Anti-glomerular basement membrane (GBM) antibody disease rarely causes thrombotic microangiopathy (TMA). We herein report the case of a 75-year-old Japanese woman who developed refractory TMA during treatment for anti-GBM antibody disease. Although secondary TMA was initially suspected, persistent hemolytic anemia and thrombocytopenia despite plasma exchange, glucocorticoids, and cyclophosphamide led us to suspect complement-mediated TMA. Eculizumab was initiated after genetic testing for complement regulatory factors was performed. The patient became transfusion-independent within one week, and genetic testing identified the c.293C＞T (p.Thr98Ile) variant in CD46. Complement-mediated TMA should thus be considered in refractory cases, and anti-C5 monoclonal antibodies may be an effective therapeutic option.

Anti-glomerular basement membrane (GBM) antibody disease is an autoimmune-mediated rapidly progressive renal injury. The coexistence of diffuse non-hereditary glomerular basement membrane thinning of uncertain etiology in elderly patients is clinically rare and poses substantial challenges in differential diagnosis and clinical management. We herein report a 70-year-old female patient admitted for elevated serum creatinine for more than 20 days. After a prodromal infection, she rapidly progressed to anuria and acute kidney injury (AKI), with markedly elevated serum anti-GBM antibody levels. Renal biopsy revealed crescentic glomerulonephritis, and electron microscopy demonstrated diffuse thinning of the glomerular basement membrane; genetic testing excluded hereditary thin basement membrane nephropathy. The patient received methylprednisolone pulse therapy, cyclophosphamide immunosuppression, plasma exchange, and maintenance hemodialysis. Long-term dynamic monitoring of antibody levels and imaging indicators was performed after discharge. During hospitalization and follow-up, anti-GBM antibody levels declined continuously, subsequent infection was gradually controlled by antimicrobial therapy, and the patient remained hemodialysis-dependent with stable overall condition. Renal biopsy combined with genetic testing is the core method to distinguish lesions of diffuse non-hereditary glomerular basement membrane thinning of uncertain etiology, from hereditary basement membrane lesions. This case represents an elderly patient with oligoimmune atypical anti-GBM antibody disease and diffuse non-hereditary glomerular basement membrane thinning of uncertain etiology, and this long-term follow-up record provides valuable clinicopathological reference for individualized treatment and prognostic evaluation of similar rare cases.

Anti-glomerular basement membrane (anti-GBM) disease is a rare autoimmune disorder characterized by rapidly progressive glomerulonephritis, with or without pulmonary hemorrhage. Central nervous system (CNS) involvement is exceedingly uncommon, and intracranial subarachnoid hemorrhage (SAH) has rarely been described in association with anti-GBM disease. We report a rare case of anti-GBM disease complicated by intracranial SAH and subsequent cerebral infarction. A 53-year-old woman presented with fever and headache and rapidly developed acute kidney injury with markedly elevated anti-GBM antibody titers. Renal biopsy confirmed anti-GBM disease. Despite treatment with plasma exchange and high-dose corticosteroids, renal function deteriorated, and the patient became dialysis-dependent. Rituximab was added to achieve serological control after an insufficient response to conventional therapy. During the clinical course, the patient developed a generalized seizure and was diagnosed with intracranial SAH, followed later by a subacute cerebral infarction. Cerebral angiography revealed no aneurysms or vascular malformations. Blood pressure had remained stable prior to the neurological event. Following intensive management, including continued plasma exchange, rituximab, corticosteroids, and strict blood pressure control, no neurological sequelae were observed. Anti-GBM antibody titers gradually declined, although renal function did not recover. This case illustrates a rare occurrence of intracranial subarachnoid hemorrhage as a central nervous system complication in anti-GBM disease and highlights the importance of careful neurological monitoring.

Anti-glomerular basement membrane (anti-GBM) disease typically presents as rapidly progressive glomerulonephritis, however an atypical anti-GBM nephritis with various light microscopic findings without crescentic formation has been reported in recent years. The findings reported including cases with membranoproliferative glomerulonephritis (MPGN) pattern. Few reports have been able to follow the course of the disease over a long period of time. We report a case of MPGN associated with the spectrum of atypical anti-GBM nephritis that showed a slowly progressive course over more than eight years. A 49-year-old man underwent kidney biopsy because of hypertension, proteinuria, and mild renal insufficiency. The findings on kidney biopsy showed the findings of MPGN. Immunofluorescence microscopy revealed bright linear staining of IgG on the GBM. Electron microscopy showed subepithelial, intra-basement membrane, subendothelial, and paramesangial electron-dense deposits. Serum anti-GBM antibodies were negative. Proteinuria had been present for 4 years prior to the renal biopsy, however no worsening of renal function was observed. Because of worsening proteinuria and the presence of endocapillary hypercellularity in the tissues, the intravenous and oral steroids were started. Although the proteinuria showed slight improvement, the serum creatinine level was stable around 1.5-1.7 mg/dl. Although some indolent cases of atypical anti-GBM syndrome were reported previously, compared with these cases, our patient had more stable renal function for a long time. This is a rare case of resembling atypical anti-GBM disease that shows MPGN with linear IgG staining having a long-term indolent course and without secondary etiology.

The heart and kidneys are connected in both health and disease. Coordinated dysfunction of these organ systems is a result of complex interactions related to vascular and biochemical maladaptations. The historical perspective that kidney dysfunction in heart failure is overwhelmingly a product of reduced cardiac forward flow and arterial underfilling has been challenged by mounting evidence. Efforts in 2004 to introduce the term cardiorenal syndrome were based on observations that increased circulatory volume, specifically venous congestion, play a key role in kidney dysfunction. Contemporary studies done after 2004, as well as revisiting historical renal physiology experiments in a new light, have illuminated some of the pathophysiology of how venous congestion in decompensated heart failure causes the "congested kidney." Cardiorenal syndrome, specifically type 1 occurring in the setting of acute heart failure, in part is defined by the fact that renal venous hypertension drives kidney dysfunction. To illuminate this point further, we compare and contrast the importance of arterial underfilling in cardiogenic shock vs cardiorenal syndrome.

Orthohantavirus infections constitute a significant global public health challenge, predominantly presenting as two distinct clinical syndromes: hemorrhagic fever with renal syndrome (HFRS) in Europe and Asia and hantavirus pulmonary syndrome (HPS) in the Americas. Epidemiological data indicate considerable geographic variability in disease incidence, influenced by intricate interactions among ecological, socioeconomic, and public health determinants. In Asia, a notable reduction in cases has been achieved through enhanced economic conditions, strategic public health initiatives, and effective management of rodent populations. Conversely, Nordic countries continue to report high HFRS incidence, which is attributed to ecological conditions conducive to sustaining reservoir rodent populations. South America has experienced an upward trend in cases, raising concerns about potential large-scale outbreaks, while emerging reports from Africa suggest a possible expansion of endemic regions. Notably, Australia remains one of the few regions without documented orthohantavirus infections and presents a unique epidemiological profile. This review comprehensively examines the global distribution of orthohantavirus infections, analyzes key epidemiological trends, and discusses the environmental and socioeconomic determinants influencing disease dynamics, providing critical insights for public health preparedness and intervention strategies.

Hantavirus infection is a zoonotic, rodent-transmitted viral disease that presents with two distinct clinical syndromes: hemorrhagic fever with renal failure (HFRS) and hantavirus pulmonary syndrome (HPS). The 2026 cruise ship hantavirus outbreak has once again brought this infrequent disease into the limelight. Gastrointestinal (GI), hepatobiliary, and pancreatic manifestations, though frequent, have garnered less attention in patients with hantavirus infections. This narrative review summarizes the available literature on GI and hepatopancreatic involvement in hantavirus infection. A comprehensive review of the literature published between 2000 and May 2026 was conducted using PubMed. Eligible studies included observational studies, systematic reviews, meta-analyses, case series, and case reports describing GI, hepatic, biliary, or pancreatic manifestations in human hantavirus infection. The literature review identified GI symptoms among the earliest and most frequent prodromal manifestations of hantavirus disease. Nausea, vomiting, abdominal pain, and diarrhea often precede organ-specific complications by several days. GI bleeding develops as a component of hemorrhagic syndrome. Hepatic involvement most frequently manifests as transient elevations in aminotransferase levels and, less frequently, as hyperbilirubinemia. Gallbladder wall thickening, acalculous cholecystitis, instances of hantavirus-triggered autoimmune hepatitis, and acute pancreatitis have also been reported. Current management strategies are primarily supportive, including renal replacement therapy for severe renal injury and ventilatory support and extracorporeal membrane oxygenation for severe pulmonary disease. Antiviral therapies such as ribavirin and favipiravir have shown inconsistent or limited clinical benefits. Limited evidence links early and prominent GI symptoms and transaminitis with more severe disease and a worse prognosis. A high index of suspicion in patients with GI symptoms may facilitate earlier diagnosis and allow risk stratification. However, the current evidence is sparse, mostly derived from case reports, case series, and small retrospective studies, which limits our understanding of GI and hepatobiliary-pancreatic manifestations in patients with hantavirus infections. Large prospective studies are needed to clarify the mechanisms, incidence, and prognostic significance of these manifestations.

Hantavirus infection is a rodent-borne zoonotic disease that can present as Hemorrhagic Fever with Renal Syndrome (HFRS) or Hantavirus Cardiopulmonary Syndrome (HCPS). Both diseases are associated with substantial morbidity and mortality. The rise of new Hantavirus species and recurrent outbreaks worldwide has renewed interest in the epidemiology, pathogenesis, diagnosis, and management of this viral infection. A narrative literature review was conducted using published articles, review papers, epidemiological reports, and clinical studies on Hantavirus up to 2026. Relevant evidence regarding epidemiology, pathogenesis, clinical manifestations, diagnostic approaches, treatment, complications, and prevention was analyzed and synthesized. Hantaviruses primarily infect endothelial cells, leading to increased vascular permeability, thrombocytopenia, and capillary leakage through immune-mediated mechanisms. HFRS affects the kidneys, and HCPS is characterized by severe cardiopulmonary symptoms, although overlap between the two syndromes has increasingly been observed. Diagnosis is based on clinical suspicion supported by epidemiological exposure history, serological testing, and virological confirmation from reverse transcription polymerase chain reaction (RT-PCR). Current management remains largely supportive, including hemodynamic stabilization, respiratory support, and renal replacement therapy when indicated. Ribavirin may provide benefit in selected HFRS cases when given early, but evidence remains inconclusive, especially for HCPS. Favipiravir has demonstrated promising antiviral activity in vitro and in animal studies, yet clinical data in humans are still lacking. Preventive measures focus primarily on minimizing exposure to infected rodents and contaminated environments, while vaccine development remains ongoing. Hantavirus infection continues to represent an important global public health concern due to its potential for severe disease and high mortality. Improved understanding of disease pathogenesis, advances in diagnostic methods, and ongoing research into antiviral therapies and vaccines are essential to improve patient outcomes and strengthen future prevention strategies.

Renal coloboma syndrome (RCS) is an autosomal dominant disorder caused by pathogenic variants in the PAX2 gene, primarily affecting renal and optic nerve development. However, the presentation of RCS is highly heterogeneous, ranging from mild renal anomalies to severe multi-organ involvement. This phenotypic variability often poses significant challenges for accurate clinical diagnosis.