The present study, as far as we are concerned, is the first that compares an important number of scorpion stings as well as envenomation cases in Khouribga region, Morocco, during three successive years. Differences among the three years and the influence of certain parameters on the patients’ outcome were investigated.
Reports of scorpion stings increased over the three years because the standardized data collection form is more and more known and the population has had easier access to medical care. In addition, the Poison Control Center of Morocco (CAPM) has promoted several campaigns alerting the population about the severity of envenomation cases and the inefficiency of the traditional treatments.
The age range showed high concordance with the age pyramid of Morocco. Actually,according to literature, scorpion stings occur accidentally, independent of age or sex (1,3,5,11,16).
Envenomation cases as well as mortality mainly affected children. Morbidity is determined by the victim’s body weight, since the same dose of venom by scorpions of the same species can lead to different morbidity, and the higher the body weight, the more diluted the venom, leading to fewer harmful effects. In these cases, death at advanced ages can be related to pre-existing flaws.
The majority of scorpion stings were recorded in July and August, corroborating the data from medical literature(3, 22, 25), which indicates that sanitary authorities must reinforce the efforts during this summery period.
Scorpion stings mostly occurred at the end of the day and during the first half of the night (from 6:00 p.m. to 12:00 p.m.; Fig. 1), which was consistent with scorpions’ ontological data (2, 7, 13-15, 17, 20).
Late medical aid constituted a negative impact on the envenomation prognosis; however, patients that arrived at the hospital within 1 hour after the accident presented favorable evolution, similarly to other studies (12, 18, 25). Comparison among the three years studied (Table 2) showed highly significant differences and a reduction in TPP, which was probably due to frequent awareness campaigns and strategies implemented by CAPM.
The stings clinical manifestations are different and depend on the sting site, the patient’s age, thegeographical area, and the scorpion species (19). Patients belonging to severity class I (local symptoms) were predominant (93.3%), as in literature (4, 21, 26). The percentage of patients belonging to severity class II (thrill, hypersudation, nausea, vomiting, diarrhea and hypertension) was lower (6.6% of the cases) than those stated in literature and included 70% children younger than 15 years old, confirming the relationship between the venom dose injected and the body weight of the patient stung (9). The percentage of patients belonging to severity class III (cardiovascular and/or respiratory and/or neurological distress and often fatal evolution in the absence of appropriate management) was 0.1%.
The envenomation incidence (% class II + % class III) increased from 2001 to 2003 because the number of recorded cases also increased.
Following CAPM instructions for scorpion sting management, the patients were observed for approximately 4 hours after the sting to detect any general signs related to envenomation.
According to literature, the mean duration of the scorpion envenomation effects is 33 minutes in Morocco; less than two hours in Algeria (23), between two and four hours in Saudi Arabia (10); less than 30 minutes in Niger (6); and between five and 30 minutes in Mexico (8).
The number of treated cases decreased between 2001 and 2003 due to the training of health professionals for scorpion stings management and the development of a clear and easy algorithm, which allows distinguishing between a scorpion sting not requiring therapy and a scorpion envenomation requiring treatment in an intensive care unit.
The referral rate increased over the years since the number of cases reported increased. When the health unit does not have any resuscitation resources and the patient presents predictive severe signs, he/she is automatically referred to a specialized center since there is high risk of death.
The present investigation showed that most of the referred patients arrived at the hospital presenting severity class II symptoms and late first aid (>1h), mainly children younger than 15 years old. The relationship between specific mortality rate and age range allowed the following conclusion: the group of patients younger than one year old showed the highest lethality; a group of patients aged between one and 10 years old presented high lethality; and the group of patients older than 10 years old showed low lethality.
In Khouribga province, general mortality rate was 0.02‰ and the outcome was generally favourable. The reduction of lethality over the three years of investigation resulted from improved health management.