CEN Case Reports最新文献

The primary defect in distal renal tubular acidosis (dRTA) is impaired H⁺ ion secretion in the distal nephron, resulting in a normal anion gap metabolic acidosis. The solute carrier family 4-member 1 (SLC4A1) gene encodes the erythroid and renal anion exchanger 1 (AE1) protein for chloride-bicarbonate exchange. Mutations in the gene can result in hereditary dRTA, red blood cell membrane defect, and hemolytic anemia. Chronic granulomatous disease (CGD) is a rare primary immunodeficiency syndrome caused by NADPH oxidase deficiency, leading to impaired neutrophil and phagocyte function, and thus predisposing the patient to multiple bacterial infections. Melioidosis is a rare infection caused by Burkholderia pseudomallei and is often linked to CGD. Here we present an interesting case of an 8-year-old girl with melioidosis secondary to CGD. Also, she had nephrocalcinosis, metabolic acidosis, hypercalciuria, and anemia. The simultaneous presence of distal RTA (Pathogenic homozygous SLC4A1 mutation on whole exome sequencing) and CGD has not been reported previously and reiterates the importance of detailed clinical evaluation combined with investigations for the long-term management of such complex cases.

Orthostatic hypotension (OH) is characterized by an excessive drop in blood pressure upon standing, leading to impaired quality of life, increased fall risk, and potential cardiovascular complications. It is frequently associated with autonomic dysfunction in patients with neurodegenerative diseases, diabetes mellitus, and aging. Despite its potential impact, OH may be underrecognized in kidney transplant (KT) recipients, particularly in the early post-transplant period, when diuresis-induced hypovolemia may serve as a precipitating factor. We present a case of severe OH in a woman in her 50s who underwent living-donor KT for diabetic kidney disease. Pre-transplant therapy with a glucagon-like peptide-1 (GLP-1) receptor agonist led to significant weight loss, followed by post-transplant diuresis, ultimately resulting in volume depletion. One month postoperatively, the patient developed persistent dizziness and fatigue. Orthostatic testing confirmed neurogenic OH, and assessment of cardiac autonomic function using the coefficient of variation of R-R intervals (CVRR) revealed significant autonomic dysfunction. Despite initial treatment with midodrine, symptoms persisted. Given concurrent mild hyperkalemia, fludrocortisone was administered. Unfortunately, no improvement in OH was observed during the observation period. This case underscores the importance of considering OH in KT recipients, particularly in the early post-transplant period when diuresis may exacerbate autonomic dysfunction. OH would be more common than recognized in routine clinical practice and is potentially underdiagnosed. Given the increasing number of elderly and diabetic KT recipients, heightened awareness and appropriate diagnostic evaluation of OH are essential for timely intervention. Fludrocortisone should also be considered in cases where volume depletion coexists with hyperkalemia, although its effectiveness may be limited, highlighting the therapeutic challenge in managing OH after KT.

A 67-year-old man with a history of hypertension and dyslipidemia presented with edema and heavy proteinuria. Light microscopic analysis of kidney biopsy revealed a diffuse segmental membranous feature. Immunofluorescence stain was segmentally positive for IgA, galactose-deficient IgA1, both κ and λ light chains, and C3 along the glomerular capillary walls, but negative for IgG, IgM, or C1q. Electron microscopy showed subepithelial and intramembranous electron-dense deposits (EDD) in the segmental glomerular capillary walls, along with foot process effacement in the corresponding areas. No EDD was observed in the mesangial or para-mesangial areas. The patient's histopathology revealed membranous nephropathy with a solitary IgA deposition. No clinical findings suggested a secondary cause of membranous nephropathy. Combination therapy with corticosteroids and cyclosporine resulted in proteinuria remission. To our knowledge, this is the first reported case of membranous nephropathy with a segmental pattern associated with solitary IgA and galactose-deficient IgA1 deposition. Further case reports and studies are required to elucidate the pathogenesis of membranous nephropathy, which shows these unique histopathological features.

Idiopathic pulmonary fibrosis (IPF) is a chronic progressive lung disease associated with inflammation implicated in the development of vasculitis, specifically microscopic polyangiitis (MPA). Herein, we report a case of MPA complicated by IPF. A woman in her 70s with a history of IPF treated with nintedanib presented with a serum creatinine level of 2.22 mg/dL, microscopic hematuria, and a serum myeloperoxidase-antineutrophil cytoplasmic antibodies (MPO-ANCA) titer level of 78.5 IU/mL. The initial renal biopsy revealed diffuse tubulointerstitial nephritis without glomerular crescent formation; therefore, prednisolone was initiated. However, the serum MPO-ANCA titer level increased to 91.1 IU/mL after tapering the prednisolone dose. A second renal biopsy revealed pauci-immune necrotizing glomerulonephritis with crescents, confirming MPA. Treatment was adjusted to include a resumed steroid regimen and combination therapy with rituximab and avacopan, resulting in stable kidney function. In conclusion, this case underscores the importance of monitoring serum ANCA titer levels as a surrogate marker for subclinical vasculitis in patients with IPF. The sequential occurrence of tubulointerstitial nephritis followed by crescentic glomerulonephritis suggests a potential progression pattern in MPA, warranting careful clinical and histopathological evaluations.

Collecting duct carcinoma (CDC) is a rare subtype of renal cell carcinoma with a poor prognosis. Moreover, despite various chemotherapeutic strategies and administration of several tyrosine kinase inhibitors for metastatic CDC, the outcomes remain unfavorable, with no established treatment. Herein, we report the cases of two patients with CDC who exhibited a good response to nivolumab and cabozantinib combination therapy. Both patients were diagnosed with CDC via a needle biopsy of the renal tumor, revealing high expression levels of programmed death ligand 1 (PD-L1), c-MET, and AXL. After 10 and 12 courses of combination therapy for Cases 1 and 2, respectively, significant response was observed against the primary and metastatic lesions. Subsequently, the patients underwent laparoscopic nephrectomy. To the best of our knowledge, this is the first report documenting the favorable therapeutic response of nivolumab and cabozantinib combination therapy against metastatic CDC in patients with high expression of the corresponding molecular targets. These findings may have a strong implication in the selection of first-line systemic therapies for metastatic CDC.

This case report highlights the effectiveness of endoluminal balloon dilation for the difficult removal of tunneled dialysis catheters. Recently, the use of tunneled catheters for vascular access has increased, and cases of difficult removal due to prolonged indwelling have been reported. We describe the case of a 66-year-old man on maintenance dialysis with a tunneled dialysis catheter that had been placed in the right internal jugular vein 8 years prior, who presented with post-dialysis fever. The procedure to remove the catheter due to a catheter-related infection using the traditional method was unsuccessful. Catheter adhesion due to the fibrin sheath was suspected. The catheter was removed using endoluminal balloon dilation. The patient had no postoperative fever or other complications. Another tunneled catheter was subsequently inserted into the same internal jugular vein. This case illustrates that prolonged catheter placement can lead to intravascular adhesions due to the formation of a fibrin sheath. Endoluminal balloon dilation is a minimally invasive treatment option that should be considered before surgical removal.

MYH9-related disease is an autosomal dominant genetic disease characterized by congenital macrothrombocytopenia, sensorineural hearing loss, and progressive kidney failure. Severe cases require kidney replacement therapy in the patient's second decade of life, and thrombocytopenia constitutes a major risk factor for hemorrhagic complications during dialysis initiation or kidney transplantation. Serious bleeding complications have been reported to occur in the perioperative period despite adequate platelet transfusions. Additionally, platelet transfusion may induce the production of anti-platelet antibodies and donor-specific anti-human leukocyte antigen antibodies. We report a case of a 19-year-old woman with MYH9-related disease due to an R702C missense variant in the motor domain of the MYH9 gene who used prophylactic eltrombopag, a thrombopoietin receptor agonist, from 6 weeks before kidney transplantation. Before transplantation, her platelet count increased from 10 × 10³/μL to 156 × 10³/μL. No major bleeding complications occurred after living donor kidney transplantation. Although perioperative eltrombopag use has been reported in other surgeries, this is the first successful case of living donor kidney transplantation in which perioperative eltrombopag administration allowed platelet transfusions to be avoided. Eltrombopag may serve as a valuable alternative in kidney transplant recipients with MYH9-related disease by avoiding platelet transfusion and reducing the risk of severe bleeding complications.

A 63-year-old woman underwent living-donor kidney transplantation three years earlier for end-stage renal disease due to diabetic nephropathy, with her younger sister as the donor. She was prescribed calcium polystyrene sulfonate for the management of hyperkalemia, which had been discontinued two years earlier. At this time, she developed recurrent abdominal and urinary symptoms, which were managed empirically with antibiotics. Four months prior to admission, she noted mucoid vaginal discharge. Pelvic MRI revealed a pelvic mass. She underwent an open biopsy and pathological examination revealed an appendiceal abscess with deposition of calcium polystyrene sulfonate crystals and an associated inflammatory pseudotumor. The lesion resolved with antibiotic therapy and drainage. Calcium polystyrene sulfonate is known to cause gastrointestinal complications; however, it may be associated with the development of inflammatory pseudotumors in rare cases. Surgical resection is generally considered the first-line treatment for inflammatory pseudotumors; however, treatment strategies for unresectable cases have not been established. Herein, we report a rare case of an inflammatory pseudotumor with calcium polystyrene sulfonate crystal deposition that was successfully managed with antibiotics.

Central venous catheter (CVC)-related kidney disease has been well documented in cases of long-term catheter use, typically manifesting as membranoproliferative glomerulonephritis with immunoglobulin (Ig)M and C3 deposits after months to years of catheterization. We report an exceptional case of rapidly progressive kidney disease that developed just 7 days after CVC insertion in a 74-year-old man who underwent laparoscopic rectal cancer surgery. The patient presented with high fever (39 ℃) and acute kidney injury, with serum creatinine rapidly escalating from a baseline of 1.1-2.7 mg/dL. Laboratory evaluation revealed marked hypocomplementemia (C3 35 mg/dL, C4 5 mg/dL), significant proteinuria (1.5 g/day), and hematuria. Catheter tip culture isolated multidrug-resistant Staphylococcus epidermidis. Kidney biopsy demonstrated distinctive pathological findings characterized by endocapillary proliferative glomerulonephritis with massive fibrin deposition, confirmed by phosphotungstic acid-hematoxylin (PTAH) staining. Immunofluorescence revealed granular deposits of IgG and C3 along the capillary wall, notably without IgA or IgM deposits. Electron microscopy identified characteristic fibrin deposits measuring 7-8 nm in thickness, predominantly in the subendothelial region. DnaJ homolog subfamily B member 9 (DNAJB9) staining was negative, definitively excluding fibrillary glomerulonephritis (FGN). Following catheter removal and targeted antibiotic therapy without steroid treatment, the patient's renal function showed remarkable improvement, with creatinine decreasing to 1.8 mg/dL at discharge and further improving to 1.0 mg/dL after 1 year. This case demonstrates that S. epidermidis can induce severe glomerular lesions through fibrin deposition within an extraordinarily short timeframe, contrasting dramatically with the immune complex-mediated injury typically observed in long-term CVC use.