Causes of Chronic Thrombocytopenia

Decreased Platelet Production

Myelodysplastic syndromes, leukemias, and other malignancies impair megakaryocyte function and represent critical causes requiring bone marrow examination in patients over 60 years or those with systemic symptoms 1
Bone marrow suppression occurs from chronic alcohol use, iron overload, certain medications, and viral infections (particularly hepatitis C and HIV) 3, 1
Inherited thrombocytopenias, including thrombocytopenia-absent radius syndrome, Wiskott-Aldrich syndrome, and MYH9-related disease, affect platelet production from birth 1, 2

Primary immune thrombocytopenia (ITP) is an autoimmune disorder with immunologic destruction of otherwise normal platelets, diagnosed by exclusion after ruling out secondary causes 1, 2
Secondary immune thrombocytopenia occurs with multiple associated conditions, including autoimmune disorders, viral infections, lymphoproliferative disorders, drug-induced thrombocytopenia, and common variable immune deficiency 1, 2
Heparin-induced thrombocytopenia (HIT) typically presents with moderate thrombocytopenia (30-70 × 10⁹/L) occurring 5-10 days after heparin initiation, evaluated using the 4T score 1

Hypersplenism from portal hypertension in advanced liver fibrosis causes platelet trapping, contributing to thrombocytopenia in up to 76% of patients with chronic liver disease 3

Initial evaluation must exclude pseudothrombocytopenia by repeating the platelet count in heparin or sodium citrate tubes, as EDTA-dependent platelet agglutination can falsely lower counts 1, 2
Complete blood count with differential distinguishes isolated thrombocytopenia from pancytopenia, which suggests bone marrow failure or infiltration 1, 2
Peripheral blood smear examination is essential to assess platelet morphology and identify abnormal white cells or red cell fragments 1, 2
Red flags requiring additional investigation include splenomegaly, hepatomegaly, or lymphadenopathy, abnormal hemoglobin, white blood cell count, or white cell morphology, and constitutional symptoms suggesting infection or malignancy 1, 2
Infectious disease screening should include HIV, hepatitis C, and H. pylori testing in adults with suspected ITP 1, 2
Bone marrow examination is indicated for patients over 60 years, those with atypical features, or when systemic symptoms suggest underlying malignancy or myelodysplasia, but is not necessary in typical ITP presentations 1, 2
Immunoglobulin measurement may identify common variable immune deficiency, as ITP can be its presenting feature 1