  Citation: Latos, W.; Aebisher, D.; Latos, M.; Krupka-Olek, M.; Dynarowicz, K.; Chodurek, E.; Cie´ slar, G.; Kawczyk-Krupka, A. Colonoscopy: Preparation and Potential Complications. Diagnostics 2022, 12, 747. https://doi.org/ 10.3390/diagnostics12030747 Academic Editor: Takuji Tanaka Received: 15 February 2022 Accepted: 17 March 2022 Published: 18 March 2022 Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affil- iations. Copyright: © 2022 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). diagnostics Article Colonoscopy: Preparation and Potential Complications Wojciech Latos 1 , David Aebisher 2 , Magdalena Latos 3 , Magdalena Krupka-Olek 4 , Klaudia Dynarowicz 5 , Ewa Chodurek 6 , Grzegorz Cie´ slar 4 and Aleksandra Kawczyk-Krupka 4, * 1 Center for Laser Diagnostics and Therapy, Department of Internal Diseases, Angiology and Physical Medicine, Specialist Hospital No. 2, 41-902 Bytom, Poland; wojlatos@gmail.com 2 Department of Photomedicine and Physical Chemistry, Medical College of Rzeszów University, University of Rzeszów, 35-959 Rzeszów, Poland; daebisher@ur.edu.pl 3 Silesian Centre for Heart Disease in Zabrze, Marii Curie Sklodowskiej 9, 41-800 Zabrze, Poland; latos.magdalena93@gmail.com 4 Center for Laser Diagnostics and Therapy, Department of Internal Medicine, Angiology and Physical Medicine, Medical University of Silesia in Katowice, 41-902 Bytom, Poland; magda.krupka94@gmail.com (M.K.-O.); cieslar1@tlen.pl (G.C.) 5 Center for Innovative Research in Medical and Natural Sciences, Medical College of the University of Rzeszów, 35-310 Rzeszów, Poland; kdynarowicz@ur.edu.pl 6 Department of Biopharmacy, Faculty of Pharmaceutical Sciences in Sosnowiec, Medical University of Silesia in Katowice, 41-208 Sosnowiec, Poland; echodurek@sum.edu.pl * Correspondence: akawczyk@gmail.com Abstract: Colonoscopy is a fairly common test that serves both diagnostic and therapeutic purposes. It has been considered the gold standard in colorectal cancer screening for several years. Due to the nature of the examination, various types of complications may occur. The purpose of this analysis is to describe the various complications related to the period of preparation for colonoscopy among hospitalized patients, including life-threatening ones, in order to know how to avoid complications while preparing for a colonoscopy. We analyzed the nursing and medical reports of 9962 patients who were prepared for colonoscopy between 2005 and 2016. The frequency of various side effects associated with intensive bowel cleansing prior to colonoscopy was assessed. In justified cases, additional medical data were collected from patients, their families or from other doctors providing advice to patients after complications. Out of 9962 patients prepared for colonoscopy, 180 procedures were discontinued due to complications and side effects, and in these cases no colonoscopy was performed. The most common complications were: vomiting; epistaxis; loss of consciousness with head injury; abdominal pain; acute diarrhea; symptoms of choking; heart rhythm disturbances; dyspnea; fractures of limbs and hands; acute coronary syndrome; hypotension; hypertension; cerebral ischemia; severe blood glucose fluctuations; increased muscle contraction and allergic reactions. In addition to the documentation of our own research, several works of other research groups were also analyzed. Currently, the literature does not provide data on the frequency and type of complications in the preparation period for colonoscopy. The advantage of our work is the awareness of the possibility of serious complications and postulating the necessary identification of threats. Individualization of the recommended procedures and increased supervision of patients undergoing bowel cleansing procedure, we hope, will reduce the occurrence of complications and side effects. Keywords: colonoscopy; gastroenterology; diagnostics 1. Introduction Colonoscopy is a widely used method of diagnosing and treating gastrointestinal disease [1,2]. Endoscopic examination of the lower gastrointestinal tract, called colonoscopy, was, is and will remain the ‘gold standard’ in the diagnosis and treatment of majority of diseases of the large intestine [3–10]. The constantly growing number of cases of various types of intestinal diseases is associated with an increased demand and availability of Diagnostics 2022, 12, 747. https://doi.org/10.3390/diagnostics12030747 https://www.mdpi.com/journal/diagnostics