### Date : 2024-06-29 10:52 ### Topic : Infections That Cause Thrombocytopenia #medicine #infectology ---- ### Infections That Cause Thrombocytopenia Thrombocytopenia, a condition characterized by low platelet counts, can be caused by a variety of infections. The mechanisms by which infections cause thrombocytopenia include direct infection of megakaryocytes (platelet precursors), immune-mediated destruction of platelets, bone marrow suppression, and increased platelet consumption. Here are some key infections known to cause thrombocytopenia: ### Viral Infections 1. **Dengue Fever** - **Etiology:** Dengue virus, transmitted by Aedes mosquitoes. - **Pathophysiology:** The virus infects bone marrow cells, including megakaryocytes, leading to decreased platelet production and increased destruction. Additionally, the immune response can cause further platelet destruction. - **Clinical Features:** High fever, severe headache, retro-orbital pain, myalgia, arthralgia, rash, and bleeding tendencies. 2. **Hepatitis C** - **Etiology:** Hepatitis C virus (HCV). - **Pathophysiology:** Chronic HCV infection can cause bone marrow suppression and immune-mediated platelet destruction. Additionally, liver disease associated with HCV can lead to splenomegaly and increased platelet sequestration. - **Clinical Features:** Jaundice, fatigue, abdominal pain, and liver dysfunction. 3. **Human Immunodeficiency Virus (HIV)** - **Etiology:** HIV, transmitted through blood, sexual contact, or vertical transmission. - **Pathophysiology:** HIV can directly infect megakaryocytes and cause immune-mediated destruction of platelets. Opportunistic infections and medications used to treat HIV can also contribute to thrombocytopenia. - **Clinical Features:** Fever, weight loss, lymphadenopathy, opportunistic infections, and various organ-specific symptoms. 4. **Epstein-Barr Virus (EBV)** - **Etiology:** EBV, the cause of infectious mononucleosis. - **Pathophysiology:** EBV infection can lead to immune-mediated platelet destruction and bone marrow suppression. - **Clinical Features:** Fever, sore throat, lymphadenopathy, splenomegaly, and fatigue. 5. **Cytomegalovirus (CMV)** - **Etiology:** CMV, a herpesvirus. - **Pathophysiology:** CMV can cause bone marrow suppression and immune-mediated destruction of platelets. - **Clinical Features:** Fever, fatigue, hepatitis, and symptoms specific to immunocompromised individuals. ### Bacterial Infections 1. **Sepsis** - **Etiology:** Various bacteria, including Gram-positive and Gram-negative organisms. - **Pathophysiology:** Sepsis causes widespread inflammation, leading to disseminated intravascular coagulation (DIC) and consumption of platelets. Additionally, direct infection of bone marrow and immune-mediated destruction can occur. - **Clinical Features:** Fever, hypotension, tachycardia, organ dysfunction, and shock. 2. **Rickettsial Infections** - **Etiology:** Rickettsia species, such as Rickettsia rickettsii (Rocky Mountain spotted fever). - **Pathophysiology:** Rickettsial organisms infect endothelial cells, causing vasculitis and increased platelet consumption. - **Clinical Features:** Fever, rash, headache, myalgia, and gastrointestinal symptoms. ### Parasitic Infections 1. **Malaria** - **Etiology:** Plasmodium species, transmitted by Anopheles mosquitoes. - **Pathophysiology:** Plasmodium parasites cause direct destruction of infected red blood cells and indirectly lead to increased platelet consumption and destruction. - **Clinical Features:** Cyclical fever, chills, headache, anemia, splenomegaly, and jaundice. 2. **Babesiosis** - **Etiology:** Babesia species, transmitted by Ixodes ticks. - **Pathophysiology:** Babesia parasites infect red blood cells, causing hemolysis and subsequent thrombocytopenia through increased platelet consumption. - **Clinical Features:** Fever, chills, fatigue, hemolytic anemia, and splenomegaly. ### Fungal Infections 1. **Histoplasmosis** - **Etiology:** Histoplasma capsulatum, found in soil contaminated with bird or bat droppings. - **Pathophysiology:** The fungus can disseminate and infect the bone marrow, leading to pancytopenia, including thrombocytopenia. - **Clinical Features:** Fever, cough, chest pain, fatigue, and disseminated disease in immunocompromised individuals. ### Example Case Study **Patient Profile:** - **Name:** Jee Hoon Ju - **Age:** 35 - **Occupation:** Construction Worker **Medical History:** - Recent travel to an area endemic for malaria. **Clinical Evaluation:** - **Symptoms:** Fever, chills, fatigue, and jaundice. - **Physical Examination:** Splenomegaly and pallor. **Laboratory Tests:** - **CBC:** Thrombocytopenia (platelets 50,000/µL), anemia. - **Peripheral Blood Smear:** Presence of Plasmodium parasites. - **Liver Function Tests:** Elevated bilirubin. **Diagnosis:** Based on clinical presentation, travel history, and laboratory findings, Jee Hoon Ju is diagnosed with malaria-induced thrombocytopenia. ### Management **1. Treatment of Underlying Infection:** - **Antimalarial Drugs:** Chloroquine, artemisinin-based combination therapies (ACTs), or other appropriate antimalarial medications based on Plasmodium species and resistance patterns. **2. Supportive Care:** - **Fluid Replacement:** Intravenous fluids to maintain hydration and electrolyte balance. - **Blood Transfusions:** For severe anemia or thrombocytopenia with bleeding. **3. Monitoring and Follow-Up:** - Regular monitoring of vital signs, blood counts, and organ function. - Follow-up care to ensure complete resolution of infection and recovery of platelet counts. ### Conclusion Thrombocytopenia can result from various infections, including viral, bacterial, parasitic, and fungal pathogens. Understanding the underlying etiology, pathophysiology, clinical features, and management strategies is crucial for effectively diagnosing and treating thrombocytopenia in the context of infectious diseases. Prompt treatment of the underlying infection and supportive care can significantly improve patient outcomes. ### Reference: - ### Connected Documents: - [[Infections That Cause Pancytopenia]]