Aplastic Anaemia

Aplastic anaemia has no clinical symptoms. However, if they at all appear, they include the following:

• Fatigue
• Shortness of breath
• Frequent or prolonged infections
• Unexplained or easy bruising
• Fever
• Rapid or irregular heart rate
• Prolonged bleeding from cuts
• Skin rash
• Pale skin
• Nosebleeds and bleeding gums
• Dizziness
• Headache

The prevalence of aplastic anaemia is unpredictable. It may be short-lived or become chronic, severe and even fatal.

Stem cells produce different varieties of blood cells, such as red blood cells, white blood cells and platelets. However, these blood cells become aplastic (empty) or hypoplastic (few blood cells present) in aplastic anaemia. The occurrence of aplastic anaemia has been linked to being autoimmune in nature. This means that the body's immune cells attack the stem cells in the bone marrow. Some other factors associated with the development of aplastic anaemia are:

• Radiation and Chemotherapy Treatments: These therapies are commonly employed to kill cancer cells. However, they may damage the healthy stem cells of the bone marrow and cause aplastic anaemia. In some cases, aplastic anaemia may be a temporary side effect of cancer therapies.
• Exposure to Toxic Chemicals: Toxic chemicals in pesticides and insecticides and an ingredient in gasoline called benzene have also been associated with developing aplastic anaemia. Avoiding exposure to these chemicals may help improve the condition.
• Use of Drugs: Some medications, like those used in treating rheumatoid arthritis and some antibiotics, can also lead to aplastic anaemia.
• Autoimmune Disorders: An autoimmune disorder in which the immune system attacks the body's healthy cells may also involve stem cells in the bone marrow and develop aplastic anaemia.
• Viral Infection: Viral infections also play a role in developing aplastic anaemia. Epstein-Barr virus, hepatitis, parvovirus B19, cytomegalovirus and HIV are linked to aplastic anaemia.
• Pregnancy: During pregnancy, the immune system might attack the bone marrow and lead to aplastic anaemia. This occurs due to the heavy changes the body goes through at the time of pregnancy.
• Unknown Factors: In many cases, the exact cause of aplastic anaemia remains unidentified. This condition is termed idiopathic aplastic anaemia.

The following tests help diagnose aplastic anaemia:

• Blood Tests: In aplastic anaemia, the number of red blood cells, white blood cells and platelets reduces to an undesired level. This reduction is a major indicator of aplastic anaemia. 
• Bone Marrow Biopsy: A biopsy of the bone marrow can help rule out other blood-related disorders. In aplastic anaemia, the bone marrow will have fewer blood cells than usual. This confirms the diagnosis of aplastic anaemia.

Further testing may be carried out to determine the exact cause of the disease.

The treatment for aplastic anaemia depends upon the severity of the condition, the patient's age, and tolerance to the treatment modality. Severe aplastic anaemia cases are life-threatening and require hospitalization. The treatment options are:

Blood Transfusions

Blood transfusions don't cure aplastic anaemia but rather help control bleeding and provide symptomatic relief. Blood transfusions allow the transfusion of red blood cells and platelets. The red blood cells raise the RBC count. As a result, a reduction in fatigue is observed. On the other hand, platelet transfusion helps prevent uncontrolled bleeding.

Unlimited transfusions can be done to improve the condition of patients with aplastic anaemia. However, multiple transfusions often cause complications. This is because transfused red blood cells contain iron. There is always a risk of this iron being accumulated in the body and damaging vital organs. To prevent such an incidence, medicines to reduce iron overload are prescribed. 

In some cases, with time, the body produces antibodies against the transfused blood. As a result, the transfused blood becomes less effective in providing symptomatic relief. However, immunosuppressant drugs often eliminate this issue.

Stem Cell Transplant

A stem cell transplant requires the replacement of diseased bone marrow with a healthy donor's bone marrow. This permits the rebuilding of the bone marrow stem cells and has shown great success for people with aplastic anaemia. In addition, a stem cell transplant, also called a bone marrow transplant, is generally the treatment of choice for younger patients with a matching donor. The donors are often siblings of the patients.

First, the recipient's bone marrow is irradiated with chemotherapy or radiation therapy. Then, healthy stem cells from the donor are filtered from the blood. Next, into the bloodstream, doctors inject healthy stem cells. From here, the cells reach the bone marrow and start multiplying. This procedure requires a considerable length of hospital stay. Finally, immunosuppressants are prescribed for a lifetime to prevent the chances of rejection of donated stem cells.

The transplant procedure carries some risks, such as the rejection of the donated cells, which may have life-threatening complications. Moreover, finding a suitable donor for a transplant is not easy.

Immunosuppressants

Immunosuppressants are drugs that prevent the immune system from functioning. It is often prescribed to patients with severe aplastic anaemia and to those who cannot undergo a transplant due to pre-existing autoimmune conditions.

Medicines such as cyclosporine (Gengraf, Neoral, Sandimmune) and anti-thymocyte globulin suppress the immune cell activity that damages the bone marrow. However, it allows the bone marrow to repair itself and produce new blood cells. Therefore, these two drugs are often prescribed together. In addition, corticosteroids, like methylprednisolone, are also administered. These drugs weaken the body's defence system and prevent it from attacking the bone marrow.

Bone Marrow Stimulants

Certain drugs, such as colony-stimulating factors (for example, sargramostim, filgrastim and pegfilgrastim), stimulate the bone marrow. On stimulation, the bone marrow produces new blood cells. In addition, growth factors enhance the function of immune-suppressing drugs that are prescribed concomitantly.

Antibiotics and Antiviral Drugs

Aplastic anaemia weakens the immune system, and thus, people with this disorder are more prone to infections. It is thus important to consult the treating doctor in case any signs of infection become evident, such as fever or pus discharge. Infections in immunocompromised individuals are life-threatening. Therefore, infections need to be addressed as a priority.

Other Treatment Options

Aplastic anaemia that occurs due to radiation and chemotherapy treatments for cancer often resolves on its own once the treatment stops. The same is applicable to medicines that cause aplastic anaemia. 

Pregnant women with aplastic anaemia are treated with blood transfusions. For many women, pregnancy-related aplastic anaemia improves once the pregnancy ends. However, if that doesn't happen, treatment is still necessary.

Aplastic anaemia is often associated with complications. Some of which include:

• Frequent infections due to weakened immunity
• Uncontrolled bleeding
• Arrhythmia due to untreated aplastic anaemia
• Enlarged heart
• Heart failure
• Disease progression to myelodysplastic syndrome or acute leukaemia

Some factors that may contribute to the development of aplastic anaemia are:

• Exposure to toxic chemicals
• Radiation or chemotherapy treatment for cancer
• Medicines such as chloramphenicol and arthritis medicines
• Blood disorders
• Autoimmune conditions
• Pregnancy (very rare)
• Viral infections

Reviewed by Dr. Rayaz Ahmed,  Director, Cancer Care / Oncology, Bone Marrow Transplant, Hematology Oncology, Medical Oncology, Hematology, Paediatric (Ped)/Medical Oncology on 13-Jan-2023.