- Decreased Platelet Production in Bone Marrow:
- Bone Marrow Disorders:
- Aplastic Anemia: Bone marrow stops producing enough new blood cells.
- Leukemia or Lymphoma: Cancer cells in the bone marrow can crowd out platelet-producing cells (megakaryocytes).
- Myelodysplastic Syndromes: A group of disorders where blood cells do not mature or function properly.
- Myelofibrosis: Bone marrow is replaced by scar tissue.
- Viral Infections: HIV, Hepatitis C, mumps, measles, parvovirus, Epstein-Barr virus.
- Chemotherapy and Radiation Therapy: Cancer treatments that can damage bone marrow.
- Toxic Chemical Exposure: Such as pesticides, arsenic, or benzene.
- Alcohol Abuse: Can suppress platelet production.
- Nutritional Deficiencies: Severe deficiencies in Vitamin B12 or folate can impair platelet production.
- Kidney Failure.
- Bone Marrow Disorders:
- Increased Platelet Destruction or Consumption:
- Immune Thrombocytopenia (ITP): An autoimmune disorder where the immune system mistakenly attacks and destroys platelets. Can be acute (often in children after a viral infection) or chronic.
- Drug-Induced Thrombocytopenia: Certain medications can trigger an immune response that destroys platelets (e.g., heparin, quinine, some antibiotics, anticonvulsants).
- Thrombotic Thrombocytopenic Purpura (TTP): A rare, life-threatening disorder where tiny blood clots suddenly form throughout the body, consuming large numbers of platelets.
- Hemolytic Uremic Syndrome (HUS): A condition often triggered by E. coli infection, leading to kidney failure and platelet destruction.
- Disseminated Intravascular Coagulation (DIC): A severe condition where proteins that control blood clotting become overactive throughout the body, leading to widespread clotting and rapid consumption of platelets and clotting factors.
- Sepsis: Severe systemic infection can lead to platelet consumption.
- Autoimmune Diseases: Systemic lupus erythematosus (SLE), antiphospholipid syndrome.
- Pregnancy (Gestational Thrombocytopenia): Mild, usually harmless drop in platelet count during late pregnancy.
- Platelet Sequestration (Pooling in Spleen):
- Enlarged Spleen (Splenomegaly): An enlarged spleen can trap too many platelets, removing them from circulation (e.g., due to cirrhosis, portal hypertension, blood cancers).
- Easy or Excessive Bruising: Small bruises (purpura) or larger bruised areas without apparent injury.
- Superficial Bleeding (Petechiae): Tiny, pinpoint red or purple spots that look like a rash, typically on the lower legs, indicating small bleeds under the skin.
- Prolonged Bleeding from Cuts: Even minor cuts may bleed for a longer time than usual.
- Spontaneous Bleeding:
- Nosebleeds (epistaxis).
- Bleeding gums.
- Blood in urine (hematuria) or stools (melena - black, tarry stools, or frank blood).
- Unusually Heavy Menstrual Periods.
- Fatigue.
- Enlarged Spleen: May be felt during a physical exam, but doesn't cause pain itself.
- Severe Symptoms (Medical Emergency):
- Internal Bleeding: Can lead to severe pain, weakness, and signs of shock.
- Intracranial Hemorrhage (Brain Bleed): Can cause severe headache, neurological changes, and can be life-threatening.
- Complete Blood Count (CBC):
- This is the primary test. It measures the number of platelets in your blood. A count below 150,000/microliter indicates thrombocytopenia.
- It also checks red and white blood cell counts, which can provide clues about the bone marrow or other conditions.
- Peripheral Blood Smear:
- A microscopic examination of a blood sample to confirm platelet count, check for platelet size and morphology, and identify any abnormal blood cells.
- Can sometimes reveal "platelet clumping," which can lead to a falsely low automated count.
- Bone Marrow Exam (Aspiration and Biopsy):
- If the cause of low platelets is unclear, a sample of bone marrow is taken.
- This assesses the number and health of megakaryocytes (cells that produce platelets) and rules out bone marrow disorders like leukemia or aplastic anemia.
- Tests for Underlying Causes:
- Antibody Tests: To detect specific antibodies that attack platelets (e.g., for ITP or drug-induced thrombocytopenia).
- Viral Studies: To test for infections like HIV or Hepatitis C.
- Coagulation Tests: (e.g., PT, PTT) To evaluate overall clotting function and rule out disorders like DIC or TTP.
- Autoimmune Markers: For conditions like lupus.
- Imaging Tests: Ultrasound of the abdomen to check for an enlarged spleen.
- Treating the Underlying Cause:
- Stop Offending Medications: If drug-induced thrombocytopenia is suspected.
- Treat Infections: Antivirals for viral infections (e.g., HIV, HCV), antibiotics for bacterial infections.
- Manage Underlying Diseases: Treating autoimmune diseases, liver disease, or cancers that affect the bone marrow.
- Medications to Increase Platelet Count (for ITP and some other causes):
- Corticosteroids: (e.g., prednisone) Suppress the immune system to reduce platelet destruction. Often first-line for ITP.
- Intravenous Immunoglobulin (IVIg): A concentrated antibody solution given intravenously to temporarily increase platelet count by blocking the immune system's attack on platelets. Used for severe bleeding or rapid count increase.
- Anti-D Immunoglobulin: For Rh-positive patients with ITP to temporarily increase platelet count.
- Thrombopoietin Receptor Agonists (TPO-RAs): (e.g., romiplostim, eltrombopag, avatrombopag) Stimulate the bone marrow to produce more platelets. Used for chronic ITP that doesn't respond to other treatments.
- Immunosuppressants: (e.g., rituximab, azathioprine, cyclosporine) May be used for ITP not responding to initial therapies.
- Splenectomy (Surgical Removal of the Spleen):
- Considered for chronic ITP that does not respond to medical treatments, as the spleen is a major site of platelet destruction.
- Also performed if an enlarged spleen is sequestering too many platelets.
- Platelet Transfusions:
- Given in cases of very low platelet counts or active significant bleeding to temporarily increase circulating platelets.
- Not typically used for ITP unless there is severe bleeding, as transfused platelets may also be rapidly destroyed.
- For TTP/HUS:
- Plasma Exchange (Plasmapheresis): A crucial treatment for TTP and HUS to remove harmful antibodies or toxins from the blood.
- Specific medications like caplacizumab for TTP.
- Lifestyle Modifications and Precautions:
- Avoid activities that carry a high risk of injury or bleeding (e.g., contact sports).
- Avoid medications that can inhibit platelet function (e.g., aspirin, NSAIDs).
- Use a soft toothbrush and electric razor.
- Be cautious to prevent falls and cuts.