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An 81-year-old man with hypertension and a history of smoking presented with renal enlargement and progressive renal dysfunction despite no family history of kidney disease. A renal biopsy revealed diffuse tubular, dilated, and atrophic distal tubules with cystic formation and thin irregularities in the tubular basement membrane. Although no known genetic abnormalities were detected, the patient was diagnosed with medullary cystic kidney disease (MCKD). In addition, idiopathic nodular glomerulosclerosis, which is characterized by significant mesangial expansion and accentuated glomerular nodularity and is associated with hypertension and cigarette smoking, was identified as a complication of MCKD. We herein report a rare case of sporadic MCKD with idiopathic nodular glomerulosclerosis.

A 42-year-old woman presented with muscle weakness and hypokalemic distal renal tubular acidosis (dRTA). Investigations revealed concurrent Sjögren's syndrome (SS) and Hashimoto's thyroiditis contributing to hypokalemic dRTA. A renal biopsy revealed focal tubulointerstitial nephritis (TIN) suggestive of SS-related renal involvement, along with distinctive ischemic glomerular changes and tubular alterations consistent with hypokalemic nephropathy. Rapid improvement in tubular injury markers and hypobicarbonemia followed potassium supplementation, suggesting that hypokalemia contributed to proximal tubular injury. This case underscores the diagnostic challenge posed by the simultaneous presence of TIN and hypokalemic nephropathy, potentially masking hypokalemic nephropathy in patients with hypokalemic dRTA secondary to SS-TIN.

A middle-aged woman presented with hypertensive emergency after corticosteroid treatment for Sjögren syndrome-associated multiple mononeuropathy with suspected systemic sclerosis. Hypertensive heart failure with hyperreninemia improved with antihypertensives, including aliskiren; however, she became hemodialysis-dependent. Clinical findings and biopsy-proven thrombotic microangiopathy indicated conditions resembling scleroderma renal crisis (SRC). Severe hypertension and heart failure with hyperreninemia occurred after stopping aliskiren for hypotension due to diverticular bleeding, which improved after the reintroduction of aliskiren. Aliskiren appears to be effective in managing hypertensive heart failure in patients with SRC. Nevertheless, hemodialysis remained necessary in our case, and whether or not aliskiren can restore the renal function is unclear.

Cryofibrinogen-associated glomerulonephritis (CryoFiGN) is rare, and its diagnosis is difficult while treatment is not established. We herein report an elderly woman with CryoFiGN who experienced recurrent purpura and nephritic features that subsequently progressed to nephrotic syndrome and required hemodialysis during the 18-month clinical course. The patient was treated with corticosteroids, which led to the discontinuation of hemodialysis. The diagnosis of CryoFiGN was based on the clinical presentation, characteristic glomerular deposits, and results of laser microdissection and liquid chromatography-tandem mass spectrometry of the glomeruli. This case highlights the potential utility of corticosteroids as a treatment option for patients with CryoFiGN, even after hemodialysis.

An elderly woman showed positive conversion of myeloperoxidase (MPO)-antineutrophil cytoplasmic antibodies (ANCAs) following the diagnosis of interstitial lung disease (ILD) and glomerular hematuria and subsequently experienced slowly progressive glomerulonephritis. A kidney biopsy revealed chronic damage and necrotizing crescentic glomerulonephritis with mesangial MPO deposits. After corticosteroid treatment, the patient's urinalysis results and MPO-ANCA titers almost normalized and her renal function stabilized. This case is similar to recently reported cases of slowly progressive ANCA-associated glomerulonephritis. ILD likely triggered the production of MPO-ANCAs, and the accumulation of MPO deposits in the glomeruli may have contributed to the progression of her renal disease.

A 50-year-old man diagnosed with anti-contactin 1 (CNTN1) antibody-associated chronic inflammatory demyelinating polyneuropathy (CIDP) was referred to our department for the evaluation of proteinuria. A kidney biopsy revealed membranous nephropathy (MN). Immunohistochemistry for CNTN1 revealed positive granular staining along the glomerular basement membrane, confirming anti-CNTN1 antibody-associated MN. Immunofluorescence showed a full-house pattern, and several autoantibodies, such as anti-nuclear antibody, anti-double-strand DNA antibody, and anti-cardiolipin antibody, were detected in the patient's serum. Although limited autoantibodies have been investigated in some of the reported cases, a variety of autoantibodies might be produced in anti-CNTN1 antibody-associated CIDP, accompanied by MN.

Exostosin 1 (EXT1) and exostosin 2 (EXT2)-associated membranous nephropathy (MN) may be associated with active autoimmune disease. We encountered an elderly man who presented with EXT1/EXT2-associated lupus-like MN with full house immune deposits, monoclonal gammopathy of uncertain significance and Sjögren's syndrome. The patient exhibited various other immune abnormalities. Although he did not fulfill the criteria of clinical systemic lupus erythematosus (SLE), he met a stand-alone renal criterion of the Systemic Lupus International Collaborating Clinics (SLICC) 2012. Whether or not a stand-alone renal criterion with EXT1/EXT2 positivity, as in the present patient, can efficiently guide decisions regarding the diagnosis and treatment of SLE remains a clinical dilemma.

A 25-year-old man presented with acute kidney injury (AKI), massive proteinuria and hyperuricemia after epileptic seizures. His AKI improved along with the disappearance of proteinuria after corticosteroid treatment. A kidney biopsy revealed no significant glomerular abnormalities, but varying degrees of tubular injury, such as proximal tubular simplification, mild distal tubular proliferation, and Tamm-Horsfall protein-like material accumulation with extravasation into the interstitium, were noted. A further analysis revealed the intratubular depositions of uric acid crystals, indicating the involvement of acute uric acid nephropathy associated with seizures. Our patient's condition is rare, and the clinicopathological aspects of the diagnostic challenges are discussed.

A young woman with microscopic polyangiitis (MPA) requiring hemodialysis showed repeated posterior reversible encephalopathy syndrome (PRES) with spatiotemporal multiple lesions over a period of two months. The first PRES episode with confusion and the second PRES episode with vertigo and nausea were caused by MPA, hypertension and renal failure. These symptoms were improved by the reinforcement of MPA treatment and blood pressure management. The third PRES episode with nausea, headache, seizure and visual changes was induced by rituximab infusion and hypertension. The PRES was improved with blood pressure and convulsant management. These conditions are challenging to diagnose and treat.

A 39-year-old man presented with peripheral eosinophilia, pulmonary eosinophilic infiltrate, and renal failure due to acute tubulointerstitial nephritis (TIN). He had experienced childhood asthma and was negative for anti-neutrophil cytoplasmic antibody (ANCA). He was tentatively diagnosed with ANCA-negative eosinophilic granulomatous polyangiitis (EGPA) or idiopathic hypereosinophilic syndrome (HES). Renal involvement of isolated TIN with eosinophil infiltration is rare in EGPA and HES and does not seem to have a good prognosis in the literature. However, his condition improved well with corticosteroids and mepolizumab. The revised classification of EGPA based on the etiology should dictate the proper treatment in suspected EGPA patients with nonsystemic vasculitis.

A 21-year-old woman was admitted to our hospital because of massive intestinal bleeding. She started hemodialysis due to myeloperoxidase antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) at 18 years of age. Her ANCA titers remained stable; however, her C-reactive protein increased on 5 mg/day prednisolone before admission. Computed tomography angiography revealed a ruptured jejunal arterial aneurysm. Transcatheter arterial embolization, blood transfusion and the reinforcement of steroid therapy resolved her symptoms of AAV. Our case of a young patient with AAV and medium-sized arterial vasculitis is rare and emphasizes that the ANCA titer does not always rise, especially in patients with nonrenal vasculitis flare-ups.

The patient was a 38-year-old man who had experienced nausea and fever for a few days and presented with back pain, oliguria, and pyuria, suggesting acute pyelonephritis (APN). He showed acute kidney injury (AKI) with bilateral kidney enlargement and was using nonsteroidal anti-inflammatory drugs (NSAIDs). AKI-induced by APN was confirmed by kidney biopsy. The AKI was successfully treated with antibiotic therapy. A search of the relevant literature for reports on histopathologically-proven APN-induced severe AKI revealed that the key characteristics were bilateral kidney enlargement with pyuria without casts. Oligoanuria was frequently associated with APN-induced severe AKI, and NSAID use may be a possible risk factor. Prompt antibiotic treatment based on the clinical characteristics of APN-induced AKI can improve the renal outcome.

A 21-year-old woman presented with renal dysfunction during macrohematuria. A kidney biopsy revealed IgA nephropathy with a small percentage of crescent formation and macrohematuria-associated tubular injury. Macrohematuria-associated acute kidney injury could explain her renal dysfunction. However, she was seropositive for myeloperoxidase (MPO)-anti-neutrophil cytoplasmic antibody (ANCA) and showed fibrin deposition around one arteriole. Corticosteroids and mycophenolate mofetil were administered as for ANCA vasculitis, and the serum creatinine, abnormal urinalysis and MPO-ANCA titer all gradually ameliorated. The presence of extra-glomerular vasculitis, which was probably induced by ANCA, suggested that MPO-ANCA was an exacerbating factor for her prolonged renal dysfunction. This condition has so far only rarely been addressed in ANCA-positive IgA nephropathy.

A 67-year-old woman presented with hematuria and proteinuria 16 and 11 months ago, respectively. She had been followed up as mixed connective tissue disease and Sjögren's syndrome for over 19 years. Blood chemistry showed no elevated serum creatinine or C-reactive protein but did reveal myeloperoxidase-antineutrophil cytoplasmic antibody (MPO-ANCA) of 300 U/dL. A kidney biopsy showed pauci-immune focal necrotizing glomerulonephritis. She was treated with prednisolone and rituximab, resulting in normal urinalysis and decreased MPO-ANCA. The complication of ANCA-associated glomerulonephritis should not be overlooked when abnormal urinalysis findings appear in the course of connective tissue disease, irrespective of the presence of rapidly progressive glomerulonephritis.

A 31-year-old woman was admitted to our hospital for thrombotic microangiopathy (TMA). She was diagnosed with systemic lupus erythematosus (SLE) and class V lupus nephritis. She had no aggravated SLE activity, Shiga toxin positivity, ADAMTS13 abnormality, or other causes of secondary TMA. Plasma exchange partially improved TMA, and eculizumab was introduced for suspected atypical hemolytic uremic syndrome (aHUS), as eculizumab was effective in suppressing the TMA activity. A kidney biopsy revealed diffusely organized crescents (pseudotubulization) with glomerular and arteriolar endothelial injury and subepithelial immune deposits. Thus, this was a rare case of lupus nephritis presenting as TMA with pseudotubulization possibly caused by aHUS.

Thrombocytopenia, ascites, myelofibrosis, renal dysfunction, and organomegaly (TAFRO) syndrome is a newly recognized but rare disease, and its treatment has not yet been established. We reported a 50-year-old woman with TAFRO syndrome diagnosed 2 years after the initial symptoms of a fever, fatigue, epigastric pain, edema, ascites, lymphadenopathy, thrombocytopenia and renal insufficiency. The patient showed refractory ascites and required hemodialysis under corticosteroid mono-therapy for suspected immune-mediated disease but was successfully treated with additive rituximab, resulting in improvement in her laboratory data, the withdrawal of hemodialysis and the disappearance of ascites. This case underscores the therapeutic utility of rituximab in patients with corticosteroid-resistant TAFRO syndrome, even long after the onset of the disease.

A 71-year-old man with hypertension and diabetes mellitus presented with proteinuria. Laboratory data showed proteinuria of 3.1 g/g creatinine, serum albumin of 3.5 g/dL and serum creatinine of 1.03 mg/dL without autoantibodies. A renal biopsy revealed segmental granular IgG depositions on glomerular capillary walls. Electron microscopy showed segmentally subepithelial, intramembranous and mesangial deposits. Diffuse segmental membranous glomerulonephritis (MGN) was diagnosed with only IgG1 deposition and without M-type phospholipase A2 receptor or thrombospondin type-1 domain-containing 7A staining, suggesting secondary MGN with an unknown target antigen in immune deposits. Physicians should keep in mind the existence of segmental MGN to better understand the clinicopathological characteristics.

We report a 70-year-old woman with Sjögren's syndrome who had severe renal dysfunction with mild proteinuria and elevated urinary low-molecular-weight proteins. Based on these clinical presentations, interstitial nephritis due to Sjögren's syndrome was strongly suspected. Unexpectedly, renal pathology revealed amyloid light-chain (AL) lambda-type depositions predominantly in the vasculatures with severe tubulointerstitial damage. Concentrated urine immunofixation was positive for Bence Jones lambda-type monoclonal proteins. Given the involvement in other organs, systemic AL amyloidosis was diagnosed. The patient underwent chemotherapy, but hemodialysis was ultimately instituted. It should be remembered that renal amyloidosis occurs as a clinical presentation of interstitial nephritis.

A 30-year-old woman with proteinuria first noted at 26 weeks of gestation was admitted to undergo further evaluation. A renal biopsy revealed membranous nephropathy (MN). There was no evidence of any secondary MN. Prednisolone was initiated 6 months after delivery. Four months later, her urine protein became negative. Enhanced granular staining for thrombospondin type-1 domain-containing 7A (THSD7A) in the glomeruli was retrospectively detected in a biopsy specimen. A literature review revealed that 60% of cases of THSD7A-related MN occurred in women of childbearing age. Therefore, THSD7A-related MN should be considered in female patients presenting with idiopathic MN in childbearing age.

Multiple myeloma presents with various kidney injuries, including cast nephropathy, light chain deposition disease, and amyloidosis. Cast nephropathy is the most common form and mostly consists of monoclonal immunoglobulin light chains with Tamm-Horsfall protein. Immunoglobulin light chain (AL) amyloidosis may affect all compartments of the kidney, but it is rare in the tubuli. We herein present a rare case with rapid progression of renal failure caused by the co-occurrence of intratubular amyloidosis and cast nephropathy due to multiple myeloma. Our case suggests unique amyloidogenic light chain cast, which can form amyloid fibrils under specific tubular fluid conditions, and illustrates the complicated light chain pathophysiology.

Objective: The goal of this study was to clarify the clinical manifestation of hypercalcemia due to hypoadrenalism in hemodialysis (HD) patients., Methods: We retrospectively analyzed the clinical characteristics of five HD patients who had presented with hypercalcemia due to adrenal insufficiency (age: 69 ± 7 [58-75] years old, time on HD: 13 ± 11 [2-32] years). We conducted corticotropin-releasing hormone (CRH) and adrenocorticotropic hormone (ACTH) stimulation tests. We also examined serum bone turnover markers before and after glucocorticoid replacement., Results: All patients had critical illnesses at the onset of hypercalcemia. They had at least one symptom, such as eosinophilia, hypoglycemia, or fever. The prevalence of hypercalcemia due to adrenal insufficiency was 1.3% in maintenance HD patients on admission. The causes of adrenal insufficiency were isolated ACTH deficiency, pituitary apoplexy, pituitary atrophy, glucocorticoid withdrawal syndrome, and unilateral adrenalectomy. Serum calcium (Ca) levels corrected by serum albumin were maximally increased to 12.9 to 14.3 mg/dL in four anuric HD patients and mildly elevated to 10.4 mg/dL in a patient with residual diuresis. Their basal serum cortisol levels ranged from <1.0 to 15.4 μg/dL. Single CRH injections failed to increase serum cortisol in any of the patients. Glucocorticoid replacement acutely normalized serum Ca and decreased levels of carboxy-terminal telopeptide of type I collagen, a marker of bone resorption., Conclusion: Adrenal insufficiency could therefore be an occult cause of hypercalcemia in anuric HD patients who are critically ill.

Acetaminophen overdose can lead to severe liver and kidney failure; however, the risk of therapeutic doses in healthy individuals causing acute kidney injury (AKI) is less clear. We herein describe the cases of two young adults with renal biopsy-proven acute tubular necrosis under a therapeutic dose of acetaminophen. The first patient exhibited mild reversible renal insufficiency, whereas, in the second case, the patient demonstrated a slightly increased serum creatinine level and enlarged kidneys and the administration of contrast media and antibiotics may have worsened the renal dysfunction, leading to the need for temporal hemodialysis. Physicians should be aware of the risk of acetaminophen causing AKI and avoid administering other nephrotoxic agents in such cases.

A 46-year-old woman was admitted to our hospital for an evaluation of progressive renal insufficiency and elevated liver enzymes. A renal biopsy revealed chronic granulomatous interstitial nephritis. Her laboratory findings indicated primary biliary cirrhosis (PBC), which was confirmed with a liver biopsy. CD4(+) T cells and CD8(+) T cells with granuloma formation were the predominant cells infiltrating into the interstitium of the kidneys and liver. The etiology of tubulointerstitial nephritis in the present patient was not clear; however, it might have shared the same pathogenesis as PBC due to the relatively close onset, the similar profiles of infiltrating cells and the presence of granulomas.

A 60-year-old man with Waldenström's macroglobulinemia (WM) was admitted to our hospital for evaluation of rapid progressive renal deterioration despite 3 cycles of oral melphalan and prednisolone (MP) therapy. Renal biopsy just before introducing hemodialysis revealed cast nephropathy and severe tubulo-interstitial infiltration of B lymphocytes. After 6 cycles of rituximab, cyclophosphamide, vincristine and prednisolone (R-COP) therapy, his renal function improved enough to discontinue hemodialysis. This is a rare case of WM-related renal involvement caused by both monoclonal protein and tumor infiltration and, to our knowledge, the second report on improved renal function by rituximab-based therapy.

Patients with bacterial endocarditis often have renal complications. This report presents the case of an elderly man with rapidly progressive glomerulonephritis (RPGN) associated with subacute bacterial endocarditis (SBE) due to Enterococcus faecalis infection. The patient was positive for anti-proteinase 3-antineutrophil cytoplasmic antibody (PR3-ANCA) and rheumatoid factor (RF) with hypocomplementemia. Treatment for SBE with antibiotics and the surgical replacement of the affected valves resulted in an improvement of RPGN, the disappearance of PR3-ANCA and RF, and the normalization of hypocomplementemia. This rare case suggests the importance of recognizing the cause of positive PR3-ANCA, because SBE could be an occult cause of RPGN mimicking ANCA-associated vasculitis.

Coronary aneurysm is rare in SLE and confirmation of etiology is usually made at postmortem examination. We encountered a giant aneurysm with multiple stenotic segments of the coronary arteries in a patient with SLE who had previous history of AAA/TAA. Resection of the aneurysm and coronary artery bypass graft were successfully performed. Histology of the coronary arterial wall showed severe damage of the media with inflammatory cell infiltration, indicating that the aneurysm was caused by arteritis. The aneurysm may have developed during the long course of inactive stage of SLE, emphasizing the need for screening of coronary lesions in the management of SLE.

Objective: Adiponectin (ADPN) has been shown to protect against cardiovascular disease for the general population with problematic metabolic syndrome. However, it remains unclear whether ADPN is associated with mortality in patients on maintenance hemodialysis (HD). METHODS, PATIENTS OR MATERIALS: We selected 85 HD patients [51 men/34 women; mean age, 64+/-2 years; underlying kidney diseases, diabetic nephropathy in 36 patients (42.3%), chronic glomerulonephritis in 29 (34.1%), hypertensive nephrosclerosis in 10 (11.8%), and others in 10 (11.8%)] who survived for more than 3 months after the start of HD. We first measured serum ADPN levels and prospectively followed patients for the next 3 years., Results: We were able to follow 74 of 85 patients; 59 survived, and 15 died. Serum log-transformed ADPN levels were negatively correlated with BMI (r=-0.43, p<0.01). Despite a similar BMI (20.7+/-0.8 vs. 20.3+/-0.4 kg/m(2)), the expired patients had significantly higher ADPN compared with the surviving patients (20.5 microg/ml [14.0-23.5] vs. 14.2 microg/ml [9.7-21.3], p<0.05). Cox-hazards multivariate regression analysis adjusted for conventional case-mix features (age, sex, and underlying kidney disease) revealed that serum ADPN became a significant determinant of all-cause mortality. There was a 10.3% risk increment for each 1-microg/ml increase in ADPN during the follow-up. Kaplan-Meier analysis revealed that patients with higher ADPN levels (> or =15 microg/ml) had a significantly lower survival rate compared with those with lower ADPN levels (<15 microg/ml) (76 vs. 92%, p<0.05)., Conclusion: These results indicated that high rather than low ADPN independently predict total mortality in HD patients.

A 53-year-old man with nephrotic syndrome and severe renal failure was diagnosed with light- and heavy-chain deposition disease (LHCDD) by renal biopsy. The patient had no monoclonal protein and mild marrow plasmacytosis (6%), but marrow plasma cells expressed CD19(-)CD56+ and predominant monoclonal kappa-chain, indicating plasma cell dyscrasia. Conventional chemotherapy was ineffective and did not improve renal failure. High dose chemotherapy/peripheral blood stem cell transplantation (HDC/PBSCT) was introduced even after hemodialysis to eliminate aberrant clone and normalization of bone marrow cell surface markers. Immunophenotypic analysis of marrow cells facilitates clinical decision making regarding the use of HDC/PBSCT for LHCDD patients without monoclonal protein.

A woman was admitted for acute renal failure and erythematous lesions. She was diagnosed with sarcoidosis after analysis of biopsy specimens revealed noncaseating epithelioid granulomas, elevated serum angiotensin-converting enzyme levels, and bilateral hilar lymphadenopathy. Serum concentrations of ionized calcium and 1,25-dihydroxyvitamin D3 [1,25-(OH)2D3] were extremely high. Serum intact osteocalcin concentration and urinary deoxypyridinoline excretion were within reference ranges. Treatment with prednisolone induced a prompt improvement with normalization of serum concentrations of ionized calcium and 1,25-(OH)2D3. Serum intact osteocalcin concentration was markedly suppressed and urinary deoxypyridinoline excretion increased. It is possible suppressed bone resorption may be associated with overproduction of 1,25-(OH)2D3.

We treated a 67-year-old Japanese woman with membranoproliferative glomerulonephritis (MPGN) and chronic active hepatitis associated with hepatitis C virus (HCV) infection. Treatment commenced with a daily dose of 6 MU IFN alpha-2b for 2 weeks, which was changed to three times weekly thereafter. After 2 weeks, HCV RNA in the serum was undetectable and there was a concomitant reduction in proteinuria. Treatment with IFN alpha-2b was discontinued because of severe headache and fever. Five weeks after the discontinuation of IFN alpha-2b, the patient experienced the sudden onset of visual loss due to retinal hemorrhage. Subsequently, proteinuria and renal function progressively deteriorated though HCV RNA was undetectable. This case exemplifies the need for careful monitoring of renal function and retinal lesions not only in patients receiving IFN but also in those following the discontinuation of IFN treatment.

We describe a 65-year-old man who presented with pulmonary hemorrhage and progressive renal insufficiency three months after resection surgery for an abdominal aortic aneurysm. Intensive treatment with corticosteroids and hemodialysis were not effective, and the patient died. Postmortem examination of the kidneys revealed widespread cholesterol clefts within the renal arterioles and a number of lamellar inclusion bodies were observed by electron microscopy. The diagnosis of Fabry's disease was made by the absence of plasma alpha-galactosidase A activity. This was a very rare case of subclinical Fabry's disease coexistent with cholesterol crystal embolization, mimicking pulmonary-renal syndrome.