Endoscopic and histopathologic examination in both groups
Oropharyngeal stenotic lesions are significantly (p-value < 0.0001) more frequent in the hot Khat group (77.3%) than in the cold Khat group (0%); whereas, laryngeal and vocal folds affections are more frequent in the cold Khat group (55.1%) than in the hot Khat group (0%), as shown in Table 2 and Figures 4 & 5. Also, chronic non-specific inflammation is significantly (p-value < 0.0001) more frequent in the hot Khat group (68.2%) than in the cold Khat group (0%), as shown in Figures 4 & 5.
Discussion:
Egypt had always been a safe haven for Yemeni exiles. According to the UN, Egypt received 6810 Yemeni refugees after the start of war in 2015 with this number constantly growing. Egyptian hospitals have provided medical treatment for immigrants from East Africa and Yemen, that is the reason of observing the khat problems in Egypt29
This current cross-sectional study aimed to investigate the relation between pesticide use in Khat irrigation and oropharyngeal fibrosis (stenosis). Only from this study, we want to develop a hypothesis that can be further tested which may help in the understanding of the Khat chewing habit and its hazards on the human health and can answer for cases described as ”idiopathic oropharyngeal stenosis”.
The results of this study showed that there is a significant difference between those using Khat irrigated by pesticides (hot Khat) and those using Khat not irrigated by pesticides (cold Khat) in the reasons for referral for clinic. The most frequent reason for referral to clinic in the hot Khat group is difficulty in nasal breathing, difficulty in oral & nasal breathing followed by phonoasthenic symptoms. While, in the cold Khat group it is phonoasthenic symptoms, aspiration followed by difficulty in oral and nasal breathing. Also, oral sores or sore throat are more frequent in the hot Khat group than in the cold Khat group.
Moreover, the endoscopic and histopathologic examination in both groups are different. Oropharyngeal stenotic lesions with almost normal larynx are significantly more frequent in the hot Khat group than in the cold Khat group; whereas, laryngeal and vocal folds affections are more frequent in the cold Khat group than in the hot Khat group. Also, chronic non-specific inflammation is significantly more frequent in the hot Khat group than in the cold Khat group.
Those aforementioned results can help to develop a hypothesis that needs further testing which is that the pesticides used in irrigation of the Khat may play a significant role in the pathogenesis of certain lesions in those people chewing Khat.
The main salient feature in all presented hot Khat chewers are the fibrosis which starts from the oropharynx (velum and faucial pillars) and extending till the hypopharynx and supralaryngeal structures (those are the sites that the Khat juice reaches during chewing) and also most of the Khat chewers were found to have normal glottis (this is the only place that is not involved in Khat juice swallowing).
Some patients suffered from dysphagia due to fibrosis in the upper esophageal segment and underwent esophageal balloon dilatation. They are in direct contact with pesticide as some of them are pesticide merchants.
The present results of histopathological studies show the presence of chronic inflammatory cells which may be the cause of the present fibrosis which may be due to prolonged irritation. The mechanical and chemical irritation together with the high level of DDT founded in Khat leaves is the possible cause of the present fibrosis in the oropharynx and upper part of esophagus. That is because DDT are widely used to increase crop outputs to improve the quality of products, and to decrease the incidence of illness propagated by insects such as malaria and typhus as proved by Beceiro et al. 30
Moreover, the study of Junko showed that chewers of Khat produced in fields where pesticides are used have more symptoms than chewers of Khat produced in fields where pesticides are never used or used rarely.26
Some of the presented patients stated that they can differentiate between types of Khat that been irrigated with water containing pesticides and the ones that been irrigated by natural water. Most of the patients stated that they do not usually wash the Khat prior to its use. This can explain the reason why Khat can cause such changes in few cases among millions of Khat chewers all around Yemen.