Pure erythrocytosis classified according to erythropoietin titers

Anemia in Children with Congenital Heart Disease: A Finding from Low-Resource Setting Hospitals

Introduction

Congenital heart disease (CHD) is the most common birth defect. Anemia is the prevailing manifestation of micronutrient deficiency. It has been demonstrated that anemia in children increases morbidity and has a negative impact on psychomotor development. Despite its negative consequences, which have been documented for a long time in clinical practice, the issue does not gain sufficient attention in developing countries, specifically in children with CHD. Thus, this study is aimes to assess the prevalence of anemia and the factors associated in children with CHD.

Methods

Institutional-based cross-sectional study was conducted on CHD children at selected governmental hospitals in Addis Ababa, Ethiopia, from February to March 2021. During this period, 373 children with acyanotic and cyanotic heart disease between 0 months and 15 years of age were included in this study. All children were assessed using structured questionnaires and anthropometric measurements. Recent hemoglobin results that are avaliable in the medical charts of children were used to diagnose anemia. The data were analyzed using SPSS version 25.

Results

From randomly included 373 children with CHD, 298 (79.9%) had acyanotic congenital heart disease (ACHD) and 75 (20.1%) had cyanotic congenital heart disease (CCHD). Twenty-five (33.3%) CCHD and 192 (64.4%) ACHD cases of children were malnourished. The most common type of CCHD and ACHD defects were ventricular septal defects and tetralogy of fallout, respectively. Overall, the prevalence of anemia in ACHD and CCHD was 24.5% and 72%, respectively. In children with ACHD, the frequency of anemia was reported to be significantly higher in the malnourished group than in the well-nourished.

Conclusions

A high prevalence of anemia is observed in children with CHD. This study highly suggests further evaluation to determine the frequency and complications of blood indices and other hematological impairments in ACHD, CCHD, and children with both problems. Moreover, the findings of this study on illness profiles in children with CHD prompt further research into the cellular and molecular mechanisms underlying immune system dysfunction.

Iron deficiency anemia in children with cyanotic congenital heart disease and effect on cyanotic spells

BACKGROUND

Iron deficiency anemia (IDA) in cyanotic congenital heart disease (CCHD) and its association with cyanotic spells has been documented in literature. However, Indian data especially in the pediatric age group is scarce. This study was conducted to find out the prevalence of IDA in this population.

METHODS

An observational study was conducted in a tertiary care hospital. Children with CCHD in the age group of birth-12 years were included in the study. Hematological parameters of these patients were determined and compared. An assessment of the incidence of cyanotic spells in the iron-deficient and iron non-deficient children was also done. Data analysis was done using Fischer's exact test.

RESULTS

The prevalence of IDA was 47.06% in the study population. The study also showed that hemoglobin and hematocrit levels were paradoxically higher in the iron-deficient group as compared to the non-deficient, though the iron studies revealed the iron deficiency. The incidence of cyanotic spells was higher in the iron-deficient group. The mean corpuscular volume (MCV), red cell distribution width (RDW), serum ferritin, serum iron, total iron binding capacity (TIBC), and transferrin saturation (TS) values were the parameters, which were found to be statistically significant to differentiate the study groups.

CONCLUSION

The prevalence of IDA in children with CCHD was found to be high. Iron-deficient group had an increased frequency of cyanotic spells as compared to the non-deficient group, which was statistically significant.

Erythrocytosis caused by giant chromophobe renal cell carcinoma: a case report indicating a 9-year misdiagnosis of polycythemia vera

Background

Erythrocytosis, a rare paraneoplastic syndrome, generally occurs in patients with clear cell renal cell carcinoma and has never been reported in patients with chromophobe renal cell carcinoma.

Case presentation

We report a case of a young man suffering from a giant (22-cm) mass on his left kidney. Because of a history of polycythemia vera, the patient had been treated for the condition for 9 years. Radical nephrectomy was successfully performed, and the postoperative pathologic examination confirmed a diagnosis of chromophobe renal cell carcinoma. Unexpectedly, the symptom of erythrocytosis disappeared after the surgery. Further examination and analysis were performed, and we finally attributed his erythrocytosis to chromophobe renal cell carcinoma.

Conclusions

Chromophobe renal cell carcinoma could cause erythrocytosis, but the clear-cut mechanism needs further research. Secondary erythrocytosis such as those related with renal tumors should be taken into consideration during the diagnosis of polycythemia vera.

Erythropoietin

During the past century, few proteins have matched erythropoietin (Epo) in capturing the imagination of physiologists, molecular biologists, and, more recently, physicians and patients. Its appeal rests on its commanding role as the premier erythroid cytokine, the elegant mechanism underlying the regulation of its gene, and its remarkable impact as a therapeutic agent, arguably the most successful drug spawned by the revolution in recombinant DNA technology. This concise review will begin with a synopsis of the colorful history of this protein, culminating in its purification and molecular cloning. It then covers in more detail the contemporary understanding of Epo's physiology as well as its structure and interaction with its receptor. A major part of this article focuses on the regulation of the Epo gene and the discovery of HIF, a transcription factor that plays a cardinal role in molecular adaptation to hypoxia. In the concluding section, a synopsis of Epo's role in disorders of red blood cell production will be followed by an assessment of the remarkable impact of Epo therapy in the treatment of anemias, as well as concerns that provide a strong impetus for the development of even safer and more effective treatment.

Pathophysiology of anemia and erythrocytosis

An increasing understanding of the process of erythropoiesis raises some interesting questions about the pathophysiology, diagnosis and treatment of anemia and erythrocytosis. The mechanisms underlying the development of many of the erythrocytoses, previously characterised as idiopathic, have been elucidated leading to an increased understanding of oxygen homeostasis. Characterisation of anemia and erythrocytosis in relation to serum erythropoietin levels can be a useful addition to clinical diagnostic criteria and provide a rationale for treatment with erythropoiesis stimulating agents (ESAs). Recombinant human erythropoietin as well as other ESAs are now widely used to treat anemias associated with a range of conditions, including chronic kidney disease, chronic inflammatory disorders and cancer. There is also heightened awareness of the potential abuse of ESAs to boost athletic performance in competitive sport. The discovery of erythropoietin receptors outside of the erythropoietic compartment may herald future applications for ESAs in the management of neurological and cardiac diseases. The current controversy concerning optimal hemoglobin levels in chronic kidney disease patients treated with ESAs and the potential negative clinical outcomes of ESA treatment in cancer reinforces the need for cautious evaluation of the pleiotropic effects of ESAs in non-erythroid tissues.

The presence of a significant association between elevated PRV-1 mRNA expression and low plasma erythropoietin concentration in essential thrombocythaemia

Approximately 45% of newly diagnosed patients with essential thrombocythaemia (ET) demonstrate subnormal plasma erythropoietin (EPO) concentrations, which constitutes a risk factor for occlusive vascular events. In 58 ET patients, a possible association between polycythaemia rubra vera-1 (PRV-1) overexpression and subnormal plasma EPO was investigated, which was always measured prior to the institution of platelet lowering agents. At the time when PRV-1 expression was measured, 28 of 58 (48%) ET patients had received platelet lowering treatment. PRV-1 expression was measured by quantitative real-time reverse transcription-polymerase chain reaction assay of mRNA extracted from purified peripheral blood buffy coat. The cycle threshold (CT) value of PRV-1 was determined and was divided with the CT value for the housekeeping GAPDH gene transcript. A quotient <0.93 was defined as PRV-1 positive. Of the ET patients 12 of 58 (21%) were PRV-1 positive and 19 of 58 (33%) demonstrated subnormal plasma EPO. In the 58 ET patients there was a significant association between low plasma EPO and PRV-1 positive results (P = 0.001). The 30 ET patients who had not received any platelet lowering treatment showed a significant (P = 0.005) relation between PRV-1 positivity and subnormal plasma EPO. No such relationship was present in the 28 ET patients who had received prior treatment with the above drugs (P = 0.147).

Patients with idiopathic myelofibrosis show increased CD34+ cell concentrations in peripheral blood compared to patients with polycythaemia vera and essential thrombocythaemia

The aim of the present work was to compare the results for some haematological variables in 12 patients with idiopathic myelofibrosis (IMF) with those of 21 patients with polycythaemia vera (PV), 22 patients with essential thrombocythaemia (ET) and 10 healthy control subjects. In each patient and control subject peripheral blood was used for analysis of flow cytometric measurement of CD34-positive (CD34+) cells, in vitro colony growth and plasma erythropoietin (EPO) concentration. The mean concentration of CD34+ cells in the IMF group was 568 +/- 686 x 10(3) mL, which significantly (P<0.001 for each group) exceeded the means in PV, ET and control groups ((10.2 +/- 32.0) x 10(3) mL, 3.0 +/- 3.7 x 10(3) mL and 1.9 +/- 0.8 x 10(3) mL, respectively). The mean number of EPO-independent erythroid colonies (EEC) was 110 +/- 215 colonies per 10(5) cells for the IMF patients. In comparison with the means for PV and ET patients (40 +/- 140 and 12 +/- 27 colonies per 10(5) cells, respectively) the difference did not reach statistical significance. The mean EEC for IMF patients was, however, significantly higher compared with the mean for the control subjects (P<0.05). The means for total erythroid colony growth with EPO added to the growth medium as well as for granulocyte-macrophage colony-forming units were significantly higher in the IMF group compared with the means for PV, ET and control groups (P<0.001 for each group). The mean plasma EPO was 204 +/- 290 IU/L in the patients with IMF compared with 6.6 +/- 7.9 IU/L in PV patients, 19.1 +/- 23.2 IU/L in ET and 10.3 +/- 7.8 IU/L in the control subjects. Due to considerable differences in haemoglobin concentrations no relevant conclusions could be drawn from the results for plasma EPO concentrations. Indeed, the majority of patients with IMF, PV and ET were on myelosuppressive treatment; additionally most PV patients received phlebotomy therapy. The results of the present study suggest that the circulating pool of stem cells and progenitor cells in peripheral blood is significantly increased in IMF patients compared with PV and ET patients as well as healthy control subjects. The most likely source for the elevated CD34+ cell concentration in peripheral blood is progenitor cells of extra-medullar origin.

The relation between plasma thrombopoietin and erythropoietin concentrations in polycythaemia vera and essential thrombocythaemia

Plasma thrombopoietin (TPO) was measured, by immunoenzymometric assay, in 39 patients with polycythaemia vera (PV), 33 patients with essential thrombocythaemia (ET) and 10 healthy volunteers. The mean TPO concentration was significantly higher in ET patients than in PV patients (p=0.04) and normals (p<0.001). The 6 untreated ET patients had a significantly lower mean TPO concentration compared to the 27 ET patients who were on myelosuppressive regimens (p=0.01). The mean plasma TPO for the 5 PV patients treated with phlebotomy only did not differ significantly from the corresponding mean for the 34 PV patients treated with myelosuppressive agents. Concomitantly, plasma EPO was measured in 25 of the PV patients and in 30 of the ET patients by an immunoradiometric assay with normal reference interval in adults 3.7-16 IU/L. In the 14 PV patients with EPO <3.7 IU/L mean plasma TPO did not differ significantly from the mean for the 11 PV patients with EPO >or=3.7 IU/L; neither of these two groups had plasma TPO concentrations significantly different from the mean for the control subjects. The 7 ET patients with subnormal plasma EPO had significantly lower mean plasma TPO compared to the ET patients with normal and high plasma EPO concentrations (p=0.03 and p=0.02, respectively). Also, the 16 ET patients with normal plasma EPO had significantly lower plasma TPO compared to the 8 patients with high plasma EPO (p=0.04). The mean plasma TPO for each of these three groups of ET patients was significantly higher than the corresponding mean for the controls (p<0.001 for each group). The results of the present study indicate that a relationship between plasma EPO and TPO concentrations may exist and that myelosuppressive treatment affects the TPO concentration in ET but not in PV patients.

The red cell mass, plasma erythropoietin and spleen size in apparent polycythaemia

It has been shown previously that measurement of the spleen size and plasma erythropoietin (EPO) concentration are valuable adjuncts in the diagnostic work-up of patients with polycythaemia vera. The aim of the present work was to evaluate their value in the assessment of apparent polycythaemia (AP). Therefore, over a 24-month period we routinely performed bone marrow biopsies, measurement of red cell mass (RCM) and plasma volume (PV), spleen size determination by gamma camera scintigraphy and determination of the plasma EPO concentration in consecutive patients referred to us because of elevated values for packed cell volume (>0.48 in females and >0.51 in males). After having excluded patients with clonal and secondary polycythaemias we were left with 38 patients (27 males and 11 females) with AP. In all of them the measured RCM was within normal range, i.e. <36 ml/kg for males and <32 ml/kg for females. The subjects were characterized by moderate increase in RCM and a concomitant moderate decrease in PV. Thus, as an average the measured RCM exceeded the predicted values by 14% in males and by 12% in females; conversely, as compared to the predicted values the average measured value for PV was reduced by 17% in males and by 8% in females. The average RCM for males was 29+/-3 ml/kg; the corresponding figure for females was 23+/-4 ml/kg. It was shown that 86% of the subjects had plasma EPO concentrations within the control range; the remaining had values slightly above or below the control range. The mean posterior spleen scan area was 57+/-16 cm2 and mean left lateral area 57+/-17 cm2; the reference value for spleen scan area (for both projections) is 57+/-12 cm2. Of the patients 35/38 (92%) had a spleen scan area within the mean+2SD for controls and 38 subjects (100%) had values within the mean+3SD. It is concluded that measurement of plasma EPO and a careful assessment of the spleen size should always be considered in the evaluation of patients with elevated values for venous packed cell volume.

Are current methods of measurement of erythropoietin (EPO) in human plasma or serum adequate for the diagnosis of polycythaemia vera and the assessment of EPO deficiency?

Current methodology for the immunoassay of erythropoietin (EPO) in human plasma or serum is reviewed, with an emphasis on measurement of EPO concentrations in the low and normal ranges, analytical interference and blood sampling requirements. In only 2 out of 8 research or in-house immunoassays reported since 1987 was there evidence that patients with polycythaemia vera (PV) could be identified, PV being an EPO-independent form of polycythaemia in which EPO concentrations are low in untreated cases. The same was true for only 1 out of 13 currently available kit methods. Remarkable differences in sample stability have been observed with different methods. Measurement of EPO in serum is recommended in most published articles. However, only EDTA plasma seems to be acceptable for the one generally available method with proven high diagnostic sensitivity for PV. It is concluded that most EPO assay methods have not been shown to be adequate for the measurement of the low EPO concentrations, and thus have poor diagnostic sensitivity for PV. It is inferred that they might not be appropriate to assess states of EPO deficiency. Only when a sufficiently sensitive diagnostic method becomes generally available will it be possible to define the various causes of low EPO concentrations. As in other fields of polypeptide hormone measurement, further developments in the field of EPO assay may be expected to be important in diagnostic medicine.

In vitro culture growth of erythroid progenitors and serum erythropoietin assay in the differential diagnosis of polycythaemia

BACKGROUND

We assessed the in vitro culture growth of erythroid progenitors [burst forming unit-erythroid (BFU-E)] and serum erythropoietin (EPO) levels in different groups of polycythaemia to determine the discriminative power in differential diagnosis of polycythaemia.

METHODS

We used the methylcellulose culture technique to study the growth of endogenous erythroid colonies (EECs) and EPO-dependent BFU-E from bone marrow (BM) and/or peripheral blood (PB) cells from 40 patients with polycythaemia vera (PV), 13 with secondary polycythaemia (SP), 19 with pure erythrocytosis (PE), five with PE and PV evolution later (PE-PV), and 12 with relative polycythaemia (RP). The serum EPO levels were measured by radioimmunoassay before treatment in 47 patients, 23 SP patients, 19 PE patients, five PE-PV patients and 16 RP patients, as well as after treatment in 38 PV patients, five PE-PV patients and 12 PE patients.

RESULTS

The results of the erythroid progenitor culture assay showed that the numbers of EPO-dependent BFU-E in BM did not differ significantly among groups. The PB BFU-E were significantly higher in PV than in SP or PE, and no statistical difference were found among patients with SP, PE and RP. There was a correlation between BM BFU-E and PB BFU-E in the individual PV and PE patients. EECs were present in all BM and PB cultures of untreated and phlebotomy-treated PV and PE-PV patients, but were absent in 6 of 17 PV patients who had received cytotoxic therapy. EECs were not found in SP, PE and RP. PB could substitute for BM in the EEC or the BFU-E assay. Both pretreatment and post-treatment serum EPO levels of PV and PE-PV were similar, which were significantly lower than SP, PE or RP. The serum EPO levels in treated PV or PE-PV patients who had normal haematocrit values were not significantly different from those in untreated patients. In contrast, the phlebotomy-treated PE patients had significantly higher serum EPO values than untreated PE patients. In the differentiation between PV and PE, the sensitivity, specificity, positive predictive value and negative predictive value of post-treatment serum EPO levels at a cut-off level of < or = 9 UL-1 were 74%, 92% and 52% respectively. The discriminative power of post-phlebotomy serum EPO levels was even higher with a positive predictive value of 80% and negative predictive value of 92% for the prediction of PV evolution in patients with pure erythrocytosis of unknown origin.

CONCLUSION

The present study showed that apart from EEC assay, the post-phlebotomy serum EPO level was a sensitive and specific parameter in the differential diagnosis of polycythaemia, in particular for the identification of PV among patients with unclassifiable polycythaemia.

Absence of polycythemia in a child with a unique erythropoietin receptor mutation in a family with autosomal dominant primary polycythemia

Primary familial and congenital polycythemia (PFCP or familial erythrocytosis) is a rare proliferative disorder of erythroid progenitor cells, characterized by elevated erythrocyte mass and hemoglobin concentration, hypersensitivity of erythroid progenitors to erythropoietin (EPO), and autosomal dominant inheritance or sporadic occurrence. A number of EPO receptor (EPOR) mutations were found in subjects with PFCP; most of these mutations resulted in the truncation of the COOH-terminal of the EPOR protein. We studied a family with autosomal dominant inheritance of PFCP in which four subjects were affected in three generations. We screened the affected individuals for EPOR gene mutations using SSCP analysis and found a C5964G mutation in exon VIII that changes tyrosine codon 426 to a translation termination codon resulting in an EPOR protein truncated by 83 amino acids. The mutant C5964G-EPOR exhibited hypersensitive EPO-dependent proliferation compared to the wild-type EPOR when tested in a murine interleukin-3-dependent myeloid cell line (FDC-P1). We also examined the segregation of the mutation with PFCP in the family and found that a child in the third generation inherited the mutation without having laboratory evidence of polycythemia. Further in vitro analysis of the erythroid progenitor cells of this affected child revealed that the progenitor cells were hypersensitive to EPO (a hallmark of PFCP) suggesting the presence of the disease at the level of progenitor cells. Failure of this child to develop polycythemia suggests the existence of as yet unidentified environmental or genetic factors that may suppress disease development.

Plasma erythropoietin by high-detectability immunoradiometric assay in untreated and treated patients with polycythaemia vera and essential thrombocythaemia

By using an immunoradiometric method with a stated detection limit of < or =1 IU/l (stated normal reference limit in adults 3.7-16 IU/l) we determined EDTA-plasma erythropoietin (EPO) in 58 patients with polycythaemia vera (PV) and 49 patients with essential thrombocythaemia (ET). At the time of blood sampling, 20 of the PV patients were newly diagnosed and untreated, 23 were treated by phlebotomy only, and 30 also received myelosuppressive treatment (with 32P, hydroxyurea or alpha-interferon). Of the ET patients 24 were untreated and 28 received myelosuppressive therapy. For comparison plasma EPO was also determined in 10 patients with pseudopolycythaemia (PP). In this latter group the results for plasma EPO agreed well with the cited normal reference limits. The majority of untreated PV patients (12/20) had undetectable plasma EPO concentration, and the remainder all had values below the lower normal reference limit. Plasma EPO in PV was not significantly influenced by phlebotomy therapy. Twelve of the 24 untreated ET patients (50%) had plasma EPO values below the reference interval (undetectable in 2 patients). The mean EPO concentration was significantly lower in PV patients receiving phlebotomy therapy than in patients with untreated ET. In the total material of PV and ET treated with myelosuppressive agents the PV patients showed significantly lower values for EPO concentration than did patients with ET. The present results support the view that EPO measurements by high-detectability methods are diagnostically useful and should be included in the panel of new criteria for the diagnosis of PV.

Polyuria and polydipsia and disturbed vasopressin release in 2 dogs with secondary polycythemia

In dogs, secondary polycythemia (SP) may be associated with polyuria and polydipsia (PU/PD). The pathogenesis of this PU/PD has not yet been explained. We hypothesized that hyperviscosity and increased blood volume in SP might affect vasopressin (VP) release, resulting in PU/PD. This hypothesis was tested in 2 dogs with SP caused by renal neoplasia and PU/PD. Osmoregulation of VP release was studied by a modified water deprivation test and by investigating the VP response to hypertonic saline infusion. Water deprivation test results were consistent with an inability to produce concentrated urine despite increasing plasma osmolality. During hypertonic saline infusion, the osmotic threshold of VP release was markedly increased in both dogs, resulting in a delayed VP response to increasing plasma osmolality. The sensitivity of VP release was low normal in both dogs. We conclude that blood hyperviscosity and increased blood volume led to impaired VP release and polyuria.

Two New EPO Receptor Mutations: Truncated EPO Receptors Are Most Frequently Associated With Primary Familial and Congenital Polycythemias

Primary polycythemias are caused by an acquired or inborn mutation affecting hematopoietic/erythroid progenitors that results in an abnormal response to hematopoietic cytokines. Primary familial and congenital polycythemia (PFCP; also known as familial erythrocytosis) is characterized by elevated red blood cell mass, low serum erythropoietin (EPO) level, normal oxygen affinity of hemoglobin, and typically autosomal dominant inheritance. In this study we screened for mutations in the cytoplasmic domain of the EPO receptor (EPOR; exons 7 and 8 of the EPOR gene) in 27 unrelated subjects with primary or unidentified polycythemia. Two new EPOR mutations were found, which lead to truncation of the EPOR similarly to previously described mutations in PFCP subjects. The first is a 7-bp deletion (del59855991) found in a Caucasian family from Ohio. The second mutation (5967insT) was found in a Caucasian family from the Czech Republic. In both cases the EPO dose responses of the erythroid progenitors of the affected subjects were examined to confirm the diagnosis of PFCP. In one of these families, the in vitro behavior of erythroid progenitors in serum-containing cultures without the addition of EPO mimicked the behavior of polycythemia vera progenitors; however, we show that antibodies against either EPO or the EPOR distinguish the in vitro growth abnormality of polycythemia vera erythroid progenitors from that seen in this particular PFCP family. We conclude that PFCP is a disorder that appears to be associated in some families with EPOR mutations. So far, most of the described EPOR mutations (6 out of 8) associated with PFCP result in an absence of the C-terminal negative regulatory domain of the receptor.

Effect of isobaric hyperoxemia on erythropoietin secretion in hypertensive patients

We assessed the influence of hyperoxemia on erythropoietin secretion in patients with various etiological forms of arterial hypertension (essential, n = 15; renoparenchymal, n = 16; renovascular, n = 15) and in 15 healthy subjects. On the first day of the study, blood was withdrawn at 1-hour intervals for the estimation of erythropoietin during a total of 6 hours and at 2-hour intervals for the assessment of PO2. Three days later the same parameters were assessed again at identical time intervals, but the subjects were breathing pure oxygen during the first 2 hours. Breathing with pure oxygen resulted in a significant increase of blood PO2 (184.85 +/- 4.47 versus 85.92 +/- 2.28 in essential, 185.21 +/- 5.52 versus 84.55 +/- 3.04 in renoparenchymal, and 181.7 +/- 3.14 versus 87.49 +/- 2.25 in renovascular hypertension groups and 189.84 +/- 5.2 versus 85.89 +/- 1.73 mm Hg in healthy subjects; P < .001 in all groups). Baseline plasma erythropoietin was not different among the groups (29.33 +/- 4.14 in essential, 24.56 +/- 3.09 in renoparenchymal, and 27.77 +/- 3.29 in renovascular hypertension groups and 24.23 +/- 2.70 mU/mL in the control group). The pattern of erythropoietin decline was different in the groups of hypertensive patients. In patients with essential hypertension, unlike in healthy subjects and patients with other etiological forms of arterial hypertension, only a very short-term suppression of erythropoietin levels was observed during hyperoxemia. No significant changes in blood pressure during breathing with pure oxygen were found in any of the studied groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Polycythaemia vera in a dog treated by repeated phlebotomies

Polycythaemia vera (PV) was diagnosed in a dog by demonstration of an increased red cell mass in association with normal arterial oxygen saturation and the absence of conditions known to be associated with secondary polycythaemia. The dog was treated exclusively by repeated phlebotomies and replacement of the removed volume by colloid and crystalloid solutions. It survived for one year and was generally free of signs.

Polycythemia vera

Polycythemia vera (PV) is one of the myeloproliferative diseases, and, as such, is an example of clonal hematopoiesis. The progeny of a single, abnormal, hematopoietic stem cell gain a growth advantage over their normal counterparts resulting in overproduction of red cells generally accompanied by overproduction of granulocytes and platelets as well. There are a variety of nonspecific symptoms at onset related to the increased red cell mass and hematocrit accompanied by the more specific manifestations of pruritus, erythromelalgia, and hepatic, portal, and mesenteric vein thrombosis. Splenomegaly and hypertension are common. The laboratory hallmark is an increased red cell mass. There is also often an increase in white cell count, platelet count, and leukocyte alkaline phosphatase along with other findings reflecting the increased rate of turnover of hematopoietic cells. The bone marrow biopsy generally displays hypercellularity involving all three cell lines and absent iron stores. The diagnosis of PV depends on excluding spurious polycythemia in which there is a high hematocrit but a normal red cell mass and secondary polycythemia in which there is an increased red cell mass in response to tissue hypoxia or the inappropriate production of erythropoietin, generally by a tumor. In addition, one should try to establish the diagnosis in a positive fashion by a combination of studies of the blood and bone marrow. Phlebotomy and occasionally plateletpheresis should be used as acute therapy. Chronic therapy is guided by the knowledge that patients treated with phlebotomy alone have an increased rate of thrombotic complications particularly in older patients and those with previous thrombotic disease. Myelosuppressive therapy can reduce the incidence of these complications, but is commonly associated with an increased incidence of second malignancies, particularly acute leukemia. At present, hydroxyurea is the myelosuppressive agent of choice. Antiplatelet agents have a limited role except in the palliation of the syndrome of erythromelalgia. Median survival is approximately 10 years. As implied above, the causes of morbidity and mortality vary with the mode of chronic therapy which has been employed, leukemia being more common after myelosuppressive therapy and thrombotic complications being more common after therapy with phlebotomy alone. Ten percent to 50% of patients move into a spent phase followed by postpolycythemic myeloid metaplasia, irrespective of previous therapy employed. Eventually, the major problems may be cytopenias and massive splenomegaly.

Hematologic manifestations of malignancy

Hematologic dysfunction occurs commonly in patients with malignancy. Over half are anemic, often because of acute or chronic blood loss, marrow involvement by the malignancy, marrow suppressive effects of chemotherapy or radiation therapy, or because of the anemia of chronic disease. Less frequently, anemia may result from red cell aplasia, folate or B12 deficiency, hemolytic processes, or hypersplenism. Occasional patients may become polycythemic because of erythropoietin-producing tumors such as renal adenocarcinomas or cerebellar hemangiomas. Elevation of the white cell count is commonly seen, especially in patients with lung cancer. Monocytosis and thrombocytosis, which may be early signs of an underlying malignancy, are also very common and occur in up to half of patients. Thrombocytopenia is commonly a result of therapy or marrow replacement; a few patients may have a syndrome resembling immune thrombocytopenic purpura. Abnormalities of coagulation are present in many patients, and may lead to superficial or deep venous thromboses, pulmonary emboli, nonbacterial thrombotic endocarditis with arterial emboli, bleeding, or acute disseminated intravascular coagulation. A sound understanding of the potential hematologic complications that can result from the malignant process is essential to the clinician caring for cancer patients.

Polycythemia: evaluation and management

The approach to diagnosis and classification of patients with polycythemia is reviewed with presentation of general and specific guidelines for the management of patients with polycythemia vera, secondary polycythemia and relative polycythemia.

Spontaneous resolution of primary erythrocytosis in two girls

We report two girls with primary erythrocytosis in whom extensive diagnostic studies revealed no underlying cause. Normal growth of colonies derived from erythroid burst forming units (BFU-E) was observed, and serum erythropoietin concentrations were within or below the normal range. The absence of a rise in serum erythropoietin levels after isovolemic phlebotomy implicated the erythroid marrow as the site of the pathophysiologic abnormality in both patients. Spontaneous resolution of erythrocytosis occurred during the second decade of life. Our experience suggests that primary erythrocytosis may be self-limited in some children. In these cases, the proliferative abnormality may be sufficiently subtle as to not be detected by standard in vitro culture systems, which support the growth of colonies derived from erythroid progenitors.

Chronic hypoxaemia and decompensated erythrocytosis in cyanotic congenital heart disease

Among forty adults with cyanotic congenital heart disease there was a subset of eleven patients with especially pronounced erythrocytosis, repeatedly rising haematocrit, recurring symptoms of hyperviscosity, and little or no shift of the haemoglobin/oxygen-dissociation curve. These patients were iron deficient as a result of many therapeutic phlebotomies; nevertheless their red-cell mass was comparable to that in iron-replete patients with similar, but stable, haematocrits. Iron repletion in the deficient patients resulted in rapidly increasing haematocrit and hyperviscosity. In one extreme case, erythropoiesis remained persistently iron deficient despite normal serum iron and ferritin levels. "Decompensated erythrocytosis" is an apt term for the excessive erythrocytic response and the associated phenomena.

Determination of serum immunoreactive erythropoietin in the investigation of erythrocytosis

We assessed the diagnostic value of determinations of serum levels of immunoreactive erythropoietin in 90 patients referred for the investigation of a raised packed red-cell volume (hematocrit) and possible erythrocytosis (a red-cell volume greater than that predicted by weight, body-surface area, or both). The mean values for erythropoietin were 16 mIU per milliliter (range, 8 to 22) in patients with polycythemia rubra vera (n = 24), 30 mIU per milliliter (range, 14 to 123) in patients with secondary erythrocytosis (n = 12), 27 mIU per milliliter (range, 13 to greater than 400) in patients with erythrocytosis of unknown origin (n = 19), and 25 mIU per milliliter (range, 18 to 35) in normal controls (n = 25). The values in the patients with polycythemia rubra vera were lower than those in the other three groups (P less than 0.01, P less than 0.05, and P less than 0.0001, respectively). In subjects with an increased packed red-cell volume but without erythrocytosis (n = 35), the levels of serum erythropoietin were the same as those in normal controls. Among patients with erythrocytosis with an unknown cause, abnormally high serum erythropoietin levels were found in 3 of 19 subjects, and in 1 of these 3 the abnormality was intermittent. Thus, measurement of serum erythropoietin in a single sample may be misleading and may not have high discriminatory value in distinguishing between polycythemia rubra vera and secondary erythrocytosis. This assay is useful in identifying patients with secondary erythrocytosis who have inappropriate erythropoietin secretion.

Secondary polycythaemia associated with large cell lymphoma

We describe the case of a 53-year-old woman in whom early stage large cell lymphoma appears to be associated with secondary erythrocytosis. A haemogram obtained six months earlier had been normal, but at the time lymphoma was diagnosed, investigations showed haemoglobin 20.5 gm/dl, total red cell count 6 X 10(12)/liter, haematocrit 0.60 liters/liter, whole blood volume 81.1 ml/kg, red cell volume 43.2 ml/kg, and plasma volume 37.8 ml/kg. Other investigations revealed no evidence of any other myeloproliferative disorder, and common causes of tissue hypoxia and other well-known causes of secondary polycythaemia were excluded. Combination chemotherapy employed to treat lymphoma reverted the abnormal blood counts to normal. We believe this to be the first described case of an association of lymphoma and secondary polycythaemia.