Tuberculosis-associated Immune Thrombocytopenia: A Case Report

Al Argan, Reem J.; Al Elq, Abdulmohsen H.

TB is a common disease in Saudi Arabia. According to a 2014 World Health Organization (WHO) report, in Saudi Arabia, the incidence of TB is 12/100,000 population and the prevalence is 16/100,000 population. [4] Further, the majority of cases are of pulmonary origin (75%), while extrapulmonary TB constitutes only 25% of the cases. [4] However, the patient in this report most likely had a latent TB infection, as he had arrived in Saudi Arabia only 4 months before his presentation. In fact, according to a 2009 WHO report, Philippines ranks 9 th among the world's top 22 high-burden countries for TB and 8 th among the world's top 27 priority countries for multidrug-resistant and extensively drug-resistant TB. [5] The patient in this report presented with extrapulmonary TB, and later developed pulmonary TB. Memish et al. reported that the most common site for extrapulmonary TB in Saudi Arabia is lymph nodes. [6] TB has been associated with several hematological abnormalities including anemia, leukocytosis, monocytosis, leuckopenia, lymphopenia, leukemoid reactions, pancytopenia, thrombocytosis and thrombocytopenia. [7] TB-induced immune thrombocytopenia, as was the case in the patient of this report, is rare. ITP is defined as isolated thrombocytopenia with no clinically apparent associated conditions or other causes of thrombocytopenia. Common secondary causes of thrombocytopenia such as medications, viral infection, systemic lupus erythematosus and leukemia had been excluded in this patient through history and negative investigations, but the possibility of diagnosis of lymphoma or TB could not be excluded during the first presentation because the patient refused lymph node biopsy. The absence of granuloma in the bone marrow biopsy also delayed the diagnosis of TB. Further, bone marrow culture for TB was also not requested.