What is Thrombocytopenia?
Thrombocytopenia is a condition where you have a lower than normal count of platelets — blood cells that help with clotting and healing wounds — in your blood. The normal range for adults is 150,000 platelets per microliter of blood or more. With thrombocytopenia, the risks can vary from none to experiencing bleeding issues or the creation of blood clots, also known as thrombosis. However, how severe the condition is doesn’t always directly relate to the risk of bleeding.
When the platelet count goes below 10,000 per microliter of blood, spontaneous bleeding — bleeding that starts on its own without a clear cause — can happen. Additionally, there’s a risk of bleeding during surgery if the count is under 50,000 platelets per microliter of blood. Thrombocytopenia can be associated with increased risk of blood clots in certain conditions like:
- Heparin-induced thrombocytopenia (HIT): a condition where the drug heparin, which is normally used to prevent blood clots, instead leads to fewer platelets and more blood clots.
- Antiphospholipid antibody syndrome (APS): a disorder that causes the immune system to attack normal proteins in the blood, creating a higher likelihood of blood clots.
- Disseminated intravascular coagulation (DIC): a disorder that involves uncontrolled clotting and then bleeding.
- Thrombotic microangiopathy (TMA): a condition involving the formation of clots in small blood vessels throughout the body.
- Paroxysmal nocturnal hemoglobinuria (PNH): a rare disorder where blood cells break down earlier than they should.
What Causes Thrombocytopenia?
Thrombocytopenia is a condition where your body has a lower than normal number of platelets – the blood cells that help your blood to clot. There are many possible causes of this condition and they can vary from person to person.
One possible cause is known as primary immune thrombocytopenia or primary ITP. This is an autoimmune condition where your body mistakenly attacks its own platelets, resulting in their destruction. Certain drugs can also cause thrombocytopenia. For instance, the drug heparin can trigger a reaction where anti-platelet antibodies activate platelets leading to blood clot formation in both arteries and veins, a condition known as heparin-induced thrombocytopenia or HIT.
Other drugs like Quinine, Sulfonamides, ampicillin, vancomycin and others can cause thrombocytopenia, as can over-the-counter remedies, certain foods (like African bean, sesame seeds, walnuts), and beverages (like herbal teas and cranberry juice).
There are also drugs like valproic acid, daptomycin, linezolid which can cause thrombocytopenia by suppressing platelet production.
Infections such as HIV, hepatitis C, and others can result in thrombocytopenia. Also, severe infections like sepsis can suppress the bone marrow, where platelets are produced. Certain bacterial and tick-borne infections, as well as some parasitic infections like malaria, can also be associated with lower platelet counts.
Other potential causes of thrombocytopenia might include chronic liver disease, chronic alcohol abuse, certain nutrient deficiencies such as folate, vitamin B12, copper, and autoimmune disorders like lupus or rheumatoid arthritis. Thrombocytopenia may be observed in pregnancy as well, especially in conditions like preeclampsia and HELLP syndrome (a serious pregnancy complication that stands for Hemolysis, Elevated Liver enzymes, and Low Platelet count).
Other causes could include certain cancers, conditions like paroxysmal nocturnal hemoglobinuria (a rare disorder that causes your body to destroy red blood cells at night) and conditions that result in small blood clots throughout your body – known as thrombotic microangiopathy.
There are also some genetic conditions that can lead to thrombocytopenia. These are often seen in children but are rare in adults. Conditions include Von Willebrand disease type 2, Alport syndrome, Wiskott-Aldrich syndrome, Fanconi syndrome and others.
Risk Factors and Frequency for Thrombocytopenia
The number of platelets someone has in their blood can differ based on their age, sex, and ethnicity. Women, younger people, and non-Hispanic black individuals typically have slightly more platelets.
Signs and Symptoms of Thrombocytopenia
Getting a full health history from a patient can help determine the cause of low platelet count, also known as thrombocytopenia. Normally, those with a platelet count above 50000/mL won’t experience symptoms. However, those with platelet counts under 20000/mL are likely to experience spontaneous bleeding.
- It’s important to ask the patient about any previous blood tests and their normal platelet count levels. A recent decrease in platelet count could be a warning sign.
- Ask about any bleeding they’ve noticed, such as small red spots on the skin (petechiae), heavy bleeding, gum bleeding, or nosebleeds.
- Ask if they’ve been exposed to any infections, especially viral, bacterial, or rickettsial (like tick-borne diseases). Probing into chance factors for HIV infection, or travel to areas where malaria, dengue, and Ebola are prevalent can also be insightful.
- Discuss their eating habits to check for any nutritional deficiencies.
- Ask about any conditions they have, such as Systemic Lupus Erythematosus (SLE), Rheumatoid Arthritis (RA), if they’ve had weight-loss surgery, or had a blood transfusion. Look at any medications they’re on, including over-the-counter drugs, beverages containing quinine (like tonic water), and herbal teas. If the patient is in the hospital, check if they’ve been exposed to any heparin products. See if there’s a family history of low platelets or bleeding disorders. If the patient is pregnant, ask about headaches, visual disturbances, abdominal pain, or flu-like symptoms, as these could indicate a serious condition like preeclampsia or HELLP syndrome.
During a physical examination, the doctor will check the skin and other areas for bleeding. They’ll also examine the liver, spleen, and lymph nodes. The type of bleeding associated with thrombocytopenia usually shows up as petechiae, non-palpable purpura (large purple skin patches), and ecchymosis (bruising). Purpura in the skin is known as “dry purpura,” while purpura in the mucous membranes is “wet purpura.” The doctor will also check for an enlarged liver or spleen, which can indicate conditions like lymphoma and chronic liver disease. They’ll also look for swollen lymph nodes, a possible sign of infection, auto-immune conditions, lymphoma, or other cancers.
Testing for Thrombocytopenia
If you have low platelet levels, also known as thrombocytopenia, your doctor will need to evaluate your condition with a series of tests. These tests include a complete blood count (CBC), a test that counts each type of cell in your blood, a review of a small drop of your blood to observe its appearance (peripheral blood smear), and tests for HIV and Hepatitis C viruses.
If your initial CBC test shows low platelet levels, your doctor will likely repeat the test to confirm that thrombocytopenia is indeed present. Why? Because certain conditions can cause both low platelet levels and other abnormalities in your blood. For instance, infections, a condition called disseminated intravascular coagulation (DIC, where small blood clots develop throughout your body’s blood vessels), sepsis (a serious infection throughout the body), thrombotic microangiopathy (a group of disorders with too much clotting), and autoimmune disorders like Felty syndrome (rheumatoid arthritis with enlargement of the spleen and low white blood count) can cause both low red blood cell levels (anemia) and low platelet levels.
Moreover, infections, cancer, and long-term inflammation can lead to high white blood cell levels (leucocytosis) and low platelet counts. A low count in all types of blood cells (pancytopenia) can be a sign of conditions negatively affecting your bone marrow, like myelodysplastic syndromes, where the bone marrow doesn’t produce enough healthy cells.
If you’re showing symptoms of autoimmune disorders like systemic lupus erythematosus (SLE) or antiphospholipid antibody syndrome (APS), another set of tests is required to check for the presence of specific antibodies. Similarly, if you’ve had blood clots, the doctor may need to test for conditions like heparin-induced thrombocytopenia, APS, disseminated intravascular coagulation (DIC), and paroxysmal nocturnal hemoglobinuria (PNH, a rare and serious blood disease).
If you have liver disease, your hepatitis C test might be linked to checking your liver enzyme levels and how well your blood can clot (coagulation tests). If the cause of your low platelet levels is unclear or a blood disorder is suspected, a bone marrow biopsy (takes a sample of your bone marrow) might be needed. This is because the number of megakaryocytes (the cells responsible for producing platelets) can indicate if your body is destroying platelets faster than it can make them, or if your body isn’t making enough to begin with. For instance, in SLE, there could be a severe decrease or absence of megakaryocytes due to an autoantibody acting against the receptor needed to produce more platelets.
Lastly, if there are abnormal red blood cells and white blood cells, it may suggest vitamin B12, folate, or copper deficiency. Abnormal cells, cells that are not formed correctly, may point towards myelodysplasia, a disorder where the bone marrow doesn’t produce enough healthy cells.
Treatment Options for Thrombocytopenia
If you have mild thrombocytopenia, a condition where you have a low number of platelets in your blood, but aren’t experiencing any symptoms, your doctor will likely just monitor your blood counts regularly. Platelets are crucial for blood clotting, so having too few can lead to excessive bleeding.
In severe cases of thrombocytopenia or if there’s bleeding or another emergency, immediate medical intervention is needed. These emergencies can be due to a variety of reasons, ranging from certain medical conditions (for instance, HIT, TTP, HUS), drug reactions, complications during pregnancy, or the need for an immediate surgical procedure.
Treatment in severe cases might include a platelet transfusion, where you’re given more platelets through an IV. The doctor will also determine and address the underlying cause of your low platelet count.
Primary immune thrombocytopenia (a condition where your immune system mistakenly targets and destroys your platelets) is often treated initially with medications called glucocorticoids and intravenous immune globulins to stop the attack on the platelets. If these don’t work, your doctor may turn to other medications, like rituximab and other immunosuppressive drugs, or even a splenectomy, which is a surgery to remove your spleen. There are also third line treatment options that help your body produce more platelets.
If thrombocytopenia is caused by a medication you’re taking, your doctor will likely ask you to stop taking that drug. For example, in cases of drug-induced thrombocytopenia or if it is caused by heparin (a blood-thinning medication), the heparin is stopped and other non-heparin blood thinners might be used.
TTP, another condition that can cause thrombocytopenia, is typically treated with a procedure called plasma exchange to replace the unhealthy plasma (the liquid part of the blood) in your body with healthy plasma.
In people with secondary ITP (where the low platelet count is caused by another illness), the underlying disease is treated. This can be anything from autoimmune diseases like SLE to infections like H.pylori. Treating the underlying condition often helps increase the platelet count.
What else can Thrombocytopenia be?
Pseudothrombocytopenia is a condition where it seems like the patient has a low platelet count, but they actually don’t. This can happen due to a variety of reasons, such as:
- The formation of platelet clumps in response to a chemical called ethylenediaminetetracetic acid (EDTA).
- If the blood sample was not properly anticoagulated (prevented from clotting).
- The use of medications that inhibit glycoprotein IIb/IIIa, an essential platelet binding protein.
- When large platelets are incorrectly counted as white blood cells instead of platelets by a machine.
These all can result in a falsely low platelet count.
What to expect with Thrombocytopenia
A forward-looking study discovered that patients with mild thrombocytopenia, a condition where you have lower than normal amounts of platelets in the blood (between 100,000 and 150,000 per microliter), have a 12% chance of developing autoimmune disorders in the next 10 years.
Possible Complications When Diagnosed with Thrombocytopenia
Severe thrombocytopenia often leads to heavy internal bleeding, and if the bleeding happens in the brain it can be fatal.
In the case of heparin-induced thrombosis (HIT), blood clots can form in both the arteries and the veins. This can lead to serious health issues like deep vein thrombosis (a blood clot in a deep vein), pulmonary embolism (a clot in the lungs), strokes, and heart attacks.
Similarly, antiphospholipid antibody syndrome is also linked with both arterial and venous clot formation, and it can even cause miscarriages.
In thrombotic thrombocytopenic purpura (TTP), very small blood clots can form in various organ systems, primarily affecting the central nervous system. Hemolytic uremic syndrome (HUS), on the other hand, primarily impacts the kidneys.
Common Symptoms and Consequences:
- Severe internal bleeding
- Potential fatal bleeding in the brain
- Blood clot formation in arteries and veins
- Possibility of deep vein thrombosis
- Chance of pulmonary embolism
- Risk of strokes and heart attacks
- Possible miscarriages due to antiphospholipid antibody syndrome
- Small blood clot formation in organ systems in TTP
- Impact on kidneys due to HUS
Preventing Thrombocytopenia
It’s important to inform patients about limitations on their activities. Those who have a platelet count above 50,000/mL need to be particularly cautious when playing contact sports. It’s advisable for those with a platelet count below 10,000/mL to avoid contact sports and any activity that might lead to injuries.
It’s also crucial to share information about certain over-the-counter medications, such as aspirin and Non-steroidal anti-inflammatory drugs, along with ginkgo biloba, as these can affect how platelets work in the body. Patients should also be aware that drinks and herbal teas that contain quinine can lower the platelet count.
In simple terms, platelets are the parts of your blood that help with clotting when you get injured. Having too many or too few platelets can affect your body’s ability to stop bleeding or may cause unnecessary clots.