A case of maculopathy from rush poppers

第二，加快民生水利建设进程。一是加强以高效节水为重点的农田水利建设。新建农业高效节水面积300万亩。二是完成剩余142项定居兴牧配套骨干水利工程建设；再解决60万农村人口的饮水安全问题，推进城乡一体化供水；加快大中型灌区节水改造、大中型病险水闸除险加固建设；加快13个水电新农村电气化县、小水电代燃料和水电增效扩容工程建设；继续加强水产工作。

W e present the first Chinese case of poppers maculopathy.Poppers are a recreational substance of abuse which composes of a series of volatile alkyl nitrite. “Rush” is a kind of poppers, which was born in the United States and has been in existence for more than 30y. Inhalation of poppers provides a brief rush of euphoria, sexual arousal and relaxation of smooth muscles including the anal sphincter. There are approximate 20% male homosexual using poppers to enhance sexual pleasure in our country.

现阶段，慢性心力衰竭临床治疗的主要措施便是抗心衰，以此减少患者出现心血管危象的风险，提高患者的存活率。细胞生物学的快速发展，帮助人们进一步明确了慢性心力衰竭的主要诱发因素，即心肌能量代谢异常。健康人心肌代谢能量为葡萄糖、脂肪酸生物氧化产生的三磷酸腺苷，而慢性心衰患者心肌长期血氧不足，代谢较差，纠正临床症状，必须保证心肌代谢能量充足。磷酸肌酸钠经人体可以向三磷酸腺苷转化，补充患者心肌代谢能量[3] 。本次研究结果显示，观察组患者的心功能以及运动耐量明显优于对照组患者，差异有统计学意义（P＜0.05）。可见，磷酸肌酸钠可以改善患者的心功能，提高患者的运动耐量，为病情抑制奠定较好的基础条件。

It is previously considered that the risk of poppers is low both physically and psychologically. However, a global drug survey showed that 12% respondents who were using or had used poppers believed that the use of poppers may have or definitely affected their eyesight. Here we present, to our knowledge,the first reported case of poppers maculopathy in China. We obtained the written informed consent from the patient.

笔者在广泛调研国内外掘进机工作特点的基础上，设计了用于掘进机模拟试验平台且可对掘进机所有状态与参数进行动态显示的监控系统，另外搭建了可对各种掘进机位姿检测方法进行验证与对比的高精度掘进机位姿测量精度验证系统。选取了具有代表性的位姿测量方法开展掘进机位姿测量试验，对系统的功能进行验证，并分析了位姿测量精度验证系统的实用性。

After poppers inhalation, patients present with similar symptoms such as blurred vision, fluctuating vision, central scotoma, photophobia, and phosphenes, and most of them have both eyes suffered. The fundus manifestations are varied, which can be normal, yellowish-white spots, or even vitelliform lesions at the fovea. OCT provides the most valuable diagnostic test, showing disruption or attenuation of the ellipsoid zone in both foveae. All patients with pathognomonic changes on OCT imaging should be asked about inhalation of poppers.

To our knowledge, nitric oxide (NO) regulates photoreceptor metabolism in rods and cones primarily through activation of guanylate cyclase, a key enzyme of phototransduction. It is widely suspected that the potential cause of retinal damage linked to inhalation of poppers is high concentration of NO.Experimental studies showed that high doses of NO induce apoptotic cell death in photoreceptors. There is another hypothesis that poppers cause rapid widespread dilation of blood vessels, as well as blood vessels in the eye, which causes an increase in intraocular pressure and damage to retina.

mfERG is also a useful tool for detecting the location and extent of retinal dysfunction, particularly in the diagnosis of retinal toxicity confined to the central retina. In some drug-reduced retinopathies, such as chloroquine and hydroxychloroquine, mfERG is considered an objective examination of retinal function that can provide earlier detection of retinal damage. As a case reported that OCT abnormality appeared 3mo later than visual symptoms and acuity loss following poppers inhalation, mfERG can be a significant method for early screening of poppers retinal toxicity and monitoring of disease progression or recovery after drug cessation.

矿区范围内未见到岩浆岩出露。矿区内发现的蚀变有硅化、碳酸盐化、绢云母化、黄铁矿化、叶腊石化、炭化及高岭石化等。其中，硅化、碳酸盐化、绢云母化和炭化与矿化关系较密切。

A 37-year-old Chinese man presented with blurred vision and central scotoma in both eyes for 7d. He admitted to regular use (at least twice or 3 times per month) rush poppers for the previous 7y. After inhaling the rush poppers, he had multiple transient blurred visions, and the symptom did not disappear since his last inhalation of rush poppers 7d ago. He did not smoke or drink and had no significant past medical, ophthalmic or family history. Slit-lamp examination was unremarkable,with normal fundus (Figure 1). Best-corrected visual acuity(BCVA) was 0.7 in the right eye and 0.5 in the left. His pupil reactions and color vision (Farnsworth D-15 test) were normal.Optical coherence tomography (OCT) revealed disruption of the ellipsoid zone confined to the fovea in both eyes (Figure 2A). Full-field electroretinography (ERG) showed normal.Multifocal electroretinography (mfERG) showed amplitude reduced at macular fovea of both eyes (Figure 3A). Visual field testing showed normal on the 5day of the onset, while there was central scotoma of the left eye on the 17day, the other eye was normal (Humphrey 24-2; Figure 4A).

The patient was advised to stop drug inhalation. With 2mo follow-up, the patient complained that the scotoma was disappeared. At the same time, his BCVA improved to 1.0 in the right eye and 0.8 in the left. OCT showed the photoreceptor layer of both eyes was return to normal (Figure 2B). mfERG showed improvement in both central regions, especially in the right eye (Figure 3B). The central scotoma on the left visual field was disappeared (Figure 4B).

Some other ancillary testings should be considered, such as visual field examination that central or paracentral scotomas are possibly seen with normal peripheral fields, but these abnormalities may not appear in the early stage of the disease.Color vision examination is also helpful to distinguish macular diseases from optic nerve diseases.

Clinical features and ellipsoid zone disruption on OCT of poppers macular lesions are similar to photic injury, the two conditions can only be reliably distinguished by the history of excess light. Therefore, it is crucial to document the relevant drug history and light exposure. Adult-onset occult macular dystrophy should be another differential diagnosis as the normal fundus and similar structural changes in the ellipsoid zone, but the patients with occult macular dystrophy usually have progressive decrease of visual acuity and red-green color defect. If the patient has yolk-like lesions at the fovea,it needs to be differentiated from best vitelliform macular dystrophy.

The prognosis of poppers maculopathy is variable. When they ceased using poppers, most patients may achieve complete or partial resolution, while others experience no improvement.The final results may be related to the duration, frequency and type of drug inhalation.

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