Monmany J, Rabella N, Margall N, Domingo P, Gich I, Vázquez G
Department of Internal Medicine, Hospital of Santa Creu and Sant Pau, Autonomous University of Barcelona, Sant Antoni Maria Claret 167, E-08025, Barcelona, Spain.
Infection. 2004 Apr;32(2):89-97. doi: 10.1007/s15010-004-3088-y.
Infection by the influenza virus may pass undetected in many adult patients attended to in the emergency department because its diagnosis usually relies on clinical manifestations, which can be distorted by symptoms of a preexisting disease, superposed complications or nontypical manifestations of influenza virus infection (confusing symptoms).
We performed this observational, prospective study with an antigen detection test by indirect immunofluorescence assay (IFA) to estimate the presence of influenza virus infection in such patients. No confirmatory test was performed to validate a positive or negative IFA result. Then we compared those who were antigen positive to those who were negative and also analyzed those who were positive classified by age, comorbidity and clinical presentation. We also evaluated the use of medical and hospital resources and vaccination status. Posterior pharynx swab specimens from 136 consecutive adult patients, 74 women and 62 men with a mean age of 68.7 +/- 17.9 (range: 18-97) years attended to in the emergency department of a university hospital in Barcelona during the 1999-2000 influenza epidemic were examined. Tested patients presented either a classical influenza syndrome, a deterioration of a previous condition or any abrupt onset of symptoms without an obvious cause.
Influenza A virus antigen was detected in 99 (72.8%) of the 136 patients included in the study. Confusing symptoms were present in 86 patients with laboratory-confirmed influenza and 40 of them lacked influenza syndrome. Prostration, aching and fever out of proportion to catarrhal symptoms (disproportionate prostration) and cough were independent predictors for this diagnosis (OR = 5.14; 95% CI: 1.98-13.35, p = 0.001 and OR = 4.40, 95% CI, 1.65-11.75, p = 0.03, respectively). Among the 99 patients who tested positive, 72 were >or= 65 years of age. This older positive group compared to the 27 also positive < 65 (non-old) had a tendency to show symptoms mediated by cytokines less frequently: malaise was present in 76.4% of the older positive patients vs 92.6% in the non-old positive ones, p = 0.07. The equivalent percentages for muscle ache were: 56.9% vs 77.8%, p = 0.06; for dysthermia: 54.2% vs 70.4%, p = 0.08; for headache: 35.2% vs 66.7%, p = 0.005, and for disproportionate prostration: 47.2% vs 66.7%, p = 0.08. Cough was more frequent in the older positive group: 94.4% vs 77.8%, p = 0.02. Older positive patients were also hospitalized and received antibiotics more frequently than the non-old positive ones: 65.3% vs 40.7%, p = 0.03 and 81.9% vs 63.0%, p = 0.046, respectively. Hospitalization was independently correlated with the presence of complications (OR = 4.5, 95% IC 1.27-15.95, p = 0.02). Patients with the highest comorbidity, evaluated with the Charlson scale, were more inadequately vaccinated than those with moderate or low comorbidity.
Influenza virus infection has a great and underestimated impact in the emergency department during influenza epidemics. High frequency of confusing symptoms, which overcome classical influenza syndrome in adult people with comorbidity, may explain this effect. Disproportionate prostration and cough are symptoms that independently predict its diagnosis in the global adult population, whereas in the elderly, fever and cough should arouse this suspicion whether or not they present classic symptoms. In our setting, individuals with high comorbidity are inadequately vaccinated.
在急诊科就诊的许多成年患者中，流感病毒感染可能未被察觉，因为其诊断通常依赖于临床表现，而这些表现可能会因既往疾病的症状、叠加的并发症或流感病毒感染的非典型表现（症状混淆）而受到影响。
我们进行了这项观察性前瞻性研究，采用间接免疫荧光法（IFA）进行抗原检测试验，以评估此类患者中流感病毒感染的情况。未进行确认试验来验证IFA结果的阳性或阴性。然后我们将抗原阳性者与阴性者进行比较，并按年龄、合并症和临床表现对阳性者进行分析。我们还评估了医疗和医院资源的使用情况以及疫苗接种状况。对1999 - 2000年流感流行期间在巴塞罗那一家大学医院急诊科就诊的136例成年患者（74名女性和62名男性，平均年龄68.7±17.9岁，范围：18 - 97岁）的咽后部拭子标本进行了检测。受试患者表现为典型流感综合征、既往病情恶化或无明显原因的任何突发症状。
在纳入研究的136例患者中，99例（72.8%）检测到甲型流感病毒抗原。86例实验室确诊为流感的患者存在症状混淆，其中40例没有流感综合征。全身乏力、疼痛和发热与卡他症状不成比例（不成比例的全身乏力）以及咳嗽是该诊断的独立预测因素（OR = 5.14；95% CI：1.98 - 13.35，p = 0.001；OR = 4.40，95% CI，范围1.65 - 11.75，p = 0.03）。在99例检测呈阳性的患者中，72例年龄≥65岁。与27例年龄＜65岁（非老年）且检测也呈阳性的患者相比，这个老年阳性组出现细胞因子介导症状的频率较低：老年阳性患者中76.4%出现不适，而非老年阳性患者中为92.6%，p = 0.07。肌肉疼痛的相应百分比分别为：56.9%对77.8%，p = 0.06；体温异常：54.2%对70.4%，p = 0.08；头痛：35.2%对66.7%，p = 0.005；不成比例的全身乏力：47.2%对66.7%，p = 0.08。咳嗽在老年阳性组中更常见：94.4%对77.8%，p = 0.02。老年阳性患者住院和使用抗生素的频率也高于非老年阳性患者：分别为65.3%对40.7%，p = 0.03；81.9%对63.0%，p = 0.046。住院与并发症的存在独立相关（OR = 4.5，95% IC范围1.27 - 15.95，p = 0.02）。用查尔森量表评估，合并症最高的患者疫苗接种不足的情况比合并症中等或低的患者更严重。
在流感流行期间急诊科，流感病毒感染具有重大且被低估的影响。症状混淆的高频率出现，在有合并症的成年人中超过了典型流感综合征，可能解释了这种影响。不成比例的全身乏力和咳嗽是在全球成年人群中独立预测其诊断的症状，而在老年人中，无论是否出现典型症状，发热和咳嗽都应引起怀疑。在我们的研究环境中，合并症高的个体疫苗接种不足。
