unrecognized subacute bacterial endocarditis associated with ANCA-PR3 positive immunocomplex glomerulonephritis: a case report and literature review

BACKGROUND

Diagnosis and treatment of either ANCA disease or silent infection-related glomerulonephritis is complicated and is a huge treatment challenge when overlapping clinical manifestations occur. We report a case of ANCA-PR3 glomerulonephritis, nervous system involvement, hepatosplenomegaly and clinically silent subacute infectious endocarditis.

CASE PRESENTATION

A 57-year-old man with known mitral valve prolaps was admitted for unexplained renal failure with signs of nephritic syndrome, hepatosplenomegaly, sudden unilateral hearing loss, vertigo, malaise, new onset hemolytic anemia and thrombocytopenia. Immunoserology revealed positive c-anti-neutrophil cytoplasm antibody (ANCA)/anti-proteinase 3 (anti-PR3), mixed type crioglobulinemia and lowered complement fraction C3. Head MRI showed many microscopic hemorrhages. Common site of infection, as well as solid malignoma were ruled out. In accordance with clinical and laboratory findings, systemic vasculitis was assumed, although the etiology remained uncertain (ANCA-associated, cryoglobulinemic or related to unrecognized infection). After kidney biopsy, clinical signs of sepsis appeared. Blood cultures revealed Streptococcus cristatus. Echocardiography showed mitral valve endocarditis. Kidney biopsy revealed proliferative, necrotizing immunocomplex glomerulonephritis. Half a year later, following intravenous immunoglobulins, glucocorticoids, antibiotic therapy and surgical valve repair, the creatinine level decreased and c-ANCA and cryoglobulins disappeared. A second kidney biopsy revealed no residual kidney disease. Four years after treatment, the patient is stable with no symptoms or signs of vasculitis recurrence.

CONCLUSIONS

Here we describe the diagnostic and treatment challenge in a patient with unrecognized subacute bacterial endocarditis associated with ANCA-PR3 immunocomplex proliferative and crescentic glomerulonephritis. In patients with ANCA-PR3 immunocomplex glomerulonephritis and other overlapping manifestations suggesting systemic disease, it is important to recognize and aggressively treat any possible coexisting bacterial endocarditis, This is the most important step for a favorable patient outcome, including complete clinical and pathohistological resolution of the glomerulonephritis.

Case Report: Bartonella quintana Endocarditis Outside of the Europe-African Gradient: Comprehensive Review of Cases within North America

Clinical syndromes associated with Bartonella quintana infection can be insidious and difficult to diagnose for multiple reasons. Clinically, B. quintana can manifest as asymptomatic bacteremia or with subtle subacute constitutional symptoms. Second, it is a fastidious organism that is difficult to identify using traditional culture methods. Last, the body lice vector of B. quintana transmission is likely not uncommon in most patients affected, who are homeless and of low socioeconomic status. Therefore, barriers in seeking medical care and financial constraints for medications are important considerations. The mainstay of literature surrounding B. quintana endocarditis is from Europe and the developing nations. Herein, we describe a case of native valve endocarditis secondary to B. quintana in a homeless male with preexisting valvular disease and undertake a comprehensive literature review of documented B. quintana endocarditis in North America.

Proteinase 3-antineutrophil cytoplasmic antibody-positive necrotizing crescentic glomerulonephritis complicated by infectious endocarditis: a case report

Background

Proteinase 3-antineutrophil cytoplasmic antibody has been reported to be positive in 5–10% of cases of renal injury complicated by infective endocarditis; however, histological findings have rarely been reported for these cases.

Case presentation

A 71-year-old Japanese man with a history of aortic valve replacement developed rapidly progressive renal dysfunction with gross hematuria and proteinuria. Blood analysis showed a high proteinase 3-antineutrophil cytoplasmic antibody (163 IU/ml) titer. Streptococcus species was detected from two separate blood culture bottles. Transesophageal echocardiography detected mitral valve vegetation. Histological evaluation of renal biopsy specimens showed necrosis and cellular crescents in glomeruli without immune complex deposition. The patient met the modified Duke criteria for definitive infective endocarditis. On the basis of these findings, the patient was diagnosed with proteinase 3-antineutrophil cytoplasmic antibody-positive necrotizing crescentic glomerulonephritis complicated by Streptococcus infective endocarditis. His renal disease improved, and his proteinase 3-antineutrophil cytoplasmic antibody titer normalized with antibiotic monotherapy.

Conclusion

Few case reports have described histological findings of proteinase 3-antineutrophil cytoplasmic antibody-positive renal injury complicated with infective endocarditis. We believe that an accumulation of histological findings and treatments is mandatory for establishment of optimal management for proteinase 3-antineutrophil cytoplasmic antibody-positive renal injury complicated with infective endocarditis.

Bartonella henselae Bloodstream Infection in a Boy With Pediatric Acute-Onset Neuropsychiatric Syndrome

BACKGROUND

With the advent of more sensitive culture and molecular diagnostic testing modalities, Bartonella spp. infections have been documented in blood and/or cerebrospinal fluid specimens from patients with diverse neurological symptoms. Pediatric acute-onset neuropsychiatric syndrome (PANS) is characterized by an unusually abrupt onset of cognitive, behavioral, or neurological symptoms. Between October 2015 and January 2017, a 14-year-old boy underwent evaluation by multiple specialists for sudden-onset psychotic behavior (hallucinations, delusions, suicidal and homicidal ideation).

METHODS

In March 2017, Bartonella spp. serology (indirect fluorescent antibody assays) and polymerase chain reaction (PCR) amplification, DNA sequencing, and Bartonella enrichment blood culture were used on a research basis to assess Bartonella spp. exposure and bloodstream infection, respectively. PCR assays targeting other vector-borne infections were performed to assess potential co-infections.

RESULTS

For 18 months, the boy remained psychotic despite 4 hospitalizations, therapeutic trials involving multiple psychiatric medication combinations, and immunosuppressive treatment for autoimmune encephalitis. Neurobartonellosis was diagnosed after cutaneous lesions developed. Subsequently, despite nearly 2 consecutive months of doxycycline administration, Bartonella henselae DNA was PCR amplified and sequenced from the patient's blood, and from Bartonella alphaproteobacteria growth medium enrichment blood cultures. B henselae serology was negative. During treatment with combination antimicrobial chemotherapy, he experienced a gradual progressive decrease in neuropsychiatric symptoms, cessation of psychiatric drugs, resolution of Bartonella-associated cutaneous lesions, and a return to all pre-illness activities.

CONCLUSIONS

This case report suggests that B henselae bloodstream infection may contribute to progressive, recalcitrant neuropsychiatric symptoms consistent with PANS in a subset of patients.

Bartonella Endocarditis Mimicking Crescentic Glomerulonephritis with PR3-ANCA Positivity

Bartonella henselae is a fastidious organism that causes cat scratch disease, commonly associated with fever and lymphadenopathy but, in rare instances, also results in culture-negative infectious endocarditis. We describe a patient who presented with flank pain, splenic infarct, and acute kidney injury with an active urinary sediment, initially suspicious for vasculitis, which was subsequently diagnosed as B. henselae endocarditis. Bartonella endocarditis may present with a crescentic glomerulonephritis (GN) and elevated PR3-ANCA antibody titers, mimicking ANCA-associated GN, with 54 cases reported in the literature. Unique to our case in this series is a positive PR3-ANCA antibody despite a negative IIF-ANCA. Thus, the presentation of Bartonella can mimic ANCA-associated GN, and renal biopsy showing immune complex deposition is critical for diagnosis and appropriate treatment.

Bartonella Infectious Endocarditis Associated With Cryoglobulinemia and Multifocal Proliferative Glomerulonephritis

Bartonella sp. are a common cause of culture-negative infective endocarditis. Glomerulonephritis is a well-documented consequence of the immune activation associated with infective endocarditis. However, Cryoglobulinemia has not previously been reported in association with Bartonella infective endocarditis. Below we report a case of a 48-year-old male with Bartonella henselae infective endocarditis complicated by cryoglobulinemia and multifocal proliferative glomerulonephritis, highlighting a possible link between Bartonella sp. infection and type III cryoglobulinemia.

Bartonella endocarditis in a child with tetralogy of Fallot complicated by PR3-ANCA positive serology, autoimmune hemolytic anemia, and acute kidney injury

Although the role of ANCA in infective endocarditis is unclear, Bartonella henselae has been implicated as the culprit in cases of PR3-ANCA positive subacute bacterial endocarditis (SBE) with glomerulonephritis. In this case, a Coombs-positive autoimmune hemolytic anemia and glomerulonephritis accompanied a PR3-ANCA positive SBE caused by Bartonella henselae.

Bartonella endocarditis with glomerulonephritis in a patient with complete transposition of the great arteries

We describe a patient with history of dextro-transposition of the great vessels, ventricular septal defect, and pulmonary valve replacement who presented with fatigue, prolonged fever, and leg edema. He was found to have kidney injury, pancytopenia, and liver congestion. Echocardiogram revealed thickened leaflets with prolapsing vegetation on the pulmonary valve. Given the negative blood cultures, high Bartonella henselae immunogobulin G titer (≥1:1024) and positive immunoglobulin M titer (≥1:20), he was diagnosed with Bartonella endocarditis complicated with glomerulonephritis.

ANCA-associated pauci-immune glomerulonephritis in a patient with bacterial endocarditis: a challenging clinical dilemma

Purpose: We report the case of a 59-year-old man with chronic hepatitis B and C infection presenting with acute kidney injury and enterococcus faecalis-infective endocarditis (IE). An elevated proteinase-3 (PR3)-ANCA and pauci-immune glomerulonephritis (GN) on renal biopsy were discovered, corresponding to ANCA-mediated GN. We conducted a literature review to assess the role of ANCA in IE and treatment implications. Methods: On systematic review of the literature, we found five previous cases whereby IE caused by streptococcus and bartonella species were related to ANCA vasculitis-associated GN. Results: Most reports of IE-related GN are mediated by immune complex deposition and resolve following microbial clearance. Of the 5 cases of ANCA GN in the setting of IE, all had markedly elevated levels of PR3-ANCA with either a subacute or chronic course of infection. Patients were treated with a combination of steroids and cyclophosphamide (2/5), steroids and antibiotics alone (1/5), or with valvular replacement (2/5). Renal function was recovered in 4/5 patients. Conclusion: Infection is a major etiologic player in the formation of ANCA; however, the role of PR3-ANCA in IE remains unclear. Kidney biopsy is essential in differentiating IE-related GN due to infection and immune complex deposition versus ANCA-associated vasculitis. A paucity of reports on the development of GN in IE-associated ANCA vasculitis exists, highlighting the rarity of our case and lack of clear therapeutic strategies in a patient with active infection requiring immunosuppression. In this case, the patient’s chronic hepatitis B and C coinfection presented a unique challenge.