It is an honor to serve as the guest authors of this edition of Polish Archives of Internal Medicine (Pol Arch Intern Med). The journal has achieved a global success as a source of scientific and clinical knowledge in internal medicine, and its numerous major accomplishments since 2008 deserve admiration. Professor Anetta Undas, MD, PhD, Editor-in-Chief, is to be applauded for her direction, passion, and leadership. This editorial aims to provide the readers with a brief introduction highlighting the relationship of stroke and chronic rhinosinusitis (CRS), which will help them understand the significance of the original study by Stryjewska-Makuch et al,1 published in this issue of Pol Arch Intern Med.

In 2019, stroke was the second leading cause of death in Poland2 and the fifth in the United States.3 Ischemia accounted for about 68% of stroke cases and is mostly caused by atherosclerosis within the large extracranial and intracranial arteries that supply the brain. White platelet–fibrin and red erythrocyte–fibrin thrombi are often superimposed upon the atherosclerotic plaque and they may also develop without severe vascular disease in patients with hypercoagulable state. Despite the fast-growing number of patients with stroke worldwide,4 specific data on the risk factors of the disease are still limited. Traditional risk factors for stroke include obesity, high blood pressure, hyperglycemia, hyperlipidemia, and renal dysfunction, while smoking, sedentary lifestyle, and an unhealthy diet constitute behavioral risk factors.4 In recent years, however, there has been a growing body of evidence showing how stroke may, through various mechanisms, be associated with inflammatory diseases such as periodontitis,5 bronchitis,6 and CRS.

Chronic rhinosinusitis, defined by the presence of persistent inflammation of sinonasal mucosa lasting for more than 12 weeks,7 is a very common inflammatory condition that affects approximately 16% and 11.6% adults in Poland8 and the United States,9 respectively. Several studies demonstrated that patients with CRS had a relatively 80% excess risk of stroke compared with those without CRS. It is generally believed that inflammatory cytokines, such as C-reactive protein, interleukin 1, interleukin 6, tumor necrosis factor, and complement proteins, can stimulate immune cells and smooth muscle cells in the subendothelial layer, resulting in accelerated atherogenesis.10 This eventually causes premature atherosclerosis and cardiovascular diseases, including stroke.11 In addition, inflammatory cytokines can cross-activate the coagulation cascade, leading to a higher probability of thrombus formation and thromboembolic events.10 Medications such as decongestants12,13 and steroids14 used to treat CRS may also increase the risk of ischemic stroke. Previous studies, however, did not explore differences in the occurrence of stroke depending on the affected sinuses—maxillary, frontal, ethmoid, and sphenoid. Such data as to which type of sinus is prone to induce stroke may provide relevant guidance in the treatment of patients with CRS and therefore prevent future strokes.

Our knowledge of CRS and its inflammatory nature has not changed significantly since our study published in 2013.15 Several past reports indicated that CRS is highly related to subsequent stroke both in claims data and imaging studies16; however, none of them addressed any breakthrough finding. In this issue of Pol Arch Intern Med, the investigators from the Upper Silesian Medical Centre in Katowice-Ochojec report their novel findings regarding a higher probability of ethmoid sinusitis in patients with stroke.1 We congratulate the authors on this relevant study and, having participated in the previous study in Taiwan, appreciate their high-quality work.

The increasing global burden of stroke strongly suggests that current strategies for primary stroke prevention have not been sufficiently implemented. As epidemiologists and otorhinolaryngologists, we are glad to see that there is another strategy to prevent the occurrence of stroke, that is, to appropriately treat CRS, particularly ethmoid sinusitis. Rhinologists should pay special attention to treating diseased sinuses, especially the ethmoid ones, to reduce the infection load of patients. Nowadays, functional endoscopic sinus surgery remains the standard of care for patients with CRS who are nonresponsive to medical treatment. During the surgery, rhinologists should avoid mucosal stripping and resultant sinus bone exposure, which have been associated with scarring and the recurrence of CRS.17 Since CRS is a complex disease that manifests itself in several forms depending on various underlying pathophysiological mechanisms, some types of sinusitis still remain difficult to treat. However, cutting edge methods such as the use of steroid-eluting implants and monoclonal antibodies, for example, dupilumab (anti–interleukin 4 receptor α) may ultimately shed some light on the treatment of recalcitrant CRS accompanied by nasal polyposis.7

Considering the intriguing association of stroke and chronic rhinosinusitis, there is no doubt that the article by Stryjewska-Makuch et al1 will be of interest to the readership of Pol Arch Intern Med.