quickLESSON Description/Etiology Aplastic anemia (AA) is a rare but potentially life-threatening syndrome of bone marrow failure characterized by about... pancytopenia (i.e., reduction of red blood cells [RBCs], white blood cells [WBCs], and platelets) and hypoplastic bone marrow (i.e., fat replacement in the bone marrow space usually occupied by hematopoietic precursor cells).
Aplastic Anemia Most cases of AA are acquired, and although the pathogenic mechanism has not been well elucidated, these cases probably result from autoimmune mechanisms. The remaining cases are classified as constitutional (i.e., linked to certain congenital conditions), as in Fanconi’s anemia, a disorder caused by chromosomal instability that affects genes responsible for recognition and repair of damaged DNA, and in Diamond-Blackfan syndrome, which is caused by genetic mutations. Acquired cases are linked to a number of factors, including exposure to specific toxic chemical and radiologic agents (e.g., benzene hexachloride, lindane [i.e., an insecticide], carbon tetrachloride, heavy metals [e.g., lead, inorganic arsenic], kerosene, and ionizing radiation); infectious processes (e.g., Epstein-Barr virus, hepatitis, HIV, Venezuelan equine encephalitis, cytomegalovirus, miliary tuberculosis); idiosyncratic drug reactions (e.g., to chloramphenicol, certain antiepileptics [e.g., carbamazepine], gold, sulfonamides, penicillamine, chemotherapeutic agents [e.g., busulfan], nonsteroidal anti-inflammatory drugs [NSAIDs], antithyroid medications, psychotropics [especially clozapine], and certain cardiovascular agents); autoimmune disorders (e.g., systemic lupus erythematosus [SLE]); thymus tumors (e.g., thymomas); and pregnancy (rare).
Patients with AA present with manifestations related to decreased bone marrow production of blood cells, including fatigue, infections, bruising, and bleeding. Diagnostic criteria require demonstration of hypocellular or hypoplastic bone marrow with peripheral blood cytopenia. AA should be differentiated from other causes of pancytopenia, including megaloblastic anemia, paroxysmal nocturnal hemoglobinuria, acute leukemia, hairy cell leukemia, SLE, disseminated infection, hypersplenism, and transient erythroblastopenia of childhood.
Hematopoietic stem cell transplantation (HSCT) offers the potential for cure, but most patients are not candidates for the procedure due to advanced age, comorbid diseases, or lack of a suitable donor. Treatment may involve immunosuppressive therapy, administration of growth factors, and supportive care (e.g., blood transfusions, ICD-9 284.9, 284.0 prophylactic antimicrobial agents, good nutrition). Combined treatment with antithymocyte globulin (ATG) and cyclosporine is the gold standard of first-line immunosuppressive therapy, with an initial response rate of 80%; efforts ICD-10 have been made to identify a third drug to add to the combination to achieve higher response rates, but results have D61.0, D61.9 been disappointing. High-dose cyclophosphamide or the tumor necrosis factor (TNF) inhibitor etanercept may be used as a salvage treatment for patients who fail to respond to immunosuppressant therapy. The major causes of morbidity ICD-10-CAN D61.0, D61.9 and mortality are infection and bleeding. Facts and Figures Authors The annual incidence of AA is 2 cases per million people in Western countries; incidence is 2- to 3-fold higher in Asia. Tanja Schub, BS AA occurs predominantly in young adults aged 15–25 and adults over the age of 60. It occurs equally in males and Gilberto Cabrera, MD females. Left untreated, the 1-year mortality rate associated with severe AA is > 70%. The estimated 5-year survival Reviewers rate for patients receiving immunosuppressant therapy is 75%, compared with > 90% for those who receive HSCT Darlene A. Strayer, RN, MBA from a matched sibling donor. Cinahl Information Systems Glendale, California Risk Factors Kathleen Walsh, RN, MSN, CCRN Approximately 20% of patients with AA have evidence of paroxysmal nocturnal hemoglobinuria (PNH), a rare cause Cinahl Information Systems of acquired hemolytic anemia, which is a genetic disorder that renders blood cells sensitive to increased complement Glendale, California lysis. (For additional risk factors, see Description/Etiology, above.)
Nursing Practice Council Glendale Adventist Medical Center Signs and Symptoms/Clinical Presentation Glendale, California 44 Idiopathic or acquired: Dyspnea, ecchymoses, petechiae, fatigue, fever, bleeding into the skin and mucosal membranes, menorrhagia, positive occult blood in the stool, melena, retinal flame and ocular fundi Editor hemorrhage, epistaxis, frequent or severe infections at sites of minor trauma (e.g., skin cuts or abrasions), Diane Pravikoff, RN, PhD, FAAN pallor, palpitations, headaches, shortness of breath, progressive weakness, and weight loss. Infection and Cinahl Information Systems hemorrhage require emergency medical attention 44 Constitutional (signs and symptoms depend on the linked condition): Short stature, microcephaly, radius and thumb abnormalities, renal anomalies, hypospadias (i.e., abnormal congenital opening of the urethra either on July 8, 2011 the underside of the penis or into the vagina), and hyperpigmentation
Published by Cinahl Information Systems. Copyright©2011, Cinahl Information Systems. All rights reserved. No part of this may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, or by any information storage and retrieval system, without permission in writing from the publisher. Cinahl Information Systems accepts no liability for advice or information given herein or errors/omissions in the text. It is merely intended as a general informational overview of the subject for the healthcare professional. Cinahl Information Systems, 1509 Wilson Terrace, Glendale, CA 91206 Assessment 44 Physical Findings of Particular Interest •• Patient may present with skin pallor, ecchymoses, petechiae, retinal hemorrhage, fever of rapid onset, oral ulcerations, and pharyngitis •• Audible systolic ejection murmur may be present with profound anemia 44 Laboratory Tests That May be Ordered •• CBC with differential and examination of blood film with differential may reveal RBC count < 1 million/mm3, reticulocyte count < 1%, WBC count < 2,000/mm3, platelet count < 30,000/mm3, serum iron > 400 ng/L, and mean corpuscular volume (MCV) > 104 μm3 •• Histologic examination of biopsied bone marrow will show fatty marrow and pathologic findings of decreased cellularity, megakaryocytes, myelocytes, and erythroid precursors •• Liver function testing with hepatitis screening may be ordered if hepatitis C is suspected •• Cultures from blood, urine, stool, nasopharynx, sputum, venous access sites, and suspicious lesions may be ordered if infection is suspected •• UA may show hemoglobinuria (i.e., loss of blood) and hemosiderinuria (i.e., loss of iron) •• Specialized genetic testing may include chromosome breakage studies and fetal hemoglobin if an inherited cause is suspected •• Ham test (i.e., acid hemolysin) may be ordered if PNH is suspected •• Human leukocyte antigen (HLA) testing may be performed on the patient and immediate family members to identify donors for HSCT 44 Other Diagnostic Tests/Studies •• X-rays of the radius and thumbs and renal ultrasonography may be ordered if Fanconi’s anemia is suspected as a cause of aplastic anemia •• Abdominal sonogram or CT scan may be ordered if splenomegaly is suspected; CT scan of the thymus region if thymoma-associated RBC aplasia is suspected
Treatment Goals 44 Promote Optimum Hematologic Status and Reduce Risk of Complications •• Monitor vital signs, assess all physiologic systems, and review laboratory/diagnostic study results; immediately report abnormalities and treat, as ordered, with the prescribed regimen of immunosuppressive therapy, e.g., antithymocyte globulin (ATG), cyclosporine, ATG/cyclosporine, oxymetholone (i.e., an androgen), and prednisolone ––Monitor treatment efficacy and for adverse effects •• Encourage a semi-Fowler’s or sitting position to facilitate breathing. Assess fall risk due to dyspnea and weakness and maintain patient safety (e.g., airway, circulation, and prevention of injury); assist with ADLs and supervise ambulation, as appropriate •• Administer other prescribed agents, including prophylactic antibiotics to prevent infection; RBC, WBC, and platelet transfusions; and granulocyte colony stimulating factor (G-CSF) to stimulate bone marrow production of RBCs. Monitor closely for adverse effects •• Monitor intake and output and encourage/assist with good oral hygiene, increased fluid intake, and eating a balanced diet •• Follow facility pre- and postsurgical protocols if patient becomes a surgical candidate (e.g., for HSCT or thymectomy); reinforce pre- and postsurgical education and ensure completion of facility informed consent documents ––Administer prescribed cyclophosphamide before HSCT ––Closely monitor postoperatively for bleeding and infection 44 Provide Emotional Support and Educate •• Assess anxiety level and coping ability; provide emotional support, educate, and encourage discussion about AA pathophysiology, cause if known, potential complications, treatment risks and benefits, postsurgical expectations, and individualized prognosis •• If appropriate, request referral to a social worker for identification of local resources for in-home services and support groups, and to a mental health clinician for counseling on patient/family member coping strategies
Red Flags 44 Avoid blood transfusions in HSCT candidates because of increased risk of graft failure 44 Institute reverse isolation procedures per facility protocols, particularly if the patient is neutropenic 44 Skin testing prior to administration of ATG is essential to determine the potential for hypersensitivity reactions
What Do I Need to Tell the Patient/Patient’s Family? 44 Educate about avoiding exposure to organic solvents, volatile chemicals, and paint thinners, particularly in a confined environment; and maintaining good hygiene to reduce risk of infections 44 Emphasize the importance of strict adherence to the prescribed treatment regimen and seeking immediate medical attention for new or worsening signs and symptoms
References
•• Audino, A. N., Blatt, J., Carcamo, B., Castaneda, V., Dinndorf, P., Wang, W. C., … Hord, J. D. (2010). High-dose cyclophosphamide treatment for refractory severe aplastic anemia in children. Pediatric Blood & Cancer, 54(2), 269-272. •• Bacigalupo, A., & Passweg, J. (2009). Diagnosis and treatment of acquired aplastic anemia. Hematology/Oncology Clinics of North America, 23(2), 159-170. •• Bakhshi, S. (2011). Aplastic anemia. Medscape Reference. Retrieved June 24, 2011, from http://emedicine.medscape.com/article/198759-overview •• D’Andrea, A. D. (2010). Susceptibility pathways in Fanconi’s anemia and breast cancer. The New England Journal of Medicine, 362(20), 1909-1919. •• Dufour, C., Giacchino, R., Ghezzi, P., Tonelli, R., Ferretti, E., Pitto, A., … Svahn, J. (2009). Etanercept as a salvage treatment for refractory aplastic anemia. Pediatric Blood & Cancer, 52(4), 522-550.