Kesserwani Hassan
Neurology, Flowers Medical Group, Dothan, USA.
Cureus. 2020 Nov 17;12(11):e11533. doi: 10.7759/cureus.11533.
Serologic tests for syphilis can be quite complex. The screening and confirmatory tests, which number at least eight, are mathematically interpreted as a total of 16 possible combinations, if we choose one test from each of two sets of four. However, this bewildering complexity is simplified if we apply certain principles. We reiterate and propose four axioms. First, we distinguish between treponemal versus non-treponemal tests. The former, the treponemal test, is specific for the spirochete, treponema pallidum, and is used as a confirmatory test. It rarely declines over time. The latter, the non-treponemal test, is a screening test and reflects treponemal or tissue damage, is reported as a titer, and is used to monitor disease activity. We usually need both for screening and confirmatory diagnostic testing. Secondly, for rapid plasma reagin (RPR) tests, a non-treponemal serology test titer of at least 1:8 is suggestive of syphilis, but not necessarily neurosyphilis. A false-negative test usually registers below this dilution level and may be due to the "prozone phenomenon". Serum RPR titers are usually greater than 1:32. Thirdly, a negative treponemal test in the cerebrospinal fluid excludes neurosyphilis and a positive test is highly sensitive but lacks specificity, usually due to blood contamination. Most patients with neurosyphilis will have a positive non-treponemal test in the cerebrospinal fluid (CSF) with elevated protein and pleocytosis. Fourthly, a serological cure is defined as at least a four-fold decline in a non-treponemal test titer at three and six months, or a persistently low titer after treatment. Patients who do not fulfill these criteria are known as "serofast". We describe the case of a 38-year-old man with human immunodeficiency virus-type 1 who developed bilateral optic disc edema with photopsias and transient visual obscurations.
梅毒的血清学检测可能相当复杂。筛查和确证试验至少有八项，如果我们从两组四项试验中各选一项，从数学角度解释共有16种可能的组合。然而，如果我们应用某些原则，这种令人困惑的复杂性就会简化。我们重申并提出四条公理。首先，我们区分密螺旋体试验和非密螺旋体试验。前者，即密螺旋体试验，对梅毒螺旋体具有特异性，用作确证试验。其结果随时间推移很少下降。后者，即非密螺旋体试验，是一种筛查试验，反映密螺旋体或组织损伤，以滴度报告，用于监测疾病活动。我们通常需要两者进行筛查和确证诊断检测。其次，对于快速血浆反应素（RPR）试验，非密螺旋体血清学试验滴度至少为1:8提示梅毒，但不一定是神经梅毒。假阴性试验通常在该稀释水平以下出现，可能是由于“前带现象”。血清RPR滴度通常大于1:32。第三，脑脊液中密螺旋体试验阴性可排除神经梅毒，阳性试验高度敏感但缺乏特异性，通常是由于血液污染。大多数神经梅毒患者脑脊液中的非密螺旋体试验呈阳性，蛋白质升高且有细胞增多。第四，血清学治愈定义为非密螺旋体试验滴度在三个月和六个月时至少下降四倍，或治疗后滴度持续较低。未达到这些标准的患者被称为“血清固定”。我们描述了一名38岁感染1型人类免疫缺陷病毒的男性患者的病例，该患者出现双侧视盘水肿，并伴有光幻视和短暂性视力模糊。
