Heparin- induced thrombocytopenia is a disease that can occur after administration of heparin. The number of platelets in the blood falls below 50 percent of the normal value.
What is heparin-induced thrombocytopenia?
According to abbreviationfinder, Heparin- induced thrombocytopenia ( HIT ) is a complication of treatment with heparin. Heparin is a standard medical drug for anticoagulation (inhibition of blood clotting). The administration of the active ingredient is intended to counteract thrombosis (blood clots).
As a rule, therapy with heparin is considered to be sensible. In some cases, however, a paradoxical effect of the drug can occur a few days after administration. This means that the thrombocytes (blood platelets) clump together, resulting in a decrease in the amount of platelets in the blood.
In the further course, there is a heparin-related blood platelet deficiency, also called thrombocytopenia or thrombocytopenia. Those affected are at an increased risk of contracting a blood clot. Overall, around ten percent of all patients treated suffer from heparin-induced thrombocytopenia.
In medicine, a distinction is made between two different forms of heparin-induced thrombocytopenia. They are called HIT type I and HIT type II and have different causes. In both cases, the thrombocytopenia occurs only after administration of the heparin.
Heparin-induced thrombocytopenia is triggered by an interaction between the blood platelets and the heparin. It is believed that the heparin is responsible for inhibiting an important enzyme, causing the platelets to activate and clump more quickly, which in turn results in faster consumption.
However, HIT type I is considered harmless, since only a slight platelet deficiency occurs and the complication disappears on its own after a few days. Because platelets do not typically drop below 80,000/µL, no treatment is required. Heparin-induced thrombocytopenia type II is due to a defense mechanism.
The human immune system produces antibodies against the heparin in the blood, which in turn leads to clumping. There is a risk of the platelet count dropping to less than 50 percent of normal. If the blood vessels are blocked as a result, there is a risk of serious health problems such as a pulmonary embolism, a stroke or a heart attack.
The risk of HIT type II increases with the duration of heparin treatment. If the doctor does not administer the heparin for more than five days, complications only rarely occur. The level of the heparin dose also plays an important role in the development of HIT type II.
Symptoms, Ailments & Signs
The symptoms that occur with heparin-induced thrombocytopenia depend on whether it is HIT type I or HIT type II because the two forms have different degrees of severity. Most HIT type I patients do not notice anything. After a few days the problem was fixed again.
In the context of heparin-induced thrombocytopenia type II, on the other hand, the number of blood platelets decreases significantly, which becomes noticeable about 5 to 14 days after the start of treatment. If the heparin is given repeatedly, the antibodies form more quickly, so that they show up after just one or two days. Due to the sharp drop in the number of blood platelets, blood clots can form, which, as an embolism, trigger a heart attack, among other things.
The veins in the legs are also badly affected because the thrombosis damages the tissue that is supplied by the arteries. In extreme cases, amputation of the affected limb may even be necessary. Furthermore, a pulmonary embolism, in which a pulmonary artery is blocked, is possible with pain, shortness of breath and fainting. Another life-threatening complication is a stroke. Sometimes the tissue near the heparin injection site also dies.
Diagnosis & History
Heparin-induced thrombocytopenia is usually suspected when the platelet count falls after heparin therapy, which occurs in particular in HIT type II. One of the most important diagnostic methods is the blood test, which can be used to detect a lack of blood platelets.
The blood sample can also be used to detect heparin-specific antibodies, which is often done using the ELISA method. Another test method is the HIPA method. Heparin is administered to the patient’s blood platelets to check for any clumping.
Because some blood disorders have symptoms similar to those of heparin-induced thrombocytopenia, differential diagnosis is also important.
It is important to rule out diseases such as dieseminated intravascular coagulation. The course depends on the form of heparin-induced thrombocytopenia that occurs. While HIT type I is mostly harmless, HIT type II often triggers venous thrombosis, which leads to further serious complications.
This disease can lead to various ailments and complications. In most cases, however, it goes unnoticed by the patient, with no particular symptoms occurring afterwards. The disease usually goes away on its own after just a few days. However, if there is a sharp drop in blood platelets, symptoms may appear about a week later.
This leads to blood clots, which significantly increases the risk of a heart attack. In the worst case, the person affected can die from a heart attack. Tissues throughout the body are also damaged, including the extremities. Limbs can sometimes die off completely, and amputation may be necessary.
Not infrequently, shortness of breath and loss of consciousness also occur, whereby the patient can also suffer injuries or a fall. A heart attack can also cause irreversible consequential damage if it is not treated immediately. The treatment is carried out with the help of medication and usually leads to a rapid relief of the symptoms. In most cases, life expectancy is not reduced when early treatment occurs.
When should you go to the doctor?
If a diffuse feeling of illness persists, a doctor should be consulted. If there are changes in the blood circulation, heart problems or abnormalities in the blood circulation, a doctor’s visit is necessary. Pain in the body that starts or spreads for no apparent reason should be evaluated and treated. Consultation with a doctor is necessary as soon as the patient wants to take any medication for the pain.
There are often side effects that must be clarified in good time and in advance. Increased vigilance is required in the presence of respiratory disorders. Shortness of breath should always be checked out by a doctor. If breathing stops or if this causes changes in the heartbeat, a doctor is needed. If the person concerned suffers from anxiety or panic attacks, he should consult a doctor. A disturbance of consciousness should also be investigated.
In the event of a failure, an ambulance must be called. Feelings of numbness on the skin or sensory disorders must be clarified by a doctor. If the sensory disturbances occur in the extremities or if there is unsteady gait or mobility problems, a doctor should be consulted. If you experience increased stress, a decrease in your usual performance or have problems concentrating, you should consult a doctor. Further investigations are needed to find a cause.
Treatment & Therapy
If the suspicion of heparin-induced thrombocytopenia is confirmed, prompt medical treatment is necessary. It may be necessary not to wait for all laboratory tests before the start of therapy in order to gain valuable time. The most important part of the therapy is stopping the heparin and administering another drug with a similar effect.
This is usually the drug argatroban. This reduces blood clotting, but does not trigger thrombocytopenia. Other drugs that can be used are lepirudin and danaparoid. In addition, no heparin must get into the patient’s organism by other means. The agent can also be found in douches, ointments or catheters.
Outlook & Forecast
The prognosis of heparin-induced thrombocytopenia depends on the type. There are basically two types of the disease. Type I heparin-induced thrombocytopenia is harmless and characterized only by a small decrease in the platelet count. It usually runs its course without any symptoms and also heals on its own. So no treatment is necessary.
In contrast, with heparin-induced type II thrombocytopenia, the outlook is much worse. The platelet count decreases very quickly here because antibodies form against the heparin-protein complexes. While the platelet count in type I rarely falls below 100,000/µl, in type II it can fall extremely short of this value. In very rare cases, values even lower than 20,000/µl are possible.
Despite a low platelet count, however, there is usually no major bleeding, but even increased formation of thrombi, because the antibodies lead to the activation of the platelets. It is an acute life-threatening condition that requires immediate medical attention. Heparin administration must be discontinued immediately and replaced with other anticoagulants.
The complications that occur in heparin-induced thrombocytopenia are almost exclusively due to the after-effects of the thrombi. Death can be caused by a pulmonary embolism or heart attack. Approximately 30 percent of all heparin-induced type II thrombocytopenias are fatal.
In order to prevent heparin-induced thrombocytopenia, it is possible to administer low molecular weight heparin instead of conventional heparin. In this way, the HIT risk is significantly reduced. In addition, the duration of therapy should be as short as possible.
In the case of this disease, the person affected should primarily consult a doctor as soon as possible so that there are no further complications or other symptoms. The measures and the options for aftercare for this disease are usually very limited, so that the focus is on early detection and treatment of the disease.
The earlier the affected person consults a doctor, the better the further course of the disease, so that a doctor should be contacted as soon as the first symptoms and signs of the disease appear. In most cases, the disease is treated by stopping the offending drug. However, the person concerned should only ever stop taking this medication and take another medication if directed by a doctor.
When taking medication, it is always important to ensure that the dosage is correct and that it is taken regularly in order to permanently relieve the symptoms. Furthermore, most of those affected depend on the help and support of their own family and friends in their everyday lives. Loving and intensive conversations also have a positive effect on the course of the disease and can prevent mental upsets or depression.
You can do that yourself
If heparin-induced thrombocytopenia is suspected, the most important course of action is to consult a doctor. It is a medical emergency that requires medical intervention.
First, the triggering drug must be discontinued and another drug with a similar effect prescribed. The drug argatroban, which reduces blood clotting and regulates blood pressure, is usually prescribed. The patient must ensure that heparin does not enter the organism in any other way.
Rinses, ointments or creams must be tested before use. Catheters can also contain the substance and should be checked before use. However, should further symptoms appear, the doctor must be informed immediately. The same applies to side effects and interactions caused by the prescribed medication.
Other self-help measures are limited to protecting the body and especially the cardiovascular system. This can be done by avoiding strenuous physical activity in the first few weeks after the incident. The patient should also avoid stress and ensure a healthy night’s sleep. A balanced diet also contributes to a speedy recovery after heparin-induced thrombocytopenia.