Clinical Nephrology. Case Studies最新文献

Familial hypomagnesemia with hypercalciuria and nephrocalcinosis (FHHNC) is an autosomal recessive tubular disorder caused by mutations in genes that encode renal tight junction proteins claudin-16 or claudin-19, which are responsible for magnesium and calcium paracellular reabsorption in the thick ascending limb of Henle's loop. Progressive renal failure is frequently present, and most of the patients require renal replacement therapy still during adolescence. In this case report, we describe a new homozygous missense mutation on CLDN16 gene (c.592G>C, Gly198Arg) in a 24-year-old male patient diagnosed with FHHNC after clinical investigation due to incidental detection of altered routine laboratorial tests, who was firstly misdiagnosed with primary hyperparathyroidism. In addition, it illustrates an atypical presentation of this disease, with late onset of chronic kidney disease, improving the phenotype-genotype knowledge of patients with FHHNC.

Here we report a fatal case of antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) due to methimazole use in a 64-year-old woman. She was initially hospitalized for abdominal pain and possible colitis, and subsequently developed hematuria, renal failure, and hemoptysis. The serologic work-up revealed positive antinuclear antibody (ANA) and perinuclear-antineutrophilic cytoplasm antibodies (p-ANCA), with positive antimyeloperoxidase. Three weeks following admission, the patient was found to be pulseless, and expired. At autopsy, microscopic review included widespread transmural necrotizing vasculitis and crescentic glomerulonephritis in the kidney, and diffuse pulmonary alveolar hemorrhage; focal coronary artery intimal vasculitis and necrotizing pericarditis were also noted. Several drugs have been associated with the development of ANCA-positive diseases, including propylthiouracil, hydralazine, allopurinol, penicillamine, and levamisole in cocaine. Association of ANCA vasculitis with methimazole exposure is less known, and severe presentation with fatal outcome, as seen in our patient, is exceedingly rare. We reviewed clinical and histopathologic features of drug-induced ANCA vasculitis associated with methimazole to raise awareness of this potentially life-threatening complication associated with this agent.

Introduction: Many techniques are available for inserting peritoneal dialysis (PD) or continuous ambulatory peritoneal dialysis (CAPD) catheters, with varying possible complications. We report a case of bladder perforation that was managed with catheter salvage.

Case report: A 48-year-old man with end-stage renal disease (ESRD) underwent CAPD catheter placement percutaneously, with tip in the pelvis. On the 3^rd day after placement, the patient complained of increase in urinary volume with PD flushing. Urine analysis showed 3(+) glucose and absent creatinine. Cystogram showed the catheter abutting the bladder wall. CT of the abdomen showed the catheter piercing the bladder and exiting through the posterior wall. The PD catheter was repositioned under fluoroscopy.

Discussion: The complications surrounding insertion of CAPD catheter can be either mechanical or infectious. Peritoneo-vesical fistula or placement of the PD catheter into the urinary bladder is a very rare complication. The possibility of catheter salvage should be entertained while discussing management options.

Background: Restless legs syndrome (RLS) is not a rare condition in patients on long-term dialysis. Pramipexole is a small molecule used in the treatment of idiopathic and uremic RLS. Although some information concerning the efficacy and safety of pramipexole in uremic patients is available, data concerning the pharmacokinetics of pramipexole in hemodialysis (HD) are lacking. Following the occurrence of accidental pramipexole intoxication in a chronic HD patient, we were concerned about the efficacy of HD in removing pramipexole. Our aim was thus to assess plasma pramipexole concentrations and pramipexole clearance in a stable chronic HD patient without any residual kidney function.

Materials and methods: Our patient was a 63-year-old man on chronic HD for 5 years who had been treated uneventfully with oral pramipexole for uremic RLS since then. During a routine 4-hour high-flux HD session, blood, ultrafiltrate, and dialysate samples were collected every hour to determine pramipexole concentrations over time.

Results: Pramipexole blood concentrations ranged from 12.1 to 23.9 µg/L. Pramipexole reduction ratio was 32.5%. Mean dialytic clearance of pramipexole was 76.8 mL/min. Postdialysis rebound was 5.6%.

Conclusion: In the absence of any side effect, pramipexole blood concentrations at steady state were 2- to 4-fold higher than those observed in subjects with normal kidney function. Like other drugs with a high volume of distribution, pramipexole was poorly removed by HD. Therefore, HD is not recommended as a treatment option for pramipexole intoxication in patients with a glomerular filtration rate superior to 30 mL/min/1.73m².

Refractory ascites as the only presenting feature of an extramedullary plasmacytoma complicating end-stage renal disease and HIV infection has not been described yet. We describe a case of a 39-year-old female with HIV-associated nephropathy manifesting with ascites formation after transition from peritoneal dialysis (PD) to hemodialysis (HD). Earlier on, she received cycler-assisted PD for 5 years uneventfully. A few weeks after HD transition, a striking refractory ascites developed requiring multiple paracenteses (5 - 7 L every second week). Serum protein electrophoresis showed hypoalbuminemia with only small amount of monoclonal IgG-κ at 0.30 g/dL. Serum immunofixation electrophoresis showed polyclonal immunoglobulins with polyclonal light chains. Both κ and λ light chains were increased, at 66.86 mg/dL (reference range: 0.33 - 1.94) and 18.55 mg/dL (reference range: 0.57 - 2.63), respectively, with a ratio of 3.6 (reference range: 0.26 - 1.65). However, an ascitic fluid analysis showed a marked increase in plasma cells with a κ : λ ratio greater than 5 : 1. Omental biopsy confirmed κ-restricted plasma cells. Multiple myeloma work-up with skeletal survey showed no evidence of focal osseous lesions, while bone marrow aspiration and biopsy also remained unremarkable. Accordingly, the diagnosis of omental extramedullary plasmacytoma with malignant ascites was confirmed. Conversion from PD to HD may unmask an underlying pathology favoring ascites formation.

Background: Anti-glomerular basement membrane (GBM) disease is caused by autoantibodies against the α3-chain of type IV collagen in the GBM. Common variable immunodeficiency (CVID) is a primary immunodeficiency manifested by hypogammaglobulinemia, inability to make functional antibody, and recurrent infections. This report extends the phenotype of CVID-associated autoimmune diseases to include anti-GBM disease.

Case presentation: A 15-year-old Caucasian female with prior normal renal function presented with nephrotic proteinuria, pedal edema, oliguria, acute kidney injury, and was found to have positive serum anti-GBM antibody. She had been diagnosed with CVID at 3 years of age. Her renal biopsy showed crescentic glomerulonephritis (50%), and immunofluorescence showed linear staining for IgG along the glomerular capillary wall. There was no clinical or imaging evidence of pulmonary hemorrhage. She was treated with pulse IV steroids, cyclophosphamide, rituximab, and several sessions of plasmapheresis. Her serum anti-GBM antibody level decreased from 194 U/mL at presentation to 0 U/mL after therapy. However, she progressed to end-stage renal disease (ESRD) within weeks, despite aggressive therapy, and required chronic renal replacement therapy in the form of dialysis. Her clinical course was also complicated by hypertensive encephalopathy, CMV viremia and meningoencephalitis, status epilepticus, and she passed away a few months later from lower respiratory tract complications.

Conclusion: Anti-GBM disease is a rare autoimmune condition that has not been reported in association with a primary immunodeficiency syndrome. ESRD secondary to anti-GBM disease in a patient with CVID is an interesting association and supports the role of immune dysregulation in systemic autoimmune disease.