Case Reports in Nephrology and Dialysis最新文献

Introduction: Unilateral renal polycystic disease is a rare condition, first described in 1964, with over 60 cases reported worldwide. In 2019, Yoshida et al. [Eur Radiol. 2019;29(9):4843-50] identified 14 patients with unilateral renal cysts, who exhibited distinctive clinical and radiological features: young adults with multiple unilateral subcapsular cortical hemorrhagic (MUCH) cysts in the left kidney. The epidemiology, etiology, clinical significance, and prognosis of this condition remain largely unknown.

Case presentation: We report a 36-year-old male who presented with nephrotic syndrome, generalized edema, and impaired renal function, requiring renal replacement therapy. Magnetic resonance imaging revealed unilateral subcapsular hemorrhagic cysts in the left kidney, with nearly normal renal size. A percutaneous biopsy of the right kidney showed acute tubular necrosis and focal segmental glomerulosclerosis, tip lesion variant. The patient achieved complete remission shortly after initiating immunosuppressive therapy, with full recovery of renal function. Whole exome sequencing did not reveal any pathogenic variants. A 99Tcm-DMSA scintigraphy, performed 20 months after the initial presentation, showed a renal uptake of 11.3% (reference range: 30 ± 6%) in the affected kidney, with normal uptake in the right kidney.

Conclusion: MUCH cysts in the left kidney, observed in young adults, may represent a novel clinical entity. However, the epidemiology, etiology, clinical implications, and prognosis of this condition remain to be fully elucidated.

Introduction: Atypical hemolytic uremic syndrome (aHUS) is a rare and potentially life-threatening condition, often linked to dysregulation of the complement system.

Case presentation: In this study, a novel heterozygous CFB mutation was identified in both the index patient and her sister, who both developed aHUS following respiratory infections. While the index patient succumbed to the condition, her sister achieved remission following treatment with eculizumab. Interestingly, other family members carrying the mutation remained asymptomatic, illustrating intrafamilial variability.

Conclusion: This study provides valuable insights for genetic counseling, prenatal diagnosis, and potential therapeutic strategies for aHUS patients with CFB mutations.

Introduction: Mutations of the OFD1 gene cause oral-facial-digital syndrome type 1 (OFD 1) and variations of the related ciliopathies Joubert syndrome and primary ciliary dyskinesia. OFD 1 manifests with skeletal, CNS, and renal abnormalities with prevalence estimated between 1 in 50,000 and 1 in 250,000. Cilia help regulate responses to mechanical forces in the renal tubules, and polycystic kidney disease (PKD) resulting from defective cilia is the primary determinant of morbidity in OFD 1. PKD associated with OFD 1 is rare before adulthood but may increase markedly with age, progressing to end-stage renal disease (ESRD) in 80% of cases.

Case presentation: We report an 18-year-old female with congenital ciliopathy presenting with declining renal function and an increase of serum creatinine to 1.7 mg/dL. A 24-h urine collection yielded 0.8 g of creatinine and 500 mg of total protein. Imaging was conducted and genetic studies were repeated as her early childhood results were not available. MRI revealed numerous bilateral renal cysts consistent with progression of ciliopathy-associated PKD. Genetic testing confirmed the presence of a novel c.1332del frameshift mutation in the OFD1 gene, prematurely truncating the OFD1 protein. Modifications to diet and hydration to preserve renal function and delay progression to ESRD were initiated.

Conclusion: This case of unusually early renal decline highlights the challenge of treating OFD 1. There are no currently approved medications and management consists of supportive measures to delay progression. Further research to better characterize and identify treatments for OFD 1 and related ciliopathies is warranted.

Introduction: Plasma cell rich-acute rejection (PCAR) is a variant of T-cell-mediated rejection in kidney transplantation. Its pathogenesis remains unknown and it is often refractory to standard immunosuppression strategies, possibly leading to allograft loss. Here, we report a case of chronic active T-cell-mediated rejection caused by PCAR 12 years after kidney transplantation.

Case presentation: A patient first visited our outpatient clinic with hematuria and proteinuria at the age of 23. He was followed as an outpatient for suspected chronic glomerulonephritis, but his kidney function gradually deteriorated and hemodialysis was initiated at age 50. ABO-compatible kidney transplantation was performed at 51. His graft function was stable for 11 years post-transplant with a serum level of creatinine of 1.5 mg/dL. Twelve years post-transplant, however, his graft function worsened to a creatinine level of 3.2 mg/dL, and he was admitted to our hospital for an allograft biopsy. The histopathology showed edematous lesions with massive tubulointerstitial plasma cell infiltration, and severe tubulitis, consistent with chronic active T-cell-mediated rejection type 1B according to the Banff classification 2019. He was treated with steroid pulse therapy (methylprednisolone 1,000 mg for 3 consecutive days), and his graft function improved to a creatinine level of 2.2 mg/dL. A repeat allograft biopsy 3 months after the steroid therapy showed improved interstitial edema and tubulitis.

Conclusion: As suggested in this case, it is still possible to achieve a favorable response by initiating appropriate treatment in early stages of PCAR.

Introduction: Post-streptococcal acute glomerulonephritis (PSAGN) is a disease in which patients develop hematuria and leg edema following streptococcal infection, which may lead to acute nephritic syndrome and nephrotic syndrome. We present a case involving acute kidney injury and nephrotic syndrome with nonspecific pathological findings for PSAGN, which posed diagnostic challenges.

Case presentation: A 25-year-old man presented with leg edema, cough, nephrotic syndrome, severe kidney dysfunction, and hematuria. Blood tests showed elevated antistreptolysin O levels and decreased complement C3 levels; therefore, PSAGN was suspected. Light microscopy revealed membranoproliferative glomerulonephritis, immunofluorescence staining revealed a full-house pattern, and electron microscopy revealed subendothelial deposition. The diagnosis was difficult, however, positive glomerular staining for nephritis-associated plasmin receptor and plasmin activity strongly suggested an infection-related etiology of glomerulonephritis. Treatment included the administration of 500 mg of methylprednisolone for 3 days, followed by 4 weeks of treatment with 50 mg of prednisolone. Subsequently, the dosage was reduced to 40 mg, and the patient was discharged. Urinary findings revealed resolution of hematuria 1 year after discharge.

Conclusion: When PSAGN is suspected and other diseases are difficult to exclude, nephritis-associated plasmin receptor staining should be considered.

Introduction: Hypokalemia in pregnancy is usually attributed to benign causes, yet persistent hypokalemia with hypertension raises concerns for rare renal potassium-wasting disorders. Among these, Geller syndrome, a rare mineralocorticoid receptor mutation that can be activated by progesterone, can precipitate severe hypokalemia and hypertension unique to pregnancy due to heightened receptor sensitivity. This case underscores the need to recognize and systematically evaluate potassium-wasting syndromes in pregnancy to optimize outcomes and inform clinical decision-making.

Case presentation: We present a 33-year-old woman, G6P2, at 21w6d of gestation, presented with abdominal pain, marked hypokalemia (2.6 mEq/L), and systolic blood pressures in the 150s. She reported no previous history of hypertension or diuretic use and had no significant family history. Initial assessment excluded common etiologies, such as preeclampsia, prompting an expanded renal workup. Laboratory findings revealed profound renal potassium-wasting, evidenced by a trans-tubular potassium gradient of 11 and a urine potassium-to-creatinine ratio of 45, alongside low aldosterone levels, normal cortisol, and thyroid function. She experienced persistent hypokalemia despite aggressive repletion which led to suspicion of Geller syndrome. Continued potassium supplementation, dietary guidance, and fetal delivery eventually led to stable potassium levels.

Conclusion: This case highlights the diagnostic complexities of addressing refractory hypokalemia and hypertension in pregnancy, advocating for the consideration of rare etiologies like Geller syndrome. Although negative in this instance, the suspicion of Geller syndrome informed a meticulous diagnostic approach, underscoring the importance of a comprehensive evaluation and genetic counseling in similar presentations. Such awareness can enhance clinicians' diagnostic frameworks, equipping them to identify and manage rare syndromes if needed. By expanding the differential diagnosis for persistent hypokalemia and hypertension in pregnancy, this case underscores the potential for improved maternal-fetal outcomes through informed and targeted management strategies.

Introduction: Whooping cough (pertussis) is an acute respiratory infection primarily caused by Bordetella pertussis, which predominantly affects children. While the disease commonly presents with upper respiratory symptoms, it can lead to severe complications such as pneumonia, encephalopathy, and even death. The association between respiratory infections and renal injury, specifically acute interstitial nephritis (AIN), remains poorly understood. This report describes a rare case of AIN in a patient with whooping cough.

Case presentations: A 73-year-old male with a history of systemic arterial hypertension, dyslipidemia, and previous left nephrectomy presented with a 5-day history of fatigue, fever, cough, and nasal obstruction. Initial laboratory findings revealed mild leukocytosis and significantly elevated serum creatinine (5.17 mg/dL), with urinalysis showing leukocyturia and proteinuria. A respiratory infection panel confirmed B. pertussis, and the patient was treated with azithromycin. Despite improvement in respiratory symptoms, renal function remained impaired. Renal biopsy revealed moderate tubulointerstitial nephritis, and the patient was treated with prednisone, leading to gradual recovery of renal function, with serum creatinine decreasing to 2.3 mg/dL at discharge and 1.85 mg/dL 3 weeks later.

Conclusion: This case highlights the potential renal complications of whooping cough, specifically AIN, a rarely reported association. Although respiratory infections such as pertussis are well known for pulmonary involvement, clinicians should be aware of the possibility of concurrent renal injury. Prompt recognition and appropriate treatment, including corticosteroids in the case of AIN, can lead to significant improvement in renal function. Further research is needed to better understand the mechanisms by which B. pertussis may cause renal damage.

Introduction: Immunotherapy has significantly changed the landscape of cancer treatment, yet it can lead to immune-related adverse events, including renal complications. This report highlights a unique case of tubular injury associated with pembrolizumab in a patient with malignant melanoma.

Case presentation: A 42-year-old female patient with malignant melanoma received adjuvant pembrolizumab treatment. Three months later, she presented with profound weakness, myalgia, abdominal pain, polyuria, and thirst. Laboratory tests revealed acute kidney injury, significant proteinuria, renal tubular acidosis (RTA) with severe electrolyte imbalances, and nephrogenic diabetes insipidus (NDI). Management involved withholding pembrolizumab, initiating high-dose prednisone therapy, and correcting hypokalemia and metabolic acidosis. The patient showed rapid clinical improvement, with normalization of renal function and symptom resolution, allowing for discharge within a week. A follow-up visit confirmed no residual renal impairment.

Conclusion: This case emphasizes the importance of recognizing renal complications in patients undergoing treatment with immune checkpoint inhibitors. Awareness of potential adverse effects such as RTA and NDI is crucial for prompt identification and management to prevent lasting damage.

Introduction: Managing active lupus nephritis (LN) in the presence of latent tuberculosis (TB) presents a significant treatment challenge. Traditional treatment with glucocorticoids combined with mycophenolic acid carries a high risk of triggering pulmonary TB infection in LN patients. In this report, we discuss a novel approach using belimumab in combination with rapidly tapering corticosteroids to treat a patient with active class IV and V LN and latent TB.

Case presentation: A 24-year-old Chinese male was diagnosed with active class IV and V LN and latent TB. He underwent induction therapy with a combination of belimumab, rapidly tapering methylprednisolone and mycophenolate mofetil. After 18 months of belimumab therapy, the patient's blood albumin levels and kidney function normalized, with 24-h urinary protein levels stabilizing between 500 mg and 725 mg. Notably, there was no recurrence of TB.

Conclusion: This case demonstrates that the combination of belimumab and rapid corticosteroid tapering effectively reduced the duration of high-dose glucocorticoid therapy, highlighting the efficacy and safety of belimumab in managing LN with latent TB.

Introduction: Light chain-mediated acute tubulointerstitial nephritis (LCTIN) is a rare and underrecognized renal manifestation of plasma cell dyscrasias, including multiple myeloma. It presents as a dense interstitial inflammatory infiltrate involving polyclonal lymphocytes and plasma cells, often mimicking other forms of tubulointerstitial nephritis and delaying the correct diagnosis.

Case presentation: A 46-year-old man was initially managed as having drug-induced acute interstitial nephritis due to NSAID use, responding only transiently to steroids. Upon relapse with worsening kidney function, hypercalcemia, and systemic symptoms, a second kidney biopsy demonstrated again an intense tubulointerstitial infiltrate and κ-light chain proximal tubulopathy.

Conclusion: This case illustrates that LCTIN can mimic relapsing interstitial nephritis. Early recognition and appropriate plasma cell-targeted therapy may significantly improve renal outcomes and guide clinical management.