Cough syncope: constrictive pericarditis

Life-Threatening and Non-Life-Threatening Complications Associated With Coughing: A Scoping Review

BACKGROUND

This is an update of the section on complications that are associated with coughing in the 2006 CHEST cough guidelines that addresses two aims: (1) to systematically identify and thematically categorize the diverse complications of cough by providing a guide for future studies and (2) to identify gaps in the literature for future research.

RESEARCH QUESTION

What are the potential complications that are associated with the act of coughing that have been reported in infants, children, adolescents, and adults?

STUDY DESIGN AND METHODS

A scoping review was performed with the use of PubMed and SCOPUS databases that were searched from their beginning until September 6, 2019.

RESULTS

Two hundred forty-seven publications met our inclusion criteria. To these, we added 38 articles from the 2006 complications paper that were not identified in the literature search plus the paper itself for a final total of 286 publications that formed the basis of this review. Since 2006, three new categories of complications have been reported: ear, nose and throat; disease transmission; and laboratory testing. Multiple additional complications that fall outside of these three categories have also been identified and included in the following categories: cardiovascular, constitutional symptoms, dermatologic, GI, genitourinary, musculoskeletal, neurologic, ophthalmologic, psychosocial/quality of life, and respiratory. Not previously highlighted is that some of the complications led to serious morbidity that included death, especially in patients with comorbid conditions, and potentially resulted in harm to others when cough resulted in a motor vehicle accident.

INTERPRETATION

Our work identified a large number of cough complications that we thematically categorized primarily by organ system so that future studies of each system or each complication can be conducted. The gap in the literature that future studies should address is to identify the frequency of the complications and the strength of their association with cough. Only then will one be able to describe the findings in a manner that allows specific recommendations for avoiding these complications. In the meantime, patients with cough should be evaluated and treated according to evidence-based guidelines to mitigate or prevent the myriad of potential complications that are associated with coughing.

Cough syncope

Loss of consciousness following cough was first described in 1876 as "laryngeal vertigo" Since then, several hundred cases of what is now most commonly termed cough syncope have been reported, often in association with various medical conditions. Some early authors assumed this entity to be a form of epilepsy, but by the mid-20th century, general consensus reflected that post-tussive syncope was a consequence of markedly elevated intrathoracic pressures induced by coughing. A typical profile of the cough syncope patient emerging from the literature is that of a middle-aged, large-framed or overweight male with obstructive airways disease. Presumably, such an individual would be more likely to generate the extremely high intrathoracic pressures associated with cough-induced fainting. The precise mechanism of cough syncope remains a matter of debate. Theories proposed include various consequences of the marked elevation of intrathoracic pressures induced by coughing: diminished cardiac output causing decreased systemic blood pressure and, consequently, cerebral hypoperfusion; increased cerebrospinal fluid (CSF) pressure causing increased extravascular pressure around cranial vessels, resulting in diminished brain perfusion; or, a cerebral concussion-like effect from a rapid rise in CSF pressure. More recent mechanistic studies suggest a neurally mediated reflex vasodepressor-bradycardia response to cough. Since loss of consciousness is a direct and immediate result of cough, elimination of cough will eliminate the resultant syncopal episodes. Thus, the approach to the patient with cough syncope requires thorough evaluation and treatment of potential underlying causes of cough, as summarized in several recently published cough management guidelines.