Severe Aplastic Anemia

Synonyms

SAA,

Overview

Severe Aplastic Anemia (SAA) is a rare, life-threatening bone marrow disorder where the body’s immune system attacks its own bone marrow, preventing it from producing enough blood cells. This leads to pancytopenia, characterized by low levels of red blood cells (causing fatigue and weakness), white blood cells (increasing infection risk), and platelets (leading to easy bruising and bleeding). Treatment options include immunosuppressive therapy (IST) to halt the autoimmune attack and, for eligible patients, a stem cell transplant (also called a bone marrow transplant) which offers the only potential cure.

Symptoms

Severe aplastic anemia symptoms stem from low red blood cell, white blood cell, and platelet counts, leading to fatigue, pallor, shortness of breath, frequent infections, easy bruising, and prolonged bleeding. Other signs include fever, dizziness, headaches, and small red or purple spots on the skin (petechiae). These life-threatening symptoms result from the bone marrow’s inability to produce enough blood cells and require immediate medical attention.

Causes

The exact cause of SAA is often unknown, but it is primarily an autoimmune disorder where autoreactive T-lymphocytes attack bone marrow cells. Other potential triggers include certain medications, exposure to chemicals, and viral infections.

Prevention

There’s no definitive way to prevent most cases of severe aplastic anemia, as the cause is often unknown. However, you can reduce your risk by minimizing exposure to known toxins like insecticides, herbicides, and organic solvents, avoiding unnecessary radiation, getting the hepatitis B vaccine, and not sharing needles if you are at risk for HIV or other blood-borne viruses.

Diagnosis

Severe aplastic anemia (SAA) is diagnosed through a combination of blood tests and a bone marrow biopsy, which reveals significantly decreased bone marrow cellularity (less than 25% normal). Additionally, the diagnosis requires at least two of the following criteria in peripheral blood: an absolute neutrophil count (ANC) less than 0.5 × 10⁹/L, a platelet count less than 20,000/μL, and a reticulocyte count less than 20,000/μL. Other tests and a thorough medical history are used to determine the specific cause and rule out other conditions.
 

Prognosis

The prognosis for severe aplastic anemia (SAA) has significantly improved with modern treatments, though outcomes vary based on age, overall health, and treatment choice. Early diagnosis and treatment, particularly through early hematopoietic stem cell transplantation (HSCT) for younger, healthy patients with a matched donor, offer the best chance for a cure and improved long-term survival. Immunosuppressive therapy (IST) is a viable alternative, especially for those without a matched donor, but carries risks of relapse and late complications.

Treatment

Treatment for severe aplastic anemia (SAA) focuses on replacing or stimulating bone marrow function through a bone marrow (stem cell) transplant, a potentially curative option, or immunosuppressive therapy with drugs to stop the immune system from attacking bone marrow stem cells. Blood transfusions provide temporary support by supplying missing blood cells and help manage symptoms but are not a cure. Treatment choice depends on age, overall health, and donor availability, with an early consultation with a transplant doctor recommended for SAA patients to explore all options.