What is sickle cell disease?

镰状细胞病是一种遗传性血液疾病. 它的标志是有缺陷的血红蛋白. That’s the protein in red blood cells that carries oxygen to the tissues of the body. So, sickle cell disease interferes with the delivery of oxygen to the tissues.

血红蛋白正常的红细胞是光滑的, disk-shaped, and flexible, 就像没有洞的甜甜圈. 它们可以很容易地穿过血管. 镰状细胞血红蛋白的细胞是坚硬的和粘性的. When they lose their oxygen, they form into the shape of a sickle or crescent, like the letter C. These cells stick together and can’t easily move through the blood vessels. This can block small blood vessels and the movement of healthy, normal oxygen-carrying blood. 堵塞会引起疼痛.

正常的红细胞可以存活120天. 但是镰状细胞只能存活10到20天. Also, sickle cells may be destroyed by the spleen because of their shape and stiffness. 脾脏有助于过滤感染的血液. 镰状细胞被卡在这个过滤器里而死亡. With less healthy red blood cells circulating in the body, you can become chronically anemic. 镰状细胞也会损害脾脏. 这就增加了你被感染的风险.

什么导致镰状细胞病?

镰状细胞是一种由基因缺陷引起的遗传性疾病.

• A person will be born with sickle cell disease only if two genes are inherited—one from the mother and one from the father.
• A person who inherits just one gene is healthy and said to be a "carrier" of the disease. A carrier has an increased chance of having a child with sickle cell disease if he or she has a child with another carrier. 

父母都携带镰状细胞基因, there is a 1 in 4, 或者有25%的几率生下患有镰状细胞病的孩子.

镰状细胞病的危险因素是什么?

Having a family history of sickle cell disease increases your risk for the disease. 在美国，它主要影响非洲裔美国人.

镰状细胞病的症状是什么?

The following is a list of symptoms and complications associated with sickle cell disease. 然而，每个人的症状可能不同. 症状和并发症可能包括:

• Anemia. 因为镰状细胞是短命的或被破坏的, 体内可用的红细胞更少了. This results in anemia. 严重的贫血会使你感到头晕、呼吸急促和疲倦.
• 痛苦危机，或者镰刀危机. This occurs when the flow of blood is blocked to an area because the sickled cells have become stuck in the blood vessel. The pain can occur anywhere, but most often occurs in the chest, arms, and legs. Infants and young children may have painful swelling of the fingers and toes. 血流中断也可能导致组织死亡.
• Acute chest syndrome. 这种情况发生在胸部发生镰状病时. 这可能会危及生命. It often occurs suddenly, when the body is under stress from infection, fever, or dehydration. The sickled cells stick together and block the flow of oxygen in the tiny vessels in the lungs. 它类似肺炎，症状包括发烧、疼痛和剧烈咳嗽.
• 脾隔离(池化). 危象是镰状细胞聚集在脾脏的结果. This can cause a sudden drop in hemoglobin and can be life-threatening if not treated promptly. The spleen can also become enlarged and painful from the increase in blood volume. After repeated episodes,  the spleen becomes scarred, and permanently damaged. Most children, by age 8, 手术切除的脾脏也不能正常工作, 或者反复发作的脾隔离. The risk of infection is a major concern of children without a working spleen. Infection is the major cause of death in children younger than age 5 in this population.
• Stroke. This is another sudden and severe complication of people with sickle cell disease. The misshapen cells can block the major blood vessels that supply the brain with oxygen. Any interruption in the flow of blood and oxygen to the brain can result in severe brain damage. 如果你有一次因镰状细胞性贫血而中风, 你更有可能有第二次和第三次中风.
• 黄疸，或皮肤、眼睛和嘴变黄. 黄疸是镰状病的常见体征和症状. 镰状细胞寿命不如正常红细胞长, therefore, 它们死亡的速度比肝脏过滤它们的速度还快. Bilirubin (which causes the yellow color) from these broken down cells builds up in the system causing jaundice.
• Priapism.  This is a painful obstruction of the blood vessels in the penis by sickle cells. 如果不及时治疗，可能会导致阳痿.

The symptoms of sickle cell disease may look like other blood disorders or medical problems. 一定要向你的医疗保健提供者咨询诊断.

如何诊断镰状细胞病?

Along with a complete medical history and physical exam, you may have blood and other tests.

Many states routinely screen newborns for sickle cell so that treatment can begin as soon as possible. 早期诊断和治疗可以减少并发症的风险.

Hemoglobin electrophoresis is a blood test that can determine if a person is a carrier of sickle cell, 或者有任何与镰状细胞基因相关的疾病.

镰状细胞病如何治疗?

你的医生会考虑你的年龄, overall health and other factors when determining the best treatment for you.

Early diagnosis and prevention of complications is critical in sickle cell disease treatment. Treatment aims to prevent organ damage including strokes, prevent infection, and treat symptoms. Treatment may include:

• Pain medications. 这是针对镰状细胞危象的.
• 每天喝足够的水(8到10杯). 这是为了预防和治疗疼痛危机. 在某些情况下，可能需要静脉输液.  
• Blood transfusions. 这些可能有助于治疗贫血和预防中风. They are also used to dilute the sickled hemoglobin with normal hemoglobin to treat chronic pain, acute chest syndrome, splenic sequestration, and other emergencies.
• 接种疫苗和抗生素. 这些是用来预防感染的.
• Folic acid. 叶酸有助于预防严重的贫血.
• Hydroxyurea. This medication helps reduce the frequency of pain crises and acute chest syndrome. 它也可能有助于减少对输血的需求. 这种药物的长期效果尚不清楚.
• Regular eye exams. 这些检查是为了筛查视网膜病变.  
• Bone marrow transplant. 骨髓移植可以治愈一些镰状细胞病患者. The decision to have this procedure is based on the severity of the disease and ability to find a suitable bone marrow donor. These decisions need to be discussed with your doctor and are only done at specialized medical centers.

镰状细胞病的并发症有哪些?

镰状细胞病会影响所有的主要器官. The liver, heart, kidneys, gallbladder, eyes, bones, and joints can suffer damage from the abnormal function of the sickle cells and their inability to flow through the small blood vessels correctly. 问题可能包括以下方面:

• Increased infections
• Leg ulcers
• Bone damage
• Early gallstones
• 肾脏损伤和尿液中身体水分的流失
• Eye damage
• Multiple organ failure

患有镰状细胞病

镰状细胞病是一种终身疾病. Although the complications of sickle cell disease may not be able to be prevented entirely, 健康的生活方式可以减少一些并发症.

多吃水果的健康饮食是很重要的, vegetables, whole grains, and protein, and drink lots of fluids.

Do not take decongestants because they cause constriction of blood vessels and could trigger a crisis.

其他可能引发危机的因素包括高海拔, cold weather, swimming in cold water, and heavy physical labor.

通过每年注射流感疫苗来避免感染, 勤洗手, avoiding those who are sick, 定期做牙齿检查.

Key points

• 镰状细胞病是一种遗传性血液疾病 marked by defective hemoglobin.
• 它抑制血红蛋白在红细胞中携带氧气的能力.
• 镰状细胞倾向于粘在一起, 阻塞小血管，引起疼痛和破坏性并发症.
• 镰状细胞病根据需要使用止痛药治疗, 每天喝8到10杯水, blood transfusions, and medications.

Next steps

Tips to help you get the most from a visit to your health care provider:

• 在拜访之前，写下你想要回答的问题.
• Bring someone with you to help you ask questions and remember what your provider tells you.
• At the visit, 写下新药的名字, treatments, or tests, 以及医生给你的任何新指示.
• If you have a follow-up appointment, write down the date, time, and purpose for that visit.
• 知道如果你有问题如何联系你的供应商.