CEN Case Reports最新文献

Peritoneal dialysis (PD) associated peritonitis is a common complication and main cause of PD failure among end-stage chronic kidney disease (CKD) patients, presenting with abdominal pain, diarrhea and cloudy dialysate. On the other side, these patients may have an increased risk for Clostridioides difficile infection (CDI), with a clinical presentation indistinguishable from PD associated peritonitis. We present the case of a female patient who presented with multiple episodes of watery diarrhea days after PD catheter insertion, treated initially as a suspected PD associated peritonitis but later identifying C. difficile toxin assay in stool and responding with triple therapy including oral vancomycin, metronidazole and tigecycline. Considering the scarce evidence, we conducted a literature search and identified 10 case reports involving 11 patients describing CDI associated peritonitis in patients with PD. Most cases initiated empiric intraperitoneal treatment for PD associated peritonitis but after lack of clinical improvement or increase in PD fluid cell count, and a positive C. difficile toxin assay in stool, treatment for CDI was started. Half of these patients had received prior antibiotic therapy or had a prior hospital admission. In conclusion, patients with PD associated peritonitis unresponsive to initial empiric intraperitoneal treatment should be tested for C. difficile in stool, especially those with previous antibiotic exposure or hospital admission.

Herein, we present the first case of chronic Campylobacter fetus infection-related glomerulonephritis (IRGN) in a 69-year-old man with a permanent cardiac pacemaker. The patient had a prior episode of fever and glomerulonephritis of undetermined etiology, and at that time, low-dose steroid therapy resulted in improved urinary findings and kidney function. This time the patient again developed deterioration of kidney function with microhematuria, proteinuria, high serum C-reactive protein levels, and positive titers of anti-double-stranded DNA antibody and proteinase 3 anti-neutrophil cytoplasmic antibody (ANCA). A kidney biopsy revealed endocapillary and mesangial hypercellularity, interstitial infiltration of neutrophils, and positive staining for C3 and IgM in the mesangium and glomerular capillary walls. Notably, histological staining for nephritis-associated plasmin receptor (NAPlr)/plasmin activity was also positive. Similar laboratory and pathological findings in the first and second kidney biopsies and repeated detection of C. fetus in blood cultures led to the diagnosis of IRGN associated with persistent pacemaker-related infection. The nephritis improved following antibiotic therapy targeting C. fetus. C. fetus can cause sustained bacteremia and prolonged infection of indwelling devices, and can be a causative organism for recurrent IRGN. Clinicians must distinguish IRGN from autoimmune diseases such as lupus nephritis and ANCA-associated vasculitis.

In recent years, sodium-glucose cotransporter 2 (SGLT2) inhibitors have become essential therapeutic agents in the management of chronic kidney disease (CKD), owing to their established renoprotective effects. Although acute kidney injury (AKI) may occasionally occur during SGLT2 inhibitor therapy, its pathological features remain incompletely understood. Here, we report a case of AKI caused by osmotic nephropathy in a patient with underlying CKD following the initiation of an SGLT2 inhibitor. We also review previously reported cases of SGLT2 inhibitor-associated osmotic nephropathy. A 71-year-old man with type 2 diabetes and CKD developed oliguric AKI, with his serum creatinine level increasing from 2.0 to 8.3 mg/dL, one month after initiating dapagliflozin. During this period, he experienced transient appetite loss associated with a COVID-19 infection. Despite initial management for presumed prerenal AKI, his renal function did not improve with intravenous fluid therapy, and he required hemodialysis. Kidney biopsy revealed characteristic features of osmotic nephropathy, including numerous isometric vacuoles within the epithelial cells of proximal tubules with preserved brush borders. His renal function began to improve approximately two weeks after discontinuation of the SGLT2 inhibitor, and eventually returned to baseline. This case and literature review highlight the potential for osmotic nephropathy as a rare but reversible complication of SGLT2 inhibitor therapy, which may be triggered by volume depletion, particularly in diabetic patients with pre-existing renal dysfunction. Recognition of this underdiagnosed entity is crucial for timely diagnosis and appropriate management.

An 82-year-old man was admitted to our hospital with edema on the upper and lower extremities that had worsened over the past 5 months. He was diagnosed with nephrotic syndrome and acute renal failure. A computed tomography evaluation revealed generalized lymphadenopathy and splenomegaly. A bone marrow biopsy confirmed the diagnosis of mantle cell lymphoma (MCL). A renal biopsy showed full-house nephropathy with diffuse global endocapillary proliferation and electron-dense deposits in the epithelial, endothelial, and mesangial areas. Lymphoma cells infiltrated the renal interstitium but were not observed within the glomeruli. The blood test demonstrated low complement levels, positive anti-single-stranded deoxyribonucleic acid antibody and anti-double-stranded deoxyribonucleic acid antibody, but negative for antinuclear antibody; no other physical findings consistent with systemic lupus erythematosus were observed. After the initiation of the treatment for MCL, the renal function and urinary protein level improved. The patient was diagnosed with immune complex-associated glomerulonephritis, resembling lupus nephritis, secondary to MCL.

Genetic disorders in neonates often present with overlapping clinical features, posing significant diagnostic challenges. Glycogen storage diseases (GSD) disrupt glycogen metabolism, leading to energy deficits. Pathogenic variants in the Wilms tumor 1 (WT1) gene represent a rare but significant cause of early-onset steroid-resistant nephrotic syndrome (SRNS), associated with a broad range of both kidney and extrakidney phenotypic manifestations. The coexistence of these genetic diseases in a single patient has not been previously reported. Herein, we present a case of a newborn with symptomatic hypoglycemia and metabolic acidosis that was transferred to the Neonatal Intensive Care Unit. During hospitalization, he developed hyponatremia and nephrotic-range proteinuria, a genetic test was performed, and he was transferred to the nephrology unit. Genetic analysis identified a compound homozygous mutation (c.247 C > T) in the G6PC gene, confirming glycogen storage disease type 1a (GSD-1a) and a pathogenic WT1 mutation (c.1400G > A) associated with Denys-Drash syndrome. This case highlights the importance of a multidisciplinary approach in the evaluation and management of neonates with a complex combination of genetically-determined conditions.

Renal limited sarcoidosis is an exceptionally rare condition characterized by non-caseating granulomas confined solely to the kidneys, without involvement of other organs. Its diagnosis is challenging because of the absence of systemic manifestations. We present a case of a 74-year-old woman with a history of type 2 diabetes mellitus, papillary thyroid carcinoma, and osteoporosis, who showed progressive renal dysfunction. Laboratory findings revealed elevated serum creatinine and urinary β₂-microglobulin, indicating tubular injury. Kidney biopsy demonstrated granulomatous interstitial nephritis with non-caseating epithelioid cell granulomas. Other potential causes, including infections, drug-induced nephritis, and autoimmune diseases were excluded. Chest computed tomography and gallium-67 scintigraphy revealed no extrarenal involvement. Based on these findings, we diagnosed the patient as having renal limited sarcoidosis. The patient was treated with low dose of oral prednisolone, resulting in significant improvement in renal function and normalization of laboratory parameters. The present case underscores the importance of considering the possibility of renal limited sarcoidosis on differentiating the case with unexplained renal dysfunction, especially when non-caseating granulomas are identified on kidney biopsy and other causes have been excluded. Corticosteroids remain the cornerstone of treatment, with most patients responding favorably. However, in steroid-resistant cases, alternative immunosuppressive agents such as mycophenolate mofetil and infliximab have been employed, though their efficacy and safety require further investigation. In this article, we present this rare case in addition to providing comprehensive literature review of previously cases to summarize clinicopathological characters, treatment strategies, and renal outcomes of renal-limited sarcoidosis for future clinical management.

Townes-Brocks syndrome (TBS) is a rare autosomal dominant disorder typically characterized by the triad of anorectal malformations, external ear anomalies and hand malformations such as preaxial polydactyly, caused by mutations in the SALL1 gene. Kidney involvement, although less common, can progress to end-stage kidney failure. Early recognition of the characteristic features, particularly those related to SALL1, is crucial for accurate diagnosis, management, and genetic counseling. Here, we present a Turkish family with TBS in which the diagnosis was delayed due to the absence of the classic triad. The proband exhibited significant developmental delay, kidney failure and a congenital foot abnormality, while other family members showed milder manifestations. A multigene panel revealed a heterozygous variant in SALL1 (NM_002968.3:c.2287dup p.R763Kfs*42), which was also identified in the affected family members presenting with milder phenotypes. This case highlights the broad clinical spectrum of TBS, even within the same family. Because major features may not always be present, it can sometimes be overlooked or misdiagnosed; as in our case, which presents with nearly isolated kidney abnormalities. Our report emphasizes the importance of a comprehensive approach, detailed family history and genetic testing in patients with chronic kidney disease of unknown origin.

Focal segmental glomerulosclerosis (FSGS), a common cause of nephrotic syndrome, is diagnosed by renal biopsy showing focal segmental sclerosis with foot-process effacement. It has a poor prognosis and can rapidly progress to end-stage kidney disease (ESKD). While the etiology of FSGS is largely unknown, many genes have been linked to the familial form of the condition. One of its subtypes, FSGS8, is caused by a heterozygous mutation in the ANLN gene on chromosome 7p14. However, reports of disease-causing ANLN variants in the literature are scarce. Here, we report a novel variant of ANLN in a Chinese family with FSGS. The proband was in hospital for proteinuria and the laboratory tests elevated levels of serum creatinine and uric acid. Histopathology study of renal biopsy showed FSGS. Genetic testing based on whole-exome sequencing (WES) was performed to explore the molecular basis. A heterozygous pathogenic variant of the ANLN gene, NM_018685 c.2343G > C, was identified in the affected patients and further confirmed by Sanger sequencing. This variant leads to a missense mutation in the anillin protein, altering its structure. This novel pathogenic variant of the ANLN gene provides a molecular basis for FSGS8 and expands the known mutation spectrum for FSGS.

Alport syndrome is an inherited kidney disease caused by pathogenic variants in COL4A3, COL4A4, or COL4A5, encoding type IV collagen chains of the glomerular basement membrane. Genetic confirmation is essential for its diagnosis, prognosis, and donor selection; however, conventional sequencing may fail to detect pathogenic variants, leaving a subset of clinically suspected patients without a genetic diagnosis. We report a 16-year-old girl with persistent hematuria and proteinuria, initially diagnosed with Alport syndrome at 2 years of age based on kidney biopsy findings of a basket-weave glomerular basement membrane and mosaic α5(IV) staining. Despite a family history compatible with this diagnosis, targeted exome sequencing at 8 years of age did not identify pathogenic variants. Whole-genome sequencing at 16 years revealed a deep intronic variant in COL4A5 (NM_000495.5) (c.276 + 1306G > A). In silico analysis with SpliceAI predicted the creation of de novo acceptor and donor splice sites, leading to the inclusion of a 103-bp cryptic exon within intron 4. A minigene assay confirmed aberrant splicing and demonstrated that the inserted exon resulted in a frameshift and premature stop codon (p.Gly93Phefs*99). This case highlights the diagnostic utility of whole-genome sequencing in combination with splicing prediction and functional validation to resolve suspected cases of Alport syndrome in which the genetic cause has remained unclear. As sequencing technologies advance, such integrative approaches may become increasingly important in clinical practice, thereby improving diagnostic yield and supporting the development of RNA-based therapies.