The current spectrum of infectious glomerulonephritis. Experience with 76 patients and review of the literature

The Pulsing Paradox: Successful Steroid Therapy in Infection-Related Glomerulonephritis

The patterns of infection-related glomerulonephritis (IRGN) are rapidly changing in terms of age at presentation and sources of infection. The existing literature on the use of steroids in IRGN is inconsistent. A diabetic male in his sixties presented with features of anasarca, bilateral flank pain, and acute pulmonary edema. He had a non-healing ulcer over his right leg, with pus culture showing growth of methicillin-resistant Staphylococcus aureus (MRSA). Computed tomography (CT) of the kidneys, ureter, and bladder (KUB) showed features of bilateral pyelonephritis. The patient went on to develop acute renal failure and eventually required hemodialysis. A renal biopsy was performed, and features of IRGN with crescents were noted. Considering the presence of crescents in renal biopsy, a trial of steroids was given under antibiotic cover, which resulted in a near-complete resolution of renal failure.

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identified using an English literature search of several commonly used literature search modalities); and four unpublished cases from our institution.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.

IgA-Dominant Staphylococcus-Associated Glomerulonephritis: An Uncommon Complication of Intravenous Drug Use

A 24-year-old female with a history of intravenous heroin use presented with two weeks of chills, myalgias, and cough and was found to be in acute hypoxemic respiratory failure. Subsequent workup revealed the presence of bilateral septic pulmonary emboli and tricuspid valve endocarditis. Several weeks into her hospitalization, she developed periorbital edema and laboratory testing revealed she had developed acute renal failure and nephrotic range proteinuria. A renal biopsy confirmed the diagnosis of IgA-dominant Staphylococcus-associated glomerulonephritis (IgA-SAGN). Early recognition of this newly recognized variant of glomerulonephritis is paramount, as improper treatment may lead to catastrophic consequences.

A case report: Infection-related glomerulonephritis and mantle cell lymphoma due to mycobacterium avium complex infection

RATIONALE

Mycobacterium avium complex (MAC) infection is common in lung, liver and skin. However, MAC presenting with peritonitis is uncommon and is particularly rare in immunocompetent patients. We report a case of infection-associated glomerulonephritis and mantle cell lymphoma caused by peritonitis due to MAC.

PATIENT CONCERNS

We report a case of a 73-year-old elderly man with fever and abdominal pain for 2 days and gradually developed anuria, ascites, and abdominal lymphadenopathy.

DIAGNOSES

The initial diagnosis was peritonitis and acute renal failure. There was no significant relief of symptoms after empirical anti-infective therapy and hemodialysis. infection-associated glomerulonephritis, mantle cell lymphoma, and peritonitis due to MAC were diagnosed by renal biopsy, abdominal lymph node biopsy, and metagenomics next-generation sequencing.

INTERVENTIONS

The patient received empirical antibiotic therapy, hemodialysis, and anti-MAC therapy.

OUTCOMES

Unfortunately, the patient eventually died of septic shock after the 21st day of admissiom.

LESSONS

Early diagnosis of MAC infection is essential. When the cause of fever is unknown, metagenomics next-generation sequencing can be considered.

Bacterial infection-related glomerulonephritis in patients with diabetes

AIM

Diabetic patients are prone to infections, thus making them a unique cohort at risk of developing bacterial infection-related glomerulonephritis (IRGN).

METHODS

In total, 1693 adult diabetic patients underwent kidney biopsy between 2005 and 2021 at our tertiary care hospital in South India. Of these, 121 consecutive cases which met criteria of bacterial IRGN were included in this study.

RESULTS

The mean age of the cohort was 53.1 ± 10.1 years and 83/121 (68.5%) were males. Majority (98.3%) had type 2 diabetes for a median duration of 6 (IQR, 2-12) years. The most common sites of infection were skin (47/121, 38.8%) and urinary tract (15/121, 12.4%). Fifty percent (58/121) of patients had underlying advanced diabetic kidney disease (DKD). Isolated C3 deposits (without immunoglobulin) occurred in 66/121 (54.5%) patients predominantly in advanced DKD patients. IgA-dominant glomerulonephritis occurred in only 9/121 (7.4%) patients. Short-course oral steroid was given to 86/121 (71.1%) patients. Steroid related dysglycemia and immunosuppression related infections occurred in 9/61 (14.8%) and 16/61 (26.2%) patients respectively. Of the 90 patients with follow up details >3 months, 46 (51.1%) progressed to kidney failure over a median period of 0.5 (IQR, 0-7.2) months. Patients diagnosed in the latter half of our study period (2013-2021) were older, less commonly presented with fever, had more pronounced hypocomplementemia and severe renal histology predominantly with a 'starry sky' immunofluorescence pattern.

CONCLUSION

Superimposed bacterial IRGN on underlying DKD is associated with poor renal outcomes. Use of short course steroid was associated with significant toxicity.

Infection-Related Glomerulonephritis in Children and Adults

Infection-related glomerulonephritis is an immunologically mediated glomerular injury after an infection. Glomerulonephritis may occur with the infection or after a variable latent period. Poststreptococcal glomerulonephritis (PSGN) is the prototype of infection-related glomerulonephritis. The streptococcal antigens, nephritis-associated plasmin-like receptor and streptococcal exotoxin B, have emerged as major players in the pathogenesis of PSGN. Although PSGN is the most common infection-related glomerulonephritis in children, in adults, glomerulonephritis is secondary to bacteria such as staphylococci, viruses such as hepatitis C, and human immunodeficiency virus, and, rarely, parasitic infections. Supportive therapy is the mainstay of treatment in most infection-related glomerulonephritis. Treatment of the underlying infection with specific antibiotics and antiviral medications is indicated in some infections. Parasitic infections, although rare, may be associated with significant morbidity. Poststreptococcal glomerulonephritis is a self-limiting condition with a good prognosis. However, bacterial, viral, and parasitic infections may be associated with significant morbidity and long-term consequences. Epidemiologic studies are required to assess the global burden of infection-related glomerulonephritis. A better understanding of the pathogenesis of infection-related glomerulonephritis may unravel more treatment options and preventive strategies.

Streptococcal Infection-related Glomerulonephritis in an Elderly Diabetic Patient Complicated by Hemophagocytic Syndrome and Cytomegalovirus Nephritis

There has been a significant shift in epidemiology and renal outcomes of infection-related glomerulonephritis (IRGN) in recent years. The renal prognosis of IRGN is often poor in adults, especially in the elderly and diabetics. We herein report an elderly diabetic patient with IRGN due to streptococcal infection complicated by hemophagocytic syndrome and cytomegalovirus nephritis, which is uncommon among non-transplant patients. Infection control and steroids did not recover the patient's renal function. For elderly IRGN patients with diabetes, a further investigation of the most effective treatment for related renal outcomes is needed.

A rare case of Immunoglobulin A dominant post-infectious glomerulonephritis (IgA PIGN) in a young patient

Background

Immunoglobulin A dominant postinfectious glomerulonephritis (IgA PIGN) is a unique medical entity that is rare in the paediatric population. It usually presents with severe renal failure, heavy proteinuria, hypertension, and hypocomplementemia and frequently has an unfavourable prognosis. IgA PIGN generally occurs in association with staphylococcal infections and diabetes mellitus in adult patients. Other pathogens include Escherichia coli and Streptococcus sp. Immunofluorescence studies of kidney biopsy samples show IgA as dominant or codominant antibody.

Case presentation

We encountered a 3-year-old girl with IgA PIGN presenting with acute renal failure, oedema, hypertension, and heavy proteinuria of 7955 mg/g creatinine. Renal biopsy specimens showed diffuse glomerular endocapillary hypercellularity with prominent neutrophil and monocyte infiltration on light microscopy. Strong deposits of IgA and C₃ were observed along the glomerular basement membranes and the mesangium by immunofluorescence microscopy, and electron microscopy revealed the presence of subepithelial humps.

The patient was managed with steroid (and probatory antibiotic) therapy and is now undergoing follow-up, with a significant improvement 6 months after the initial presentation (glomerular filtration rate (GFR) and cystatin C clearance rate of 165 ml/min/1.73m² and 106 ml/min/1.73m², respectively). No signs of bacterial infection were detectable.

Conclusion

This variant of IgA PIGN must be distinguished from other clinical entities, especially IgA nephropathy (mesangial IgA deposits) and postinfectious glomerulonephritis (C3, IgG and occasional IgM capillary loop deposits with or without mesangial distribution), since patients with IgA PIGN may require steroid treatment in addition to antibiotic therapy. Differential diagnosis should also include C₃ glomerulopathy.

IgA PIGN is a recently identified disease entity that generally manifests in adult patients with both IgA and C3 mesangial and glomerular capillary wall deposits. We present a biopsy-proven case of IgA PIGN that manifested in a patient at an exceptionally young age and that has had a good clinical outcome. To the best of our knowledge, this is the youngest IgA PIGN patient reported thus far.

C3 Glomerulopathy: A Review with Emphasis on Ultrastructural Features

C3 glomerulopathy (C3G) is a rare disease resulting from dysregulation of the alternative complement pathway, resulting in the deposition of complement component 3 (C3) in the kidney. It encompasses two major subgroups: dense deposit disease and C3 glomerulonephritis (C3GN). Although the alternative complement pathway is typically a very tightly controlled system, dysregulation can be a result of genetic mutations in the fluid phase or membrane-bound inhibitors or accelerators. In addition, de novo/acquired autoantibodies against any of the regulatory proteins can alter complement activation either by negating an inhibitor or activating an accelerator. Triggering events can be complex; however, the final pathway is characterized by the uncontrolled deposition of C3 in glomeruli and the formation of the membrane attack complex. Light microscopic findings can be quite heterogeneous with a membranoproliferative pattern most commonly encountered. Diagnostic confirmation of C3G is based on a characteristic pattern of glomerular immunofluorescence staining, with C3-dominant deposits that are at least 2 orders of intensity greater than staining for any immunoglobulin (Ig) or C1q. Electron microscopy is necessary for diagnosing DDD in particular, but can also help to distinguish C3GN from other glomerular disease mimickers.

Infective Endocarditis-Associated Purpura and Glomerulonephritis Mimicking IgA Vasculitis: A Diagnostic Pitfall

BACKGROUND

Purpura and glomerulonephritis are typical presentations in IgA vasculitis. Infective endocarditis mimicking IgA vasculitis by presenting with glomerulonephritis and purpura is rarely reported.

METHODS

We searched for cases with infective endocarditis-associated purpura and glomerulonephritis in a tertiary hospital in China and retrospectively reviewed their clinicopathological features. Differential diagnosis and treatment in patients with infective endocarditis-associated purpura and glomerulonephritis were discussed.

RESULTS

A total of 20 cases with infective endocarditis-associated purpura and glomerulonephritis were identified among 548 cases with infective endocarditis in our center during an 8-year period: 7 of the 20 cases (35%) were initially misdiagnosed as IgA vasculitis and 10 cases (50%) presented with left-sided endocarditis caused by Streptococcus viridans. Fever (100%, 20 out of 20), prior valvular deformities (80%, 16 out of 20), cardiac murmur (95%, 19 out of 20), splenomegaly (84%, 16 out of 19), embolism (55%, 11 out of 20), and hypocomplementemia (76%, 13 out of 17) were present in most patients. Crescents and mesangial hypercellularity with or without endothelial hypercellularity were the primary findings on light microscopy, with C3-dominant deposition on immunofluorescence. But IgA-dominant staining was also observed (40%, 2 out of 5). In patients with rapidly progressive glomerulonephritis, patients with complete recovery of renal function had shorter disease duration and higher ratio (67% vs 20%) of immunosuppressive therapy compared with patients with partial recovery.

CONCLUSIONS

Infective endocarditis-associated glomerulonephritis and purpura can closely mimic IgA vasculitis. Differential diagnosis is challenging, particularly when typical presentations of infective endocarditis are absent. In adults with presentations like IgA vasculitis, infective endocarditis should be evaluated through comprehensive clinical and pathological investigations. Immunosuppressive therapy can be considered in patients with severe glomerulonephritis who do not improve after proper anti-infective therapy.

Latency, Anti-Bacterial Resistance Pattern, and Bacterial Infection-Related Glomerulonephritis

BACKGROUND AND OBJECTIVES

Bacterial infection-related GN occurs concurrent to or after known or unknown infections. It is important to understand the clinical implications of the bacterial isolates, antimicrobial resistance patterns, and effect of latency-based classification on kidney and patient outcomes.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

In total, 501 consecutive adults diagnosed with bacterial infection-related GN between 2005 and 2017 were included from a biopsy registry of 15,545 patients at a single center in South India, and follow-up data were collected from electronic medical records until December 2019. Latency was defined as time between resolution of infection and onset of GN, which was classified as parainfectious, peri-infectious, or postinfectious GN. Longitudinal kidney and patient outcomes were studied.

RESULTS

The mean age of the cohort was 40 (± 15) years, 6% were above 65 years, and 330 (66%) were men. Diabetes was present in 93 (19%) patients. Seventy percent (353 of 501) of patients had known infections, with the median latent period for parainfectious (115 of 353, 33%), peri-infectious (97 of 353, 27%), and postinfectious (141 of 353, 40%) GN being 0, 5 (4-7), and 15 (10-31) days, respectively. The most common predisposing organism was Streptococcus pyogenes (137 of 353, 39%). Drug-resistant nonstreptococcal bacteria were methicillin-resistant Staphylococcus aureus (25%, four of 16), extended-spectrum β-lactamases (20%, 12 of 59), and carbapenem-resistant organisms (10%, six of 59). Twenty of 22 (91%) of the drug-resistant organisms were isolated from the parainfectious group. The most common site of infection was skin in peri- (23 of 97, 24%) and postinfectious GN (61 of 141, 43%), and urinary tract in parainfectious GN (35 of 115, 30%). Of 321 patients with >3 months of follow-up, 48 (15%) developed kidney failure over a median period of 10 (2-37) months and 14 (4%) died. Parainfectious GN, eGFR<30 ml/min per 1.73 m², moderate-to-severe interstitial fibrosis and tubular atrophy, and nontreatment with renin-angiotensin system blockers were significant risk factors for progression to kidney failure by a Cox proportional-hazards model.

CONCLUSIONS

Along with clinical and histologic predictors, parainfectious GN caused predominantly by nonstreptococcal and drug-resistant bacterial infections was associated with poor kidney prognosis.

Introduction to Nephrocardiology

The interaction between nephrology and cardiovascular medicine is much broader than the cardiorenal syndrome. Many different aspects of cardiovascular medicine are interconnected with and substantially influenced by the conditions that fall into the realm of nephrology, and vice versa. Those aspects include pathophysiology, risk factors, epidemiology, prognosis, prevention, diagnosis, monitoring, and therapy. Discovery of the interconnected areas and development of appropriate knowledge and skill to optimally approach those circumstances can improve the quality of care and outcome of a large population of patients. Therefore, establishment of the distinct subspeciality of nephrocardiology is imperative.

Crescentic postinfectious glomerulonephritis in an adult patient with juvenile nasopharyngeal angiofibroma

Crescentic glomerulonephritis is usually associated with an acute nephritic syndrome with rapidly declining renal function. Postinfectious cases usually have a higher possibility of recovery. Juvenile nasopharyngeal angiofibroma (JNA) is a rare, locally aggressive tumour affecting mostly young men. A 28-year-old man presented with recurrent JNA initially excised 2 years prior. The patient was initially managed as a case of airway obstruction and pneumonia. He developed tea-coloured urine, oedema and acute kidney failure requiring dialysis while awaiting surgery. Urine and immunological studies (low C3, negative antineutrophil cytoplasmic antibody and antinucleosomal antibody and high antistreptolysin O) suggested a nephritic aetiology. Nasopharyngeal swab cultures of the mass revealed gram-negative organisms. Kidney biopsy showed diffuse proliferative glomerulonephritis compatible with a postinfectious glomerulonephritis with 77% cellular crescents. The mass was excised with histopathology consistent with JNA. The patient was eventually discharged off dialysis.

A Novel Glomerular C4d Scoring System: A Tool to Prognosticate Proliferative Exudative Pattern of Glomerular Injury

Aim:

Proliferative exudative pattern of glomerular injury is usually a manifestation of an infection related or a post-infectious glomerulonephritis (PIGN). Rarely, it may represent a C3 glomerulopathy, which is a dysfunction of the alternative pathway of complement activation, and is then termed an atypical PIGN (aPIGN). C4d deposits in the glomerulus are footprints of the classical and/or lectin pathway of complement activation and hence is expected to be positive in immune-mediated glomerulonephritis (GN) like classical infection-related GN, and could be used to differentiate classical PIGN from atypical PIGN.

Materials and Methods:

We report a novel C4d scoring system based on the intensity and the proportion of glomerular tuft staining, in a series of 104 biopsies with the proliferative exudative pattern of glomerular injury. Using a statistically derived cut-off score of 1.45, the cases were divided into C4d positive and C4d negative groups and compared to IF findings and the follow-up, available in 36 cases.

Results:

The C4d positive group had a significantly greater proportion of cases with immune complexes compared to the group with C3 deposits alone. In the follow-up, C4d negative group had also a greater number with partial/incomplete response compared to the C4d positive group.

Conclusions:

We recommend that the C4d stain be done in all cases with a proliferative exudative pattern of glomerular injury to identify patients who would need a close follow up and further assays of complement function.

Staphylococcus-induced glomerulonephritis: potential role for corticosteroids

Staphylococcus aureus is a troublesome pathogen, responsible for a broad range of clinical manifestations, ranging from benign skin infections to life-threatening conditions such as endocarditis and osteomyelitis. The kidney can be affected through a rapidly progressive glomerulonephritis mediated by an inflammatory reaction against a superantigen deposited in the glomerulus during the infection's course. This glomerulopathy has a poor prognosis, often leading to chronically impaired kidney function, eventually progressing to end-stage renal disease. Treatment rests on antibiotherapy. Despite the inflammatory role in this disease's pathophysiology, most authors discourage a simultaneous immunosuppressive approach given the concomitant infection. However, there are some reports of success after administration of systemic corticosteroids in these patients. We present a 66-year-old man with a staphylococcus-induced glomerulonephritis brought on by a vascular graft infection, with rapidly deteriorating kidney function despite extraction of the infected graft and 3 weeks of antibiotherapy with achievement of infection control. Kidney function improved after the introduction of corticosteroids. This case highlights the potential role of corticosteroids in selected cases of staphylococcus-induced glomerulonephritis, particularly those in which the infection is under control.

Asymptomatic sinusitis as an origin of infection-related glomerulonephritis manifesting steroid-resistant nephrotic syndrome: A case report

RATIONALE

Infection is a major trigger or pathogenic origin in a substantial proportion of glomerulonephritis (GN) patients, typically manifesting infection-related GN (IRGN). Various microorganisms, infection sites, and clinical and histopathological features are involved in IRGN. Once an infectious origin is identified and successfully eradicated, nephrotic syndrome or kidney dysfunction is spontaneously resolved. However, if patients are asymptomatic and the origin is undetermined, the diagnosis and treatment of GN is challenging. This case presentation reported on an IRGN case manifesting steroid-resistant nephrotic syndrome associated with asymptomatic sinusitis as a pathogenic origin.

PATIENT CONCERNS

A 68-year-old male presented with severe kidney dysfunction and edema in both extremities.

DIAGNOSIS

The patient was clinically diagnosed with hypocomplementemic nephrotic syndrome and kidney dysfunction and histopathologically with diffuse proliferative GN and a focal pattern of membranoproliferative GN. The findings suggested that idiopathic membranoproliferative glomerulonephritis type I was more likely than IRGN, given a critical lack of apparent infection.

INTERVENTIONS

Combined intravenous methylprednisolone, oral prednisolone, and cyclosporin did not improve the patient's condition. Thus, IRGN associated with inapparent infectious origin was suspected. Repeated thorough and careful examinations including CT scan showed sinusitis in his left maxillary sinus. Moreover, reanalysis of kidney specimen revealed positive nephritis-associated plasmin receptor in glomeruli, a typical finding for IRGN, supporting a pathogenic significance of his sinusitis. Medical treatment was initiated with 200 mg oral clarithromycin daily.

OUTCOMES

Oral clarithromycin gradually improved proteinuria and hypocomplementemia and resulted in nephrotic syndrome remission in parallel with opacification resolution of sinuses shown on CT.

LESSONS

This case presentation showed that asymptomatic sinusitis is potentially a pathogenic IRGN origin. A gold standard therapy for idiopathic GN, corticosteroid could be damaging in uncontrolled or underdiagnosed infection. In asymptomatic patients, a thorough screening of infectious diseases, including sinusitis, together with a renal histological evaluation of glomerular nephritis-associated plasmin receptor deposition is also essential in treating a wide spectrum of GN.

Patterns in renal diseases diagnosed by kidney biopsy: A single-center experience

Background

The worldwide incidence of renal disease diagnosed by a kidney biopsy varies with age, race, sex, and region. Owing to a lack of studies and limited research resources for this disease in Korea, we investigated renal disease patterns by analyzing data from kidney biopsies performed over 13 years in a university-based teaching hospital in Korea.

Methods

Among 2,053 kidney biopsies performed from 2001 to 2013 at Kyungpook National University Hospital, 1,924 were retrospectively analyzed for histopathologic, demographic, and clinical data as well as laboratory results.

Results

Among the 1,924 studied kidney biopsies, 1,078 were males (56.0%) and the mean age was 37.7 ± 16.5 years. Asymptomatic urinary abnormalities were the most common clinical manifestation (62.5%). Immunoglobulin A nephropathy (IgAN) was the most common primary glomerular disease (37.4%), followed by minimal change disease (MCD), membranous nephropathy (MN), focal segmental glomerulonephritis and crescentic glomerulonephritis. Secondary glomerular diseases accounted for 10.3% of the total biopsies, with lupus nephritis being the most common (4.6%) followed by Henoch-Schönlein purpura nephritis and diabetic nephropathy. The most common cause of nephrotic syndrome was MCD (42.1%) followed by MN. Among patients seropositive for hepatitis B or C, IgAN (28.3% and 21.4%, respectively) was the most common cause.

Conclusion

IgAN and lupus nephritis were the most common primary and secondary glomerular diseases, respectively. Race, region, and practice patterns may affect renal disease patterns in different cohorts.

Epidemiology, pathogenesis, treatment and outcomes of infection-associated glomerulonephritis

For over a century, acute 'post-streptococcal glomerulonephritis' (APSGN) was the prototypical form of bacterial infection-associated glomerulonephritis, typically occurring after resolution of infection and a distinct infection-free latent period. Other less common forms of infection-associated glomerulonephritides resulted from persistent bacteraemia in association with subacute bacterial endocarditis and shunt nephritis. However, a major paradigm shift in the epidemiology and bacteriology of infection-associated glomerulonephritides has occurred over the past few decades. The incidence of APSGN has sharply declined in the Western world, whereas the number of Staphylococcus infection-associated glomerulonephritis (SAGN) cases increased owing to a surge in drug-resistant Staphylococcus aureus infections, both in the hospital and community settings. These Staphylococcus infections range from superficial skin infections to deep-seated invasive infections such as endocarditis, which is on the rise among young adults owing to the ongoing intravenous drug use epidemic. SAGN is markedly different from APSGN in terms of its demographic profile, temporal association with active infection and disease outcomes. The diagnosis and management of SAGN is challenging because of the lack of unique histological features, the frequently occult nature of the underlying infection and the older age and co-morbidities in the affected patients. The emergence of multi-drug-resistant bacterial strains further complicates patient treatment.

Postinfectious Acute Glomerulonephritis in Renal Transplantation: An Emergent Aetiology of Renal Allograft Loss

Despite the high incidence of posttransplant infections, postinfectious acute glomerulonephritis (PIAGN) in renal allograft is a rare entity, without effective treatment and a bad prognosis. We describe two cases of PIAGN: the first one was developed 2 years after kidney transplantation, secondary to Staphylococcus aureus bacteremia with presence of extracapillary proliferation in biopsy. The patient was treated with methylprednisolone and plasma exchanges without response, remaining dialysis dependent. The second case was reported 5 years after kidney transplantation, secondary to influenza A infection. Kidney biopsy showed an IgA-dominant PIAGN and methylprednisolone boluses were initiated without clinical response, suffering a progressive worsening and loss of kidney graft. Due to the aggressive clinical course of this entity, PIAGN should be considered in the differential diagnosis of acute kidney graft failure in the context of an infection. Elderly patients have a higher risk of more severe acute renal dysfunction, requiring dialysis in a great proportion of cases.

The features in IgA-dominant infection-related glomerulonephritis distinct from IgA nephropathy: a single-center study

BACKGROUND

IgA-dominant infection-related glomerulonephritis (IgA-IRGN) is a unique form of IRGN, which needs to be distinguished from IgA nephropathy (IgAN).

METHODS

Thirteen patients with IgA-IRGN (IgA-IRGN group) and 122 with IgAN (IgAN group) were selected from 1788 patients who underwent kidney biopsy between 2000 and 2015 in Kitano Hospital. Data selected included clinical and serological parameters; light and electron microscope findings; immunofluorescence findings; and prognostic parameters like renal and overall survival and creatinine increase by > 50%. In addition, a 26-patient IgAN cohort (matching-IgAN), matching with IgA-IRGN group with respect to age, sex, estimated glomerular filtration rate (eGFR), and proteinuria was segregated for comparison.

RESULTS

Compared to IgAN group, IgA-IRGN group were older, had lower hemoglobin, higher CRP, lower eGFR, heavier proteinuria, lower serum albumin, and higher serum IgG and IgA levels (p < 0.05). Endocapillary hypercellularity, deposition of immune complexes along the glomerular capillary wall, and subendothelial and subepithelial electron dense deposits were more frequently observed (p < 0.05); and they were more susceptible to renal dysfunction and poorer prognosis. After propensity score-matching, serum albumin was significantly lower in the IgA-IRGN group. Significantly subendothelial and subepithelial deposits were frequently observed in this group. Matching-IgAN group showed relatively advanced sclerotic lesions with more global sclerosis and fibrous crescent.

CONCLUSION

Local inflammation involved glomerular capillary wall in IgA-IRGN, in contrast to relatively chronic and sclerotic renal lesion in IgAN, might result in poorer prognosis in former, even under indistinguishable condition of deteriorated renal function and proteinuria.

Analysis of clinical presentation, pathological spectra, treatment and outcomes of biopsy-proven acute postinfectious glomerulonephritis in adult indigenous people of the Northern Territory of Australia

AIM

Acute postinfectious glomerulonephritis is common in indigenous communities in the Northern Territory, Australia. It is a major risk factor for the high prevalence of chronic kidney disease. We aimed to analyse the clinical presentation, pathological spectra, treatment and outcomes of biopsy-proven acute postinfectious glomerulonephritis in the Northern Territory.

METHODS

We performed a retrospective cohort analysis of all adult patients (≥18 years) who were diagnosed with acute postinfectious glomerulonephritis on native renal biopsies from 01/01/2004 to 31/05/2014. The outcome measure was end-stage renal disease requiring long-term dialysis.

RESULTS

Forty-three of 340 patients who had renal biopsies had acute postinfectious glomerulonephritis. Most were Aboriginals (88.4%). They had co-morbidities; diabetes mellitus (60.5%), hypertension (60.5%) and smoking (56.4%). Forty-nine per cent had multiple pathologies on biopsy. Predominant histological pattern was diffuse proliferative glomerulonephritis (72%). Main sites of infections were skin (47.6%) and upper respiratory tract infection (26.2%) with streptococcus and staphylococcus as predominant organisms. Fifty per cent of patients developed end-stage renal disease. On multivariable logistic regression analysis, those on dialysis had higher baseline creatinine (P = 0.003), higher albumin/creatinine ratio at presentation (P = 0.023), higher serum creatinine at presentation (P = 0.02) and lower estimated glomerular filtration rate at presentation (P = 0.012).

CONCLUSION

Overall, most patients had pre-existing pathology with superimposed acute postinfectious glomerulonephritis that led to poor outcomes in our cohort.

Plasmapheresis for treatment of immune complex-mediated glomerulonephritis in infective endocarditis: a case report and literature review

We report the case of a 57-year-old man who presented with subacute bacterial endocarditis secondary to Streptococcus mutans complicated by biopsy-proven immune complex-mediated glomerulonephritis (ICGN). Despite initial treatment with antibiotics and a short course of corticosteroids, the kidney function further deteriorated, and plasmapheresis was introduced as third-line therapy to remove circulating immune complexes. Following 7 treatment sessions, the patient recovered kidney function. We discuss the potential merit of plasmapheresis for patients with subacute bacterial endocarditis who develop ICGN.

A Rare Clinical Entity: Staphylococcus-Related Glomerulonephritis

Staphylococcus aureus is a rare cause of postinfectious glomerulonephritis, and Staphylococcus-related glomerulonephritis primarily occurs in middle-aged or elderly patients. Patients with Staphylococcus-related glomerulonephritis also present with hematuria, proteinuria of varying degrees, rising serum creatinine levels, and/or edema. The severity of renal insufficiency is proportional to the degree of proliferation and crescent formation. Here, we present a diabetic patient admitted with a history of 1 week of left elbow pain. Laboratory results revealed that erythrocyte sedimentation rate was 110 mm/hour, serum creatinine level was 1 mg/dL, C-reactive protein level was 150 mg/L, and magnetic resonance imaging showed signal changes in favor of osteomyelitis at the olecranon level, with diffuse edematous appearance in the elbow skin tissue and increased intra-articular effusion. After diagnosis of osteomyelitis, ampicillin/sulbactam and teicoplanin were administered. After day 7 of admission, the patient developed acute kidney injury requiring hemodialysis under antibiotic treatment. Kidney biopsy was performed to determine the underlying cause, which showed Staphylococcus-related glomerulonephritis. Recovery of renal functions was observed after antibiotic and supportive treatment.

The Epidemiology, Clinical Features, and Outcome of Infection-related Glomerulonephritis from East India: A Single Center Experience

Infection-related glomerulonephritis (IRGN) is an example of immunological renal injury due to non-renal infections. With the changing face of IRGN over the years, renal biopsy definitely has an important role to play in differentiating this disease from the other masquerades and helps in prognosticating the long-term outcomes. This prospective study includes biopsy-proven IRGN cases who presented to us from July 2010 to July 2013 from a single center in East India. Of the 168 patients suspected and screened, 137 patients were proved to have IRGN. About 11.67% cases were proven to be immunoglobulin A-IRGN variant. The mean age of presentation was 22.7 ± 15.8 years with a slight male preponderance. A nephrotic range of proteinuria was seen in 13.8% cases and 17.5% patient required renal replacement therapy at presentation. Around 8.75% patients had persistent proteinuria despite normal renal function beyond 6 months of follow-up and 8.09% patients progressed to chronic kidney disease. It may no longer be classified as a glomerular disease with the definite favorable outcome as an important number of patients may progress to chronicity following this disease. Renal biopsy plays an important role in the assessment of prognosis of IRGN and detection of the presence of other underlying glomerulonephritis and should be considered early, especially in patients with atypical presentation.

Safety and effectiveness of transjugular renal biopsy: A single center study

Although percutaneous renal biopsy remains the preferred method, there are several scenarios where transjugular approach is more suitable. We hereby describe our technique of transjugular renal biopsy (TJRB) and evaluate its safety and efficacy. We retrospectively collected data regarding indication for the transjugular route of biopsy, its complications, clinical and laboratory data, and adequacy of samples from patients' records. TJRB was performed when the patients were at a high risk for bleeding from percutaneous renal biopsy. Tissue samples were assessed by a pathologist for adequacy. All patients were followed up with ultrasonographic scan 3 h after the procedure and on day 3. Nine patients (age 41.5 ± 15.4 years; 8 men) underwent 9 TJRB procedures. The procedure was technically successful in all patients. Six patients (66.67%) had a platelet count of <50,000/mcL, 2 (33.3%) had an elevated International Normalized Ratio of more than 1.4, and 1 had both. 3.2 ± 0.4 cores were obtained, with median (range) number of glomeruli being ten (7-11). Adequate renal tissue sample was obtained in all the patients. Though capsular perforation developed in 5 patients, none had major complication requiring management (endovascular treatment or blood transfusion). TJRB is a safe and effective in patients with contraindications to percutaneous biopsy.

C3 glomerulopathy and current dilemmas

C3 glomerulopathy (C3G) is a recently identified disease entity caused by dysregulation of the alternative complement pathway, and dense deposit disease (DDD) and C3 glomerulonephritis (C3GN) are its components. Because laboratory detection of complement dysregulation is still uncommon in practice, "dominant C3 deposition by two orders greater than that of immunoglobulins in the glomeruli by immunofluorescence", as stated in the consensus report, defines C3G. However, this morphological definition possibly includes the cases with glomerular diseases of different mechanisms such as post-infectious glomerulonephritis. In addition, the differential diagnosis between DDD and C3GN is often difficult because the distinction between these two diseases is based solely on electron microscopic features. Recent molecular and genetic advances provide information to characterize C3G. Some C3G cases are found with genetic abnormalities in complement regulatory factors, but majority of cases seem to be associated with acquired factors that dysregulate the alternative complement pathway. Because clinical courses and prognoses among glomerular diseases with dominant C3 deposition differ, further understanding the background mechanism, particularly complement dysregulation in C3G, is needed. This may resolve current dilemmas in practice and shed light on novel targeted therapies to remedy the dysregulated alternative complement pathway in C3G.

C3 Glomerulopathy and post-infectious glomerulonephritis define a disease spectrum

BACKGROUND

Post-infectious glomerulonephritis (PIGN) usually follows a benign course, but few children have an atypical, severe presentation, and these exceptional cases have been linked to the dysregulation of the complement alternative pathway (CAP). There is a considerable overlap in the histopathological features of PIGN and C3 glomerulopathy (C3G), which is also associated with CAP dysregulation but has a poorer outcome. We hypothesized that PIGN and C3G define a disease spectrum, and that in the past there may be some children with C3G who were misclassified with PIGN before C3G was described as a separate disease entity.

METHODS

Children with PIGN (n = 33) diagnosed between 1985 and 2010 who underwent a renal biopsy due to their unusual course were reviewed and of them, 8 were reclassified into C3G based on the current classification criteria. Outcome was based on the degree of proteinuria, C3 level, and renal function at follow-up.

RESULTS

Sixteen (72.7%) children with typical PIGN recovered completely as compared to only 2 (25%) with C3G. Of note, children with "typical" PIGN had a more severe disease course at onset; however, the outcome at last follow up was favorable.

CONCLUSIONS

Our results support the hypothesis that PIGN and C3G form a disease spectrum and have different long-term clinical implications and management strategies.

Temporal Changes in Post-Infectious Glomerulonephritis in Japan (1976-2009)

Background

The incidence of post-infectious glomerulonephritis (PIGN) in developed countries has decreased over the last 50 years. Here we identified the trends of the incidence of PIGN in Japan during the past four decades.

Methods

We explored the frequency, clinicopathological findings, and prognosis of PIGN based on 6,369 cases from the Renal Biopsy Database of our institute in the Kanto region of Japan, diagnosed histologically from 1976 to 2009.

Results

The numbers of PIGN cases were 131 (2.1%) in total, and 2.4%, 1.1%, 2.6% and 2.1% identified in the 1970s, 1980s, 1990s, and 2000s, respectively. Acute glomerulonephritis (AGN), including post-streptococcal glomerulonephritis (PSGN), accounted for almost all of the PIGN cases in the 1970s, but decreased to approx. 40%–50% since the 1990s. In the 1990s, Staphylococcus aureus infection-related nephritis (SARN) showed a rapid increase in rate, reaching 30%. The incidence of hepatitis C virus infection-associated GN (HCVGN) has increased since the 1990s. The average age at onset rose from 33 to 51 years over the study period. These transitions can be summarized as increases in SARN and HCVGN and decreases in PSGN and other types of AGN, since SARN and HCVGN have older onsets compared to PSGN and other AGN types. The clinicopathological features were marked for each PIGN. Regarding the prognosis, the renal death rates of both the SARN and HCVGN groups were significantly higher than those of other PIGN.

Conclusion

Based on our analysis of the Renal Biopsy Database, the incidence of PIGN in Japan reached its peak in the 1990s. The temporal changes in the incidence of PIGN reflected the trends in infectious diseases of each decade and the continual aging of the population, with a related higher susceptibility to infections.

Clinical, Pathological, and Prognostic Characteristics of Glomerulonephritis Related to Staphylococcal Infection

Staphylococcal infection has become a common cause of postinfectious glomerulonephritis in the past 3 decades. Because few investigations focus on this disease, the demographics and clinicopathological features of glomerulonephritis related to staphylococcal infection are not well characterized. We conducted a pooled analysis of published literature in electronic databases and analyzed the clinical features, laboratory findings, and histopathological changes. The patients were divided into 4 groups based on their prognosis: remission, persistent renal dysfunction, end-stage renal disease (ESRD), or death. A logistic regression model was used to identify the determinants of disease outcome. A total of 83 (64 men) patients with glomerulonephritis related to staphylococcal infection from 31 reports were analyzed. The mean age was 58 years (58 ± 17). Majority of the reports originated from Taiwan, Japan, and the United States. Clinical characteristics of the cases were hematuria (82/83), proteinuria (78/83), and acute kidney injury (75/83). Visceral abscesses (26/83) and skin infections (24/83) were the common sites of infection. Methicillin-resistant Staphylococcus aureus was the most common pathogen. The dominant or codominant deposition of IgA or C3 along the glomeruli was an important feature identified by immunofluorescence. There were 19 patients (22.9%) that progressed to dialysis-dependent ESRD. Twelve patients (14.5%) died. A univariate regression analysis indicated that diabetes mellitus (DM) (odds ratio [OR] 2.96; 95% confidence interval [CI] 1.03-8.48; P = 0.04) and age (OR 4.80; 95% CI 1.84-12.53; P = 0.001) were risk factors for ESRD or death. A multivariate regression analysis also revealed that age (OR 4.90; 95% CI 1.82-13.18; P = 0.002) and DM (OR 3.07; 95% CI 0.98-9.59; P = 0.05) were independent risk factors for unfavorable prognosis. Glomerulonephritis related to staphylococcal infection has different features than typical postinfectious glomerulonephritis. The diagnosis of glomerulonephritis related to staphylococcal infection relies on immunofluorescence and electron microscopy findings. Age and DM are independent risk factors of poor prognosis for glomerulonephritis related to staphylococcal infection.

Post-infectious glomerulonephritis with crescents in adults: a retrospective study

Background

Crescent formation generally reflects severe glomerular injury. There is sparse literature on post-infectious glomerulonephritis (PIGN) with crescents in adults. This retrospective study looked at nine such cases to see if there is a correlation between the severity of presentation, steroid treatment, histological severity and outcome.

Methods

Biopsy reports of all the adults who underwent kidney biopsy from February 2010 to June 2014 in a tertiary care hospital were screened and all the cases with the diagnosis of PIGN with crescents were selected. Clinical presentation, laboratory data, histology, treatment and outcome were analysed.

Results

Six patients had evidence of recent/current infection, but all except two were non-streptococcal. The mean creatinine was 360.67 μmol/L (range 70.72–770.85) and the mean estimated glomerular filtration rate (MDRD eGFR) was 30.28 mL/min/1.73 m² (range 6.4–111.1) on presentation. All five patients who were treated with steroids had an excellent response. Among the four patients who did not receive steroids, two were left with significant renal impairment (mean MDRD eGFR 23.5 mL/min/1.73 m²) at a mean follow-up of 15.5 months (range 10–21). The mean percentage of glomeruli with crescents was 36.13% (range 11.76–100) and except in one, there was no tubular atrophy or interstitial fibrosis and none had glomerulosclerosis. None of the patients progressed to end-stage renal disease.

Conclusion

Non-streptococcal infections are more common precipitants. There was no correlation between histological and clinical severity. Patients treated with steroids had better renal outcomes.

Cryoglobulinemic Glomerulonephritis as a Presentation of Atypical Post-Infectious Glomerulonephritis

Post-infectious glomerulonephritis (PIGN) usually occurs within few days to weeks following an infection. Clinical presentation is variable, but in general, it is considered a benign entity with good prognosis. It rarely requires kidney biopsy to confirm the diagnosis. We present a case of a 55-year-old, previously healthy, male who presented for worsening shortness of breath, persistent cough, and right-sided pleuritic chest pain. Initial workup revealed a right exudative effusion with empyema. Hospital course was complicated by acute kidney injury requiring renal replacement therapy with a peak creatinine of 10.2 mg/dL from a baseline of 1.18 mg/dL. On kidney biopsy, findings were compatible with a diagnosis of cryoglobulinemic glomerulonephritis or an atypical form of PIGN. While a wide variety of histopathological findings on renal biopsies have been described to complement the usual diffuse proliferative glomerulonephritis pattern, cryoglobulinemic features with negative cryoglobulin have never been reported. Our case is unique not only by having an atypical histological presentation but also by meeting the criteria of atypical PIGN with persistent hypertension and microscopic hematuria.

C4d as a Diagnostic Tool in Proliferative GN

Proliferative GN is classified as immune complex-mediated or complement-mediated (C3 glomerulopathy). Immune complex-mediated GN results from glomerular deposition of immune-complexes/Ig and C3; the C3 is derived from activation of the classical and/or lectin pathways of complement. C3 glomerulopathy results from deposition of C3 and other complement fragments with minimal or no deposition of immune complexes/Ig; the C3 is derived from activation of the alternative pathway of complement. C4d is a byproduct of activation of the classic and lectin pathways. Although widely used as a marker for antibody-mediated rejection, the significance of C4d in C3 glomerulopathy is undetermined. We studied glomerular C4d staining in 18 biopsy specimens of immune-complex GN, 30 biopsy specimens of C3 GN, and 13 biopsy specimens of postinfectious GN. All specimens of immune complex-mediated GN, except two specimens of IgA nephropathy and one specimen of sclerosing membranoproliferative GN, showed bright (2-3+) C4d staining. The staining pattern of C4d mirrored the staining patterns of Ig and C3. Conversely, C4d staining was completely negative in 24 (80%) of 30 specimens of C3 glomerulopathy, and only trace/1+ C4d staining was detected in six (20%) specimens. With regard to postinfectious GN, C4d staining was negative in six (46%) of 13 specimens, suggesting an abnormality in the alternative pathway, and it was positive in seven (54%) specimens. To summarize, C4d serves as a positive marker for immune complex-mediated GN but is absent or minimally detected in C3 glomerulopathy.

Staphylococcus-related glomerulonephritis and poststreptococcal glomerulonephritis: why defining "post" is important in understanding and treating infection-related glomerulonephritis

A spate of recent publications describes a newly recognized form of glomerulonephritis associated with active staphylococcal infection. The key kidney biopsy findings, glomerular immunoglobulin A (IgA) deposits dominant or codominant with IgG deposits, resemble those of IgA nephritis. Many authors describe this condition as "postinfectious" and have termed it "poststaphylococcal glomerulonephritis." However, viewed through the prism of poststreptococcal glomerulonephritis, the prefix "post" in poststaphylococcal glomerulonephritis is historically incorrect, illogical, and misleading with regard to choosing therapy. There are numerous reports describing the use of high-dose steroids to treat poststaphylococcal glomerulonephritis. The decision to use steroid therapy suggests that the treating physician believed that the dominant problem was a postinfectious glomerulonephritis, not the infection itself. Unfortunately, steroid therapy in staphylococcus-related glomerulonephritis can precipitate severe staphylococcal sepsis and even death and provides no observable benefits. Poststreptococcal glomerulonephritis is an authentic postinfectious glomerulonephritis; poststaphylococcal glomerulonephritis is not. Making this distinction is important from the perspective of history, pathogenesis, and clinical management.

Clinicopathologic features of IgA-dominant infection-associated glomerulonephritis: a pooled analysis of 78 cases

BACKGROUNDS

IgA-dominant infection-associated glomerulonephritis (IgA-dominant IAGN) is a unique form of glomerulonephritis. There are numerous case reports in the literature. However, the risk factors, treatment approach, and outcomes of the disease are not clearly characterized.

METHODS

We completed a pooled analysis based on published literature. Clinical features, laboratory findings, and histopathological changes were analyzed. A logistic regression model was employed to identify the determinants of disease outcome, for example, end-stage renal disease (ESRD) or death.

RESULTS

Seventy-eight patients with IgA-dominant IAGN from 28 reports were analyzed. All of these patients showed granular IgA deposits predominantly along the glomerular peripheral capillary walls using immunofluorescence and majority showed subepithelial 'hump-shaped' electron-dense deposits using electron microscopy. The majority of patients had hematuria (76/78), proteinuria (75/78), acute kidney injury (AKI) (66/78) and hypocomplementemia (43/75) without a previous history of renal disease. All of the patients had clinical infections at the time of presentation. Skin infections (19/78) and visceral abscesses (15/78) were frequently encountered, and staphylococcus was the most common pathogen. After treatment with antibiotics and/or supportive therapy, the renal function of 42 patients (54.5%) improved, 9 patients (11.7%) had persistent renal dysfunction, 15 patients (19.5%) progressed to ESRD, and 11 patients (14.3%) died. A multivariate regression analysis revealed that age (odds ratio [OR], 30.71; 95% confidence interval [CI], 2.53-373.07; p = 0.007) and diabetes mellitus (DM) (OR, 16.65; 95% CI, 1.18-235.84; p = 0.038) were independent risk factors for ESRD or death.

CONCLUSIONS

IgA-dominant IAGN has unique clinicopathological manifestations and treatment responses. Age and DM are independent risk factors associated with an unfavorable prognosis for IgA-dominant IAGN.

The clinical characteristics and pathological patterns of postinfectious glomerulonephritis in HIV-infected patients

Background

Postinfectious glomerulonephritis (PIGN), a form of immune complex GN, is not well-defined in HIV-infected patients. This study characterizes PIGN in this patients’ population and determine the impact of histopathological patterns on renal outcome and mortality.

Methods

HIV-infected patients with PIGN from September 1998 to July 2013 were identified. Archived slides were reviewed by a blinded renal pathologist, classified into acute, persistent and healed PIGN. Groups were compared using Wilcoxon rank-sum and Fisher’s exact test. Survival analyses were performed to determine association of histopathological pattern with renal outcome and mortality.

Results

Seventy-two HIV-infected predominantly African American males were identified with PIGN. Median (interquartile range) age and creatinine at the time of renal biopsy was 48 years (41, 53) and 2.5 mg/dl (1.5, 4.9) respectively. Only 2 (3%) had acute PIGN, 42 (58%) had persistent PIGN and 28 (39%) had healed PIGN. Three patients (4%) had IgA-dominant PIGN. Only 46% of the patients had confirmed positive cultures with Staphylococcus the most common infectious agent. During a median follow up of 17 months, the pathological pattern had no impact on renal outcome (P = 0.95). Overall mortality was high occurring in 14 patients (19%); patients with healed PIGN had significantly increased mortality (P = 0.05).

Conclusion

In HIV-infected patients, Staphylococcus is the most common cause of PIGN. Renal outcome was not influenced by the histopathological pattern but those with healed PIGN had greater mortality which was potentially due to a confounder not accounted for in the study.

IgA dominant postinfectious glomerulonephritis: Report of two cases

Immunoglobulin A (IgA) dominant postinfectious glomerulonephritis (IgA PIGN) is a distinct clinical entity increasingly recognized in adult. It usually presents with reduced glomerular filtration rate, heavy proteinuria, and has unfavorable prognosis. Immunofluorescence study of renal biopsy specimens have IgA as dominant or codominant antibody. We encountered two cases of IgA dominant PIGN recently presenting as rapidly progr essive glomerulonephritis and managed conservatively. Both the patients are on follow-up and do not have complete recovery of renal function till date. Long-term follow-up is needed to assess the progression of the disease in these patients.

Garland-pattern postinfectious glomerulonephritis with IgA-dominant deposition

A histological subtype of acute postinfectious glomerulonephritis (APIGN), the garland pattern, is identified not only by characteristic histological findings, but also by severe clinical course as compared with typical APIGN. However, since the morbidity of APIGN has decreased globally, there have been few reports on this disease form in developed countries during the last two decades. Herein, we report a case of adolescent garland-pattern APIGN with IgA-dominant deposits, presenting with severe nephrotic syndrome and protracted hematuria and proteinuria. We also review the clinical and histological features of 13 previously reported cases in Japan and compare them with our present case. In our review, we confirmed IgA deposition in at least three of these patients, in whom urinary protein excretion tended to be greater than those patients without IgA. Greater awareness of this condition is necessary to ensure appropriate follow-up of the clinical course of patients with garland-pattern APIGN with IgA deposition.

Atypical presentation of post infectious glomerulonephritis as malignant hypertension and thrombotic microangiopathy

Infection-related glomerulonephritis presents commonly as acute nephritic illness, hypertension, hypocomplementinemia following an episode of pharyngitis or pyoderma. Atypical features like thrombotic microangiopathy (TMA), produced by neuraminidase antigen targeting endothelium have been described rarely. We report a case of TMA secondary to malignant hypertension, coexisting with post infectious glomerulonephritis.

Diagnosis and treatment of glomerular diseases in elderly patients

Glomerular diseases are common in elderly patients and are a major cause of kidney failure. Most glomerular diseases in the elderly are caused by chronic systemic diseases, including arterial hypertension, diabetes, and atherosclerotic vascular diseases, although acute systemic vasculitis, especially anti-neutrophil-cytoplamic-antibody-mediated vasculitis, and membranous nephropathy related to malignancy, drug toxicity, and idiopathic form also occur often. Complex age-related changes and sensitivity to drug toxicity can render diagnosis and treatment for elderly patients challenging. As the general population is aging and the rate of CKD rising, updating knowledge on managing these patients is critical for care providers. We provide a comprehensive review and update of the diagnosis and treatment of glomerular diseases in the elderly.

IgA-dominant postinfectious glomerulonephritis associated with Escherichia coli infection caused by cholangitis

A 76-year-old man with a history of type 2 diabetes mellitus was admitted with cholangitis caused by cholangiocarcinoma. Cholangitis with Escherichia coli (E. coli) bacteremia recurred due to the unstable bile drainage. At 1 month after recurrence, rapidly progressive glomerulonephritis with nephrotic syndrome was manifested. Renal biopsy findings were consistent with immunoglobulin A (IgA)-dominant postinfectious glomerulonephritis (PIGN). After ensuring that the recurrent cholangitis was controlled by drainage and antibiotic therapy, oral prednisolone was initiated, and the patient's renal function and proteinuria subsequently gradually improved. This is the first case report of IgA-dominant PIGN associated with cholangitis caused by E. coli infection.