Pancytopenia--a clinico-hematologic analysis of 77 cases

The present study was conducted in the department of Haematology and Transfusion Medicine, Government Medical College & Hospital, Chandigarh over a period of 32 months. During this period pancytopenia was an indication for bone marrow (aspiration and or trephine) in 77 out of a total of 205 cases (37.6%). The most common cause of pancytopenia as revealed by bone marrow was megaloblastic anaemia (68%) followed by aplastic anaemia (7.70%). This study also revealed few uncommon and rare, but interesting causes of pancytopenia like drug induced agranulocytosis, hemophagocytic syndrome and waldenstroms macroglobinemia.

Intrathecal methotrexate-induced megaloblastic anemia in patients with acute leukemia

OBJECTIVE

To evaluate the occurrence of megaloblastic anemia induced by the infusion of therapeutic or prophylactic methotrexate in patients with acute leukemia.

DESIGN

Data on 3 patients with acute leukemia receiving intrathecal methotrexate were prospectively analyzed.

SETTING

Large tertiary-care center.

RESULTS

All 3 patients with acute leukemia developed megaloblastic anemia confirmed by examination of the bone marrow aspirate and biopsy. Two of the 3 patients had low folic acid levels, while all patients had normal serum B(12) levels. All patients responded favorably to a therapeutic trial of folic acid. The median time for recovery of the hematologic parameters in these patients was 7 days.

CONCLUSIONS

Intrathecally administered methotrexate may result in megaloblastic changes in the bone marrow of leukemic patients. The morphologic clues suggestive of folate deficiency in patients with acute leukemia may be masked by coexisting factors, such as the effects of cytotoxic treatment, prior transfusions, or persistent changes from the leukemic clone itself. Caution should be exercised to avoid attributing these changes to the neoplastic process, since the prognosis and treatment for the conditions involved are totally different. Repeat examination of the bone marrow, obtaining folic acid and vitamin B(12) levels, and a therapeutic trial of folic acid may help identify and reverse these changes.

Haemolytic uraemic syndrome and pulmonary hypertension in a patient with methionine synthase deficiency

An 18-month-old girl presented with macrocytic megaloblastic anaemia followed by haemolytic uraemic syndrome. Metabolic investigations led to the identification of an inborn error of cobalamin metabolism consisting of defective methylcobalamin biosynthesis, probably cobalamin G, since methionine synthase activity was decreased under standard reducing conditions. Despite treatment, pulmonary hypertension progressively developed and responded to oxygen therapy. Renal involvement evolved to terminal failure and haemodialysis, while pulmonary hypertension was controlled by oxygen therapy. Such clinical manifestations have never been reported in association with a defect of methylcobalamin and thus of methionine biosynthesis. A congenital abnormality of cobalamin metabolism was suspected then confirmed in the presence of typical haematological features associated with unusual clinical manifestations such as progressive renal failure and pulmonary hypertension.

Mutations in SLC19A2 cause thiamine-responsive megaloblastic anaemia associated with diabetes mellitus and deafness

Thiamine-responsive megaloblastic anaemia (TRMA), also known as Rogers syndrome, is an early onset, autosomal recessive disorder defined by the occurrence of megaloblastic anaemia, diabetes mellitus and sensorineural deafness, responding in varying degrees to thiamine treatment (MIM 249270). We have previously narrowed the TRMA locus from a 16-cM to a 4-cM interval on chromosomal region 1q23.3 (refs 3,4) and this region has been further refined to a 1.4-cM interval. Previous studies have suggested that deficiency in a high-affinity thiamine transporter may cause this disorder. Here we identify the TRMA gene by positional cloning. We assembled a P1-derived artificial chromosome (PAC) contig spanning the TRMA candidate region. This clarified the order of genetic markers across the TRMA locus, provided 9 new polymorphic markers and narrowed the locus to an approximately 400-kb region. Mutations in a new gene, SLC19A2, encoding a putative transmembrane protein homologous to the reduced folate carrier proteins, were found in all affected individuals in six TRMA families, suggesting that a defective thiamine transporter protein (THTR-1) may underlie the TRMA syndrome.

Mutations in a new gene encoding a thiamine transporter cause thiamine-responsive megaloblastic anaemia syndrome

Thiamine-responsive megaloblastic anaemia syndrome (TRMA; MIM 249270) is an autosomal recessive disorder with features that include megaloblastic anaemia, mild thrombocytopenia and leucopenia, sensorineural deafness and diabetes mellitus. Treatment with pharmacologic doses of thiamine ameliorates the megaloblastic anaemia and diabetes mellitus. A defect in the plasma membrane transport of thiamine has been demonstrated in erythrocytes and cultured skin fibroblasts from TRMA patients. The gene causing TRMA was assigned to 1q23.2-q23.3 by linkage analysis. Here we report the cloning of a new gene, SLC19A2, identified from high-through-put genomic sequences due to homology with SLC19A1, encoding reduced folate carrier 1 (refs 8-10). We cloned the entire coding region by screening a human fetal brain cDNA library. SLC19A2 encodes a protein (of 497 aa) predicted to have 12 transmembrane domains. We identified 2 frameshift mutations in exon 2. a 1-bp insertion and a 2-bp deletion, among four Iranian families with TRMA. The sequence homology and predicted structure of SLC19A2, as well as its role in TRMA, suggest that its gene product is a thiamine carrier, the first to be identified in complex eukaryotes.

The gene mutated in thiamine-responsive anaemia with diabetes and deafness (TRMA) encodes a functional thiamine transporter

Thiamine-responsive megaloblastic anaemia with diabetes and deafness (TRMA; MIM 249270) is an autosomal recessive disease thought to be due to a defect in thiamine (vitamin B1) transport. Pharmacological doses of thiamine correct the anaemia, and in some cases improve the diabetes, although progressive sensorineural deafness is irreversible. Previous studies localized the TRMA gene to a 4-cM region on chromosome 1q23.3 (ref. 5), and fine-mapping has recently narrowed that region further. We have previously demonstrated that fibroblasts from people with TRMA lack high-affinity thiamine transport. Expression of a gene encoding a known yeast thiamine transporter, THI10 (refs 8-10), in TRMA mutant cells prevents apoptotic cell death in thiamine-depleted medium. On the basis of these studies, we hypothesized that a defective thiamine transporter causes TRMA. We undertook a candidate gene approach to identify putative thiamine transporters in the 1q23.3 critical region. Here we present evidence that the gene SLC19A2 (for solute carrier family 19 (thiamine transporter), member 2) encodes the first known mammalian thiamine transporter, which we designate thiamine transporter-1 (THTR-1).

Pancytopenia in Zimbabwe

BACKGROUND

There has been little systematic study of the clinical spectrum of pancytopenia, and the optimal diagnostic approach to pancytopenia remains undefined.

METHODS

The authors studied 134 hospitalized pancytopenic patients in Zimbabwe in both consecutive and nonconsecutive fashion.

RESULTS

The most common cause of pancytopenia was megaloblastic anemia, followed by aplastic anemia, acute leukemia, acquired immunodeficiency syndrome (AIDS), and hypersplenism. Severe pancytopenia was usually due to aplastic anemia. Patients with aplastic anemia and acute leukemia were usually children, whereas those with megaloblastic anemia were adults. Moderate to severe anemia was noted throughout the series, but was most striking in patients with megaloblastic anemia, aplastic anemia, and acute leukemia. The mean corpuscular volume (MCV) was elevated in most patients with megaloblastic hematopoiesis, aplastic anemia, and acute nonlymphocytic leukemia. Normal or low MCV values were noted in almost one third of patients with megaloblastic anemia. Anisocytosis, poikilocytosis, macroovalocytosis, microcytosis, fragmentation, and teardrop erythrocytes were more prominent on the blood films of patients with megaloblastic anemia.

CONCLUSIONS

Megaloblastic anemia, aplastic anemia, and AIDS are the most common causes of pancytopenia in Zimbabwe. Aplasia is the most frequent cause of severe pancytopenia. The authors have formulated tentative guidelines for the evaluation of pancytopenic patients in this setting.

Folate deficiency beyond megaloblastic anemia: hyperhomocysteinemia and other manifestations of dysfunctional folate status

Folate plays a key role in nucleic acid synthesis. As a consequence, the most conspicuous complication of folate deficiency or of derangements of folate metabolism is megaloblastic macrocytic anemia caused by interdiction of normal proliferation of rapidly dividing bone marrow cells. Other rapidly dividing cells, including those in the gastrointestinal tract, may also be affected by the megaloblastic process. This may result in malabsorption. However, there is mounting evidence to indicate that there are other earlier manifestations of folate deficiency or of longstanding suboptimal folate nutrition. Chief among these manifestations of folate deficiency are an increased predisposition to occlusive vascular disease and thrombosis, which have been linked to increased levels of homocysteine found in folate deficiency and abnormal states of folate metabolism. In addition, folate deficiency, previously considered free of neurological consequences, is now known to be associated with disturbances of mood, and even spinal cord syndromes similar to those seen in vitamin B12 deficiency. Finally, there is both experimental and clinical evidence to suggest that folate deficiency may interfere with immunologic status and may be associated with an increased predisposition to neoplasia. Nutritional as well as genetic factors may contribute to these various nonhematological manifestations of folate insufficiency.

Long-term follow-up of diabetes in two patients with thiamine-responsive megaloblastic anemia syndrome

OBJECTIVE

To describe a 15-year follow-up of diabetes and to present data regarding pancreatic beta-cell function in two adolescents affected by the thiamine-responsive megaloblastic anemia (TRMA) syndrome.

CASE REPORTS

The first patient (PMR) is a 17.5-year-old Italian girl who presented megaloblastic anemia at 7.5 months of age. At age 2.5 years, because of the presence of diabetes and sensorineural deafness, she was diagnosed with TRMA syndrome and started treatment with thiamine-HCl, followed very early by benzoyloxymethyl-thiamine (BOM-T). The second patient (PF) is a 16.8-year-old Italian boy born to consanguineous parents. Sensorineural deafness was diagnosed at age 1.5 years, while diabetes with ketoacidosis and megaloblastic anemia were diagnosed at age 3 years. Treatment with thiamine HCl was started immediately after diagnosis and changed to BOM-T 2 months later. Subsequent to the initiation of the vitamin, the two patients did not require insulin for approximately 7 and 10 years, respectively. Puberty was determinant in deteriorating the metabolic control in these patients, leading to treatment with an oral hypoglycemic agent and finally to a reinstitution of insulin therapy.

CONCLUSIONS

The hormonal assessment in our patients (normal insulin response to oral glucose in childhood, preserved C-peptide secretion in case 2) and the good response to an oral hypoglycemic agent would indicate that the pancreatic disease may initiate as type 2 diabetes and may progress after several years to an insulin-requiring diabetes, as indicated by the exhaustion of the insulin secretory capacity.

Neurologic findings of vitamin B12 deficiency: presentation of 7 cases

In this report, seven children, four males and three females, between the ages of five and 16 years with megaloblastic anemia and neuropsychiatric disorders are presented. Macrocytosis was identified in peripheral blood smears in all seven patients. Serum B12 levels were markedly reduced in four and were at the lower limit of normal in three patients. The Schilling test showed that B12 deficiency was due to specific cobalamin malabsorption in five and to inadequate dietary intake in two patients. Both neurological and hematological findings returned to normal after B12 replacement. This study shows that B12 deficiency should be considered in the differential diagnosis of neuropsychiatric disorders in children, including those with nonvegetarian habits, and that such patients should undergo a thorough hematological evaluation.

Failure to thrive is an early symptom of the imerslund Gräsbeck syndrome

PURPOSE

The Imerslund-Gräsbeck syndrome (IGS) is a rare inherited disorder characterized by a megaloblastic anemia due to a selective vitamin B12 malabsorption in association with a mild proteinuria. Usually recurrent infections, gastrointestinal complaints, and pallor are presenting symptoms. We report two cases of IGS with an unusual presentation.

PATIENTS AND METHODS

Two girls are described with the Imerslund-Gräsbeck syndrome who had a failure to thrive as a presenting symptom without infections or gastrointestinal complaints. The diagnosis of IGS was based on marked macrocytic anemia, very low serum vitamin B12 levels, abnormal Schilling urinary excretion test results, and mild proteinuria. When parenteral vitamin B12 was started, a rapid catch-up growth was seen in both girls.

CONCLUSIONS

The absence of well-known causes of failure to thrive, such as recurrent infections and gastrointestinal complaints, favors the concept that the metabolic disturbances caused by an isolated cobalamin deficiency as seen in IGS causes a failure to thrive.

Thiamine-responsive megaloblastic anemia with diabetes mellitus and sensorineural deafness

This study introduces a patient who has thiamine and thiamine pyrophosphokinase (TPKase) enzyme deficiency associated with diabetes mellitus, sensorineural deafness and thiamine-responsive megaloblastic anemia. Diabetes mellitus was diagnosed when she was 20 months old. After 1 year, macrocytic anemia developed and the thiamine therapy was started at 75 mg/day. During the follow-up, the insulin requirement decreased and even ceased, and macrocytic anemia improved with thiamine treatment. After thiamine therapy was ceased an increase in insulin requirement was observed and macrocytic anemia developed again.

[Selective vitamin B12 absorption disorder (Imerslund-Gräsbeck syndrome)]

The authors present a case of Imerslund-Gräsbeck syndrome, i. e. a familial megaloblastic anemia with proteinuria. The disease is due to congenital, selective malabsorption of vitamin B12. The subnormal absorption of vitamin B12 is not altered by orally given intrinsic factor, but parenteral vitamin B12 therapy results in complete recovery. Approximately 150 cases have been described in literature, the authors' case is the first in Hungary.

Bilateral retinal hemorrhages from megaloblastic anemia: case report and review of literature

A 33-year-old woman who was a chronic alcohol abuser and had bilateral visual loss was found to have megaloblastic anemia with thrombocytopenia. Both fundi showed retinal venular dilatation and tortuosity, superficial and deep intraretinal hemorrhages, white-centered retinal hemorrhages, and optic disc edema. Her megaloblastic anemia was caused by vitamin B12 and folate deficiencies, resulting from an inadequate diet and alcohol abuse. The retinal changes were believed to be the result of the severe anemia and thrombocytopenia. Both the megaloblastic anemia and retinal changes resolved promptly after she received vitamin B12 and folate supplements. This case shows that megaloblastic anemia should be suspected as a cause of bilateral retinal hemorrhages.

Megaloblastic anemia associated with psoriasis: case report and review of the literature

A 68-yr-old male with severe psoriasis developed megaloblastic anemia due to folate deficiency 3 months after the cessation of low-dose methotrexate therapy. The mechanism of megaloblastic anemia in this case was suggested to be multifactorial. The case report and a review of megaloblastic anemia associated with psoriasis are presented.

[Long-term follow up of patients with pernicious anemia]

The authors give several data of 357 patients with megaloblastic anaemia diagnosed, treated and controlled between 1958-1988. 334 of the patients had anaemia perniciosa and 23 of them had postresectional megaloblastic anaemia. After listing the criteria of the diagnosis the authors detail the mean age of the patients at the time of diagnosis, the distribution of sexes, age and blood groups among the patients, the number of new cases per year, the frequency of relapsus of the disease and its association with other autoimmune diseases. They also deal with the characteristic seasonal fluctuation and the accumulated cases in families. Its association with malignant tumours, especially with stomach carcinoma was examined.

[Megaloblastic anemia and platelet function--a qualitative platelet defect in pernicious anemia]

In order to know the entities of platelet defect in pernicious anemia, we investigated platelet functions in ten cases with pernicious anemia. Three of the cases had total gastrectomy. Five cases showed thrombocytopenia and four cases revealed prolongation of Ivy bleeding time. Decreased adhesiveness was observed in three cases. Various abnormalities in platelet aggregation were observed. However, almost all of the cases showed remarkable improvement of decreased platelet functions after the therapy of Vitamin B12 injection. The results of adenine nucleotides in platelets and the release of them following collagen or epinephrine aggregation were analysed in comparison with normal platelets. The ADP was definitely decreased and the ATP/ADP ratio was increased. In addition, the release of ATP and ADP at collagen or epinephrine induced aggregation was markedly decreased, and after the therapy of Vitamin B12, the decrease of adenine nucleotide release remarkably increased. In summary, the acquired defects of platelet function in pernicious anemia are regarded as a secondary storage pool disease, and its defects improve after Vitamin B12 therapy.

Pancytopenia in nutritional megaloblastic anaemia. A study from north-west India

We have analysed 139 consecutive cases (71 males and 68 females) of nutritional megaloblastic anaemia over a period of four and a half years. The majority of these patients belonged to the low socio-economic class and many of them were strict vegetarians. Sixty one percent were in the second and third decades of life. At the time of presentation, 46% had mild hepatomegaly, 42% fever, 34% mild splenomegaly and 20% bleeding manifestations. Of 102 cases in whom the biochemical parameters were available, vitamin B12 deficiency was detected in 76%, folate deficiency in 6.8%, combined B12 and folate deficiency in 8.8%; the remaining 7.8% had normal vitamin levels at presentation. All 139 patients had severe anaemia, 80.5% had thrombocytopenia and 43.8% had neutropenia as well as thrombocytopenia. It appears that during progression (in terms of duration) of megaloblastosis, anaemia is followed by thrombocytopenia and then neutropenia. Infection and bleeding in these patients may be aggravated by impaired functions of neutrophils and platelets, respectively.

Bleeding manifestations in megaloblastic anemia

Ten children with megaloblastic anemia and a hemorrhagic diathesis are reported. Four of them had life-threatening bleeds necessitating an emergency blood transfusion. Seven had platelet counts of less than 30,000/cu mm, and nine had hemoglobin values of less than or equal to 5.2 g/dl at initial presentation. Deficiency of vitamin B12 was more frequently encountered. Response to therapy was excellent and hemostasis was possible within 12 to 24 hours of initiating treatment.

Neuropsychiatric disorders caused by cobalamin deficiency in the absence of anemia or macrocytosis

Among 141 consecutive patients with neuro-psychiatric abnormalities due to cobalamin deficiency, we found that 40 (28 percent) had no anemia or macrocytosis. The hematocrit was normal in 34, the mean cell volume was normal in 25, and both tests were normal in 19. Characteristic features in such patients included paresthesia, sensory loss, ataxia, dementia, and psychiatric disorders; longstanding neurologic symptoms without anemia; normal white-cell and platelet counts and serum bilirubin and lactate dehydrogenase levels; and markedly elevated serum concentrations of methylmalonic acid and total homocysteine. Serum cobalamin levels were above 150 pmol per liter (200 pg per milliliter) in 2 patients, between 75 and 150 pmol per liter (100 and 200 pg per milliliter) in 16, and below 75 pmol per liter (100 pg per milliliter) in only 22. Except for one patient who died during the first week of treatment, every patient in this group benefited from cobalamin therapy. Responses included improvement in neuropsychiatric abnormalities (39 of 39), improvement (often within the normal range) in one or more hematologic findings (36 of 39), and a decrease of more than 50 percent in levels of serum methylmalonic acid, total homocysteine, or both (31 of 31). We conclude that neuropsychiatric disorders due to cobalamin deficiency occur commonly in the absence of anemia or an elevated mean cell volume and that measurements of serum methylmalonic acid and total homocysteine both before and after treatment are useful in the diagnosis of these patients.

Vitamin B12 responsive homocystinuria and megaloblastic anemia: heterogeneity in methylcobalamin deficiency

A male infant with methyl-B12 deficiency (cblE) presented at age 6 weeks with lethargy, staring spells, and vomiting. He later became hypotonic and unresponsive to stimuli and required intubation and ventilation. He had homocystinuria and hypomethioninemia with megaloblastic anemia but normal serum folate and vitamin B12 concentrations. No methylmalonic aciduria was detected. Fibroblasts, cultured from the patient, were unable to grow in medium in which homocysteine replaced methionine and incorporated abnormally small amounts of [14C]-methyl-tetrahydrofolate but normal amounts of [14C]-propionate into protein. Methyl-B12 content of fibroblasts was low, while the adenosyl-B12 content was normal. Methionine synthase activity was decreased when the assay was performed under both optimal and suboptimal reducing conditions, suggesting heterogeneity in the cblE disease. The patient responded dramatically to hydroxocobalamin treatment. Homocystinuria disappeared after 10 days of therapy, and methionine was normalized after 3 weeks. Psychometric testing at age 15 months showed a developmental age of 9 months.

Successful reversal by chelation therapy of congestive cardiomyopathy due to iron overload

A patient who developed severe iron overload cardiomyopathy is described. Venesection could not be performed because the patient had chronic anemia. Deferoxamine mesylate, a chelating agent, was administered daily for more than 2 years and produced significant improvement in ventricular function which was associated with a biopsy-proven decrease in myocardial iron stores. This is the first reported case in which a severe cardiomyopathy due to iron overload was reversed by chelation therapy alone.

[Coexistence of late spondyloepiphyseal dysplasia and congenital megaloblastic anemia with proteinuria in the same family]

A case of spondyloepiphyseal dysplasia tarda was noted in a dwarf (130 cm tall) 18 years old boy associated with congenital megaloblastic anemia and proteinuria. His two sisters and a cousin are also suffering from similar hematologic disorder. One of his brothers, 145 cm tall, is also involved by spondyloepiphyseal dysplasia, but there is no known hematologic abnormalities. Review of family history revealed that two aunts from mother's side were deceased in adulthood following a chronic anemic disease. The findings in this anemia are compatible with Imerslund-Grâsbech syndrome and coexistence of these two rare genetic disorders in a single family has not been reported previously.

Altered vitamin B12 metabolism in fibroblasts from a patient with megaloblastic anemia and homocystinuria due to a new defect in methionine biosynthesis

Cultured fibroblasts from a recently described patient with homocystinuria and megaloblastic anemia of infancy without methylmalonic aciduria were previously shown to have normal cobalamin uptake and a specific decrease in the proportion of intracellular methylcobalamin. As in control cells but unlike in those from patients with combined homocystinuria and methylmalonic aciduria (cobalamin C and cobalamin D), accumulated 57Co-labeled cobalamin was bound in appropriate amounts and proportion to intracellular binders which are known to be the two vitamin B12-dependent enzymes, methionine synthetase and methylmalonyl-CoA mutase. Despite the association of a normal quantity of intracellular cobalamin with methionine synthetase, the proportion of intracellular cobalamin which was methyl-B12 was below normal and in the range observed in cobalamin C and D cells. This methyl-B12 was decreased by exposure of fibroblasts in culture to nitrous oxide as was observed with control cells. Exposure of control fibroblasts during culture, but not of fibroblasts from this patient, to nitrous oxide significantly reduced the holoenzyme activity of methionine synthetase assayed in cell extracts. In addition, although methionine synthetase activity in cell extracts of control and cells from the patient were similar in the presence of standard assay concentrations of thiols, at low thiol concentrations, methionine synthetase activity in extracts of cells from the patient was much lower than in control extracts. Mixing of control patient extracts corrected this decreased activity in excess of that explained by addition of the individual activities added. The defect of this patient appears to be in a reducing system required for methionine synthesis.

Unusual presentation of multiple myeloma. A report of 2 cases

The diagnosis of multiple myeloma (overt plasma cell dyscrasia) is usually not considered in patients under 30 years of age. Furthermore, multiple myeloma with coexistent megaloblastic and iron deficiency anaemia is very uncommon. Within 6 months we encountered 2 patients under 30 years of age who had multiple myeloma, one with advanced secondary amyloidosis and the other with severe megaloblastic and iron deficiency anaemia.

[Thalassemia major manifested by megaloblastic anemia caused by folate deficiency]

In a 11 month-old child, a deep anemia with reticulocytopenia and megaloblastosis on bone marrow aspiration revealed a thalassemia major. The low folate intake and the increased needs probably account for initial findings. Folic acid deficiency has already been described in patients with dyserythropoiesis or chronic hemolysis. Daily folic acid treatment is necessary in these patients.

Acidosis and severe megaloblastic anaemia

Ten patients with severe megaloblastic anaemia were studied to investigate whether the causative metabolic defects might predispose them to lactic or other acidosis. One patient had compensated acidosis with hyperlactataemia before treatment but there were obvious causes other than anaemia. No other patient developed an acidosis. Neither anaemia per se nor the metabolic defects of vitamin B(12) or folic acid deficiency are likely to cause clinically significant lactic acidosis or hyperlactataemia.