Heparin-Induced Thrombocytopenia
肝素诱导的血小板减少

What is heparin-induced thrombocytopenia (HIT)?
什么是肝素诱导的血小板减少症（HIT）？

Heparin-induced thrombocytopenia (HIT) is a potentially life-threatening complication of taking the drug heparin. Heparin is an anticoagulant (blood thinner) that prevents blood clots. A blood clot is a gel-like collection of blood in your veins or arteries. Your healthcare provider may prescribe heparin to treat a blood clot you already have or to prevent blood clots after a major medical procedure, like surgery.
肝素诱导的血小板减少症（HIT）是一种潜在的危及生命的并发症，服用药物肝素。肝素是一种抗凝剂（血液稀释剂），可防止血液凝块。血凝块是血液在静脉或动脉中的凝胶状聚集。您的医疗保健提供者可能会开肝素来治疗您已经有的血凝块，或在主要医疗程序（如手术）后预防血凝块。

In rare cases, heparin triggers a reaction that causes your blood to clot excessively instead of preventing clots. It causes your immune system to make antibodies that activate your platelets. Your platelets are blood cells that cause your blood to clot. In the presence of heparin, excessive blood clotting puts you at risk of developing life-threatening blood clots (thrombosis). The reaction also causes your platelet levels to drop (thrombocytopenia).
在极少数情况下，肝素会引发一种反应，导致您的血液过度凝结，而不是防止凝块。它会导致你的免疫系统产生抗体，激活你的血小板。血小板是导致血液凝结的血细胞。在肝素存在的情况下，过度的血液凝固会使您面临发生危及生命的血液凝块（血栓形成）的风险。这种反应也会导致血小板水平下降（血小板减少症）。

As HIT is a complication that may cause you to have too few platelets and dangerous blood clots, it’s sometimes called heparin-induced thrombocytopenia and thrombosis (HITT).
由于HIT是一种并发症，可能会导致您的血小板过少和危险的血凝块，它有时被称为肝素诱导的血小板减少症和血栓形成（HITT）。

What are the types of heparin-induced thrombocytopenia?
肝素诱导的血小板减少症有哪些类型？

There are two types of heparin-induced thrombocytopenia, HIT I and HIT II. Only HIT II is considered a medical complication that requires treatment.
肝素诱导的血小板减少症有两种类型，即HIT I和HIT II。只有HIT II被认为是需要治疗的医疗并发症。

• HIT I: Your platelet levels may drop within the first few days of taking heparin but then return to normal. This type of HIT doesn’t put you at risk of blood clots and doesn’t require treatment.
  HIT I：您的血小板水平可能在服用肝素的最初几天内下降，但随后恢复正常。这种类型的HIT不会使您面临血栓风险，也不需要治疗。
• HIT II: Your body’s immune system activates your platelets in response to heparin. This reaction causes your platelet levels to drop and puts you at risk of developing serious blood clots.
  HIT II：您身体的免疫系统激活血小板以响应肝素。这种反应会导致您的血小板水平下降，并使您面临严重血栓的风险。

Most people who reference heparin-induced thrombocytopenia mean HIT II, as it’s the only serious form.
大多数提到肝素诱导的血小板减少症的人指的是HIT II，因为它是唯一严重的形式。

Who does heparin-induced thrombocytopenia affect?
肝素诱导的血小板减少症会影响谁？

Anyone taking heparin can potentially develop HIT, regardless of dose or frequency. It’s more common in women and people assigned female at birth (AFAB) who are 40 or older. Doctors aren’t sure why some people react to heparin while others don’t.
任何服用肝素的人都可能发生HIT，无论剂量或频率如何。它在40岁或40岁以上的女性和出生时指定为女性的人中更常见。医生不确定为什么有些人对肝素有反应，而另一些人没有。

How common is heparin-induced thrombocytopenia?
肝素诱导的血小板减少症有多常见？

Heparin-induced thrombocytopenia is uncommon. Approximately 5% of people who take heparin for more than four days develop HIT.
肝素诱导的血小板减少症并不常见。大约5%服用肝素超过四天的人会出现HIT。

What are the signs and symptoms of heparin-induced thrombocytopenia?
肝素诱导的血小板减少症的体征和症状是什么？

Your healthcare provider will keep track of how many blood cells you have if you’re taking heparin. Low levels of platelets may be a sign of HIT. About half of people with HIT develop a new blood clot, such as a deep vein thrombosis (DVT) or pulmonary embolism (PE).
如果您正在服用肝素，您的医疗保健提供者将记录您有多少血细胞。血小板水平低可能是HIT的一个标志。大约一半的HIT患者会形成新的血栓，如深静脉血栓形成（DVT）或肺栓塞（PE）。

Symptoms may include: 症状可能包括：

• Pain, swelling, redness or tenderness in your arm or leg.
  手臂或腿部疼痛、肿胀、发红或压痛。
• Sudden sharp pain in your chest (like a heart attack).
  胸部突然剧烈疼痛（如心脏病发作）。
• High blood pressure (hypertension).
  高血压（hypertension）。
• Feeling faint, dizzy or light-headed.
  感觉虚弱、头晕或头晕。
• Rapid heartbeat (tachycardia).
  心跳加速（心动过速）。
• Coughing and wheezing. 咳嗽和喘息。
• Feeling out of breath. 感觉上气不接下气。
• Excessive sweating. 过度出汗。
• Fever and chills. 发烧发冷

You may also notice pain, soreness or a rash at the injection site where you received heparin.
您也可能会注意到在您接受肝素的注射部位出现疼痛、酸痛或皮疹。

Seek emergency medical attention immediately if you’re taking heparin and experiencing any of these symptoms.
如果您正在服用肝素并出现任何这些症状，请立即寻求紧急医疗护理。

When does heparin-induced thrombocytopenia occur?
肝素诱导的血小板减少症何时发生？

Symptoms often begin five days to two weeks after you start taking heparin. HIT can occur at other times, too.
症状通常在开始服用肝素后开始5天至2周开始。HIT也可能发生在其他时间。

• Early-onset HIT appears one to three days after you start taking heparin. This early form of HIT occurs when you’ve taken heparin in the past (usually within the last three months). When this happens, your body “remembers” heparin because it’s already been exposed to it. It’s already made antibodies to heparin that are ready to react.
  早发性HIT出现在您开始服用肝素后1 - 3天。这种早期形式的HIT发生在您过去服用肝素时（通常在过去三个月内）。当这种情况发生时，你的身体会“记住”肝素，因为它已经暴露在肝素中，它已经产生了肝素抗体，准备好反应。
• Refractory (persistent) HIT lasts for weeks after you’ve stopped heparin.
  停用肝素后，难治性（持续性）HIT持续数周。
• Delayed onset HIT doesn’t appear until you’ve stopped taking heparin. It starts five or more days after you quit your medication.
  延迟发作的HIT在停止使用肝素之前不会出现。它在你停止服药后的五天或更长时间内开始。

What causes heparin-induced thrombocytopenia?
肝素诱导的血小板减少症的病因是什么？

HIT occurs when heparin binds to a protein in platelets called PF4. Heparin and PF4 form what’s called a complex. The complex is named heparin-PF4 after its parts (heparin and PF4). The presence of heparin-PF4 triggers your immune system to make antibodies. These antibodies bind to heparin-PF4. Once the antibodies attach, your platelets start clotting.
当肝素与血小板中一种名为PF 4的蛋白质结合时，就会发生HIT。肝素和PF 4形成了一种复合物。该复合物以其组成部分（肝素和PF 4）命名为肝素-PF 4。肝素-PF 4的存在会触发你的免疫系统产生抗体。这些抗体与肝素-PF 4结合。一旦抗体附着，你的血小板就开始凝结。

The clotting platelets release more PF4, causing a chain reaction. In other words, the newly released PF4 binds with more heparin, creating more heparin-PF4. Antibodies bind to heparin-PF4, triggering more clotting and so on.
凝血血小板释放更多的PF 4，引起连锁反应。换句话说，新释放的PF 4与更多的肝素结合，产生更多的肝素-PF 4。抗体与肝素-PF 4结合，引发更多凝血等。

All the clotting action uses up your platelets. As a result, your platelet levels drop. All the clotting can lead to large, life-threatening blood clots that block your veins and arteries.
所有的凝血作用都会消耗你的血小板。结果，你的血小板水平下降。所有的凝血都可能导致大的、危及生命的血栓，阻塞你的静脉和动脉。

What are the risk factors for heparin-induced thrombocytopenia?
肝素诱导的血小板减少症的危险因素有哪些？

Risk factors for HIT include:
HIT的风险因素包括：

• Your sex: HIT is more common in women and people AFAB.
  你的性别：HIT在女性和AFAB人群中更常见。
• Taking certain forms of heparin: Some studies suggest that the form of heparin you take may reduce your risk of HIT. It’s possible that taking unfractionated heparin instead of low-molecular-weight heparin can reduce your risk. More research is needed to know for sure.
  服用某些形式的肝素：一些研究表明，您服用的肝素形式可能会降低HIT的风险。服用普通肝素而不是低分子量肝素可能会降低您的风险。需要更多的研究来确定。
• Taking heparin after surgery: People who receive heparin to prevent blood clots after surgery are more likely to develop HIT than people receiving treatment for clots they already have. Orthopaedic surgery, heart surgery and cardiopulmonary bypass are all associated with an increased risk of developing heparin-induced thrombocytopenia.
  手术后服用肝素：手术后接受肝素预防血栓的人比接受血栓治疗的人更容易发生HIT。骨科手术、心脏手术和心肺转流术均与肝素诱导的血小板减少症风险增加相关。

How is heparin-induced thrombocytopenia diagnosed?
如何诊断肝素诱导的血小板减少症？

Blood tests can show if you have HIT. Blood tests measure:
血液测试可以显示您是否患有HIT。血液测试测量：

• Platelet levels: Your platelet levels reveal whether you have low platelets, or thrombocytopenia.
  血小板水平：您的血小板水平显示您是否患有血小板减少症或血小板减少症。
• Clot formation: Blood tests can show if your blood is forming clots.
  血块形成：血液检查可以显示您的血液是否正在形成血块。
• PF4 antibody levels: The amount of PF4 antibody levels in your blood can confirm that your immune system is activating your platelets. Antibody tests confirm a HIT diagnosis.
  PF4抗体水平：血液中的PF4抗体水平可以确认您的免疫系统正在激活血小板。抗体检测证实了HIT诊断。

Your healthcare provider may also order ultrasounds to screen your legs for blood clots (deep vein thrombosis, DVT). Depending on your condition, your healthcare provider may perform imaging on other areas, such as your arms, to check for clots.
您的医疗保健提供者也可以订购超声波扫描您的腿部血栓（深静脉血栓形成，DVT）。根据您的病情，您的医疗保健提供者可能会对其他部位（如手臂）进行成像，以检查是否有血栓。

The antibody test results may take a while to confirm that you have HIT. As HIT can be fatal without treatment, your provider won’t wait to receive the results to begin treatment. Instead, they’ll decide to start treatment based on how likely it is you have HIT.
抗体测试结果可能需要一段时间才能确认您有HIT。由于HIT在不治疗的情况下可能是致命的，您的提供者不会等待收到结果才开始开始治疗。相反，他们会决定开始治疗的基础上，它是如何可能是你有击中。

What is the 4Ts test in heparin-induced thrombocytopenia?
肝素诱导的血小板减少症的4Ts试验是什么？

The 4Ts test is a scoring system used to determine how likely it is you have HIT. It provides enough information about your condition so your provider doesn’t have to delay treatment while waiting on the results of an antibody test. Your healthcare provider assigns a score (from 0 points to 2 points) for the following criteria:
4Ts测试是一种评分系统，用于确定您有多大可能性患有HIT。它提供了关于您的病情的足够信息，因此您的提供者不必在等待抗体测试结果时延迟治疗。您的医疗保健提供者会根据以下标准进行评分（从0分到2分）：

• Thrombocytopenia: How low is your platelet count?
  血小板减少症：您的血小板计数有多低？
• Timing of your reaction to heparin: When did your platelet levels fall?
  肝素反应的时间：您的血小板水平何时下降？
• Thrombosis: Are there signs of clotting?
  血栓形成：是否有凝血迹象？
• Other causes of thrombocytopenia: Is it possible that what’s causing your low platelets isn’t heparin?
  血小板减少症的其他原因：有没有可能导致血小板减少的不是肝素？

The higher the score, the greater the likelihood that you have HIT.
分数越高，你有命中的可能性就越大。

What is the treatment for heparin-induced thrombocytopenia?
肝素诱导的血小板减少症的治疗方法是什么？

Treatment includes stopping heparin and switching to a different blood thinner. Your platelet count should start increasing within a few days of stopping heparin. In the meantime, your healthcare provider will recommend an alternative to heparin to prevent blood clots.
治疗方法包括停用肝素和改用不同的血液稀释剂。停用肝素后几天内，血小板计数应开始增加。与此同时，您的医疗保健提供者将推荐肝素的替代品，以防止血液凝块。

Alternatives to heparin may include:
肝素的替代品可能包括：

• Direct thrombin inhibitors (argatroban, bivalirudin).
  直接凝血酶抑制剂（阿加曲班、比伐卢定）。
• Fondaparinux. 磺达肝素
• Direct oral anticoagulants.
  直接口服抗凝剂。

Your healthcare provider may switch you to a blood thinner called warfarin once your platelet levels have returned to normal and you’re no longer at risk of clots associated with HIT.
一旦您的血小板水平恢复正常，您的医疗保健提供者可能会将您转换为称为华法林的血液稀释剂，并且您不再有与HIT相关的血栓风险。

How can I prevent heparin-induced thrombocytopenia?
如何预防肝素诱导的血小板减少症？

There’s nothing you can do to prevent HIT. Still, your healthcare provider can monitor your platelet count closely to reduce your risk of complications from heparin.
你无法阻止HIT。尽管如此，您的医疗保健提供者可以密切监测您的血小板计数，以降低肝素并发症的风险。

What can I expect if I have heparin-induced thrombocytopenia?
如果我有肝素诱导的血小板减少症，我会有什么期望？

Heparin-induced thrombocytopenia (HIT) is serious without early treatment. Large clots in your arms and legs can do long-term damage to your limbs. Clots affecting major organs can be fatal. Fortunately, greater awareness about HIT and better treatments have improved the survival rate.
肝素诱导的血小板减少症（HIT）是严重的，无需早期治疗。手臂和腿部的大血块会对四肢造成长期损害。影响主要器官的凝块可能是致命的。幸运的是，人们对HIT的认识提高了，治疗方法也更好，提高了生存率。

Getting diagnosed early, before serious blood clots have formed, is key to a positive outcome. Once your provider recognizes signs of HIT, like low platelets, they can prescribe treatments to reduce your risk of developing dangerous blood clots.
在严重的血栓形成之前及早诊断是积极结果的关键。一旦你的医生发现了HIT的迹象，比如血小板减少，他们就可以开出治疗方案来降低你形成危险血栓的风险。

How do I take care of myself?
我该怎么照顾自己？

You’ll need to see your healthcare provider regularly to monitor your platelets and ensure you remain free of blood clots. In addition, your provider will watch for side effects that can arise when switching from heparin to a new blood thinner. For instance, some people experience bleeding as a side effect of blood thinners.
你需要定期去看你的医疗保健提供者，以监测你的血小板，并确保你保持无血凝块。此外，您的提供者将注意从肝素转换为新的血液稀释剂时可能出现的副作用。例如，有些人经历出血是血液稀释剂的副作用。

In the meantime, take medications as prescribed. Even if you don’t have a clot, you might need to take a non-heparin blood thinner for a month at a minimum. If you did have a clot, you might need to be on blood thinners for longer.
在此期间，按处方服药。即使你没有血栓，你也可能需要至少服用一个月的非肝素血液稀释剂。如果你确实有血栓，你可能需要更长时间的血液稀释剂。

One of the best ways to take care of yourself is to ensure that future healthcare providers know you’ve experienced this complication. You shouldn’t take heparin in the future if you’ve had HIT.
照顾自己的最佳方法之一是确保未来的医疗保健提供者知道您经历过这种并发症。如果你有过HIT，你以后不应该服用肝素。

A note from Cleveland Clinic
来自Cleveland Clinic的评论

Seek emergency medical attention immediately if you’re noticing changes in your body while taking heparin. Although heparin-induced thrombocytopenia (HIT) is rare, it’s too serious to ignore signs of a potential clot. Without treatment, HIT can be life-threatening. With treatment, your platelet count should return to normal and your risk for clots should decrease. Work with your healthcare provider to determine the best substitutes for heparin moving forward.
如果您在服用肝素时发现身体发生变化，请立即寻求紧急医疗护理。虽然肝素诱导的血小板减少症（HIT）是罕见的，但它太严重了，不能忽视潜在的血栓迹象。如果不治疗，HIT可能会危及生命。通过治疗，您的血小板计数应恢复正常，血栓风险应降低。与您的医疗保健提供者合作，以确定未来肝素的最佳替代品。