Spectrum of renal involvement in paroxysmal nocturnal hemoglobinuria: report of three cases and a brief review of the literature

Megalin-related mechanism of hemolysis-induced acute kidney injury and the therapeutic strategy

Hemolysis-induced acute kidney injury (AKI) is attributed to heme-mediated proximal tubule epithelial cell (PTEC) injury and tubular cast formation due to intratubular protein condensation. Megalin is a multiligand endocytic receptor for proteins, peptides, and drugs in PTECs and mediates the uptake of free hemoglobin and the heme-scavenging protein α1-microglobulin. However, understanding of how megalin is involved in the development of hemolysis-induced AKI remains elusive. Here, we investigated the megalin-related pathogenesis of hemolysis-induced AKI and a therapeutic strategy using cilastatin, a megalin blocker. A phenylhydrazine-induced hemolysis model developed in kidney-specific mosaic megalin knockout (MegKO) mice confirmed megalin-dependent PTEC injury revealed by the co-expression of kidney injury molecule-1 (KIM-1). In the hemolysis model in kidney-specific conditional MegKO mice, the uptake of hemoglobin and α1-microglobulin as well as KIM-1 expression in PTECs was suppressed, but tubular cast formation was augmented, likely due to the nonselective inhibition of protein reabsorption in PTECs. Quartz crystal microbalance analysis revealed that cilastatin suppressed the binding of megalin with hemoglobin and α1-microglobulin. Cilastatin also inhibited the specific uptake of fluorescent hemoglobin by megalin-expressing rat yolk sac tumor-derived L2 cells. In a mouse model of hemolysis-induced AKI, repeated cilastatin administration suppressed PTEC injury by inhibiting the uptake of hemoglobin and α1-microglobulin and also prevented cast formation. Hemopexin, another heme-scavenging protein, was also found to be a novel ligand of megalin, and its binding to megalin and uptake by PTECs in the hemolysis model were suppressed by cilastatin. Mass spectrometry-based semiquantitative analysis of urinary proteins in cilastatin-treated C57BL/6J mice indicated that cilastatin suppressed the reabsorption of a limited number of megalin ligands in PTECs, including α1-microglobulin and hemopexin. Collectively, cilastatin-mediated selective megalin blockade is an effective therapeutic strategy to prevent both heme-mediated PTEC injury and cast formation in hemolysis-induced AKI. © 2024 The Pathological Society of Great Britain and Ireland.

Pediatric Paroxysmal Nocturnal Hemoglobinuria Presenting as Acute Kidney Injury

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare disease characterized by variable and diverse symptoms including the classic triad of hemolytic anemia, thrombosis, and bone marrow failure. It is a disorder primarily seen in the adult population. The authors report a unique case of an 8-year-old girl diagnosed with PNH after initially presenting with a febrile illness and acute kidney injury. Though rare in children, PNH should remain in the differential diagnosis of a child presenting with acute kidney injury. The disease has serious long-term complications, mandating timely diagnosis and appropriate therapy.

Complement Inhibition Therapy and Dialytic Strategies in Paroxysmal Nocturnal Hemoglobinuria: The Nephrologist's Opinion

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare clonal disease that presents an estimated incidence of 1.3 cases per million per year, with a prevalence of 15.9 cases per million. It is characterized by hemolysis, bone marrow dysfunction with peripheral blood cytopenia, hypercoagulability, thrombosis, renal impairment and arterial and pulmonary hypertension. Hemolysis and subsequent hemosiderin accumulation in tubular epithelium cells induce tubular atrophy and interstitial fibrosis. The origin of PNH is the somatic mutation in the X-linked phosphatidylinositol glycan class A (PIG-A) gene located on Xp22: this condition leads to the production of clonal blood cells with a deficiency in those surface proteins that protect against the lytic action of the activated complement system. Despite the increased knowledge of this syndrome, therapies for PNH were still only experimental and symptomatic, until the introduction of the C5 complement blockade agent Eculizumab. A second generation of anti-complement agents is currently under investigation, representing future promising therapeutic strategies for patients affected by PNH. In the case of chronic hemolysis and renal iron deposition, a multidisciplinary approach should be considered to avoid or treat acute tubular injury or acute kidney injury (AKI). New promising perspectives derive from complement inhibitors and iron chelators, as well as more invasive treatments such as immunoadsorption or the use of dedicated hemodialysis filters in the presence of AKI.

Transplantation of a Blue Kidney: A Case Report

A blue kidney, although very rare, can be encountered upon a live kidney donor. Literature has shown hemosiderin deposits, lipofuscin pigment, and melanosis as possible reasons. We report on a 37-year-old woman who wished to donate a kidney to her husband. The donor's preoperative biochemistry and imaging tests showed normal renal function. During the laparoscopic left kidney nephrectomy, the kidney was observed to be blue in color. Perioperatively, Doppler ultrasonography was used to rule out vascular reasons, and a wedge biopsy was performed. The other kidney was also explored, and it turned out to be blue as well. Histopathological analysis showed melanosis in the tubules without malignity or pathologic changes in the glomeruli, the interstitium, or the vessels. Even though some causes of blue kidney may result in impairment of the renal function, after the necessary tests show no signs of malignity and functional impairment, a blue-colored kidney may be suitable for transplantation.

Renal involvement in paroxysmal nocturnal haemoglobinuria: a brief review of the literature

SUMMARY INTRODUCTION: Paroxysmal Nocturnal Haemoglobinuria (PNH) is an acquired genetic disorder characterized by complement-mediated haemolysis, thrombosis and variable cytopenias. Renal involvement may occur and causes significant morbidity to these patients. OBJECTIVE: To review the literature about pathophysiology and provide recommendations on diagnosis and management of renal involvement in PNH. METHODS: Online research in the Medline database with compilation of the most relevant 26 studies found. RESULTS: PNH may present with acute kidney injury caused by massive haemolysis, which is usually very severe. In the chronic setting, PNH may develop insidious decline in renal function caused by tubular deposits of hemosiderin, renal micro-infarcts and interstitial fibrosis. Although hematopoietic stem cell transplantation remains the only curative treatment for PNH, the drug Eculizumab, a humanized anti-C5 monoclonal antibody is capable of improving renal function, among other outcomes, by inhibiting C5 cleavage with the subsequent inhibition of the terminal complement pathway which would ultimately give rise to the assembly of the membrane attack complex. CONCLUSION: There is a lack of information in literature regarding renal involvement in PNH, albeit it is possible to state that the pathophysiological mechanisms of acute and chronic impairment differ. Despite not being a curative therapy, Eculizumab is able to ease kidney lesions in these patients.

Acetaminophen as a Renoprotective Adjunctive Treatment in Patients With Severe and Moderately Severe Falciparum Malaria: A Randomized, Controlled, Open-Label Trial

Background

Acute kidney injury independently predicts mortality in falciparum malaria. It is unknown whether acetaminophen's capacity to inhibit plasma hemoglobin-mediated oxidation is renoprotective in severe malaria.

Methods

This phase 2, open-label, randomized controlled trial conducted at two hospitals in Bangladesh assessed effects on renal function, safety, pharmacokinetic (PK) properties and pharmacodynamic (PD) effects of acetaminophen. Febrile patients (>12 years) with severe falciparum malaria were randomly assigned to receive acetaminophen (1 g 6-hourly for 72 hours) or no acetaminophen, in addition to intravenous artesunate. Primary outcome was the proportional change in creatinine after 72 hours stratified by median plasma hemoglobin.

Results

Between 2012 and 2014, 62 patients were randomly assigned to receive acetaminophen (n = 31) or no acetaminophen (n = 31). Median (interquartile range) reduction in creatinine after 72 hours was 23% (37% to 18%) in patients assigned to acetaminophen, versus 14% (29% to 0%) in patients assigned to no acetaminophen (P = .043). This difference in reduction was 37% (48% to 22%) versus 14% (30% to -71%) in patients with hemoglobin ≥45000 ng/mL (P = .010). The proportion with progressing kidney injury was higher among controls (subdistribution hazard ratio, 3.0; 95% confidence interval, 1.1 to 8.5; P = .034). PK-PD analyses showed that higher exposure to acetaminophen increased the probability of creatinine improvement. No patient fulfilled Hy's law for hepatotoxicity.

Conclusions

In this proof-of-principle study, acetaminophen showed renoprotection without evidence of safety concerns in patients with severe falciparum malaria, particularly in those with prominent intravascular hemolysis.

Clinical Trials Registration

NCT01641289.

Maintenance of renal function in a patient with a history of acute paroxysmal nocturnal hemoglobinuria-associated kidney injury

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare, life-threatening blood disorder characterized by intravascular hemolysis, thrombosis and bone marrow failure. Acute kidney injury, including acute renal failure, have been reported in patients with PNH. We report the case of a 36-year-old male patient with PNH who developed acute kidney injury following an infection of undetermined diagnosis. Although hemolysis was initially controlled and renal function stabilized following packed red blood cell transfusion and empirical levofloxacin and prednisone, he later experienced recurrent episodes of hemolysis and hematuria requiring monthly red blood cell support. Given the high risk of thromboembolic events, treatment with standard-dose eculizumab was started. The patient's hematologic values improved, renal function was maintained, and no thromboembolic events occurred.

Renal involvement in paroxysmal nocturnal hemoglobinuria: an update on clinical features, pathophysiology and treatment

OBJECTIVES

The present review summarizes the available knowledge regarding acute and chronic kidney dysfunction in patients with paroxysmal nocturnal hemoglobinuria (PNH) focusing on its clinical features, pathophysiology and treatment.

METHODS

A thorough PubMed search was performed using as main keywords: 'paroxysmal nocturnal hemoglobinuria', 'acute kidney injury', 'chronic kidney disease' and 'eculizumab'.

RESULTS

PNH's etiopathogenesis is based on acquired mutations that lead to the reduction or absence of CD55 and CD59 complement regulators, which are responsible for some of the disease's major clinical features, like intravascular hemolysis, cytopenias and thrombosis. PNH is often underdiagnosed, mainly due to its occasional mild manifestations and to its ability to mimic other severe clinical conditions. Various mechanisms have been proposed for the kidney damage attributed to the release of cell-free heme and free iron, including inflammatory response, oxidative stress, nitric oxide depletion, renal ischemia, membrane damage and apoptosis. Eculizumab, a terminal complement inhibitor, provides a safe and effective treatment option, especially when it is initiated early in the presence of kidney damage.

DISCUSSION

Kidney injury is a poorly investigated clinical feature of PNH that affects a significant portion of patients. Increased awareness is needed by physicians to recognize the early signs and symptoms of acute and chronic renal insufficiency, so as to initiate the necessary therapy. It is also important to re-evaluation of PNH-specific treatments during the course of the disease.

CONCLUSION

Understanding the difficult but at the same time impressive mechanisms behind PNH remains a challenge for treating physicians.

Podocytes are new cellular targets of haemoglobin-mediated renal damage

Recurrent and massive intravascular haemolysis induces proteinuria, glomerulosclerosis, and progressive impairment of renal function, suggesting podocyte injury. However, the effects of haemoglobin (Hb) on podocytes remain unexplored. Our results show that cultured human podocytes or podocytes isolated from murine glomeruli bound and endocytosed Hb through the megalin-cubilin receptor system, thus resulting in increased intracellular Hb catabolism, oxidative stress, activation of the intrinsic apoptosis pathway, and altered podocyte morphology, with decreased expression of the slit diaphragm proteins nephrin and synaptopodin. Hb uptake activated nuclear factor erythroid-2-related factor 2 (Nrf2) and induced expression of the Nrf2-related antioxidant proteins haem oxygenase-1 (HO-1) and ferritin. Nrf2 activation and Hb staining was observed in podocytes of mice with intravascular haemolysis. These mice developed proteinuria and showed podocyte injury, characterized by foot process effacement, decreased synaptopodin and nephrin expression, and podocyte apoptosis. These pathological effects were enhanced in Nrf2-deficient mice, whereas Nrf2 activation with sulphoraphane protected podocytes against Hb toxicity both in vivo and in vitro. Supporting the translational significance of our findings, we observed podocyte damage and podocytes stained for Hb, HO-1, ferritin and phosphorylated Nrf2 in renal sections and urinary sediments of patients with massive intravascular haemolysis, such as atypical haemolytic uraemic syndrome and paroxysmal nocturnal haemoglobinuria. In conclusion, podocytes take up Hb both in vitro and during intravascular haemolysis, promoting oxidative stress, podocyte dysfunction, and apoptosis. Nrf2 may be a potential therapeutic target to prevent loss of renal function in patients with intravascular haemolysis. Copyright © 2017 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Acute kidney injury in a postpartum woman with paroxysmal nocturnal hemoglobinuria: A case report and literature review

Paroxysmal nocturnal hemoglobinuria is a rare clonal hematopoietic stem cell disorder characterized by intravascular hemolysis, hemoglobinuria, and inflammatory thrombotic state. Intravascular hemolysis in paroxysmal nocturnal hemoglobinuria (PNH) can lead to acute and chronic renal injury through hemoglobin-mediated toxicity. A 32-year-old pregnant woman with myelodysplastic syndrome was admitted to our hospital with severe preeclampsia. Shortly after an urgent caesarean section, she became obtunded and showed signs of acute kidney injury (AKI) with anuria, severe intravascular hemolysis, and hypermagnesemia. She was diagnosed with PNH with a positive Ham test and flow cytometry analysis. Renal magnetic resonance imaging revealed decreased signal intensity in the renal cortex due to hemosiderin deposition. Hemodialysis, plasma exchange, and administration of corticosteroids ameliorated her clinical condition and renal function. This case illustrates that careful management is required to prevent postpartum AKI in pregnant women with PNH.

Renal Biopsy in Paroxysmal Nocturnal Hemoglobinuria: An Insight into the Spectrum of Morphologic Changes

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare, acquired, potentially life-threatening disease of blood, characterized by complement-induced intravascular hemolytic anemia and thrombosis. PNH can sometimes present directly with renal manifestations, without showing any hematological manifestation. It, therefore, becomes essential for clinicians and pathologists to be aware of the spectrum of renal changes in PNH. The aim of this study was to document the morphologic changes observed in renal biopsies in patients with PNH. This is an observational study. We report three cases that presented with acute or chronic renal insufficiency and were suspected as PNH on viewing their renal biopsy in light of their clinical and laboratory details. All the three cases were confirmed as PNH on the basis of flow cytometric analysis of CD55 and CD59. Renal biopsy in these patients showed a variety of morphologic changes, however the most consistent finding was moderate-to-heavy siderosis in their kidneys. PNH per se may be difficult to diagnose clinically and sometimes present directly with renal manifestations. It is, therefore, prudent for nephrologists and nephropathologists to be aware of the spectrum of renal changes in PNH.

Renal Manifestations in Paroxysmal Nocturnal Hemoglobinuria

Paroxysmal nocturnal hemoglobinuria (PNH) is an acquired chronic disorder characterized by a triad of clinical features - hemolytic anemia, pancytopenia, and thrombosis. Not many reports of renal involvement in PNH are available in literature. We present a case series of PNH with renal involvement. We present the data of PNH patients who attended to Departments of General Medicine and Nephrology at a government-run tertiary care institute in South India. The diagnosis of PNH in these patients during initial phase, between 1998 and 2004 was based on sucrose lysis and Ham's test. After 2004, the diagnosis was based on flow cytometry to detect CD59 (membrane inhibitor of reactive lysis), a glycoprotein, and CD55 (decay accelerating factor) in regulation of complement action. The patient data were collected from 1998 to 2014. There were 14 patients of PNH in this period. The mean age was 37 years and the range was 16–68 years. There were eight females. Acute kidney injury (AKI) was noted in six patients. Dialysis was performed in four of them. The mean serum creatinine and urea at the initiation of dialysis were 5.4 ± 0.6 and 64.1 ± 6.1 mg/dl, respectively. The median number of hemodialysis sessions done was four. Renal biopsy was done in four patients. In three patients, the urinalysis and serum chemistry were suggestive of Fanconi syndrome. In our patients, three renal manifestations of PNH were identified. They were AKI, renal vessel thrombosis, and Fanconi syndrome. Chronic renal failure was not identified.

Eculizumab for treating patients with paroxysmal nocturnal hemoglobinuria

BACKGROUND

Paroxysmal nocturnal hemoglobinuria (PNH) is a chronic, not malignant, disease of the hematopoietic stem cells, associated with significant morbidity and mortality. It is a rare disease with an estimated incidence of 1.3 new cases per one million individuals per year. The treatment of PNH has been largely empirical and symptomatic, with blood transfusions, anticoagulation, and supplementation with folic acid or iron. Eculizumab, a biological agent that inhibits complement cascade, was developed for preventing hemolytic anemia and severe thrombotic episodes.

OBJECTIVES

To assess the clinical benefits and harms of eculizumab for treating patients with paroxysmal nocturnal hemoglobinuria (PNH).

SEARCH METHODS

We conducted a comprehensive search strategy. We searched the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library 2014, Issue 5), Ovid MEDLINE (from 1946 to 15 May 2014), EMBASE (from 1980 to 25 June 2014), and LILACS (from 1982 to 25 June 2014). We did not apply any language restrictions.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) irrespective of their publication status or language. No limits were applied with respect to period of follow-up. We excluded quasi-RCTs. We included trials comparing eculizumab with placebo or best available therapy. We included any patient with a confirmed diagnosis of PNH. Primary outcome was overall survival.

DATA COLLECTION AND ANALYSIS

We independently performed a duplicate selection of eligible trials, risk of bias assessment, and data extraction. We estimated risk ratios (RRs) and 95% confidence interval (CIs) for dichotomous outcomes, and mean differences (MDs) and 95% CIs for continuous outcomes. We used a random-effects model for analysis.

MAIN RESULTS

We identified one multicenter (34 sites) phase III RCT involving 87 participants. The trial compared eculizumab versus placebo, and was conducted in the US, Canada, Europe, and Australia with 26 weeks of follow-up. This small trial had high risk of bias in many domains (attrition and selective reporting). It was sponsored by a pharmaceutical company. No patients died during the study. By using the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire (scores can range from 0 to 100, with higher scores on the global health status and functioning scales indicating improvement), the trial showed improvement in health-related quality of life in patients treated with eculizumab (mean difference (MD) 19.4, 95% CI 8.25 to 30.55; P = 0.0007; low quality of evidence). By using the Functional Assessment of Chronic Illness Therapy Fatigue instrument (scores can range from 0 to 52, with higher scores indicating improvement in fatigue), the trial showed a reduction in fatigue (MD 10.4, 95% CI 9.97 to 10.83; P = 0.00001; moderate quality of evidence) in the eculizumab group compared with placebo. Eculizumab compared with placebo showed a greater proportion of patients with transfusion independence: 51% (22/43) versus 0% (0/44); risk ratio (RR) 46.02, 95% CI 2.88 to 735.53; P = 0.007; moderate quality of evidence; and withdrawal for any reason: 4.7% (2/43) versus 22.72% (10/44); RR 0.20, 95% CI 0.05 to 0.88; P = 0.03; moderate quality of evidence. Due to the low rate of events observed, the included trial did not show any difference between eculizumab and placebo in terms of serious adverse events: 9.3% (4/43) versus 20.4% (9/44); RR 0.15, 95% CI 0.15 to 1.37; P = 0.16; low quality of evidence. We did not observe any difference between intervention and placebo for the most frequent adverse events. One participant receiving placebo showed an episode of thrombosis. The trial did not assess overall survival, transformation to myelodysplastic syndrome and acute myelogenous leukemia, or development or recurrence of aplastic anemia on treatment.

AUTHORS' CONCLUSIONS

This review has detected an absence of evidence for eculizumab compared with placebo for treating paroxysmal nocturnal hemoglobinuria (PNH), in terms of overall survival, nonfatal thrombotic events, transformation to myelodysplastic syndrome and acute myelogenous leukemia, and development and recurrence of aplastic anemia on treatment. Current evidence indicates that compared with placebo, eculizumab increases health-related quality of life and increases transfusion independence. During the execution of the included trial, no patients died. Furthermore, the intervention seems to reduce fatigue and withdrawals for any reason. The safety profile of eculizumab is unclear. These conclusions are based on one small trial with risk of attrition and selective reporting bias.Therefore, prescription of eculizumab for treating patients with PNH can neither be supported nor rejected, unless new evidence from a large high quality trial alters this conclusion. Therefore, we urge the reader to interpret the trial results with much caution. Future trials on this issue should be conducted according to the SPIRIT statement and reported according to the CONSORT statement by independent investigators, and using the Foundation of Patient-Centered Outcomes Research recommendations.

Normal black kidney

A black kidney has 3 major differential diagnoses: hemosiderosis, lipofuscin pigment and melanotic renal cell carcinoma. Excluding lipofuscin, the other 2 are accompanied by an abnormal renal function. We report on a 25-year-old man who intended to donate a kidney to his cousin. On the operating room table when we incised the left flank region and exposed the kidney, we found a firm and black kidney so the operation was cancelled due to potential vascular injuries. Days after the incomplete procedure, we reviewed the donor's biochemistry and imaging to reassess his renal function, but the results showed quite normal renal function again. The result of Ham test was also negative. Two weeks later, we began the operation, removed the same left kidney and found that it was in the same conditions as it was before. We took the opportunity to send needle biopsies of the kidney for histopathologic analysis. The analysis showed a melanotic kidney without pathological changes in glomeruli and interstitium and vessels. A black kidney may result in hemosiderin, lipofuscin or melanin deposits in the kidney, which can confirm the diagnosis; however, special tests for underlying disease and renal function should be considered. Some causes of black kidney lead to abnormal function, but our patients's kidney returned to normal.

Paroxysmal nocturnal hemoglobinuria: rare cause of acute renal failure

Paroxysmal nocturnal hemoglobinuria is a rare acquired disease, characterized by hemolytic anemia, recurrent infections, cytopenias, and vascular thrombosis. It occurs by non-malignant clonal expansion of one or more hematopoietic stem cells that acquired somatic mutations in PIG-A gene linked to chromosome X. This mutation results in lower erythrocyte expression of CD55 and CD59 surface proteins and consequently increased susceptibility to the complement system. The renal involvement is generally benign, resulting in mild impairment in urinary concentration. Acute renal failure requiring hemodialytic support accompanying PNH is rarely observed. The authors report a case of a 37-year-old male who presented with bicytopenia (hemolytic anemia and thrombocytopenia) associated with acute renal failure requiring dialysis. Diagnosis was challenging because of the rarity and unfamiliarity with this entity, but was confirmed by flow cytometry. In the course of the disease, acute pyelonephritis with multiple renal abscesses was diagnosed requiring prolonged antibiotic therapy. Patient outcome was favorable after the control of hemolysis and the infection treatment.

Acute renal failure associated to paroxysmal nocturnal haemoglobinuria leads to intratubular haemosiderin accumulation and CD163 expression

Decreased renal function has been observed in diseases with intravascular haemolysis, including paroxysmal nocturnal haemoglobinuria (PNH). However, the mechanisms via which haemoglobin enhances renal damage in this pathology are not fully known. We report a case of acute renal failure associated to PNH and extensive haemosiderin deposits in tubular cells. Renal biopsy also revealed a strong immunostaining of CD163 (a haemoglobin scavenger receptor expressed in macrophages) and oxidative stress markers (NADPH-p22 phox and haeme oxigenase-1) in areas with deposits of iron. This fact provides evidence for a pathogenic role for free haemoglobin in tubulointerstitial renal injury in human PNH disease.

Recurrent acute renal failure

While acute renal failure secondary to intravascular hemolysis is well described in hemolytic anemias, recurrent acute renal failure as the presenting manifestation of a hemolytic anemia is rare. We report a patient with recurrent acute renal failure who was found to have paroxysmal nocturnal hemoglobinuria (PNH), on evaluation.

A closer look at paroxysmal nocturnal hemoglobinuria

Knowledge of the molecular mechanisms leading to the paroxysmal nocturnal hemoglobinuria (PNH) phenotypes has substantially increased in the past two decades. The associated intravascular hemolysis, hypercoagulablilty, and bone marrow failure result in a wide range of clinical sequlae. Although treatment has usually been symptomatic through several modalities and rarely curative through hematopoietic cell transplantation, recent development of the novel targeted therapeutic agent eculizumab has offered new promises for this highly morbid and fatal disease. This review summarizes current knowledge of the pathophysiology, diagnostic modalities, clinical implications, and treatment approaches of patients with PNH.

Blue kidney in a pale patient-a case for a causal association between renal haemosiderosis in paroxysmal nocturnal haemoglobinuria and chronic kidney disease

A 50-year-old man presented with pancytopenia and chronic renal impairment. He had evidence of intravascular haemolysis. The direct antiglobulin (Coomb’s) test was negative. Paroxysmal nocturnal haemoglobinuria (PNH) was diagnosed by the Ham acid haemolysis test. There were no other clinical risk factors that could be implicated in chronic kidney disease (CKD). A renal biopsy revealed extensive haemosiderosis affecting proximal tubular cells and associated interstitial fibrosis as well as tubular atrophy. No glomerular or vascular lesions were seen. These findings strengthen the case for a causal relationship between renal haemosiderosis in PNH and CKD.

Brain stimulation, reinforcement and behavior

Objective

In patients that require treatment for hepatic giant cavernous hemangiomas (GCH), radiofrequency ablation (RFA) has been suggested to represent a safe and effective alternative to invasive surgery. In a recent report of bipolar RFA, using two expandable needle electrodes, was uneventfully performed in patients with large GCH (>10 cm). The objective of this report is to present two cases in which bipolar RFA of symptomatic GCH was complicated by acute kidney injury.

Materials and methods

In 2015 we treated two patients for very large symptomatic GCH (15.7 and 25.0 cm) with bipolar RFA during open laparotomy.

Results

In both patients the urine showed a red–brown discoloration directly after the ablation. They became anuric and presented with progressive dyspnea, tachypnea, and tachycardia, requiring hemodialysis for a period of 1 month in one case. Lab results revealed hemepigment-induced acute kidney. Both patients fully recovered and both showed a complete relief of symptoms at 3 months following the procedure.

Conclusion

RFA for large GCHs can cause hemepigment-induced acute kidney injury due to massive intravascular hemolysis. The presented cases suggest that caution is warranted and advocate an upper limit regarding the volume of GCHs that can be safely ablated.