【病例分享】亚硝酸盐中毒一例

Severe Methemoglobinemia due to Sodium Nitrite Poisoning

亚硝酸钠中毒引起的严重血红蛋白血症

Academic Editor: Ritesh Agarwal

Received19 Mar 2016

Revised04 Jul 2016

Accepted25 Jul 2016

Published03 Aug 2016

学术编辑： Ritesh Agarwal

收到 19 三月 2016

修订 04 七月 2016

接受 25 七月 2016

发布 03 八月 2016

Abstract 摘要

Case. We report a case of severe methemoglobinemia due to sodium nitrite poisoning.

我们报告一例因亚硝酸钠中毒引起的严重高铁血红蛋白血症。

A 28-year-old man was brought to our emergency department because of transient loss of consciousness and cyanosis. He was immediately intubated and ventilated with 100% oxygen.

一名28岁的男子被带到我们的急诊科，因为短暂的意识丧失和发绀。他立即被插管，用100%氧气通气。

A blood test revealed a methemoglobin level of 92.5%. Outcome. We treated the patient with gastric lavage, activated charcoal, and methylene blue (2 mg/kg) administered intravenously.

血液测试显示高铁血红蛋白水平为92.5%。结局。我们通过洗胃、活性炭和静脉注射亚甲蓝(2毫克/千克)来治疗患者。

Soon after receiving methylene blue, his cyanosis resolved and the methemoglobin level began to decrease.

接受亚甲蓝治疗后不久，他的紫绀消失，高铁血红蛋白水平开始下降。

After relocation to the intensive care unit, his consciousness improved and he could recall ingesting approximately 15 g sodium nitrite about 1 hour before he was brought to our hospital.

在被转移到重症监护室后，他的意识得到了改善，他记得在被带到我们医院的大约1小时前摄入了大约15克亚硝酸钠。

The patient was discharged on day 7 without neurologic impairment.

患者在第7天出院，无神经损伤。

Conclusion. Severe methemoglobinemia may be fatal.

结论。严重的高铁血红蛋白血症可能是致命的。

Therefore, accurate diagnosis of methemoglobinemia is very important so that treatment can be started as soon as possible.

因此，准确诊断高铁血红蛋白血症非常重要，以便尽快开始治疗。

1. Introduction 引言

Although methemoglobin levels of >70% are generally fatal, patients with methemoglobin levels of up to 94% have survived [1].

虽然高铁血红蛋白水平超过70%通常是致命的，但高铁血红蛋白水平高达94%的患者存活了下来[1]。

Sodium nitrite intoxication is a common cause of severe methemoglobinemia;

亚硝酸钠中毒是严重高铁血红蛋白血症的常见原因；

 however, only one suicidal case has been reported [2].

然而，只有一例自杀病例被报道[2]。

 The concentration of methemoglobin does not exceed 1%-2% in the normal physiological state [3] and levels of 10%–20% generally cause cyanosis.

正常生理状态下高铁血红蛋白的浓度不超过1%-2%[3]，10%-20%的水平通常会导致发绀。

On the other hand, methemoglobin levels of 20%–50% may cause symptoms such as respiratory distress, dizziness, headache, and fatigue.

另一方面，20%-50%的高铁血红蛋白水平可能会导致呼吸窘迫、头晕、头痛和疲劳等症状。

Furthermore, loss of consciousness and death can occur at methemoglobin levels of 50%–70% [4].

此外，高铁血红蛋白水平在50%-70%时会导致意识丧失和死亡[4]。

Methylene blue is the first choice for treating acute methemoglobinemia. It functions along with natural reduction systems to convert methemoglobin to normal hemoglobin.

亚甲蓝是治疗急性高铁血红蛋白血症的首选。它与自然还原系统一起将高铁血红蛋白转化为正常血红蛋白。

It is typically administered at doses of 1-2 mg/kg body weight intravenously over 5 min, with symptom improvement expected immediately after the administration.

它通常以1-2毫克/千克体重的剂量静脉给药，持续5分钟，给药后症状有望立即改善。

In this report, we describe the successful treatment of a case of severe methemoglobinemia due to sodium nitrite poisoning.

在本报告中，我们描述了一例因亚硝酸钠中毒导致的严重高铁血红蛋白血症的成功治疗。

2. Case Presentation案例演示

A 28-year-old man was brought to our emergency department because of transient loss of consciousness and cyanosis.

一名28岁的男子被带到我们的急诊科，因为短暂的意识丧失和发绀。

He was immediately intubated without concomitant drug administration and ventilated with 100% oxygen.

他立即被插管，没有同时给药，并用100%氧气通气。

Heart rate was 72 beats/min and blood pressure was 82/50 mmHg;

心率72次/分，血压82/50 mmHg；

 oxygen saturation was undetectable on pulse oximetry.

脉搏血氧饱和度检测不到。

His Glasgow Coma Scale score was 3 and he had blue-gray discoloration of the skin, particularly of the face and nail beds (Figure 1).

他的格拉斯哥昏迷评分为3分，皮肤呈蓝灰色变色，尤其是面部和甲床(图1)。

Figure 1 

His face, lips, and toes were deeply cyanosed on admission.

入院时，他的脸、嘴唇和脚趾都严重发紫。

He was initially treated with 100% oxygen, gastric lavage, and activated charcoal administration.

他最初接受了100%氧气、洗胃和活性炭治疗。

Arterial blood gas analysis and blood tests revealed the following: pH, 7.31; PaCO2, 31.4 mmHg; PaO2, 564 mmHg; base excess, −10.2 mmol/L; sodium, 137 mmol/L; potassium, 3.2 mmol/L; lactate, 12.1 mmol/L; and methemoglobin, 92.5%.

动脉血气分析和血液化验显示:pH，7.31；二氧化碳，31.4mmHg；PaO2，564mmHg；碱剩余，-10.2mmol/升；钠，137mmol/升；钾，3.2mmol/升；乳酸盐，12.1mmol/升；高铁血红蛋白，92.5%。

The patient was immediately given 150 mg methylene blue (2 mg/kg body weight) intravenously over 5 min only at one time.

患者在大于5分钟一次性静脉注射150毫克亚甲蓝(2毫克/千克体重)。

 He regained consciousness, and cyanosis resolved within minutes after methylene blue injection;

他恢复了知觉，注射亚甲蓝后，发绀在几分钟内消失；

 methemoglobin concentration decreased to 19% after 60 min.

60分钟后，高铁血红蛋白浓度降至19%。

On the second day of admission, the patient was extubated.

入院第二天，患者拔管。

He then recalled intentionally ingesting approximately 15 g sodium nitrite about 1 hour before ambulance call.

随后，他回忆说，在打电话叫救护车前约1小时，他故意摄入了约15克亚硝酸钠。

Methemoglobin level was again determined along with serum concentration of sodium nitrite.

高铁血红蛋白水平与血清亚硝酸钠浓度一起再次测定。

 Methemoglobinemia resolved soon after injection of methylene blue;

注射亚甲蓝后，高铁血红蛋白血症很快消失；

however, the serum concentration of sodium nitrite decreased gradually (Figure 2).

然而，亚硝酸钠的血清浓度逐渐降低(图2)。

And there was no rebound methemoglobin formation given the persistence of sodium nitrite in the patient.

尽管患者体内持续存在亚硝酸钠，却没有出现反弹性高铁血红蛋白形成。

Cranial T2-weighted magnetic resonance imaging (MRI) demonstrated bilateral and symmetrical hyperintense lesions in the globus pallidus (Figure 3).

头颅T2加权磁共振成像显示苍白球双侧对称高信号病变(图3)。

The patient was transferred to the general ward and was subsequently discharged on day 7 without neurologic impairment.

患者被转移到普通病房，随后在第7天出院，无神经损伤。

3. Discussion 讨论

Sodium nitrite is generally used as a coloring agent or preservative in food and as an antimicrobial agent in meat products.

亚硝酸钠通常在食品中用作着色剂或防腐剂，在肉制品中用作抗菌剂。

The estimated lethal dose of sodium nitrite in adults is approximately 2.6 g [5]; however, a case of a patient surviving after ingesting 6 g sodium nitrite has been reported [6]. Severe methemoglobinemia with fatal outcomes following ingestion of sodium nitrite and intentional self-poisoning have been reported [3, 7].

成人亚硝酸钠的估计致死剂量约为2.6克[5]；然而，已有一例患者在摄入6克亚硝酸钠后存活的报道[6]。据报道，严重的高铁血红蛋白血症在摄入亚硝酸钠和故意服毒后会导致致命的后果。

The initial sign of methemoglobinemia is cyanosis [8] and the diagnosis should be considered in all patients who present with cyanosis, particularly if it does not improve with supplemental oxygen.

高铁血红蛋白血症的最初症状是发绀[8]，所有出现发绀的患者都应考虑诊断，尤其是在吸氧后没有改善的情况下。

 As the levels reach 30%–40%, symptoms such as headache, fatigue, tachycardia, weakness, and dizziness are experienced. Methemoglobin levels of 60% produce lethargy, convulsions, and coma.

当水平达到30%-40%时，会出现头痛、疲劳、心动过速、虚弱和头晕等症状。高铁血红蛋白水平达到60%会导致嗜睡、抽搐和昏迷。

Methemoglobin levels of >70% are generally lethal, although survival has been reported with a level of 94% [2]. Nitrite is also a potent vasodilator and can cause coronary ischemia and stroke as a result of hypotension, tachycardia, and hypoxia.

高铁血红蛋白水平超过70%通常是致命的，尽管据报道存活率为94% [2]。亚硝酸盐也是一种有效的血管扩张剂，可因低血压、心动过速和缺氧而导致冠状动脉缺血和中风。

Methylene blue [9] is indicated as the first-line antidote therapy for patients with severe methemoglobinemia.

亚甲蓝[9]是严重高铁血红蛋白血症患者的一线解毒剂疗法。

 It is recommended that patients with methemoglobin levels >30%, high risk factors such as anemia, or symptoms at any level should be treated using methylene blue at a dose of 1-2 mg/kg body weight intravenously over 5 min.

建议高铁血红蛋白水平> 30%的患者、贫血等高危因素或任何水平的症状应使用亚甲蓝进行治疗，剂量为1-2毫克/千克体重，静脉注射5分钟以上。

 Generally, methemoglobin concentration decreases significantly within 1-2 h after a single dose; additional doses may be necessary.

一般在单次给药后1-2 h内高铁血红蛋白浓度显著下降；可能需要额外的剂量。

In this case, we could suspect whether the patient had some poisoning because of his cyanosis and severe methemoglobinemia. So we could use methylene blue very quickly in the emergency room.

在这种情况下，因为发绀和严重的高铁血红蛋白血症，所以我们可以怀疑病人亚硝酸盐中毒。因此我们可以在急诊室快速使用亚甲蓝。

Cranial T2-weighted MRI findings 3 days after sodium nitrite ingestion were similar to those in carbon monoxide poisoning.

摄入亚硝酸钠后3天的头颅T2加权磁共振成像结果与一氧化碳中毒相似。

 It has been reported that the globus pallidus is most susceptible to hypoxia. Severe methemoglobinemia can cause severe tissue hypoxia similar to that in carbon monoxide poisoning; this may explain the involvement of the globus pallidus in our case.

据报道，苍白球最容易缺氧。严重高铁血红蛋白血症可引起与一氧化碳中毒相似的严重组织缺氧；这可能解释了在我们的病例中苍白球的参与。

In conclusion, we reported a case of severe methemoglobinemia secondary to intentional ingestion of sodium nitrite.

总之，我们报告了一例因故意摄入亚硝酸钠导致的严重高铁血红蛋白血症。

Methemoglobinemia should be considered in all cyanotic patients who are unresponsive to oxygen therapy.

所有对氧疗无反应的紫绀患者都应考虑高铁血红蛋白血症。

Rapid diagnosis and early intervention with methylene blue infusion can prevent a fatal outcome as in the present case with an initial methemoglobin level of 92.5%.

快速诊断和亚甲蓝输注早期干预可防止致命结果，如本例中初始高铁血红蛋白水平为92.5%。

Competing Interests

The authors declare that there are no competing interests regarding the publication of this paper.

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Copyright

Copyright © 2016 Kenichi Katabami et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.