Sedentary Work Exerting up to 10 pounds (4.5 kg) of force occasionally and/or a negligible amount of force frequently or constantly to lift, carry, push, pull, or otherwise move objects, including the human body. Sedentary work involves sitting most of the time, but may involve walking or standing for brief periods of time. Jobs are sedentary if walking and standing are required only occasionally and other sedentary criteria are met.

Light Work Exerting up to 20 pounds (9.1 kg) of force occasionally and/or up to 10 pounds (4.5 kg) of force frequently, and/or negligible amount of force constantly to move objects. Physical demand requirements are in excess of those for Sedentary Work. Light Work usually requires walking or standing to a significant degree. However, if the use of the arm and/or leg controls requires exertion of forces greater than that for Sedentary Work and the worker sits most the time, the job is rated Light Work.

Medium Work Exerting up to 50 (22.7 kg) pounds of force occasionally, and/or up to 25 pounds (11.3 kg) of force frequently, and/or up to 10 pounds (4.5 kg) of forces constantly to move objects.

Heavy Work Exerting up to 100 pounds (45.4 kg) of force occasionally, and/or up to 50 pounds (22.7 kg) of force frequently, and/or in excess of 20 pounds (9.1 kg) of force constantly to move objects.

Very Heavy Work Exerting in excess of 100 pounds (45.4 kg) of force occasionally, and/or in excess of 50 pounds (22.7 kg) of force frequently, and/or in excess of 20 pounds (9.1 kg) of force constantly to move objects.

Job Classification

In most duration tables, five job classifications are displayed. These job classifications are based on the amount of physical effort required to perform the work. The classifications correspond to the Strength Factor classifications described in the United States Department of Labor's Dictionary of Occupational Titles. The following definitions are quoted directly from that publication.

Sedentary Work Exerting up to 10 pounds (4.5 kg) of force occasionally and/or a negligible amount of force frequently or constantly to lift, carry, push, pull, or otherwise move objects, including the human body. Sedentary work involves sitting most of the time, but may involve walking or standing for brief periods of time. Jobs are sedentary if walking and standing are required only occasionally and other sedentary criteria are met.

Light Work Exerting up to 20 pounds (9.1 kg) of force occasionally and/or up to 10 pounds (4.5 kg) of force frequently, and/or negligible amount of force constantly to move objects. Physical demand requirements are in excess of those for Sedentary Work. Light Work usually requires walking or standing to a significant degree. However, if the use of the arm and/or leg controls requires exertion of forces greater than that for Sedentary Work and the worker sits most the time, the job is rated Light Work.

Medium Work Exerting up to 50 (22.7 kg) pounds of force occasionally, and/or up to 25 pounds (11.3 kg) of force frequently, and/or up to 10 pounds (4.5 kg) of forces constantly to move objects.

Heavy Work Exerting up to 100 pounds (45.4 kg) of force occasionally, and/or up to 50 pounds (22.7 kg) of force frequently, and/or in excess of 20 pounds (9.1 kg) of force constantly to move objects.

Very Heavy Work Exerting in excess of 100 pounds (45.4 kg) of force occasionally, and/or in excess of 50 pounds (22.7 kg) of force frequently, and/or in excess of 20 pounds (9.1 kg) of force constantly to move objects.

Aplastic Anemia


Related Terms

  • Anemia Gravis
  • Ehrlich's Anemia
  • Hypoplastic Anemia
  • Refractory Anemia

Differential Diagnosis

Specialists

  • Clinical Psychologist
  • Family Physician
  • Hematologist
  • Infectious Disease Internist
  • Medical Toxicologist
  • Pharmacologist
  • Rheumatologist

Comorbid Conditions

Factors Influencing Duration

The length of disability may be influenced by the severity of symptoms, the underlying cause, the treatment required, the individual's compliance with and response to treatment, and the extent of fatigue or other complications. Other factors include previous blood transfusions, availability of a matched sibling donor for bone marrow transplant, presence of infection, severity of pancytopenia, availability of appropriate drugs for treatment, and rejection following transplant.

The individual's age is a significant factor in determining whether he or she is a candidate for bone marrow transplant because the risk of graft rejection increases with age.

Medical Codes

ICD-9-CM:
284.09 - Constitutional Aplastic Anemia, Other; Fanconis Anemia; Pancytopenia with Malformations
284.89 - Aplastic Anemias, Other Specified; Aplastic Anemia (Due to): Chronic Systemic Disease, Drugs, Infection, Radiation, Toxic (Paralytic)
284.9 - Aplastic Anemia, Unspecified; Aplastic NOS, Aregenerative, Hypoplastic NOS, Nonregenerative; Medullary Hypoplasia

Overview

Aplastic anemia is the failure of the bone marrow to produce blood cells (red blood cells, white blood cells, and platelets) because the stem cells have been damaged. Stem cells are precursor cells from which all blood cell lines develop. Because fewer new blood cells are produced, the old blood cells at the end of their life spans are not replaced. This results in a decrease in the number of all blood cell types within the circulating blood (pancytopenia). Without red blood cells, anemia develops, and oxygen cannot be distributed throughout the body. Without white blood cells, infections cannot be fought. Without platelets, blood does not clot normally.

Aplastic anemia may be acquired, inherited (congenital), or self-originating (idiopathic). The congenital form is called Fanconi anemia; for individuals to be affected, they must inherit one gene from each parent (autosomal recessive disease). Congenital aplastic anemia (Fanconi) develops before the ages of 30 to 40 in predisposed individuals. In addition to pancytopenia, individuals with Fanconi anemia often have other physical anomalies involving the skin, heart, genitourinary tract, skeletal system, central nervous system, growth, and mental capacity. It is estimated that 1 individual in 100 to 600 have the gene for this disease (are carriers), although they are not affected.

Acquired aplastic anemia is more common. Damage to the stem cells may be caused by a variety of external agents such as ionizing radiation, the chemical benzene and its derivatives, chemotherapeutic cancer drugs, certain antibiotics, and other toxic chemicals like inorganic arsenic. Other agents only occasionally associated with aplastic anemia include a wide variety of drugs and chemicals such as some antibiotics, analgesics, and insecticides. Certain infections are also associated with aplastic anemia, including non-A, non-B, and non-C hepatitis; Epstein-Barr virus; HIV; and parvovirus B19. Acquired aplastic anemia may also result from an immune reaction in which an individual's own immune system attacks the stem cells. Aplastic anemia can develop during pregnancy and may be associated with the accompanying rise in the female hormone estrogen. In more than half the cases of acquired or idiopathic aplastic anemia, the cause is never determined.

Incidence and Prevalence: Although there is no accurate prospective data on the national incidence of aplastic anemia, several studies based on reviews of death registries suggest that the US incidence ranges from 0.6 to 6.1 cases per million population; in Europe and Israel, the incidence is 2 individuals per million, and in some parts of Asia, the incidence is 4 individuals per million (Bakhshi). It is believed that the increased incidence of aplastic anemia in Asia is due to exposure to toxic substances, rather than genetic factors.

Source: Medical Disability Advisor



Causation and Known Risk Factors

Those with a history of exposure to bone marrow suppressing toxins or medications, such as benzene or ionizing radiation, may be at increased risk of developing aplastic anemia.

Males and females develop the disease at equal rates with an average age at diagnosis of 25.

Source: Medical Disability Advisor



Diagnosis

History: Symptoms may begin weeks or months after exposure to a causative agent. The individual may report bleeding from the gums or other mucous membranes, bleeding under the skin, heavy menstrual flow, and easy bruising because of a low number of platelets. Individuals may feel weak and fatigued and have pallor due to anemia (low hemoglobin). Initially, individuals usually present with few, if any, systemic complaints. They may have ulcers of the mouth and tongue, fever, or a sore throat. There may be history of infection because of a low number of white blood cells (neutropenia). The individual may be pregnant; have a family history of Fanconi anemia; or have a history of exposure to radiation, infection, chemicals, or drugs known to be associated with aplastic anemia.

Physical exam: Small capillary hemorrhages (bleeding) under the skin (petechiae) or larger areas of bruising under the skin (ecchymoses) may be seen. There may also be evidence of bleeding in the eye (retinal hemorrhage). If anemia is severe, a heart murmur may be detected. With Fanconi anemia, conditions such as skeletal anomalies, skin discoloration, mental retardation, or learning disabilities may be detected, but often are not present.

Tests: A complete blood count (CBC) will show significant pancytopenia. A reticulocyte count shows a low number of immature red blood cells (reticulocytes). Diagnosis is generally confirmed by a bone marrow biopsy with an assessment of cellularity. The marrow is evaluated for the degree of maturation of all cell lines and has a low number of cells (hypocellular marrow). Abnormal cells are not found. Additional tests may be performed to identify the cause of the aplastic anemia. These tests may include serological tests to check for infection. If Fanconi anemia is suspected, a peripheral chromosome analysis (cytogenetic breakage study) may be performed.

Source: Medical Disability Advisor



Treatment

Individuals with mild or moderate aplastic anemia generally do not require immediate treatment. They should, however, be monitored for any decline in their blood counts. When aplastic anemia is diagnosed, all drugs or medications should be stopped, if possible. Some drugs such as chemotherapeutic drugs and some forms of radiation may be medically necessary as a treatment for another serious condition such as cancer. In these cases, the benefit of the drug or radiation as opposed to its risks must be weighed before making the decision to continue or discontinue its use. If a toxic agent is determined as the cause of the aplastic anemia, it should be removed immediately.

In many cases, removal of the toxic agent allows the bone marrow to regenerate. During this time only temporary supportive treatment may be necessary, such as transfusions of red blood cells and platelets to keep blood counts adequate and administration of antibiotics to prevent infection. Menstruation should also be suppressed.

In cases of severe aplastic anemia, a bone marrow transplant is the treatment of choice. The marrow must come from a matched donor, preferably a sibling. The risk of rejection increases with age, so bone marrow transplant is usually limited to individuals in good health under age 55. Blood transfusion should be avoided, if possible, in individuals who are candidates for a bone marrow transplant. The risk of graft rejection increases significantly with prior transfusion. When the bone marrow transplant is successful, no additional transfusions or transplants will be required.

If the individual is not a candidate for transplant or a donor is not available, immunosuppressive therapy is the next best option. One or a combination of immunosuppressive drugs is taken. Male hormones (androgens) may successfully raise blood counts in some individuals in which standard immunosuppression does not work. During immunosuppression or androgen therapy, transfusion of red blood cells and platelets is usually needed on an ongoing or temporary basis, depending on the individual's response to therapy. After approximately 50 transfusions, an iron chelator drug should be given to remove excess iron introduced into the body by the transfused blood.

Antibiotics should be given prophylactically to prevent infections. Following immunosuppressive therapy, those with severely low white blood cell counts may be given subcutaneous or intravenous doses of a bioengineered drug designed to enhance function of the more mature white blood cells. This is done as supportive therapy to reduce the risk of subsequent infections.

Individuals with Fanconi anemia are treated with androgens or bone marrow transplantation. Approximately half these individuals have increased production of red blood cells and platelets following androgen therapy, and some may have increased production of white blood cells. This type of therapy can continue for years but usually becomes ineffective over time, ultimately requiring bone marrow transplant to obtain a cure.

Source: Medical Disability Advisor



Prognosis

Aplastic anemia is a chronic disorder that requires ongoing medical monitoring. The 5-year survival rate for aplastic anemia ranges from 70% to 90% (Ferri 61). Left untreated, severe aplastic anemia has a median survival of only 3 months, and only 20% of untreated individuals live for as long as a year. Death usually results from infection or hemorrhage.

Bone marrow transplant that uses marrow from a matched sibling donor has a 70% to 80% cure rate in individuals with no previous blood transfusion. Previous transfusions increase the risk of rejection and decrease the cure rate. Younger individuals (under age 25) who receive prompt bone marrow transplants are most likely to return to a normal life with good long-term survival (Ferri 61).

Approximately 60% of individuals receiving immunosuppression therapy respond within 4 to 12 weeks. Recovery is usually not complete, but the blood count rises to a level high enough that transfusion is no longer necessary. The response to treatment may be long-lasting, but many individuals will suffer a relapse after immunosuppression therapy is discontinued. If relapse does occur, treatment resumes, and the prognosis is not affected.

Aplastic anemia brought on by pregnancy typically resolves following delivery or spontaneous or induced abortion.

Source: Medical Disability Advisor



Complications

Years later, approximately 25% of individuals treated with immunosuppression therapy develop other blood disorders including paroxysmal nocturnal hemoglobinuria (PNH) and myelodysplasia.

Individuals with Fanconi anemia have a significantly higher risk of later developing leukemia. Infection is always a significant complication because of the individual's low number of white blood cells. If the individual's platelet count drops to a dangerously low level, severe, even life-threatening bleeding can occur particularly within the brain (intracranial hemorrhage).

Source: Medical Disability Advisor



Ability to Work (Return to Work Considerations)

As anemia advances, physical exertion must be reduced. Exposure to toxic chemicals must be limited. Time off for immunosuppressive therapy and blood transfusions must be allotted, along with a leave of absence for bone marrow transplant and recovery.

Individuals with significantly decreased platelet counts need a safe work environment where they can avoid the risk of trauma or injury that could trigger acute bleeding. Where indicated, protective gear, especially head protection, should be worn. Office work or sedentary work is more appropriate than strenuous work involving heavy lifting or other physical exertion. The employer should be made aware of the condition so that the appropriate level of care can be obtained quickly in the event of an on-the-job injury.

Those with low white blood cell counts should avoid exposure to anyone with community-acquired infections, such as colds and flu.

Source: Medical Disability Advisor



Failure to Recover

If an individual fails to recover within the expected maximum duration period, the reader may wish to consider the following questions to better understand the specifics of an individual's medical case.

Regarding diagnosis:

  • Did individual present with symptoms consistent with aplastic anemia, such as unusual bleeding, bruising, weakness, fatigue, poor color, and perhaps shortness of breath?
  • Was diagnosis confirmed with bone marrow biopsy? Was a CBC performed?
  • Was a cytogenetic breakage study done to determine congenital aplastic anemia?
  • Does individual have acquired, congenital, or idiopathic aplastic anemia?
  • Was a thorough exposure history investigated to detect an underlying cause?

Regarding treatment:

  • Were all possible causative agents eliminated?
  • Was a bone marrow transplant indicated (for those with severe symptoms and under age 55)?
  • Was individual treated with immunosuppressive medications, antibiotics, and transfusions, because of age (greater than 55)?
  • If individual has Fanconi anemia, was androgen therapy effective or was a bone marrow transplant necessary?

Regarding prognosis:

  • Did anemia resolve as expected? For example, in acquired anemia, did symptoms resolve upon removal of the toxic substance? In pregnancy-related aplastic anemia, did anemia resolve following delivery?
  • Was a bone marrow transplant successful in resolving anemia?
  • Does individual have any comorbid conditions (cancer, heart disease, liver or kidney failure) that may affect the ability to recover?
  • Did individual suffer any complications (hemorrhage, heart failure or infection) that would influence length of disability?

Source: Medical Disability Advisor



References

Cited

Bakhshi, Sameer, and Roy Baynes. "Aplastic Anemia." eMedicine. Eds. David Aboulafia, et al. 29 Sep. 2004. Medscape. 17 Oct. 2004 <http://emedicine.com/med/topic162.htm>.

Ferri, Fred, ed. "Diseases and Disorders." Ferri's Clinical Advisor: Instant Diagnosis and Treatment. St. Louis: Mosby, Inc., 2004. 61-62.

Source: Medical Disability Advisor






Feedback
Send us comments, suggestions, corrections, or anything you would like us to hear. If you are not logged in, you must include your email address, in order for us to respond. We cannot, unfortunately, respond to every comment. If you are seeking medical advice, please contact your physician. Thank you!
Send this comment to:
Sales Customer Support Content Development
 
This publication is designed to provide accurate and authoritative information in regard to the subject matter covered. It is published with the understanding that the author, editors, and publisher are not engaged in rendering medical, legal, accounting or other professional service. If medical, legal, or other expert assistance is required, the service of a competent professional should be sought. We are unable to respond to requests for advice. Any Sales inquiries should include an email address or other means of communication.