Acquired amegakaryocytic thrombocytopenia

AAT, Acquired pure megakaryocytic aplasia, Severe thrombocytopenia and selective, marked decrease or absence of megakaryocytes


Acquired amegakaryocytic thrombocytopenia is a rare blood disorder that causes severe thrombocytopenia with no other blood abnormalities and absent, or severely decreased marrow megakaryocytes. It is so named because the level of large bone marrow cells that produce platelets, called megakaryocytes, are significantly lower or absent. The etiology may be immune suppression of megakaryocyte development. It is so named because the level of large bone marrow cells that produce platelets, called megakaryocytes, are significantly lower or absent.

Symptoms - Acquired amegakaryocytic thrombocytopenia

  • Prolonged bleeding, even from minor cuts
  • Easy bruising
  • Rash (pinpoint red spots called petechia)
  • Bleeding in the mouth and gums
  • Frequent nose bleeds
  • Reduced blood platelets
  • Megakaryocyte deficiency  
  • Reduced blood platelets
  • Impaired blood clotting
  • Bleeding into the skin
  • Bleeding problems

Causes - Acquired amegakaryocytic thrombocytopenia

There are many potential causes of acquired amegakaryocytic thrombocytopenia. It can be either idiopathic or caused by a variety of conditions, For example, the condition can be associated with:

  • Viral infections
  • Bacterial infections
  • Chemotherapy
  • Exposure to environmental toxins
  • Autoimmune diseases (i.e. systemic lupus erythematosus)
  • Drug sensitivities
  • Pregnancy
  • Acquired clonal cytogenetic abnormalities,
  • Toxin exposure
  • Infectious diseases (viral infection)
  • Systemic sclerosis
  • Eosinophilic fasciitis
  • Malignancy

Patients with acquired amegakaryocytic thrombocytopenia may have additional hematological abnormalities such as macrocytosis or dyserythropoiesis, abnormalities which may indicate potential future progression to aplastic anemia or myelodysplasia.

Prevention - Acquired amegakaryocytic thrombocytopenia

Not supplied.

Diagnosis - Acquired amegakaryocytic thrombocytopenia

A diagnosis of acquired amegakaryocytic thrombocytopenia is often suspected based on the presence of characteristic signs and symptoms. Additional testing can then be ordered to confirm the diagnosis. This may include:

  • Complete blood count (CBC)
  • Blood smear
  • Blood clotting studies (PTT and PT)
  • Bone marrow tests (i.e. a bone marrow aspiration and/or biopsy)

Prognosis - Acquired amegakaryocytic thrombocytopenia

The long-term outlook (prognosis) for people with acquired amegakaryocytic thrombocytopenia varies based on the underlying cause. Some people respond well to treatment and long-term remissions have been documented in several case reports. In others, the condition progresses rapidly to aplastic anemia or myelodysplasia. There are currently no good predictors to aid in assessing the likelihood of response to therapy or overall prognosis.

Treatment - Acquired amegakaryocytic thrombocytopenia

Although standard treatment guidelines have not been established, various immunosuppressive treatment approaches have been utilized with success in affected people.


Standard treatment guidelines have not been established for acquired amegakaryocytic thrombocytopenia. However, various immunosuppressive treatment approaches have been utilized in affected people. In several case reports, affected people were successfully treated with cyclosporine either alone or in combination with other immunosuppressive medications (i.e. antithymocyte globulin). Other therapies for acquired amegakaryocytic thrombocytopenia have included rituximab, danazol, azathioprine, and bone marrow transplant with variable success.

Administration of human polyclonal immunoglobulins preceded increased reticulocyte count by 3 days. A second bone marrow examination confirmed restoration of erythroblasts and megakaryocytes. After 1 relapse, the disease was successfully controlled with prednisolone for > 3 years.

Resources - Acquired amegakaryocytic thrombocytopenia

  • NIH
Orphan Therapies
Research Publications