Thrombocytopenia is a condition characterized by a platelet count of less than 150,000 units per microliter of blood. A tour of its possible causes and most common approaches.
Blood is a liquid connective tissue that circulates through the capillaries, veins, and arteries of all vertebrates. An average human being contains 4.5 to 5.5 liters of this fluid throughout his body, and the heart pumps almost all of this figure in a matter of 60 seconds. Within the blood, we find several cell types: erythrocytes, leukocytes and platelets.
Of all the cell bodies circulating in blood, erythrocytes or red blood cells are the most dominant. It is estimated that an average human being possesses about 5 million erythrocytes per cubic millimeter of blood, approximately 1,000 times more than leukocytes or white blood cells. These cells, without nucleus or mitochondria, have the sole function of transporting oxygen to each and every one of the parts of our body.
Beyond red blood cells, it is estimated that 0.5% of the cellular portion of the blood are white blood cells (basic units of the immune system) and 1% are platelets. Generally forgotten, the latter perform a series of essential tasks in the homeostasis and well-being of human beings, especially becausethey initiate blood coagulation when we suffer a wound.
Platelets are essential for the well-being of the body, as they prevent the patient from losing blood uncontrollably when suffering an injury, which would result in the most serious pictures in hypovolemic shock and death. What happens when there are not enough circulating platelets in a diseased organism? To answer this question and many more, here we tell you all about thrombocytopenia.
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What is thrombocytopenia?
Thrombocytopenia is a clinical entity that is reflected with a platelet count less than 150,000 units per microliter of blood, or what is the same, 150 × 10^9 / L. By comparison, the circulating platelet count in a normal patient is 150,000 to 450,000 per microliter of blood.
However, it should be noted that thrombocytopenia is not a disease in itself, but a condition or sign that there is an underlying pathology that is causing the low production or destruction of platelets in the patient. There are more than 200 recognized diseases that manifest themselves with a low platelet count, ranging from asymptomatic symptoms to internal bleeding that can end the life of the sufferer.
Thrombocytopenia is usually an indication of hematological irregularities, infections in the blood tract, thrombotic microangiopathies, blood cancers, immunological diseases and adverse effects of medications, among other scenarios. After anemia, it is the most frequent mismatch in the blood count: 0.9% of patients with an acute disease suffer from it, while 25 to 46% of patients in intensive care units (ICU) have a platelet count below what is expected.
All healthcare agencies encompass thrombocytopenia into three possible categories, depending on the underlying reason for the condition. These are as follows:
- Thrombocytopenia due to lack of platelet production.
- Thrombocytopenia due to loss of platelets.
- Thrombocytopenia due to platelet destruction (autoimmune disorders).
Causes of thrombocytopenia
As we have already said in previous lines, thrombocytopenia is not a disease in itself, but a consequence of an underlying pathological process. Below, we explore some of the most common causes of low platelet count in the patient.
1. Primary immune thrombocytopenia (TIP)
TIP is considered a very rare clinical entity, affecting 4 people per 100,000 inhabitantsin any given place per year. In this case, the reduced platelet count is due to the action of the patient’s own antibodies, as they recognize the autoantigens of the platelet membrane as harmful This causes the T lymphocytes of the immune system to destroy these cell bodies essential for coagulation to occur.
Although the underlying mechanisms of primary immune thrombocytopenia are not fully understood, certain triggers and risk factors are known to exist. The first is to present an advanced age, and the second, to have gone through a previous episode of hemorrhage (with a relative risk of 27.5).
2. Infections
Thrombocytopenia is a frequent complication in patients with HIV (9.2%), a percentage that increases to 21% in those who end up developing AIDS due to the lack of adequate treatments.
On the other hand, leptospirosis, anaplasmosis, brucellosis and other bacterial diseases that are transferred from animals to humans (sometimes by invertebrate vectors, such as ticks) also cause thrombocytopenia, in this case acquired throughout the patient’s life. Malaria and babeiosis, caused by intracellular parasites, also promote it.
3. Other causes
Infection-acquired thrombocytopenia or TIP are the best-known variants in the clinical setting, but there are many more. For example, chronic alcohol abuse, nutritional deficiencies, and hypersplenism (hyperfunctionality of the spleen) can lead to it. Finally, the consumption of some drugs (heparins, sulfonamides, ampicillin, etc.) can favor the appearance of immune thrombocytopenia, in this case secondary.
Symptoms of thrombocytopenia
As you can imagine, the most obvious symptoms of thrombocytopenia are related to the circulatory system. However, it should be noted that the first obvious clinical signs occur when the platelet count is less than 80,000 units per microliter, whilethe patient’s life is in danger when the count is less than 10,000 platelets/microliter.
One of the first signs of thrombocytopenia (especially TIP) is the appearance of petechiae under the skin, small red lesions that indicate the extravasation of a reduced number of erythrocytes when a capillary is damaged. Bruises also usually appear in any part of the body due to minimal blows, since localized and superficial internal bleeding is occurring due to the lack of platelets.
Also common is epistaxis, a nosebleed that is not cut with normal methods that induce clotting. The gums usually bleed profusely without obvious exogenous stimuli, women have exceptionally copious periods and even blood can be seen in urine and / or feces. The lower the platelet count, the more severe the symptoms.
Finally, it should be noted that severe thrombocytopenia is associated with internal bleeding, being the fatal cerebral type in almost all cases. Cerebral hemorrhage can be spontaneous, intraventricular, subarachnoid, subdural hematoma type or epidural hematoma type. In all cases, the average mortality rate is 40%, not counting the irreversible sequelae resulting from neuronal injury in the affected area.
Treatment
If thrombocytopenia is immune, the treatment of choice is glucocorticoids, specifically prednisone. This drug depresses the mechanisms of action of the immune system, which can help platelets stop being destroyed and their number in the blood increases. However, this drug should not be taken for too long unless strictly necessary: prolonged immunosuppression promotes infections and other associated problems.
If thrombocytopenia is caused by infection or blood malignancy, it should be treated based on the underlying problem. On the other hand, if the patient’s situation is critical (less than 10,000 platelets/microliter of blood), platelet transfusion is required, in order to avoid bleeding that may endanger the life of the affected person. Unfortunately, sometimes exogenous platelets can be destroyed by the same underlying mechanism that has caused the pathology.
Summary
As you can see, thrombocytopenia is a condition that responds to many triggers. The most normal thing is that the low platelet count is transient, an event resulting from a bacterial, viral or protozoan infection that disappears as soon as the pathogen that has infected the patient’s body is fought. Unfortunately, the prognosis for people with TIP is not so simple.
If you notice that you bleed more than usual or you always have a body full of bruises, these may be signs of the onset of thrombocytopenia. Go to the doctor promptly in this case, because keeping the platelet count above 100,000 units can save the patient’s life in the long term.
To the classic question “what do you do?” I always answer “basically I am a psychologist”. In fact, my academic training has revolved around the psychology of development, education and community, a field of study influenced my volunteer activities, as well as my first work experiences in personal services.
