Clinical Nephrology. Case Studies最新文献

Dense deposit disease (DDD), a subtype of complement component 3 (C3) glomerulopathy (C3G), results from alternative complement pathway hyperactivity leading to membrane attack complex formation. DDD treatment strategies are limited. We report a case of a 13-year-old girl diagnosed with DDD at 9 years of age, with nephritic and nephrotic syndrome and C3 nephritic factor-negative alternative complement pathway activation. Initial treatment with prednisolone, methylprednisolone pulses (MPs), and mizoribines was effective for 3 years, after which she relapsed. Despite MP treatment followed by prednisolone and mycophenolate mofetil (MMF), her kidney function and proteinuria deteriorated with a high soluble (s)C5b-9 level; she also developed dyspnea and pleural effusion (PE). Three days after the first eculizumab (ECZ) infusion, urine volume increased, respiratory condition improved, PE resolved, and proteinuria decreased in 1 month. Serum creatinine level decreased, and kidney function completely normalized within 7 weeks. The sC5b-9 level normalized, and although proteinuria decreased, nephrotic range proteinuria persisted during ECZ treatment with MMF for 53 weeks, even with increased treatment interval. Thus, complement activation pathway-targeted therapy may be useful for rapidly progressing DDD. Our data support the role of complement pathway abnormalities in C3G with DDD.

Hypercalcemia is a common electrolyte disorder and is typically caused by parathyroid-dependent and parathyroid-independent causes. The most common parathyroid-independent causes include malignancy, granulomatous diseases, over-supplementation with calcium, and hypervitaminosis D. We present an unusual case of a woman who had Stimulan implanted after an artificial knee joint infection. When a washout was done, the patient's serum calcium started rising, peaking at an astounding 21.2 mg/dL (normal range 8.4 - 10.2 mg/dL) with acute kidney injury. After aggressive hydration and treatment with furosemide, bisphosphonates, and calcitonin, the serum calcium dropped to 10.1 mg/dL. A full hypercalcemia workup did not reveal an alternate cause. On further investigation, it was found that Stimulan is calcium based, and the agitation of these beads during washout was hypothesized to result in the observed profound hypercalcemia.

Dent disease is an inherited proximal renal tubulopathy leading to low molecular weight proteinuria, hypercalciuria with nephrocalcinosis and nephrolithiasis, and progressive renal failure. Two genetic mutations have been identified. The disease usually presents in childhood or early adult life and may be associated with other proximal tubular defects, which can lead to significant morbidity, especially in children. The disorder can extend to interstitial and glomerular cells, which contributes to progression to end-stage kidney disease. The pathophysiologic process remains incompletely understood, and no specific treatment is available. Dent disease is likely under-recognized. It needs to be included in the differential, especially in young males, presenting with recurrent kidney stones, proteinuria, and impaired renal function.

Longstanding, severe hyperparathyroidism (HPT) can lead to the formation of "brown tumors". A brown tumor is a radiolucent bone lesion that is locally destructive; it is not a neoplasm, but rather a stromal mass consisting of fibrous tissue, poorly mineralized woven bone, and supporting vasculature. These tumors are a rare complication of advanced primary or secondary HPT. We present a young female with chronic kidney disease (CKD) on hemodialysis with uncontrolled secondary HPT (SHPT). The patient presented with progressive lower extremity weakness and back pain. CT imaging showed multiple lytic bone lesions involving several ribs and the spine. Subsequent MRI imaging of the thoracic and lumbar spine confirmed expansile bone lesions consistent with brown tumors. One mass protruded into the spinal canal causing severe stenosis at T3 with underlying cord edema. The other lesion at T12 caused only moderate spinal canal stenosis. Our patient underwent urgent neurosurgical resection of the tumor at T3 followed by subtotal parathyroidectomy (PTX).

Particularly large acetaminophen overdoses, termed massive, create a therapeutic challenge given the standardized, N-acetylcysteine-based treatment. One consideration in addition to N-acetylcysteine is the initiation of hemodialysis due to the dialyzable nature of acetaminophen, though encumbered by the concurrent removal of the antidote, N-acetylcysteine. Such cases of large acetaminophen overdose, along with possible concomitant ingestions of other drugs or inactive ingredients, can be complicated by challenging-to-interpret clinical signs and laboratory findings. We describe a case of a 46-year-old man for whom we were consulted regarding consideration of dialysis treatment 7 hours after ingestion of 125 g of acetaminophen. The patient developed multiple early signs and laboratory findings consistent with a significant acetaminophen overdose. He also developed a rarely described, likely acetaminophen-interference-induced laboratory abnormality. Finally, he possibly had toxicity from an "inactive" ingredient. He was treated with a single session of prolonged hemodialysis (9.5 hours) and increased dosing of N-acetylcysteine with a positive outcome. Herein, we discuss the decision making and interpretation of clinical data pertaining to dialysis treatment and other therapies after a massive acetaminophen overdose.

Background: Alemtuzumab can induce secondary autoimmunity affecting multiple organs. While kidney involvement is uncommon, it can be associated with devastating forms of glomerulonephritis (GN).

Case presentation: A 32-year-old African American woman presented with hypertension, proteinuria, and progressive renal failure. Her medical history was remarkable for secondary progressive multiple sclerosis (SPMS). She had received her first induction dose of alemtuzumab 1 year prior to presentation. Upon evaluation, she had scanning speech, multidirectional nystagmus, and mild edema. Her serum creatinine was 2 mg/dL. Urine studies revealed proteinuria and microscopic hematuria. Her serologic tests were positive for c-antineutrophil cytoplasmic antibodies (> 1 : 640). In addition, she was found to have new-onset severe thyroid dysfunction with antibodies against thyroglobulin and thyroid peroxidase. Kidney biopsy was diagnostic for pauci-immune crescentic GN. The patient was treated with methylprednisolone and rituximab with subsequent renal, thyroid, and neurological recovery.

Conclusion: This is an atypical case of GN following therapy with alemtuzumab. We hypothesize that immune reconstitution may be a potential mechanism. Alemtuzumab is a new treatment for SPMS that can be associated with GN. Practice guidelines should address the management of its renal complications.

There are few studies reporting diffuse alveolar hemorrhage (DAH) caused by hypertensive emergency. We describe a 41-year-old man who visited the emergency room with hemoptysis and dyspnea. He had a 5-year history of hypertension, though he had not received any treatment. His blood pressure was 233/159 mmHg, his percutaneous oxygen saturation level was 88% on room air, and he had a serum creatinine level of 11.7 mg/dL. Laboratory data showed microangiopathic hemolytic anemia, thrombocytopenia, and severe kidney damage, suggesting thrombotic microangiopathy (TMA). Chest computed tomography and bronchoalveolar lavage revealed pulmonary alveolar hemorrhage. In addition to steroid treatment and plasma exchange, antihypertensive therapy was started immediately. On day 3, activity of a disintegrin and metalloproteinase with thrombospondin type 1 motif, member 13 (ADAMTS13) activity was not significantly reduced, and clinical markers for vasculitis and connective tissue disease were negative. Therefore, steroid administration and plasma exchange were discontinued. Although antihypertensive therapy centering on angiotensin II receptor blocker was effective for DAH and TMA, renal function did not recover, and maintenance hemodialysis was required. Renal pathological findings were consistent with malignant nephrosclerosis, and features suggestive of vasculitis were not found. The pathophysiology in this case was considered to be mainly hypertension and vascular endothelial injury with renin-angiotensin-aldosterone system (RAAS) activation. The use of RAAS inhibitor was effective in converging DAH and TMA, and it was expected to repair vascular endothelial damage associated with appropriate antihypertensive intervention. The authors present this rare condition with a review of previous reports.

Background: Children with nephrotic syndrome are vulnerable to developing infections due to a state of relative immunodeficiency, malnourishment, and use of immunosuppression. Case characteristics: We herein report the case of a 3-year-old child with steroid-dependent nephrotic syndrome who presented to us with fever of unknown origin.

Observation: The child was found to have an atypical mixed infection with mycoplasma and cytomegalovirus.

Outcome: The infection completely resolved with appropriate treatment and lowering of immunosuppression. Message: Persistently febrile pediatric patients, especially in the setting of recent immunosuppression and absence of otherwise-identified infectious pathogens, should be screened for atypical mixed infections.

Collapsing glomerulopathy (CG) is a severe form of glomerulopathy which results in nephrotic syndrome and often ensues in rapid progression to end-stage kidney disease (ESKD). Although most commonly a result of HIV infection, other conditions such as parvovirus B19 (PB19) infection have been associated with CG. We present a case of an 18-year-old male with CG associated with PB19 infection who was heterozygous for APOL1 G1 and G2 genetic variants. In an attempt to treat, he was started on intravenous immunoglobulin (IVIg), however rapidly progressed to ESKD. During workup for a living donor kidney transplant he was found to have persistent low-grade PB19 viremia. Despite having no major immunodeficiency and given subsequent courses of IVIg, viremia continued to persist. In a final attempt to eradicate the PB19 we began treatment with cidofovir, an antiviral agent with in vitro efficacy against PB19. Subsequent to initiation of cidofovir, PB19 viremia slowly cleared after which he received a living unrelated kidney transplant. The patient had an early cellular rejection treated with rabbit antithymocyte globulin after which he recovered kidney function without signs of recurrent CG. Our case report suggests efficacy of IVIg and cidofovir for persistent PB19 infection in ESKD to allow subsequent transplantation, while minimizing the risk of recurrent CG.