Paroxysmal nocturnal hemoglobinuria in children

Anemia in the pediatric patient

The World Health Organization estimates that approximately a quarter of the world's population suffers from anemia, including almost half of preschool-age children. Globally, iron deficiency anemia is the most common cause of anemia. Other important causes of anemia in children are hemoglobinopathies, infection, and other chronic diseases. Anemia is associated with increased morbidity, including neurologic complications, increased risk of low birth weight, infection, and heart failure, as well as increased mortality. When approaching a child with anemia, detailed historical information, particularly diet, environmental exposures, and family history, often yield important clues to the diagnosis. Dysmorphic features on physical examination may indicate syndromic causes of anemia. Diagnostic testing involves a stepwise approach utilizing various laboratory techniques. The increasing availability of genetic testing is providing new mechanistic insights into inherited anemias and allowing diagnosis in many previously undiagnosed cases. Population-based approaches are being taken to address nutritional anemias. Novel pharmacologic agents and advances in gene therapy-based therapeutics have the potential to ameliorate anemia-associated disease and provide treatment strategies even in the most difficult and complex cases.

Paroxysmal Nocturnal Hemoglobinuria: Case Report of a Rare Cause of Thrombosis in the Pediatric Age

Paroxysmal nocturnal hemoglobinuria (PNH) is an acquired life-threatening disorder that is extremely rare in the pediatric age. Patients with PNH may present a wide range of clinical manifestations. In most cases, the severity is associated with the size of the PNH clones; yet, some patients can be asymptomatic with a large clone. Thrombosis occurs less frequently as a presenting symptom, but it is considered the leading cause of mortality. In this article, we describe a case of PNH in a pediatric patient, complicated with venous thrombosis and with portal hypertension, associated with gastroesophageal varices at the time of diagnosis.

Paroxysmal Nocturnal Hemoglobinuria: An Underestimated Cause of Pediatric Thromboembolism

Paroxysmal nocturnal hemoglobinuria (PNH) is a chronic disease caused by complement-mediated hemolysis. Clinical symptoms include intravascular hemolysis, nocturnal hemoglobinuria, thromboses, cytopenia, fatigue, abdominal pain, and a strong tendency toward bone marrow failure. It is a rare disease, especially in children, with high mortality rates without appropriate treatment.

We here present the case of a 17-year-old girl with unprovoked muscle vein thrombosis. Flow cytometric analysis showed deficiency of glycosyl-phosphatidylinositol-anchored membrane proteins on all three hematopoietic cell lines and confirmed the diagnosis of PNH. Treatment with the monoclonal antibody eculizumab achieved long-term remission.

As flow cytometry is normally not part of the routine diagnostics for pediatric thrombosis, awareness is crucial and PNH is important to consider in all children with thrombosis at atypical sites and abnormalities in blood counts with regard to hemolysis and cytopenia.

Missing Cells: Pathophysiology, Diagnosis, and Management of (Pan)Cytopenia in Childhood

Peripheral blood cytopenia in children can be due to a variety of acquired or inherited diseases. Genetic disorders affecting a single hematopoietic lineage are frequently characterized by typical bone marrow findings, such as lack of progenitors or maturation arrest in congenital neutropenia or a lack of megakaryocytes in congenital amegakaryocytic thrombocytopenia, whereas antibody-mediated diseases such as autoimmune neutropenia are associated with a rather unremarkable bone marrow morphology. By contrast, pancytopenia is frequently associated with a hypocellular bone marrow, and the differential diagnosis includes acquired aplastic anemia, myelodysplastic syndrome, inherited bone marrow failure syndromes such as Fanconi anemia and dyskeratosis congenita, and a variety of immunological disorders including hemophagocytic lymphohistiocytosis. Thorough bone marrow analysis is of special importance for the diagnostic work-up of most patients. Cellularity, cellular composition, and dysplastic signs are the cornerstones of the differential diagnosis. Pancytopenia in the presence of a normo- or hypercellular marrow with dysplastic changes may indicate myelodysplastic syndrome. More challenging for the hematologist is the evaluation of the hypocellular bone marrow. Although aplastic anemia and hypocellular refractory cytopenia of childhood (RCC) can reliably be differentiated on a morphological level, the overlapping pathophysiology remains a significant challenge for the choice of the therapeutic strategy. Furthermore, inherited bone marrow failure syndromes are usually associated with the morphological picture of RCC, and the recognition of these entities is essential as they often present a multisystem disease requiring different diagnostic and therapeutic approaches. This paper gives an overview over the different disease entities presenting with (pan)cytopenia, their pathophysiology, characteristic bone marrow findings, and therapeutic approaches.

Pediatric myelodysplastic syndromes: they do exist!

One of the most common hematologic malignancies in adults, myelodysplastic syndrome (MDS) is a heterogenous group of clonal disorders characterized by peripheral cytopenia(s) and normal or hypercellular bone marrow with dysplasia in ≥1 blood cell lineages. MDS frequently evolves to secondary acute myeloid leukemia with poor prognosis. Although uncommon among pediatric hematologic malignancies, both de novo and secondary MDS occur in children and may be the first presentation of an inherited bone marrow failure syndrome. Unlike its adult counterpart, pediatric MDS is more frequently associated with hypocellular bone marrow and monosomy 7. Refractory cytopenia is more typical than refractory anemia, as seen in the elderly. Its recognition and management can be quite challenging and requires the expertise of an experienced hematopathologist. In this review, we describe the epidemiology, genetics, and clinical spectrum of pediatric MDS along with its diagnostic and therapeutic challenges. We also compare and contrast pediatric and adult MDS.

Treatment of pseudomonas and Staphylococcus bronchopulmonary infection in patients with cystic fibrosis

The optimal antibiotic regimen is unclear in management of pulmonary infections due to pseudomonas and staphylococcus in cystic fibrosis (CF). We systematically searched all the published literature that has considered the evidence for antimicrobial therapies in CF till June 2013. The key findings were as follows: inhaled antipseudomonal antibiotic improves lung function, and probably the safest/most effective therapy; antistaphylococcal antibiotic prophylaxis increases the risk of acquiring P. aeruginosa; azithromycin significantly improves respiratory function after 6 months of treatment; a 28-day treatment with aztreonam or tobramycin significantly improves respiratory symptoms and pulmonary function; aztreonam lysine might be superior to tobramycin inhaled solution in chronic P. aeruginosa infection; oral ciprofloxacin does not produce additional benefit in those with chronic persistent pseudomonas infection but may have a role in early or first infection. As it is difficult to establish a firm recommendation based on the available evidence, the following factors must be considered for the choice of treatment for each patient: antibiotic related (e.g., safety and efficacy and ease of administration/delivery) and patient related (e.g., age, clinical status, prior use of antibiotics, coinfection by other organisms, and associated comorbidities ones).

Paroxysmal nocturnal haemoglobinuria. Experience over a 10 years period

INTRODUCTION

Paroxysmal nocturnal hemoglobinuria (PNH) is a hemolytic, clonal and acquired disorder of the hematopoietic stem cell with a deficiency of all glycophosphatidyl-inositol (GPI) linked proteins. The aim of this retrospective study was to analyse haematological and biochemical data from 152 patients referred to our laboratory for diagnosis of PNH by flow cytometry (FC).

METHODS

Patients and healthy donor (152 and 99 respectively) were studied. Ham, sucrose, lactate dehydrogenase (LDH), Iron, haptoglobin (Hp), blood cell morphology and Kaplow cytochemical stain for leukocyte alkaline phosphatase (LAP) were carried out. GPI-proteins anti-CD55 and CD59 in erythrocytes and the former, plus anti CD16b and CD66b on neutrophils were evaluated by FC.

RESULTS

Anemia and/or leukopenia and/or thrombocytopenia, increased reticulocyte count and LDH were observed in patients with PNH clone. Some of them had dacriocytes, schistocytes. LAP was low. On average, we detected 50% CD59 (-) erythrocytes and 29, 83, 78% CD55/59 (-), CD16b (-), CD66b (-) neutrophils, respectively.

CONCLUSION

Paroxysmal nocturnal hemoglobinuria clone was detected in 20/152 patients. Negative population's percentages were high in patients with classic PNH, Hematimetry, LAP and adequate use of CF contribute to PNH clone detection in the laboratory.

Successful use of eculizumab in a pediatric patient treated for paroxysmal nocturnal hemoglobinuria

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare, debilitating life-threatening clonal hematopoietic stem cell disease. The clinical manifestations of PNH are usually seen in adulthood and are very rarely reported in children. Eculizumab, a humanized monoclonal antibody targeting and preventing cleavage of the terminal complement protein C5, has become the "gold standard" of treatment for hemolysis or significant disease-related complications in patients with PNH. Although eculizumab is not licensed for use in pediatrics, we report a young PNH patient with bone marrow failure and severe episodes of hemolytic anemia who was treated successfully with eculizumab for >18 months.

Classification of childhood aplastic anemia and myelodysplastic syndrome

Hypoplastic BM disorders in children and adolescents comprise a broad spectrum of disorders. Acquired severe aplastic anemia (SAA), refractory cytopenia of childhood (RCC), a subtype of myelodysplastic syndrome (MDS), and inherited BM failure (IBMF) disorders are the main and most difficult hematological differential diagnoses. Whereas IBMF disorders can often be diagnosed by their clinical features and/or underlying genetic aberrations, the morphological distinction between SAA and hypocellular RCC has been controversial. The histopathological pattern of RCC consists of islands of immature erythroid precursors accompanied by sparsely distributed granulocytic cells. Megakaryocytes are significantly decreased or absent and, rarely, micromegakaryocytes are detected on immunohistochemistry. Because fatty tissue between areas of hematopoiesis can mimic SAA, 2 biopsies are recommended to facilitate the detection of representative BM spaces. Recent data indicate that the response to immunosuppressive therapy is inferior in RCC compared with SAA. Furthermore, approaches to allogeneic hematopoietic transplantation differ. Controlled prospective clinical studies in patients with hypoplastic BM failure disorders will require comprehensive guidelines for diagnosing SAA, RCC, and the different IBMF disorders.

Acquired aplastic anemia in childhood

In comparison to past decades, children who have acquired aplastic anemia (AA) enjoy excellent overall survival that reflects improvements in supportive care, more accurate exclusion of children who have alternate diagnoses, and advances in transplantation and immunosuppressive therapy (IST). Matched sibling-donor hematopoietic stem cell transplants (HSCT) routinely provide long-term survival in the range of 90%, and 75% of patients respond to IST. In this latter group, the barriers to overall and complication-free survival include recurrence of AA, clonal evolution with transformation to myelodysplasia/acute myelogenous leukemia, and therapy-related toxicities. Improvements in predicting responses to IST, in alternative-donor HSCT, and in rationalizing therapy by understanding the pathophysiology in individual patients are likely to improve short- and long-term outcomes for these children.