J Korean Med Sci.  2020 May;35(20):e134. 10.3346/jkms.2020.35.e134.

Syncope after Influenza Virus Infection

• Noh SM
• Kang HG
• Kim BJ

• KMID: 2500844
• DOI: http://doi.org/10.3346/jkms.2020.35.e134

Abstract

Influenza is an epidemical acute respiratory disease caused by viral infection. Several complications in the respiratory tract, such as pneumonia can occur. However, rare but serious neurological complications are also observed. Here, we described the prevalence, characteristics and suggestive pathomechanism of syncope after influenza infection season. Of 2.2% of patients diagnosed as influenza experienced syncope. None of the patients had severe cough, low blood pressure (BP) or dehydration. Patients suffered with frequent dizziness before syncope. Patient with long duration of loss of consciousness was more observed in those with high fever or positive orthostatic BP drop.

Keyword

Influenza; Syncope; Orthostatic Blood Pressure Drop

Figure

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  Fig. 1 Abnormal results of positional BP test. A decrease in BP without an increase in heart rate was observed in 3 patients (dysautonomia). Results of positional BP test are classified according to the following criteria: 1) Dysautonomia: more than 20 mmHg or 10 mmHg drop in systolic or diastolic BP, respectively; 2) Neuro-cardiogenic syncope: decrease of BP with bradycardia; and 3) Postural orthostatic tachycardia syndrome: increase of heart rate more than 30 per minute after standing.BP = blood pressure, HR = heart rate.aSignificant BP lowering without a significant increase of heart rate.

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