WORKUP	Section 5 of 11
Author Information Introduction Clinical Differentials Workup Treatment Medication Follow-up Miscellaneous Pictures Bibliography

Lab Studies:

• Determination of CBC count and peripheral smears

• A paucity of platelets, RBCs, granulocytes, monocytes, and reticulocytes is found. Mild macrocytosis is occasionally Observed. The degree of cytopenia is useful in assessing the severity of aplastic anemia. The corrected reticulocyte count is uniformly low in aplastic anemia.

• The peripheral blood smear is often helpful in distinguishing aplasia from infiltrative and dysplastic causes. Teardrop poikilocytes and leucoerythroblastic changes suggest an infiltrative process.

• Patients with MDS often have certain characteristic abnormalities such as dyserythropoietic RBCs and neutrophils with hypogranulation, hypolobulation, or apoptotic nuclei reaching to the edges of the cytoplasm. Monocytes are similarly hypogranular, and their nuclei may contain nucleoli.

• A leukemic process may result in evidence of blasts on the peripheral smear.

• Peripheral blood testing

• Hemoglobin electrophoresis and blood-group testing may show elevated levels fetal hemoglobin and red cell I antigen, suggesting stress erythropoiesis. These findings are observed in both aplastic anemia and MDS and are often proportional to the macrocytosis.

• Ordering a biochemical profile is useful in evaluating the etiology and in differential diagnosis. The profile includes a Coombs test; an analysis of kidney function; and measurement of transaminase, bilirubin, and lactic dehydrogenase levels

• Serologic testing for hepatitis and other viral entities, such as EBV, CMV, and HIV, may be useful.

• An autoimmune-disease evaluation for evidence of collagen-vascular disease may be performed.

• The Ham test, or the sucrose hemolysis test, is frequently performed. However, at present, the fluorescence-activated cell sorter (FACS) profile of PIGA anchor proteins, such as CD55 and CD59, may be more accurate than the Ham test for excluding PNH.

• Diepoxybutane incubation is performed to assess chromosomal breakage for Fanconi anemia. This test is required even in the absence of phenotypic features of Fanconi anemia because 30% of patients may not have any clinical stigmata.

• Histocompatibility testing should be conducted early to identify potential related donors, especially those for young patients. Because the extent of previous transfusion significantly affects the outcomes of patients undergoing BMT for aplastic anemia, the rapidity with which these data are obtained is crucial.

Imaging Studies:

• Radiologic studies are generally not needed to establish a diagnosis of aplastic anemia.

• A skeletal survey is especially useful for the inherited marrow-failure syndromes, many of which cause skeletal abnormalities.

Procedures:

• Review of peripheral smears.

• Bone-marrow aspiration and biopsy

• Bone-marrow biopsy is performed in addition to aspiration to assess cellularity both qualitatively and quantitatively. In aplastic anemia, the specimens are hypocellular. Aspiration samples alone may appear hypocellular because of technical reasons (eg, dilution with peripheral blood), or they may appear hypercellular because of areas of focal residual hematopoiesis. By comparison, core-biopsy better reveals cellularity: The specimen is considered hypocellular if it is <30% cellular in individuals <60 years or if it is <20% in those >60 years. A relative or absolute increase in mast cells may be observed around the hypoplastic spicules. A proportion of marrow lymphocytes >70% is correlated with poor prognosis in aplastic anemia. Some dyserythropoiesis with megaloblastosis may be observed in aplastic anemia.

• In MDS, the cellularity may be increased or decreased. Myelodysplastic features are usually observed in hematopoietic precursors and progeny. Islands of immature cells or abnormal localization of immature progenitors (ALIP) indicate MDS. These patients may have megakaryocytic abnormalities (micromegakaryocytes, megakaryocytes with dyskaryorrhexis), >5% ring sideroblasts (observed only on iron stains), and granulocytic abnormalities (pseudo–Pelger-Huët cells, hypogranulation, excess of blasts) On occasion, marrow fibrosis may be observed.

• Leukemia and metastatic cancers may be diagnosed with bone-marrow examination.

• Chromosomal rearrangements are considered diagnostic of MDS, with trisomies of 8 and 21 and deletions of 5, 7, and 20 being most common. However, the conventional karyotype technique reveals abnormalities in only about 50% of patients with MDS. In hypoplastic marrows, obtaining sufficient sample for karyotyping is often difficult.

• The issue of malignant versus nonmalignant clonality in aplastic anemia can sometimes be resolved by using fluorescent in situ hybridization (FISH) to visualize chromosomal abnormalities in interphase cells.

• Bone-marrow culture is useful in diagnosing mycobacterial and viral infections. However, the yield is generally low.

Staging: Staging is based on criteria of the International Aplastic Anemia Study Group, as follows (Camitta, 1983):

• Blood

• Neutrophils - Less than 0.5 X 10⁹/L

• Platelets - Less than 20 X 10⁹/L

• Reticulocytes - Less than 1% corrected (percentage of actual hematocrit [Hct] to normal Hct)

• Marrow

• Severe hypocellularity

• Moderate hypocellularity with hematopoietic cells representing less than 30% of residual cells

• Severe aplasia is defined as any 2 or 3 peripheral blood criteria and either marrow criterion.

• A further subclassification developed after the recognition that individuals with neutrophil counts lower than 0.2 X 10⁹/L had very SAA (VSAA). This group is less likely than others to respond to immunosuppressive therapy.

	TREATMENT	Section 6 of 11
Author Information Introduction Clinical Differentials Workup Treatment Medication Follow-up Miscellaneous Pictures Bibliography

Medical Care:

• Transfusions
  • Patients with aplastic anemia require transfusion support until the diagnosis is established and until specific therapy can be instituted.

  • For patients in whom BMT may be attempted, transfusions should be used judiciously because minimally transfused subjects have achieved superior therapeutic outcomes.

  • Avoiding transfusions from family members is important because of possible sensitization against non-HLA tissue antigens of the donors.

  • In considering blood-bank support, attempt to minimize the risk of CMV infection. If possible, the blood products should undergo leuko-poor reduction to prevent alloimmunization, and they should be irradiated to prevent third-party GVHD in BMT candidates.

  • Judicious use of blood products is essential, and transfusion in conditions that are not life threatening should be performed in consultation with a physician experienced in the management of aplastic anemia.

• Treatment of infections
  • Infections are a major cause of mortality.

  • Risk factors include prolonged neutropenia and the indwelling catheters used for specific therapy. Fungal infections, especially those due to Aspergillus species pose a major risk.

  • Empirical antibiotic therapy should be broad based, with gram-negative and staphylococcal coverage based on local microbial sensitivities. Especially consider including antipseudomonal coverage at start of treatment for patients with febrile neutropenia, and consider early introduction of antifungal agents for those with persistent fever.

  • Cytokine support with granulocyte colony-stimulating factor (G-CSF) and granulocyte-macrophage colony-stimulating factor (GM-CSF) may be considered in refractory infections, though it should be weighed against cost and efficacy.

• BMT with an HLA-matched sibling donor
  • HLA-matched sibling-donor BMT is the treatment of choice for a young patient with SAA (controversial but generally accepted for age <60 y).

  • One of the major problems of BMT in aplastic anemia is the high 10% rate of rejection (range, 5-50%), and this is positively correlated with the number of transfusions and duration of disease prior to undergoing transplantation.

  • The conditioning regimen most often used includes a combination of antithymocyte globulin (ATG), cyclosporin (CSA), and cyclophosphamide. The addition of ATG and CSA to the conditioning regimen has resulted in reduction of graft rejection. When radiation was used as part of the conditioning regimen, the incidence of graft rejection was <5%, but the incidence of chronic GVHD, interstitial pneumonitis, and malignant disease was increased; no survival advantage resulted.

  • GVHD is a complication of BMT. It is positively correlated with increasing age of the patient. Grafts depleted of T cells reduce the risk of GVHD but increase the risk of graft failure.

  • The addition of CSA along with methotrexate has substantially reduced the incidence of GVHD.

• BMT with an unrelated donor
  • Unrelated-donor BMT probably is justified only if the donor is a full match and on if immunosuppressive therapy or treatment as part of a clinical trial fails. Early referral to a transplantation center at diagnosis is recommended in all young patients, even if they lack a suitable related donor.

  • Both increased graft rejection and increased GVHD remain obstacles to success for unrelated-donor BMT for patients with SAA. Partial T-cell depletion may decrease the risk of severe GVHD while still maintaining sufficient donor T lymphocytes to ensure engraftment.

  • In unrelated-donor transplantation, radiation along with cyclophosphamide may be used to reduce graft rejection. Fludarabine-based conditioning regimens have recently been tried, along with ATG and cyclophosphamide.

• Immunosuppressive therapy

• Immune suppression is especially useful if a matched sibling donor for BMT is not available or if the patient is older than 60 years.

• Options include combination therapy, including ATG, CSA, and methylprednisolone, with or without cytokine support. ATG and CSA alone may also produce a response in aplastic anemia, but the combination improves the likelihood of a response.

• In 1 study, response rates to CSA alone were 45% overall, 16% for VSSA, 47% for SAA, and 85% for moderate aplastic anemia (Maschan, 1999). Therefore, the only predictor of response to CSA was an absolute neutrophil count (ANC) of <200/mm³. Adding G-CSF to ATG and CSA in patients with an ANC of >200/mm³ does not produce any additional advantage in reducing the infection rate or in increasing survival or therapeutic responses.

• The response in aplastic anemia, unlike other autoimmune diseases, is slow. At least 4-12 weeks is usually needed to observe early improvement, and the patient continues to improve only slowly thereafter. About 50% patients respond by 3 months after ATG administration, and about 75% respond by 6 months. Most patients improve and become transfusion independent, but many still have evidence of a hypoproliferative bone marrow.

• Although the initial response rate is good, relapses are common, and continued immune suppression is often needed. Approximately one third of patients have a relapse, most of whom have a relapse at the time of CSA taper. About one third of responders are CSA dependent. Of patients with no response or relapse, 40-50% respond to a second course of immunosuppressive therapy.

• In rare cases, full hematologic recovery observed, but most patients improve to a functional hematologic recovery that obviates further transfusion support. Furthermore, the risk of some form of clonal disease other than PNH is 15-30% and may be due to the inability of these therapies to completely correct bone-marrow function, to a missed diagnosis of MDS, or to the fact that the stem cells under proliferative stress may be more prone than other cells to mutation.

• Preliminary data suggest that high-dose cyclophosphamide may result in durable remissions in some patients with aplastic anemia. However, some of these patients develop PNH and cytogenetic abnormalities on follow-up. At present, the use of high-dose cyclophosphamide should be limited to clinical trials.

Surgical Care: A central venous catheter is required before immunosuppressive therapy or BMT.

Consultations: Hematologist and/or BMT specialist

Diet: The diet for the patient with aplastic anemia who has neutropenia or who is receiving immunosuppressive therapy should be tailored carefully to exclude raw meats, dairy products, or fruits and vegetables that are likely to be colonized with bacteria, fungus, or molds. Furthermore, a salt-limited diet is recommended during therapy with steroids or CSA.

Activity:

• The patient should avoid any activity that increases the risk of trauma during periods of thrombocytopenia.

• The risk of community-acquired infections increases during periods of neutropenia.

	MEDICATION	Section 7 of 11
Author Information Introduction Clinical Differentials Workup Treatment Medication Follow-up Miscellaneous Pictures Bibliography

The goals of pharmacotherapy are to reduce morbidity, prevent complications, and eradicate malignancy.

Drug Category: Immunosuppressive agents -- The merits of additional immunosuppression versus the increased risk and cost should be considered. Data from a randomized prospective study indicated that an increased proportion of patients responded to the addition of CSA to ATG, but this did not translate into a long-term survival advantage.

	MISCELLANEOUS	Section 9 of 11
Author Information Introduction Clinical Differentials Workup Treatment Medication Follow-up Miscellaneous Pictures Bibliography

Medical/Legal Pitfalls:

• Failure to correctly diagnose the disease and initiate appropriate treatment is a pitfall.

• Aplastic anemia has a >70% mortality rate with supportive care alone. It is a hematologic emergency, and care should be instituted promptly.