Syncope as a sign of occult cancers: a population-based cohort study

Association between Syncope and the 6-Month Incidence of Ischemic Stroke, Arrhythmia, Brain Tumor, Epilepsy, and Anxiety Disorder

OBJECTIVES

the aim of the present study is to investigate the associations between syncope and subsequent diagnoses of brain tumor, cardiac arrhythmia, stroke/transient ischemic attack (TIA), epilepsy, and anxiety disorder in a large outpatient population in Germany.

METHODS

This retrospective cohort study uses data from the Disease Analyzer database (IQVIA). Adults who received syncope diagnosis from one of 1284 general practices between January 2005 and December 2021 (index date) were included and matched (1:1) to individuals without syncope diagnosis using a propensity score based on age, sex, the number of consultations during the follow-up period (up to 6 months), and defined co-diagnoses documented within 12 months prior to and on the index date. Finally, associations between syncope and subsequent outcome diagnoses were investigated using multivariable logistic regression models.

RESULTS

Data related to 64,016 patients with and 64,016 patients without syncope (mean age 54.5 years, 56.5% female) were available. In total, 6.43% of syncope patients and 2.14% of non-syncope patients were diagnosed with one of the five outcome diagnoses within 6 months of the index date. There was a positive and significant association between syncope and incidences of ischemic stroke/TIA (OR = 2.83, 95% CI = 2.41-3.32), arrhythmia (OR = 3.81, 95% CI = 3.44-4.18), brain tumor (OR = 4.24, 95% CI = 2.50-7.19), epilepsy (OR = 5.52, 95% CI = 4.27-7.14), and anxiety disorder (OR = 1.99, 95% CI = 1.79-2.21).

CONCLUSIONS

Syncope is significantly associated with an increased risk of subsequent ischemic stroke/TIA, cardiac arrhythmia, brain tumor, epilepsy, and anxiety disorder. Nevertheless, the cumulative incidences for all five diagnoses are very low.

Syncope caused by lymphomatous encasement of the internal carotid artery

We present a case of a 77-year-old man who reported 5 months of syncopal episodes. He was found to have diffuse large B-cell lymphoma encasing the left internal carotid artery but not impeding blood flow. The syncopal episodes resolved after his first cycle of chemotherapy. Recurrent syncope in non-cardiac lymphomas and other head and neck masses is exceedingly rare and may be due to reflex syncope prompted by carotid baroreceptor activation. There are 11 previously described cases of recurrent syncope associated with non-cardiac lymphoma. In all cases, lymphadenopathy abutting the carotid artery was present and the syncopal episodes resolved with treatment. Our case illustrates that malignancy should be considered in patients with unexplained recurrent syncope.