Ifosfamide-induced nephrogenic diabetes insipidus and Fanconi syndrome in a patient with femur osteosarcoma.

Background: Ifosfamide-induced Fanconi syndrome is a relatively infrequent complication that generally occurs in young patients with a high cumulative dose of ifosfamide; and is commonly characterized by glycosuria, proteinuria, electrolyte abnormalities, and a normal anion gap metabolic acidosis. Case Presentation: In this study, we present the case of a 16-year-old male patient with of osteosarcoma of the right femur with pulmonary metastasis, who received ifosfamide as part of chemotherapy 1 year and 2 months ago and required hospitalization for cellulitis. During inpatient management, he presented with hypokalemia, hypophosphatemia, polyuria, glycosuria, and proteinuria, by which he was diagnosed with Fanconi syndrome and nephrogenic diabetes insipidus, induced by ifosfamide. Management was focused on the control of the internal environment and use of potassium supplements and potassium-sparing diuretics. Conclusion: Patients receiving ifosfamide should be periodically monitored for kidney function and internal environment to detect any potential complications. It is thus important to carefully observe the cumulative dose of ifosfamide to prevent its associated nephrotoxicity, since its appearance can impoverish the prognosis in patients with neoplasms. Therefore, physicians should always be aware about the possibility of nephrotoxicity development.

Renal Injuries Induced by Supplements Containing Red Yeast Rice.

Red yeast rice has been highlighted as a health-food ingredient that reduces serum cholesterol levels. Recently, an increased number of cases of renal impairment induced by a supplement containing red yeast rice have been reported in Japan. A 42-year-old man with no history of chronic kidney disease developed renal dysfunction with proximal tubular damage after supplementation with red yeast rice. An 83-year-old woman with advanced diabetic kidney disease experienced further deterioration of her renal function after supplementation with red yeast rice. We herein report cases of acute kidney injury likely induced by a supplement containing red yeast rice.

Fanconi syndrome and renal tubular necrosis in patients following ingestion of potentially contaminated red yeast rice supplement: Two case reports.

We present two cases of middle-aged men who developed Fanconi syndrome and renal dysfunction after consuming "foods with functional claims (FFC)" containing red yeast rice. In the first case, the patient had consumed an FFC for 1 year and another FFC suspected to have contained nephrotoxin for 3 weeks; kidney biopsy performed during the acute phase of renal injury showed severe acute tubular necrosis and tubular cell regeneration. He achieved near-complete recovery 40 days after the FFC was discontinued. In the second case, the patient had consumed FFC for 4 years and stopped 70 days prior to presentation; kidney biopsy revealed significant tubular recovery, persistent tubular injuries, and interstitial fibrosis. Although the manifestations of Fanconi syndrome subsided, mild renal dysfunction persisted. These cases suggest that FFC with nephrotoxins may induce Fanconi syndrome owing to acute tubular necrosis. Recovery is possible after discontinuing the FFC; while short-term ingestion of FFC allows for tubular regeneration, its long-term ingestion may cause irreversible damage and lead to chronic kidney disease. Long-term follow-up is crucial for preventing further renal deterioration.

Familial renal glycosuria identified in an Indian family.

Glycosuria can be isolated or it can be associated with other tubulopathies like proximal renal tubular acidosis, Fanconi syndrome and endocrine conditions like diabetes mellitus. The SLC5A2 gene codes for the SGLT2 transporter, which is responsible for glucose reabsorption in the proximal tubule. Previously reported cases show that mutation in this gene is associated with intellectual disability, seizure disorder and renin and angiotensin system dysfunction. In his early childhood, a male child displayed persistently high urine glucose levels. We ruled out diabetes mellitus and other tubulopathies before diagnosing the child with familial renal glycosuria, with a novel mutation in the SLC5A2 gene, and screened family members for the same condition. Child's father was found to have isolated renal glycosuria and tested positive for mutation in the SLC5A2 gene.

Renal Impairment of Proximal Tubular Injury Caused by Red Yeast Rice Supplement: Report of 2 Cases.

Introduction: Drug-induced tubulointerstitial injury is a common cause of renal impairment. Since the mechanisms of drug-induced tubular injury are diverse, various treatment approaches are needed according to the pathogenesis. Renal biopsy is indispensable to determine not only the pathological diagnosis, but also the underlying mechanism, and to guide appropriate treatment. Most recently, one of the red yeast supplements has been widely highlighted as a novel cause of tubular damage, mainly in Japan and Asia. However, neither detailed pathological findings nor the mechanism of renal impairment has been sufficiently reported. Case Presentation: Two cases of renal impairment after taking red yeast supplement internally are presented. Both cases showed renal dysfunction with low uric acid, potassium, and phosphorus levels, characteristic features of Fanconi syndrome. The renal biopsy findings of both cases showed severe injury to the proximal tubules with mild inflammatory cell infiltration. The proximal tubules exhibited diffuse loss of the brush border, flattening, and tubular lumen dilation. Immunofluorescence showed no deposition of immunoglobulin and complement in the glomeruli and tubules. Electron microscopic findings indicated proximal tubular damage without crystal deposition. Moreover, immunohistochemistry using the proximal tubular marker CD10 and a marker for distal tubules including the loop of Henle, E-cadherin, collectively demonstrated that the focus of renal injury in both cases was mainly the proximal tubules. Conclusions: The red yeast rice supplement itself, its metabolized product, or other unknown contaminant components might directly induce proximal tubulopathy rather than an allergic reaction-related tubulointerstitial nephritis.

Recurrent Fanconi Syndrome Induced by Lenalidomide: A Case Report.

Fanconi syndrome (FS) is a complex disorder characterized by a reabsorption defect in the proximal renal tubule (PT), leading to urinary loss of molecules such as glucose, phosphate, calcium, amino acids, bicarbonate, potassium, and low-molecular-weight proteins. Its etiology can be genetic or acquired, with drug toxicity being a significant cause of the acquired forms. The heterogeneous manifestations of FS, whether in its partial or complete form, can pose challenges in the emergency department; nevertheless, it should be considered in certain patients, as understanding its cause is crucial for initiating effective treatment. We present the case of a 59-year-old female patient with FS who was treated with lenalidomide in the context of stage III IgG kappa multiple myeloma according to the Salmon Durie classification. We highlight the recurrent nature of this syndrome in this patient.

Long-term effects of luteolin in a mouse model of nephropathic cystinosis.

In infantile nephropathic cystinosis, variants of the CTNS gene cause accumulation of cystine in lysosomes, causing progressive damage to most organs. Patients usually present before 1 year of age with signs of renal Fanconi syndrome. Cysteamine therapy allows cystine clearance from lysosomes and delays kidney damage but does not prevent progression to end-stage kidney disease, suggesting that pathways unrelated to cystine accumulation are also involved. Among these, impaired autophagy, altered endolysosomal trafficking, and increased apoptosis have emerged in recent years as potential targets for new therapies. We previously showed that luteolin, a flavonoid compound, improves these abnormal pathways in cystinotic cells and in zebrafish models of the disease. Herein, we have investigated if prolonged luteolin treatment ameliorates kidney damage in a murine model of cystinosis. To this end, we have treated Ctns-/- mice from 2 to 8 months with 150 mg/kg/day of luteolin. No significant side effects were observed. Compared to untreated animals, analyses of kidney cortex samples obtained after sacrifice showed that luteolin decreased p62/SQSTM1 levels (p <0.001), improved the number, size, and distribution of LAMP1-positive structures (p <0.02), and decreased tissue expression of cleaved caspase 3 (p <0.001). However, we did not observe improvements in renal Fanconi syndrome and kidney inflammation. Kidney function remained normal during the time of the study. These results indicate that luteolin has positive effects on the apoptosis and endo-lysosomal defects of cystinotic proximal tubular cells. However, these beneficial effects did not translate into improvement of renal Fanconi syndrome.

An Interesting Case of Acquired Renal Fanconi Syndrome.

Renal Fanconi syndrome (RFS) is a proximal tubular dysfunction characterized by abnormalities in the absorption of electrolytes and substances by the proximal tubule. It can manifest as proteinuria, glycosuria, aminoaciduria, phosphaturia, and proximal renal tubular acidosis (RTA) type 2. Heavy metal-induced nephrotoxicity from heavy metals such as iron, cadmium, mercury, and lead is a common risk factor for type 2 RTA. Environmental contamination or prolonged contact with pesticides, such as lead arsenate, Bordeaux mixture, and copper sulfate, may also contribute to heavy metal exposure. A 25-year-old female patient with RFS was diagnosed, and the bicarbonate loading test showed typical features of generalized proximal tubular dysfunction and proximal RTA. A metabolic disorder in the bone was the predominant feature, and renal wasting of phosphorus and calcium was linked to osteoporosis and increased intact parathyroid hormone (PTH) levels. Due to reports of zoledronate-induced RFS, calcitriol was administered instead of bisphosphates. Drug-induced nephrotoxicity is the most probable cause of adult-onset RFS. Acute tubulointerstitial nephritis is a plausible hypothesis, and treatment was based on observations and assessments that improved clinical outcomes. Ayurvedic medicine, popular in India due to its traditional roots and cultural aversion to artificial drugs, has high levels of heavy metal content.

Latent metabolic bone disease, skeletal dysplasia and other conditions related to low bone formation among 38 patients with subtrochanteric femoral fractures: a retrospective observational study.

Subtrochanteric femoral fracture is rare and intractable due to the possible association with low bone formation. Retrospective analysis of 38 patients with subtrochanteric femoral fractures revealed that four patients suffered from disorders related to low bone formation and there were specific treatments for two of them. PURPOSE: The main aim of this study was to detect latent metabolic bone diseases and skeletal dysplasia associated with low bone formation among patients with morphologic atypical femoral fracture (AFF). A second aim was to evaluate the frequency of recognized risk factors, such as antiresorptive agents, glucocorticoids, and age. METHODS: Clinical information was retrospectively analyzed among 38 Japanese patients who were admitted to the Department of Orthopedic Surgery and Spinal Surgery and the Division of Emergency and Critical Care Medicine at the University of Tokyo Hospital with diagnoses of subtrochanteric fractures between February 2012 and March 2022. RESULTS: Among 38 patients (including 30 females), 21 patients were aged 75 and over. Ten patients had past oral glucocorticoid use, and 18 had past antiresorptive agent use. Two patients were diagnosed with hypophosphatemic osteomalacia after the development of fractures. One patient was suspected to be a carrier of a loss-of-function variant of alkaline phosphatase, biomineralization associated (ALPL), and one other patient had previously been genetically diagnosed with pycnodysostosis. Among four patients with a diagnosis or suspicion of these metabolic bone diseases and skeletal dysplasia, four had past clinical fractures, two had past subtrochanteric femoral fractures, and two had subtrochanteric femoral fractures on both sides. CONCLUSION: If clinicians encounter patients with morphologic AFF, latent diseases related to low bone formation should be carefully differentiated because appropriate treatment may prevent delayed union and recurrent fractures. Additionally, it may be desirable to exclude these bone diseases in advance before initiating long-term use of antiresorptive agents in osteoporotic patients by screening with serum alkaline phosphatase levels to reduce the risk of morphologic AFF.

Long-term Evolution of Hypophosphatemia and Osteomalacia in a Patient With Multiple Myeloma.

Multiple myeloma commonly manifests with symptoms arising from the involvement of various organs, particularly the bone and kidneys. In this report, we detail the case of a 44-year-old man who was diagnosed with multiple myeloma associated with reduced bone density. He exhibited clinical findings of osteomalacia due to Fanconi syndrome (characterized clinically by bone pain and proximal weakness and biochemically by elevated serum alkaline phosphatase, hypophosphatemia, hypouricemia, and glucosuria). With phosphate replacement, there was a notable improvement in bone pain, osteomalacia, and bone mineral density. Nevertheless, the patient continued to experience renal wasting of phosphate, uric acid, and glucose despite achieving remission from multiple myeloma for nearly 2 years. Our case highlights several important clinical features of myeloma-associated Fanconi syndrome, including the need to recognize this complication to appropriately treat the underlying bone disease while avoiding osteoclast inhibitors and the long-term persistence of the proximal renal tubulopathy despite achieving remission from myeloma and correction of osteomalacia.

Fanconi syndrome with karyomegalic interstitial nephritis after ifosfamide treatment for osteosarcoma: a case report.

Patients with ifosfamide-induced renal damage present with Fanconi syndrome. Karyomegalic nephropathy/interstitial nephritis (KNIN) is a rare form of chronic tubulo-interstitial nephritis that was initially considered a type of familial nephropathy. However, several reports of drug-induced KNIN, i.e., KNIN-like nephropathy, have been reported in recent years. We present the case of an 18-year-old man who presented with Fanconi syndrome and progressive renal dysfunction after receiving chemotherapy including ifosfamide and cisplatin for right femoral osteosarcoma. Renal biopsy revealed numerous atrophied tubular epithelial cells with large, polymorphic nuclei, and the definitive diagnosis was KNIN. Most patients with KNIN-like nephropathy who receive ifosfamide are concomitantly treated with cisplatin, indicating that ifosfamide and cisplatin might act synergistically to increase the risk for KNIN-like nephropathy. Further investigation in case series is warranted to reveal potential treatment approaches and to evaluate prognosis.

A case of Fanconi syndrome that developed following a year of consumption of a red yeast rice supplement.

Although some dietary supplements have been reported to cause renal dysfunction, there have been few reports of supplement-induced Fanconi syndrome. We present the case of a 56-year-old woman with Fanconi syndrome that developed after she consumed a red yeast rice supplement. She was referred to our hospital because of renal dysfunction, and was found to have electrolyte abnormalities, including hypophosphatemia and hypouricemia, renal diabetes, and hyperchloremic metabolic acidosis, and was, therefore, diagnosed with Fanconi syndrome. Renal biopsy revealed proximal tubular injury characterized by severely degenerated tubular epithelial cells as well as mild hypocellular fibrosis. We speculated that the red yeast rice supplement, which the patient had been consuming for approximately 1 year, might be a cause of her syndrome, because reports of renal dysfunction associated with the consumption of red yeast rice supplements have emerged in Japan since 2024. After the supplement was discontinued and oral prednisolone treatment was initiated, the patient's renal function improved and her electrolyte abnormalities were ameliorated. Furthermore, even after tapering off and discontinuing the prednisolone over approximately 12 weeks, her renal function remained. Because Fanconi syndrome may be caused by various exogenous substances, the taking of a thorough medical history is crucial, including with respect to the use not only of prescription medications, but also other substances, including supplements.

A female patient with Dent disease due to skewed X-chromosome inactivation.

X-linked proximal tubulopathies are rare diseases that predominantly affect men. Women are generally carriers and clinical or biochemical manifestations are usually absent or mild. We present the case of a young woman who presented with a full phenotype of Dent disease type 1 due to a de novo mutation in the CLCN5 gene and a skewed X-chromosome inactivation. Although cases of overt Dent disease type 2 and Lowe syndrome in women have been described in the literature, to our knowledge this is the first case of overt Dent disease type 1.

A case of acute kidney injury and Fanconi syndrome while taking multiple supplements, including Red Yeast Rice Cholesterol Help®.

A 62-year-old man visited his primary care physician with the complaints of loss of appetite and fatigue. He was admitted to our hospital based on a diagnosis of acute kidney injury, Fanconi syndrome as indicated by hypokalemia, hypouricemia, hypophosphatemia, elevated glucose levels in urine, and aminoaciduria. He had been taking multiple supplements, including Red Yeast Rice Cholesterol Help®, for one and a half years. After admission, all the supplements were stopped. Blood samples were collected; however, the samples were negative for diseases that could cause Fanconi syndrome. Renal biopsy revealed renal proximal tubular damage, mainly characterized by simplification of the proximal tubular epithelium. The mycotoxin, citrinin, which is reported to be produced by the mold used for producing red yeast rice, but not the mold Monascus pilosus used for Red Yeast Rice Cholesterol Help®, reportedly causes proximal tubular damage. However, although the causative agent has not been identified, it was thought that a substance similar to citrinin, produced by the mold used for Red Yeast Rice Cholesterol Help®, caused proximal tubular damage, leading to acute kidney injury and Fanconi syndrome. Hence, all supplements were stopped, and the patient was treated with oral potassium and phosphorus preparations, leading to gradual recovery of his kidney function. We herein report the first case of acute kidney injury and Fanconi syndrome in a patient taking multiple health supplements, including Red Yeast Rice Cholesterol Help®. Early discontinuation of the oral supplements was probably useful in improving the patient's kidney function.

Monoclonal immunoglobulin crystalline nephropathies.

Monoclonal Ig crystalline nephropathies are rare lesions resulting from precipitation of monoclonal Igs in the kidney as crystalline inclusions. They can be categorized into lesions with predominant intracellular crystals (light chain [LC] proximal tubulopathy, LC crystal-storing histiocytosis, and LC crystalline podocytopathy) and lesions with predominant extracellular crystals (crystalglobulin-induced nephropathy and crystalline variant of LC cast nephropathy). The majority of these lesions are associated with low tumor burden lymphoproliferative disorders, with the exception of crystalline variant of LC cast nephropathy. Extrarenal involvement (e.g., skin and cornea) is frequent. Kidney biopsy is the cornerstone for diagnosis, which often requires electron microscopy and antigen retrieval. A thorough hematologic workup and evaluation of extrarenal involvement is mandatory for management. Treatment of these lesions is with clone-directed therapy, with the goal of achieving hematologic very good partial response or complete response, which preserves or improves kidney function. In vitro and in vivo studies, animal models, and novel sequencing techniques have been invaluable tools to understand the pathogenesis of LC proximal tubulopathy and can be used to increase our limited knowledge of the pathogenesis of the other monoclonal Ig crystalline nephropathies. This review provides an update on the pathology, renal and hematologic characteristics, extrarenal manifestations, prognosis, treatment, and pathogenesis of monoclonal Ig crystalline nephropathies.

Tenofovir induced Fanconi syndrome in a middle age African female from Kenya, East Africa: Case report and brief literature review.

This case presentation highlights the need to routinely monitor renal function in patients on Tenofovir Disoproxil Fumarate (TDF) due to its side effect of proximal tubule dysfunction. Abstract: This is a case presentation of a 50-year-old African female who had been on a Tenofovir based regimen for 12 years and developed Fanconi syndrome. She recovered after discontinuation of the Tenofovir Disoproxil Fumarate (TDF).

Chronic bromine intoxication complicated with Fanconi syndrome: A case report.

In this report, we describe a unique case of an 80-year-old woman who developed chronic bromine poisoning due to the prolonged ingestion of over-the-counter (OTC) medication containing bromovalerylurea (BVU), thus leading to the onset of drug-induced partial Fanconi syndrome and resultant osteomalacia. The patient's condition improved following the cessation of bromide intake. This case highlights the potential risks of chronic BVU exposure and the importance of caution regarding the use of OTC medications containing BVU.

Concurrent Crystalline Light-Chain Proximal Tubulopathy and Membranous Nephropathy: A Case Report and Literature Review.

Light-chain proximal tubulopathy (LCPT) is typically characterized by the intracytoplasmic deposition of light chains within the proximal tubular epithelial cells, which is usually classified into crystalline and noncrystalline subgroups. Membranous nephropathy (MN) is a common glomerular disease characterized by diffused subepithelial electron-dense deposits along the capillary loop accompanied by the effacement and microvillus transformation of the foot process. Here, we report a biopsy-confirmed case of a concurrence of LCPT with crystals (κ light chains restricted) and antigen-undetermined MN in a male patient. The patient presented with low-molecular-weight proteinuria, increased serum creatinine levels, and incomplete Fanconi syndrome. To our knowledge, this is the first report of a concurrence of LCPT and independent MN of unknown target antigens, which may enrich our recognition of monoclonal gammopathy of renal significance with synchronous MN.

Kidney involvement in Wilson's disease: a review of the literature.

Wilson's disease (WD) is a rare inherited disease due to the mutation of the ATP7B gene, resulting in impaired hepatic copper excretion and its pathological accumulation in various organs such as the liver, the nervous system, or the kidneys. Whereas liver failure and neuropsychiatric disorders are the most common features, less is known about the renal complications. We conducted a review of the literature to define the characteristics and pathophysiology of kidney involvement during WD. This review shed light on strong evidence for direct copper toxicity to renal tubular cells. Excessive tubular copper accumulation might present with various degrees of tubular dysfunction, ranging from mild hydroelectrolytic and acid-base disorders to complete Fanconi syndrome. Proximal and distal renal tubular acidosis also favors development of nephrolithiasis, nephrocalcinosis, and bone metabolism abnormalities. Indirect complications might involve renal hypoperfusion as occurs in hepatorenal or cardiorenal syndrome, but also tubular casts' formation during acute hemolysis, rhabdomyolysis, or bile cast nephropathy. Acute kidney failure is not uncommon in severe WD patients, and independently increases mortality. Finally, specific and long-term therapy by D-penicillamin, one of the most efficient drugs in WD, can cause glomerular injuries, such as membranous nephropathy, minimal-change disease, and, rarely, severe glomerulonephritis. Altogether, our study supports the need for interdisciplinary evaluation of WD patients involving nephrologists, with regular monitoring of tubular and glomerular functions, to provide adequate prevention of renal and bone involvement.