Renal Manifestations in Paroxysmal Nocturnal Hemoglobinuria

Advances in research on renal injury in paroxysmal nocturnal hemoglobinuria

Paroxysmal nocturnal hemoglobinuria (PNH) is an acquired clonal hematopoietic stem cell disease. Clinical manifestations include intravascular hemolysis, renal dysfunction, fatigue, jaundice, pulmonary hypertension, and so on. Renal injury, as a clinical feature of PNH, is difficult to diagnose and is one of the causes of death in patients with PNH. This article reviews the progress in research on PNH combined with renal injury to improve clinicians' understanding of renal injury in PNH patients, define and judge staging in a timely and accurate manner, enable patients to receive timely and appropriate treatment and reduce mortality.

Classical Paroxysmal Nocturnal Hemoglobinuria Presenting With Severe Anemia and Pigmented Acute Kidney Injury

Paroxysmal nocturnal hemoglobinuria is a rare form of intravascular hemolysis caused by an acquired deficiency of complement regulatory glycoproteins. In our case, a 53-year-old male presented with fatigue, discoloration of urine, and reduced urine output. Preliminary investigations showed severe anemia (3.7 g/dl) and hyperkalemia (7.6 mmol/L) in the setting of acute kidney injury, requiring urgent dialysis. Four units of packed cell volumes were transfused for the correction of anaemia. Following initial stabilization, flow cytometry and a fluorescein-labeled proaerolysin (FLAER) study showed a total deficiency of CD59 in 95.92% of granulocytes and a 97.14% deficiency in monocytes. A bone marrow biopsy showed erythroblast hyperplasia confirming the diagnosis of classical paroxysmal nocturnal hemoglobinuria. The patient was treated with steroids, androgens, and iron supplementation and made a complete recovery with a near-total resolution of his acute kidney injury. This paper aims to review the clinical features and investigations in order to focus on acute kidney injury as an outcome of paroxysmal nocturnal hemoglobinuria.

Heme Burden and Ensuing Mechanisms That Protect the Kidney: Insights from Bench and Bedside

With iron at its core, the tetrapyrrole heme ring is a cardinal prosthetic group made up of many proteins that participate in a wide array of cellular functions and metabolism. Once released, due to its pro-oxidant properties, free heme in sufficient amounts can result in injurious effects to the kidney and other organs. Heme oxygenase-1 (HO-1) has evolved to promptly attend to such injurious potential by facilitating degradation of heme into equimolar amounts of carbon monoxide, iron, and biliverdin. HO-1 induction is a beneficial response to tissue injury in diverse animal models of diseases, including those that affect the kidney. These protective attributes are mainly due to: (i) prompt degradation of heme leading to restraining potential hazardous effects of free heme, and (ii) generation of byproducts that along with induction of ferritin have proven beneficial in a number of pathological conditions. This review will focus on describing clinical aspects of some of the conditions with the unifying end-result of increased heme burden and will discuss the molecular mechanisms that ensue to protect the kidneys.

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.

A Rare Case of Paroxysmal Nocturnal Hemoglobinuria With Bilateral Renal Vein Thrombosis

Paroxysmal nocturnal hemoglobinuria (PNH) is an acquired hematopoietic stem cell (HSC) disorder characterized by a partial or complete deficiency of glycosyl-phosphatidylinositol (GPI)-linked membrane proteins, which leads to intravascular hemolysis. The loss of CD55 and CD59, two GPI-anchored proteins on red blood cell surfaces, from mutations in the X-linked phosphatidylinositol glycan class A (PIGA) gene, causes unrestricted proliferation of complement activation. The loss of CD59 especially leads to ‘paroxysms’ of acute intravascular hemolysis during events of stress. Extravascular hemolysis also occurs without CD55 as the accumulation of C3 on red blood cell surfaces leads to their destruction by the reticuloendothelial system. Diagnosis of PNH relies primarily on clinical presentation and flow cytometry assays used to detect the GPI-anchored proteins, CD55 and CD59; however, fluorescein‐labeled proaerolysin variant (FLAER) is seen to have a significant advantage over CD55 and CD59. Typical symptoms of the disorder include fatigue, shortness of breath, hemoglobinuria, abdominal pain and bone marrow failure. Thrombosis also occurs secondary to nitric oxide (NO) deficiency, release of procoagulants, increased tissue factor and reduced fibrinolysis. The classification of PNH is subdivided into three types: classical, PNH with another bone marrow disorder and subclinical PNH. Management of hemolysis, thrombosis and pancytopenia is based on the pathogenesis involved. Inhibition of complement in the form of humanized monoclonal antibody against complement C5 (eculizumab) is seen as an emerging treatment option, while stem cell/bone marrow transplant may also be offered. We present a rare case of PNH with bilateral renal vein thrombosis, who was diagnosed with classical PNH on clinical presentation and flow cytometry. He was initially offered bone marrow transplantation but was lost to follow-up and later presented with bilateral renal vein thrombosis. He was managed conservatively with transfusions and anticoagulation, and was discharged for follow-up on an outpatient basis.

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.

Risk factors of haemoglobinuria after microwave ablation of liver tumours

AIM

To explore the risk factors predicting haemoglobinuria after ultrasound-guided percutaneous microwave ablation (MWA) of liver tumours and discuss the treatments and outcomes.

MATERIALS AND METHODS

The present study comprised 2,829 patients admitted for liver tumours treated with MWA from Jan 2011 to April 2017. Ethics committee approval was waived and informed consent for treatment procedures were obtained from the patients. Haemoglobinuria after MWA was found in 149 patients. The influence of 19 risk factors was assessed. Binary logistic regression and receiver operating characteristic (ROC) curve analysis were used for statistical analysis. The treatments and outcomes of patients with haemoglobinuria were summarised.

RESULTS

By univariate analysis, histopathology, liver cirrhosis, MWA volume, MWA energy, and MWA duration were significant risk factors. By multivariate analysis and ROC curve, MWA energy, duration, and volume were identified as predictors of haemoglobinuria after MWA. Drug treatments including kidney protection, adequate hydration, alkalisation of urine, and diuresis were administrated to the patients with haemoglobinuria. One patient progressed to acute kidney injury (AKI) while others had good clinical outcomes.

CONCLUSION

Haemoglobinuria is a controllable side effect after MWA of liver tumours, which is related to high MWA energy, long MWA duration, and great MWA volume. It usually caused few side effects on renal function with correct treatment.

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.

Renal vein thrombosis complicating severe acute pyelonephritis with renal abscesses and associated bacteraemia caused by extended-spectrum beta-lactamase producing Escherichia coli

Acute pyelonephritis might be complicated by the formation of renal and perirenal abscesses and very rarely by renal vein thrombosis, which is a life-threatening condition. The main causative agents of acute pyelonephritis are enterobacteriaceae with the incidence of extended-spectrum beta-lactamase (ESBL)-producing strains increasing worldwide. We present the case of a 71-year-old Greek man with history of diabetes mellitus and recent hospitalization, who suffered from severe pyelonephritis with renal abscesses formation and associated bacteraemia caused by ESBL-producing Escherichia coli, complicated by extensive thrombosis of the ipsilateral renal vein and its branches, protruding also in the inferior venal cava. Our patient was effectively treated with anticoagulants and targeted antibiotic therapy, respectively, consisted of low molecular weight heparin transitioned to oral acenocoumarol for 3 months and 2-week course of intravenous meropenem followed by oral fosfomycin for additional 3 weeks as quidded by clinical and computed tomographic follow-up. In conclusion, in complicated urinary infections, caused by ESBL-producing enterobacteriaceae, oral fosfomycin might represent an effective option for step-down therapy of carbapenems, allowing the shortness of the duration of patient's hospitalization and carbapenem use.

Clinical profile and outcome of pigment-induced nephropathy

Background

Pigment nephropathy represents one of the most severe complications of rhabdomyolysis or hemolysis.

Methods

We performed a retrospective observational study to analyze the etiology, clinical manifestation, laboratory profile and outcome in patients with biopsy-proven pigment-induced nephropathy between January 2011 and December 2016. History, clinical examination findings, laboratory investigations and outcome were recorded.

Results

A total of 46 patients were included with mean follow-up of 14 ± 5.5 months. Mean age was 40.15 ± 12.3 years, 65% were males (male:female, 1.8:1) and ∼37 (80.4%) had oliguria. Mean serum creatinine at presentation and peak creatinine were 7.5 ± 2.2 and 12.1 ± 4.3 mg/dL, respectively. Evidence of rhabdomyolysis was noted in 26 patients (64%) and hemolysis in 20 patients (36%). Etiology of rhabdomyolysis include snake envenomation (10 patients), seizures (7), strenuous exercise (5), wasp sting (2) and rifampicin induced (2). The causes of hemolysis include rifampicin induced (7 patients), sepsis (5), malaria (3), mismatched blood transfusion/transfusion reaction (3) and paroxysmal nocturnal hemoglobinuria (2). On renal biopsy, two patients had acute interstitial nephritis and two had immunoglobulin A deposits in addition to pigment nephropathy. All except one (97.8%) required hemodialysis (HD) during hospital stay and mean number of HD sessions was 9 ± 2. A total of three patients with sepsis/disseminated intravascular coagulation died, all had associated hemolysis. On statistical analysis, there was no difference between AKI due to rhabdomyolysis and hemolysis except for high creatine phosphokinase in patients with rhabdomyolysis and Lactate dehydrogenase level in patients with hemolysis. At mean follow-up, five patients (12%) progressed to chronic kidney disease (CKD).

Conclusions

Pigment nephropathy due to rhabdomyolysis and hemolysis is an important cause of renal failure requiring HD. The prognosis was relatively good and depends on the etiology; however, long-term studies and follow-up are needed to assess the true incidence of CKD due to pigment nephropathy.