Haematological changes associated with miliary tuberculosis of the bone marrow

The peripheral blood and bone marrow findings in 25 patients found to have tuberculous granulomata on bone marrow examination were examined to determine whether specific haematological findings are associated with tuberculous infiltration of the bone marrow. All the patients had one abnormality or more on their full blood count. The presence of a peripheral lymphopaenia was the single factor common to all 25 patients studied. The peripheral lymphopaenia was only associated with bone marrow lymphopaenia in 14% of patients. Other findings of note were an association of peripheral monocytopaenia and absence of giant cells in the granulomata, and decreased iron stores in almost a third of the total number of patients. The relevance of the lymphopaenia, monocytopaenia and decreased iron stores are discussed and we propose that the absence of a peripheral lymphopaenia makes it very unlikely that there will be tuberculous localization in the bone marrow.