肾结石

概述

肾结石（也称为肾积石、肾石病或尿石病）是由矿物质和盐在肾脏内形成的坚硬沉积物。

导致肾结石有许多原因，包括饮食、超重、某些医疗状况以及某些补剂和药物。肾结石会影响到您从肾脏到膀胱的整个。通常情况下，当尿液浓缩时，使矿物质结晶并粘合在一起，就会形成结石。

排出肾结石会很痛苦，但如果及时发现，这些结石通常不会造成永久性损害。根据您的情况，您可能只需要吃止痛药和喝大量的水来排出肾结石。在其他情况下，如结石卡在尿路，并伴有尿路感染或引起并发症，则可能需要手术治疗。

如果您再次患肾结石的风险增加，医生可能会建议您进行预防性治疗，以降低复发的风险。

症状

肾结石通常不会引起症状，除非它在肾脏内部游走，或者进入输尿管。输尿管是连接肾脏和膀胱的管道。

如果肾结石卡在输尿管中，可能会阻碍尿流，造成肾脏肿胀和输尿管痉挛，这可能会引发剧烈疼痛。在这种情况下，您可能出现以下症状：

• 肋骨下方体侧和背部出现重度锐痛
• 辐射到下腹部和腹股沟的疼痛
• 一阵阵发作且强度存在波动的疼痛
• 排尿时疼痛或灼热感

其他体征和症状可能包括：

• 粉色、红色或棕色尿
• 浑浊或恶臭尿
• 尿意持续、排尿比平时更频繁或尿量少
• 恶心和呕吐
• 如果存在感染，则发热或寒战

肾结石所致疼痛可能会变化，比如随着结石穿过尿路移动，疼痛转移到不同位置或者强度渐增。

何时就诊

如果您对任何体征和症状感到担心，请与医生约诊。

如果您出现以下情况，请立即就医：

• 剧烈疼痛，导致您无法安坐或者找不到能让自己觉得舒服的姿势
• 疼痛伴随恶心和呕吐
• 疼痛伴随发热和寒战
• 尿中有血
• 排尿困难

病因

肾结石通常没有明确的单一原因，尽管有几个因素可能会增加您的风险。

当尿液中含有的结晶体物质（如钙、草酸和尿酸）比尿液中的液体所能稀释的多时，就会形成肾结石。同时，您的尿液可能缺乏防止结晶体粘在一起的物质，这为肾结石的形成创造了理想的环境。

肾结石的类型

了解您的肾结石类型有助于确定病因，并且可能给出线索以降低形成更多肾结石的风险。如果可能，请保存您排出的肾结石并交给医生进行分析。

肾结石的类型包括：

• 钙结石。大多数肾结石是钙结石，一般以草酸钙形式存在。草酸这种物质每天由肝脏产生，或从膳食吸收。某些水果蔬菜富含草酸，坚果和巧克力也如此。

  膳食因素、大剂量维生素 D、肠旁路手术和几种代谢性疾病可以增加尿中钙或草酸的浓度。

  钙结石还可能以磷酸钙的形式存在。这种类型的结石更常见于代谢性疾病中，例如肾小管性酸中毒。还可能与某些用于治疗偏头痛或癫痫发作的药物相关，例如托吡酯（Topamax、Trokendi XR、Qudexy XR）。

• 磷酸铵镁结石。磷酸铵镁结石的形成是对尿路感染的反应。这类结石可以快速生长，并变得很大，有时伴随少许症状或几乎没有预警。
• 尿酸结石。尿酸结石可能形成于以下人群中：因慢性腹泻或吸收不良而丢失过多体液、摄食高蛋白膳食和患糖尿病或代谢综合征的人群。某些遗传因素也可能增加出现尿酸结石的风险。
• 胱氨酸结石。这类结石形成于患有一种遗传性疾病的人群中，该病叫做胱氨酸尿症，导致肾脏排出过多的一种特殊氨基酸。

风险因素

增加肾结石患病风险的因素包括：

• 家庭或个人病史。如果您家里有人患肾结石，则您患上结石的可能性更高。如果您已经有了一颗或多颗肾结石，则出现其他结石的风险将增加。
• 脱水。每天饮水不足会增加患肾结石的风险。生活在温暖干燥气候中的人以及出大量汗的人与其他人相比患病风险更高。
• 某些饮食。饮食中的蛋白质、钠（盐）和糖分过高可能会增加患某些类型的肾结石的风险。高钠饮食尤其如此。饮食中的盐分过量会增加您肾脏必须过滤掉的钙含量，并且将显著增加患肾结石的风险。
• 肥胖症。高身体质量指数 (BMI)、大腰围和体重增长与肾结石风险增加有关。
• 消化疾病和手术。胃旁路手术、炎性肠病或慢性腹泻会改变影响钙和水吸收的消化过程，从而增加尿液中形成结石的物质含量。
• 其他医学疾病（如肾小管性酸中毒、胱氨酸尿、甲状旁腺功能亢进症和反复的尿路感染）也会增加患肾结石的风险。
• 某些补充剂和药物（如维生素 C、膳食补充剂、泻药（使用过量时）、钙基抗酸剂，以及某些用于治疗偏头痛或抑郁症的药物）会增加患肾结石的风险。

预防

Prevention of kidney stones may include a mix of lifestyle changes and medicines.

Lifestyle changes

You may lower your risk of kidney stones if you:

• Drink water throughout the day. This is the most important lifestyle change you can make. If you've had kidney stones before, your healthcare professional may tell you to drink enough fluids to pass about 2.1 quarts (2 liters) of urine a day or more. You may be asked to measure how much urine you pass to make sure that you're drinking enough water.

  If you live in a hot, dry climate or you exercise often, you may need to drink even more water to produce enough urine. If your urine is light and clear, you're likely drinking enough water.

• Eat fewer oxalate-rich foods. If you tend to form calcium oxalate stones, your healthcare professional may recommend limiting foods rich in oxalates. These include rhubarb, beets, okra, spinach, Swiss chard, sweet potatoes, nuts, tea, chocolate, black pepper, sesame or tahini products, and soy products. Reviewing your diet with a dietitian with expertise in kidney stones is usually helpful.
• Choose a diet low in sodium and animal protein. Lower the amount of sodium you eat. And choose protein sources that don't come from meat or fish, such as legumes. Think about using a salt substitute to flavor foods.

• Keep eating calcium-rich foods, but use caution with calcium supplements. Calcium in food doesn't have an effect on your risk of kidney stones. Keep eating calcium-rich foods unless your healthcare professional recommends otherwise.

  Ask your healthcare professional before taking calcium supplements. These have been linked with a higher risk of kidney stones. You may lower the risk by taking supplements with meals. Diets low in calcium can make kidney stones more likely to form in some people.

Ask your healthcare professional to refer you to a dietitian. The dietitian can help you make an eating plan that lowers your risk of kidney stones.

Medications

Medicines can control the amount of minerals and salts in the urine. They may be helpful in people who form certain kinds of stones. The type of medicine that your healthcare professional prescribes depends on the kind of kidney stones you have. Here are some examples:

• Calcium stones. To help prevent calcium stones from forming, your healthcare professional may prescribe a thiazide diuretic or potassium citrate. If you have calcium oxalate stones due to the rare genetic condition primary hyperoxaluria, you may need other treatments to lower the amount of oxalate in your blood. Your healthcare professional may recommend that you take vitamin B6, also called pyridoxine. Or you may need prescription medicines such as lumasiran (Oxlumo) or nedosiran (Rivfloza).
• Uric acid stones. Your healthcare professional may prescribe allopurinol (Zyloprim, Aloprim, others) to lower uric acid levels in your blood and urine. You also may be prescribed potassium citrate. Sometimes, these medicines may dissolve existing uric acid stones.
• Struvite stones. To prevent struvite stones, your healthcare professional may recommend ways to keep your urine free of bacteria that cause infection. For instance, you may be told to urinate more often and to drink fluids to keep your urine flow good. Rarely, long-term use of antibiotics in small or occasional doses may help achieve this goal. For instance, your healthcare professional may suggest that you take an antibiotic before and for a while after surgery to treat your kidney stones. Medicines called acetohydroxamic acid also may help prevent struvite stones.
• Cystine stones. A diet that's lower in sodium and protein may help prevent cystine stones. Your healthcare professional also may recommend that you drink more fluids so that you urinate more. If those changes alone don't help, medicines called thiol drugs or other newer medicines also may be prescribed. They might make crystals less likely to form.