Myelodysplasia

Myelodysplastic disorders (or myelodysplastic syndrome) are a group of acquired clonal disorders of the haemopoietic stem cell characterised by:

• peripheral blood cytopenias
• a hypercellular bone marrow
• morphological abnormalities in two or more haemopoietic cell lines

A single abnormal multipotential cell in the bone marrow is affected. These disorders were formerly grouped under the the term "preleukaemia" since they may transform into acute myeloid leukaemia, but this term is now used to describe any condition predisposing to leukaemia.

The majority of patients myelodysplastic syndrome present with fatigue due to anaemia, although it is not uncommon for the diagnosis to be made as a result of unexplained macrocytosis or cytopaenia

• infections do tend to occur in patients with neutrophil counts <1x 10^9/litre, the most common of which are bacterial pneumonia and skin abscesses
• bleeding is a rare presentation but can occur with severe thrombocytopaenia (platelet count <10x10^9/litre)
• there is an association between MDS and various autoimmune abnormalities such as cutaneous vasculitis, fever, arthritis, pericarditis, peripheral oedema, pulmonary infiltrates, iritis, myositis, and peripheral neuropathy. However, a causal relationship with MDS and autoimmune disorders has not yet been established

Approximately 2/3 of patients succumb to the disease within 3-4 years after presentation, and individuals with high-risk MDS generally survive about 1 year. Given that the disease is more prevalent in the elderly who often have comorbid conditions, the current treatment of MDS consists mainly of supportive care. Curative treatments are restricted to younger, healthy individuals with histocompatible (HLA)-matched donors for allogenic transplant or those able to undergo intensive chemotherapeutic regimens (2).

Notes:

• that it is important to exclude other causes of anaemia in the elderly, particularly iron deficiency or pernicious anaemia. The patient needs to be referred to a haematologist, where a bone marrow aspirate will confirm the diagnosis and exclude other haematological disorders such as acute myeloid leukaemia, myeloma, or myelofibrosis. Sometimes it is difficult to distinguish hypoplastic MDS from aplastic anaemia, but this is a problem of little significance since management in the elderly is essentially similar. Neoplastic infiltration of the bone marrow causing pancytopenia is readily distinguished by characteristic clinical features and a leucoerythroblastic film

Reference:

• 1. Enright H, Jacob HS, Vercellotti G, et al. Paraneoplastic autoimmune phenomena in patients with myelodysplastic syndromes: response to immunosuppressive therapy. Br J Haematol 1995; 91:403-8
• 2. Myelodysplasic syndromes: a comprehensive review. Blood Rev. 2005 Nov;19(6):301-19