Differential Diagnosis for Thrombocytopenia (Platelet Count < 100)

Single Most Likely Diagnosis

• Immune Thrombocytopenic Purpura (ITP): This is an autoimmune condition where the body's immune system mistakenly attacks and destroys its own platelets, leading to a low platelet count. It's a common cause of thrombocytopenia and often presents with isolated thrombocytopenia without other significant abnormalities in the blood count.

Other Likely Diagnoses

• Viral Infections: Certain viral infections, such as HIV, hepatitis C, and Epstein-Barr virus, can lead to thrombocytopenia due to mechanisms like immune-mediated destruction, bone marrow suppression, or splenic sequestration.
• Drugs: Many medications can induce thrombocytopenia, either through immune-mediated mechanisms (e.g., heparin-induced thrombocytopenia) or by suppressing bone marrow production (e.g., chemotherapy).
• Chronic Liver Disease: Liver diseases, particularly cirrhosis, can lead to thrombocytopenia due to splenic sequestration (hypersplenism) as a result of portal hypertension.
• Bone Marrow Failure Syndromes: Conditions like aplastic anemia or myelodysplastic syndromes can cause thrombocytopenia due to a failure of the bone marrow to produce sufficient platelets.

Do Not Miss Diagnoses

• Heparin-Induced Thrombocytopenia (HIT): Although less common, HIT is a life-threatening condition that occurs in patients exposed to heparin, leading to the formation of antibodies that activate platelets, causing both thrombocytopenia and a prothrombotic state.
• Thrombotic Thrombocytopenic Purpura (TTP): A rare disorder characterized by thrombocytopenia, microangiopathic hemolytic anemia, renal failure, neurological symptoms, and fever. It's caused by a deficiency in ADAMTS13, a enzyme responsible for cleaving von Willebrand factor.
• Disseminated Intravascular Coagulation (DIC): A condition characterized by both widespread clotting and bleeding in the vascular system, leading to thrombocytopenia, among other coagulation abnormalities. It can be triggered by severe infections, trauma, or malignancies.

Rare Diagnoses

• Congenital Thrombocytopenias: A group of rare genetic disorders that affect platelet production or function, such as Bernard-Soulier syndrome or Wiskott-Aldrich syndrome.
• Gaucher Disease: A genetic disorder leading to the accumulation of glucocerebroside in cells, which can cause thrombocytopenia due to splenomegaly and bone marrow infiltration.
• Lymphoproliferative Disorders: Certain cancers like lymphomas or chronic lymphocytic leukemia can lead to thrombocytopenia through mechanisms like bone marrow infiltration or immune-mediated destruction.