Pregnancy Associated Aplastic Anemia--A Series of 10 Cases with Review of Literature

INTRODUCTION

Pregnancy induced aplastic anemia is a rare entity and the association is not well explained. There are approximately 80 cases in the literature and we are presenting the largest series, so far, of 10 cases.

RESULTS

Total of 10 cases had 11 pregnancies. Mean age at presentation was 25.45 years and mean gestation when symptoms first developed was 17.09 weeks. Pallor and bleeding manifestations were the most common presenting complaints. Mean Hb, TLC, ANC and platelets were 4.97 g/dl, 2.74 x 10(9)/l, 1.11 x 10(9)/l and 41 x 10(9)/l, respectively. Bone biopsy cellularity ranged from <5 to 25%. Nine out of 11 (81%) pregnancies were successful of which 7 was full term and 2 were premature. Two babies were small for dates. One spontaneous abortion and one intra uterine death (IUD) were observed. Two out of 11 mothers died due to disease after delivery. Two of the 8 surviving mothers, had spontaneous partial response (22%); 4 mothers were asymptomatic after therapy with immunosuppressives given for 6 months and 3 were lost to follow up without response. Specific therapy (cyclosporin) was tried in two mothers antenatally with partial response in one. One child whose mother was given cyclosporin antenatally had jejunal atresia at birth.

CONCLUSION

Pregnancy associated aplastic anemia is a rare association. Spontaneous remission can occur in 25-30% of patients. In the first trimester patients, pregnancy can be terminated while in advanced pregnancy patients can be followed up with stringent supportive care. Cyclosporin may be a safe drug antenatally in such patients. Patients with established aplastic anemia should avoid pregnancy.

Epidemiological features of aplastic anaemia in Pakistan

OBJECTIVE

To complete the data on the demographic features of patients diagnosed to have aplastic anemia at a single institution over a 7.5 years period.

METHODS

Demographic information was retrieved from the patients medical records retrospectively as well as prospectively of those patients who presented with features of aplastic anaemia. Their diagnosis was confirmed by performing a complete blood count and bone marrow trephine.

RESULTS

One hundred and forty four patients were diagnosed to have aplastic anemia; there were 106 males and 38 females. Their ages ranged from 2 to 75 years, with a median of 17 years, 112 (77.7%) patients were below the age of 30 years. Severe aplastic anemia (SAA) was seen in 74 (51.4%), very severe (VSAA) in 24 (16.7%) and non-severe aplastic anemia (NSAA) in 46 (31.9%) patients. No obvious cause could be established for 74.3%. Thirteen patients admitted using drugs known to cause AA and one was a radiographer (9%). Out of 44 patients tested, 7 (15.9%) were found to have either hepatitis B virus markers or antibody to hepatitis C at the time of diagnosis of AA. However it was difficult to establish a cause and effect relationship with either drugs or viruses.

CONCLUSION

Aplastic anaemia is found to occur mostly in young males. The most common type was idiopathic severe aplastic anaemia.

Spontaneous remission of aplastic anemia: a retrospective analysis

BACKGROUND AND OBJECTIVES

Although acquired aplastic anemia is usually a chronic disorder, a small proportion of patients with aplastic anemia was reported to recover spontaneously without specific therapy such as allogeneic bone marrow transplantation or immunosuppressive treatment. We attempted to determine the rate of spontaneous remission in the patients with AA.

DESIGN AND METHODS

We reviewed the medical records of adult patients (n=136) who were diagnosed as aplastic anemia at the Asan Medical Center from 1990 to 2000. The hematologic criteria of spontaneous remission were defined according to the proposed remission criteria of the SAA Working Party of the EBMT.

RESULTS

Eighteen (13%) of 136 patients satisfied the criteria for spontaneous remission at median 14 days (range, 4-332) from the diagnosis of aplastic anemia. In fifteen (83%) of 18 patients, spontaneous remission occurred within 50 days. Spontaneous remission was complete in fourteen patients (78%). Only two patients relapsed at 208 and 1,857 days after spontaneous remission, respectively. Multivariate logistic regression analysis showed that presence of infection at diagnosis (p = 0.017), drug as an etiology of aplastic anemia (p = 0.028), and serum albumin level less than 3.4 g/dL (p = 0.005) were independent predictive factors for spontaneous remission.

INTERPRETATION AND CONCLUSIONS

Our study confirmed that a minority of patients with AA recovered spontaneously. Spontaneous remission was rapid and complete in most patients, and relapses were rarely observed. In most cases with spontaneous remission, aplastic anemia might be associated with external factors such as drug or infection.

HLA-DR4-Ala74 beta is associated with risk and poor outcome of severe aplastic anemia

Severe aplastic anemia (SAA) is a heterogeneous hematological disorder with a high mortality. Genetic predisposition has been shown to play a role in a considerable proportion of SAA cases. For instance, the human lymphocyte antigen HLA-DR2 has been repeatedly demonstrated to be over-represented in SAA patients. In this paper, we expand on the evidence for the contribution of HLA polymorphism in the susceptibility to SAA, which was obtained using the "high-resolution" technique of HLA-DRB1 subtyping. The DRB1*1501 allele appeared to be responsible for the predominance of DR2 specificity in SAA patients and was the most significant risk factor for this disease. It was observed in 23/44 (52.3%) patients versus 22/100 (22.0%) donors [odds ratio (OR) = 3.9; 95% confidence interval (CI): 1.8-8.3; P = 0.0005, corrected P (Pc) < 0.05]. In addition, DRB1*04 alleles also displayed non-random distribution in the SAA group. In particular, DRB1*04 variants coding for alanine at position 74 of the DR beta 1 chain (HLA-DR4-Ala74 beta subtype) were detected in all 13 DR4-positive SAA patients but only in 15/24 (62.5%) controls (OR = 16.6; 95% CI: 0.9-312.0; P = 0.015). Multiple comparison analysis confirmed that the HLA-DR4-Ala74 beta subtype confers susceptibility to SAA independently from the DRB1*1501 allele. Finally, examination of the clinical records has shown that the HLA-DR4-Ala74 beta subtype is associated with poor outcome of SAA.

Agranulocytosis associated with calcium dobesilate clinical course and risk estimation with the case-control and the case-population approaches

OBJECTIVE

Calcium dobesilate is used in the treatment of diabetic retinopathy, chronic venous insufficiency, haemorrhoids and other ill-defined vascular conditions. It has been associated with agranulocytosis in anecdotal reports. We describe the clinical course of a series of patients who developed agranulocytosis while taking this drug, and we estimate the risk by means of both a case-control and a case-population strategy.

METHODS

All cases of agranulocytosis meeting strict predefined diagnostic criteria in an area of 3.3 to 3.9 x 106 inhabitants in the period 1980-1998 were identified. Cases and age-, gender- and hospital-matched controls were interviewed with a structured questionnaire including a detailed drug history. Each case was reviewed and confirmed by a haematologist, who was blind with respect to drug exposures. Consumption data were used to estimate the risk of agranulocytosis associated with calcium dobesilate using a case-population approach in which the incidence of agranulocytosis among users of calcium dobesilate was compared with that among the non-exposed population.

RESULTS

After a follow up of 68.55 x 10(6) person-years, 345 cases of agranulocytosis (242 community cases) were assembled. Reliable information was obtained from 216 cases. Two patients exhibited positive rechallenge. Twelve cases (5.6%) and 5 of 1380 controls (0.4%) had taken calcium dobesilate in the week before. With the case-control approach, the odds ratio was 23.66 [95% confidence interval (CI), 7.54-74.24], the attributable risk was 5.3% (95% CI, 3.0-9.4), and the number of cases attributable to dobesilate in the study area during the study period was 12.8. The case-population estimates were an incidence of 121.03 cases per 10(6) patient-years, a relative risk of 39.55 (95% CI, 17.96-77.49), an attributable risk of 6.73% (CI 3.4-12.9), and 16.30 cases attributable to dobesilate in the study area during the study period.

DISCUSSION

This study adds to evidence indicating that the case-population method is adequate for the study of rare type B adverse drug reactions. An additional advantage of this approach is that the incidence of the disease of interest among those exposed to the drug can be estimated. The risk of agranulocytosis associated with calcium dobesilate should be considered in relation to poor evidence of its clinical efficacy.

Bone marrow failure in children with acute liver failure

BACKGROUND

Aplastic anemia is a rare but well-recognized complication of acute hepatitis and acute liver failure. The cause is unknown, and the condition is fatal without bone marrow recovery. Treatment includes immunosuppression regimens or bone marrow transplantation. The purpose of this study was to investigate the incidence, cause, treatment, and outcomes of this disorder in children.

METHODS

Retrospective chart review of 75 patients with acute liver failure in a major pediatric liver center.

RESULTS

Eight patients had evidence of bone marrow failure. Of those, six had aplastic anemia, and two had transient bone marrow suppression. There were five boys, median age 57 months (range, 36-132 months). Two had parvovirus B19, six had non-A, non-B, non-C hepatitis. Five underwent liver transplantation: auxiliary in one, orthotopic in four. The interval between initial symptoms and development of aplastic anemia and/or bone marrow suppression was 21 to 99 days (median, 39 days). Four patients with aplastic anemia received intravenous antithymocyte globulin (ATG) or antilymphocyte globulin (ALG). Median recovery period of granulopoiesis was 62 days (range, 27-115 days). Two made a full recovery, one had myelodysplasia, and one with unresponsive disease died of septic complications. Four did not receive ATG/ALG, two had aplastic anemia, and two had bone marrow suppression. Three underwent liver transplantation, and all four resumed granulopoiesis. One child who underwent liver transplantation died of sepsis with chronic rejection. Median recovery of granulopoiesis was 99 days (range, 20-153 days).

CONCLUSIONS

Bone marrow failure occurs in 10.7% of children with acute liver failure. It sometimes occurs in association with non-A, non-B, non-C hepatitis and parvovirus B19 infection. Treatment with ATG/ALG is successful and is well tolerated in most cases.

Benzene and lymphohematopoietic malignancies in China

While this study is larger than previous investigations and includes workers with a wide range of exposures to benzene, the estimates of risk, as measured by statistical confidence intervals, are still fairly broad, and would benefit from the larger numbers that could be provided by continued follow-up of this population. Nevertheless, the study confirms earlier findings of increased risk for ANLL and aplastic anemia among benzene-exposed workers, provides the first substantial evidence that MDS is linked to benzene exposure, and provides evidence that benzene increases risk for ANLL/MDS at lower levels of exposure than had previously been demonstrated. Currently we are evaluating the potential for extending the follow-up of workers included in this study. A new study would include expanded data collection for cases of hematopoietic malignancy and related disorders and for an appropriate control series.

Impact of pesticides use on human health in Mexico: a review

Pesticides having a high adverse effect on the health and environment of inhabitants of the Mexican Republic were studied to establish the main parameters to bear in mind for their use and application. The investigation showed that Mexico is the agricultural zone with the highest health damage to its population from pesticides. The valid regulation norms for the use and application of these agrochemicals were analyzed. Case histories recorded by the public health sector in Mexico were reviewed. In this way, a strong relation was found between the health problems and the pesticides applied. Finally, the study concludes that the various Mexican States appear as a risk zone because of contamination by pesticides that are permitted by the regulation norms and by others whose use is prohibited in other countries and in Mexico. This situation causes a serious effect on the health deterioration of people who are exposed to these agro-chemicals and, in some cases, leads to death.

TT virus infection in Thailand: prevalence in blood donors and patients with aplastic anemia

Aplastic anemia has been reported to occur after viral hepatitis of unknown etiology. Recently, TT virus (TTV), a novel DNA virus, was identified in a Japanese patient with posttransfusion non-A-E hepatitis. The prevalence of TTV infection was investigated among blood donors and patients with aplastic anemia in Thailand. Of 99 blood samples from blood donors, 37 tested positive for TTV DNA via semi-nested polymerase chain reaction (PCR) using TTV-specific primers. Seventeen percent of samples from blood donors younger than 20 were positive for TTV DNA, whereas 48% from donors older than 20 were positive. The high prevalence of TTV infection in Thailand is comparable to that reported in China (28%), Mongolia (43%), and Egypt (29%). Forty-two percent of newly diagnosed aplastic anemia patients tested also had TTV DNA in blood. The detection rate of TTV DNA in aplastic anemia patients does not differ significantly from rates in normal blood donors. Our present data thus argue against the role of this novel hepatitis-associated virus in the pathogenesis of aplastic anemia in Thailand. However, larger epidemiological studies may be needed to further evaluate their association.

Haematological safety of antipsychotic drugs

Many clinicians have become concerned about the safety of new antipsychotics particularly in view of the association of agranulocytosis with clozapine and of aplastic anaemia with remoxipride. The Committee on Safety of Medicines and Medicines Control Agency 'yellow card' post-marketing surveillance data were analysed for reports of haemopoietic disorders with the 16 antipsychotics in common use. Corrections for relative risk were made in three separate ways: (i) control for degree of use, using Northern Ireland prescribing data for 1995; (ii) percentage of total reports from 1963 to 1996; and (iii) examination of the first 5 years' post-marketing data only. After clozapine and remoxipride the highest risks of haemopoietic reactions appeared to be associated with the aliphatic phenothiazine derivatives thioridazine and chlorpromazine. There is therefore no evidence of any increased risk with high-potency drugs such as haloperidol or pimozide or with the newer drugs such as sulpiride or risperidone. Continued vigilance, however, is necessary as more new atypicals become available and begin to be widely prescribed.

Antihypertensive drugs and the risk of idiopathic aplastic anaemia

AIMS

A recent report has raised concern that nifedipine may be associated with an increased risk of aplastic anaemia. This large population-based study evaluated the risk of idiopathic aplastic anaemia in users of calcium channel blockers compared with that of other antihypertensive drugs.

METHODS

The study was based on information derived from the General Practice Research Database. We conducted a follow-up study with a nested case-control analysis of 322 448 subjects who received antihypertensive drugs. Cases were people who had a first-time diagnosis of aplastic anaemia during January 1, 1988 through September 30, 1997. The risk estimate of aplastic anaemia was calculated for all antihypertensive drugs. For the nested case-control analysis, six controls were matched to each case on age, sex and general practice attended. Odds ratios compared the risk of idiopathic aplastic anaemia for all antihypertensive drugs relative to nonusers.

RESULTS

There were 13 cases of newly diagnosed idiopathic aplastic anaemia. The estimated risk of aplastic anaemia per 100 000 users was 0.8 (95% CI 0.1, 4.7) for calcium channel blockers, 1.4 (95% CI 0.5, 4.1) for beta-adrenoceptor blockers, 2.3 (95% CI 0.6, 8.6) for angiotension-converting enzyme (ACE) inhibitors and 5.9 (95% CI 1.6, 21.5) for users of other antihypertensive drugs. In the case-control analysis of 13 cases and 77 controls, the odds ratio was 0.3 (95% CI 0.02, 3.3) for calcium channel blockers, 0.5 (95% CI 0.1, 2.5) for beta-adrenoceptor blockers, 0.7 (95% CI 0.1, 5.6) for ACE inhibitors, 1.2 (95% CI 0.1, 11.8) for users of other antihypertensive drugs and 0.7 (95% CI 0.1, 7.2) for users of multiple drugs with a calcium channel blocker compared with nonusers.

CONCLUSIONS

The present study suggests that the use of calcium channel blockers is not associated with an increased risk of aplastic anaemia.

Epidemiology of aplastic anemia in Thailand. Thai Aplastic Anemia Study Group

A population-based case-control study of aplastic anemia has been conducted in Thailand since 1989. This is the largest single epidemiologic study of aplastic anemia ever performed. The objectives have been to document the incidence of the disease and to study the etiologic factors in a case-control analysis. The overall incidence of aplastic anemia was 3.9 per million per year in Bangkok, two times higher than in the West; 3.0 per million in Songkla; and 5.0 per million in Khonkaen. A difference appears in the age incidence pattern between Bangkok and the two rural areas, with double incidence peaks at ages 15 to 24 and over 60 in Bangkok, yet a more steady increase in incidence with increasing age in the rural areas. With regard to possible etiologic factors, there is a strong inverse association between incidence of the disease and socioeconomic status as determined by total household income and years of education. There are also significant positive associations with occupational exposure to solvents and agricultural pesticides. Only a few drugs, including thiazide diuretics, sulfonamide, and mebendazole are associated with the disease. There continues to be no evidence of association with chloramphenicol. The etiologic fraction for all associated drugs is lower than 5%. Household pesticide use is not associated with the disease. Exposure to hepatitis A virus is a risk indicator for aplastic anemia and may be a surrogate marker for another enteric infectious agent.

Regional patterns in the incidence of aplastic anemia in Thailand. The Aplastic Anemia Study Group

The annual incidence of aplastic anemia has been determined in a rigorous and standardized epidemiologic study conducted in Thailand. A total of 374 cases were identified over a period of 3-6 years in three geographically defined and distinct regions of the country; Bangkok, Khonkaen in the northeast, and Songkla in the south. The incidence was 3.9 cases per million persons in Bangkok, 3.0 per million in Songkla, and 5.0 per million in Khonkaen. These rates are as high or higher than in any region of Europe or Israel as reported in the International Agranulocytosis and Aplastic Anemia Study, in which the methods and case definition were the same. Rates were stable over the course of the study. There were marked differences in incidence between northern and southern rural regions of Thailand, and among Bangkok suburbs. These differences, together with an unusual peak in the incidence among young people in Bangkok, suggest the possibility of occupational and environmental factors in the etiology of aplastic anemia.

Hospitalizations for aplastic anemia and agranulocytosis in Saskatchewan: incidence and associations with antecedent prescription drug use

A population-based study to estimate the incidence of hospitalizations for aplastic anemia and agranulocytosis and to evaluate associations between these disorders and antecedent prescription drug use was performed using the Saskatchewan administrative health care databases. Hospital charts and cancer registration data were utilized to apply strict diagnostic criteria to case identification. Estimates of the annual incidence of aplastic anemia and agranulocytosis were 2.7 and 3.0 per million, which are similar to those from other recent population-based studies with comparable case identification criteria. Only a small number of cases were available to evaluate potential drug causes, leading to an analysis of limited power. Nevertheless, significant associations were found between aplastic anemia and tocainide, gold salts, and antidepressants; and between agranulocytosis and anti-thyroids, trimethoprim-sulfamethoxazole, beta-lactams, sulfasalazine, chlorpromazine, carbamazepine, glyburide, and procainamide, although the associations with antibiotics may indicate a response to the disorders rather than a possible cause. These findings are generally consistent with the results of other case-control investigations.

Possible association between ocular chloramphenicol and aplastic anaemia--the absolute risk is very low

AIMS

To determine whether topical ocular chloramphenicol increases the risk of aplastic anaemia and to estimate the magnitude of this risk, if any.

METHODS

Population-based prospective case-control surveillance of aplastic anaemia in a community of 4.2 million inhabitants from 1980 to 1995 (67.2 million person-years) plus case-population estimate of the risk, based on sales figures of ocular chloramphenicol in the study area during the study period.

RESULTS

One hundred and forty-five patients with aplastic anaemia and 1,226 controls were included in the analysis. Three cases (2.1%) and 5 controls (0.4%) had been exposed to ocular chloramphenicol during the relevant etiological period. The adjusted odds ratio was 3.77 (95% confidence interval, 0.84-16.90). Two cases had also been exposed to other known causes of aplastic anaemia. The incidence of aplastic anaemia among users of ocular chloramphenicol was 0.36 cases per million weeks of treatment. The incidence among non users was 0.04 cases per million weeks.

CONCLUSIONS

An association between ocular chloramphenicol and aplastic anaemia cannot be excluded. However, the risk is less than one per million treatment courses.