Clinical Nephrology. Case Studies最新文献

Primary Sjögren's syndrome (pSS) is a complex, multisystem autoimmune disorder. It is characterized by lymphocytic infiltration of the exocrine glands. In the setting of pSS, the presence of systemic disease is an important prognostic determinant, but involvement of the kidney is uncommon. The triad of pSS, distal renal tubular acidosis (dRTA), and central pontine myelinolysis (CPM) is rare and potentially fatal. A 42-year-old woman presented with dRTA, profound hypokalemia, and CPM characterized by progressive global quadriparesis, ophthalmoplegia, and encephalopathy. Sjögren's syndrome was diagnosed based on sicca symptoms, clinical features, and strongly positive anti-SSA/Ro and anti-SSB/La autoantibodies. The patient responded well to electrolyte replacement, acid-base correction, corticosteroids, and subsequent cyclophosphamide therapy. Early recognition and appropriate treatment resulted in good kidney and neurological outcomes in this case. This report highlights the need to consider the diagnosis of pSS in unexplained dRTA and CPM, as it has a favorable prognosis if recognized and managed timeously.

Renal vein thrombosis (RVT), defined as the presence of a thrombus in the major renal vein or one of its tributaries, can present acutely or go unnoticed resulting in acute kidney injury or chronic kidney disease. RVT is associated with multiple etiologies, including nephrotic syndrome, thrombophilia, autoimmune disorders, and malignancy. Patients with systemic lupus erythematosus (SLE), a multiorgan autoimmune disorder, are predisposed to coagulopathy and thus are at a higher risk of venous and arterial thromboembolism. We describe the case of a 41-year-old man with SLE and biopsy-proven membranous glomerulonephritis (WHO class V lupus nephritis) in clinical remission with no evidence of nephrotic range proteinuria who presented with macroscopic hematuria and was diagnosed with acute-on-chronic bilateral RVT. We discuss the different causes of RVT and compare the clinical presentation, diagnostic imaging findings, and management of acute and chronic RVT.

Agromyces mediolanus is a catalase-positive gram-positive rod typically found in the soil and not commonly known to be pathogenic. We present a rare case of Agromyces mediolanus bacteremia with aortic valve endocarditis in a patient who required prolonged inpatient care with a tunneled dialysis catheter for renal replacement therapy (RRT). Infection is the second leading cause of mortality among patients with end-stage renal disease and vascular access. The incidence of bacteremia is higher in patients with indwelling tunneled catheters than in those with an arteriovenous fistula or graft. The most critical risk factor is its prolonged use. Anticipation of the need for long-term definitive renal replacement therapy and planning for the best approach is crucial in preventing catheter-related bloodstream infections (CRBSIs). Human infections caused by Agromyces mediolanus are rare; it has been reported twice, and both cases were associated with prolonged use of catheters, not only parenteral catheter but also peritoneal catheter, which is of special importance for patients with end-stage renal disease (ESRD). Limited data is available for the appropriate antibiotic therapy.

The term COVAN (COVID-19-associated nephropathy) has been used to describe collapsing focal segmental glomerulosclerosis (FSGS) in individuals who have been infected with the SARS-CoV-2. This helps differentiate it from the majority of cases of acute kidney injury in COVID-19 patients, which are typically caused by acute tubular injury. The exact pathophysiology is unclear but is proposed to involve pro-inflammatory cytokines such as type 1 interferons, which are thought to increase expression of the APOL1 gene in glomerular epithelial cells. This triggers a cascade of inflammatory events that cause damage to the epithelia and underlying podocytes. The treatment of COVAN is centered on general supportive measures including dietary sodium restriction, optimization of hyperlipidemia and hypertension, RAAS blockade, and diuresis for edema. There is limited data to support the use of glucocorticoids in COVAN; however, the mechanism of podocytopathy is similar to that in HIVAN (HIV-associated nephropathy), with high disease burden in those with APOL1 gene mutation. Based on previous experience, treatment of HIVAN with glucocorticoids is beneficial and safe in selected patients. Here we present a case of COVAN which was successfully treated with glucocorticoids, and at 22-month follow-up patient remained in full remission (proteinuria < 1,000 mg/g) with stable kidney function.

Kidney function may be impaired during pregnancy due to various reasons, and the physiological changes of pregnancy may unmask or worsen pre-existing kidney disease. Herein, we report a pregnant patient presenting with nephrotic-range proteinuria. She later developed acute kidney injury and pre-eclampsia. However, hemolytic anemia and thrombocytopenia persisted after delivery, and she was diagnosed with atypical hemolytic uremic syndrome (aHUS). Although hematological abnormalities resolved with eculizumab treatment, her renal functions did not improve. Kidney biopsy showed crescentic glomerulonephritis without thrombotic microangiopathy features. Concurrently, she was evaluated for hearing impairment, and a diagnosis of Alport syndrome was confirmed with genetic testing. Kidney function may worsen in patients with Alport syndrome during pregnancy. However, crescentic glomerulonephritis (GN) is a rare finding in Alport disease. Pauci-immune crescentic GN has been shown to be related to dysregulated activation of the alternative complement pathway, which is also the underlying pathophysiological mechanism in aHUS.

Introduction: Starvation ketoacidosis (SKA) is a rare cause of ketoacidosis in the general population but can be seen with malignancy. Patients often respond well to treatment, but some rarely develop refeeding syndrome (RFS) as their electrolytes drop to dangerous levels causing organ failure. Typically, RFS can be managed with low-calorie feeds, but sometimes patients require a halt in feeds until their electrolyte imbalances are managed.

Case report: We discuss a woman with synovial sarcoma on chemotherapy who was diagnosed with SKA and then developed severe RFS after treatment with intravenous dextrose. Phosphorus, potassium, and magnesium levels dropped precipitously and remained fluctuant for 6 days. She also developed normal sinus ventricular tachycardia, premature ventricular beats, and bigeminy. She could not tolerate calorie supplementation at that time. She was managed with electrolyte repletions until clinically stable and then progressed to a liquid diet.

Discussion: We present a unique case of severe SKA that resulted in RFS requiring nihil per orem (NPO) treatment for 6 days. There are no specific guidelines for SKA or RFS management. Patients with pH < 7.3 may benefit from baseline serum phosphorus, potassium, and magnesium levels. Clinical trials are needed to further study which patients may benefit from starting at a low-calorie intake versus those that require holding nutrition until clinically stable.

Conclusion: Completely stopping caloric intake until a patient's electrolyte imbalance improves is an important management aspect of RFS to underscore and study, as grave complications can occur even with cautious refeeding regimens.

Background: Among different forms of de novo focal segmental glomerulosclerosis (FSGS), which can develop after kidney transplantation (KTx), collapsing glomerulopathy (CG) is the least frequent variant, but it is associated with the most severe form of nephrotic syndrome, histological findings of important vascular damage, and a 50% risk of graft loss. Here, we report two cases of de novo post-transplant CG.

Clinical presentation: A 64-year-old White man developed proteinuria and worsening of renal function 5 years after KTx. Before the KTx, the patient was affected by an uncontrolled resistant hypertension, despite multiple antihypertensive therapies. Blood levels of calcineurin inhibitors (CNIs) were stable, with intermittent peaks. Kidney biopsy showed the presence of CG. After introduction of angiotensin receptor blockers (ARBs), urinary protein excretion progressively decreased in 6 months, but subsequent follow-up confirmed a progressive renal function decline. A 61-year-old White man developed CG 22 years after KTx. In his medical history, he was hospitalized twice to manage uncontrolled hypertensive crises. In the past, basal serum cyclosporin A levels were often detected above the therapeutic range. Low doses of intravenous methylprednisolone were administered due to the histological inflammatory signs shown on renal biopsy, followed by a rituximab infusion as a rescue therapy, but no clinical improvement was seen.

Discussion and conclusion: These two cases of de novo post-transplant CG were supposed to be mainly caused by the synergic effect of metabolic factors and CNI nephrotoxicity. Identifying the etiological factors potentially responsible for de novo CG development is essential for an early therapeutic intervention and the hope of better graft and overall survival.

Introduction: Malignant hypertension (mHTN) damages multiple target organs, including the kidneys. mHTN has been regarded as one of the causes of secondary thrombotic microangiopathy (TMA); however, a high prevalence of complement gene abnormalities was recently reported in cohorts of mHTN.

Case report: We herein describe a 47-year-old male who presented with severe hypertension, renal failure (serum creatinine (sCr): 11.6 mg/dL), heart failure, retinal hemorrhage, hemolytic anemia, and thrombocytopenia. Renal biopsy findings were consistent with acute hypertensive nephrosclerosis. The patient was diagnosed with secondary TMA associated with mHTN. However, his previous medical history of TMA of unknown origin and family history of atypical hemolytic uremic syndrome (aHUS) suggested as aHUS presenting mHTN, and genetic testing revealed a pathogenic C3 mutation (p.I1157T). The patient required plasma exchange and hemodialysis for 2 weeks and was able to withdraw from dialysis by antihypertensive therapy without eculizumab. Renal function gradually improved to a sCr level of 2.7 mg/dL under antihypertensive therapy for 2 years after the event. There was no recurrence, and renal function was preserved throughout a 3-year follow-up.

Discussion: mHTN is a common presentation of aHUS. In cases of mHTN, abnormalities in complement-related genes may be involved in the development of the disease.

A 72-year-old female was admitted with severe calciphylaxis-associated bilateral leg pain on a background of end-stage renal failure on hemodialysis. Palliative care input was requested, and following transfer to our unit she was commenced on low-dose methadone as adjunctive analgesic therapy. A remarkable and sustained analgesic response was observed. Calciphylaxis is associated with severe pain, and careful consideration of analgesic agents and their pharmacokinetics in patients with end-stage renal failure is required.

Sinomenine (SIN), the alkaloid monomer extracted from Sinomenium acutum, is a kind of non-steroidal anti-inflammatory drug widely used in China to treat rheumatoid arthritis (RA) and various glomerular diseases. It has various pharmacological effects such as anti-inflammatory, analgesic, and anti-tumor. As a strong histamine-releasing agent, SIN has drawn increasing attention in regards to its side effects such as allergic, gastrointestinal, and circulatory systemic reactions. In this report, we first described a patient with primary membranous nephropathy (PMN) who was treated with oral intake of SIN and developed medicine-induced toxic epidermal necrolysis (TEN) and subsequently died of septic multi-organ failure. The present case report intends to demonstrate the underestimated side effects of SIN that can eventually lead to death.