Horse chestnut (Aesculus hippocastanum) is a common tree found on roads and parks. The shape of the fruit is very similar to that of the edible Korean chestnut (Castanea crenata); thus, people can eat it by mistake. However, reports of the side effects and toxicity from ingestion are very rare. A 46-year-old male who had no unusual findings in the past had eaten horse chestnut seed which he had mistaken to be Korean chestnut. He visited the emergency department (ED) with complaints of epigastric pain, nausea, and sweating. Blood tests showed a slight increase in the levels of liver enzymes, serum amylase, and pancreatic amylase. During the monitoring, he complained of palpitations, and electrocardiogram showed atrial fibrillation. On the following day after conservative treatment, blood testing and electrocardiogram showed normal findings. He was discharged from the ED as he did not complain of any further symptoms. When a patient who has eaten horse chestnut visits the ED, blood examination and electrocardiogram monitoring are needed, and conservative treatment is required.

Objective
Especially in emergency departments (EDs), a lack of internal medicine (IM) residents in charge causes difficulties in medical care and ED overcrowding. Thus, protocols without IM residents in EDs is needed. This study aimed to investigate changes in medical care when emergency medicine residents replaced the roles of IM residents.
Methods
This study was conducted at a single-site ED of a university medical center. The study group contained patients admitted to the IM department between September and December 2015, during which IM residents were absent in the ED. The control group contained patients admitted to the IM department between September and December 2014, during which IM residents were present in the ED. Changes in medical care between the presence and absence of IM residents in the ED were studied by comparing admission rates from the ED, length of ED stay, duration of hospitalization, and concordance of diagnoses between admission and discharge by the IM department.
Results
The study group contained 2,341 patients; the control group contained 2,215 patients. Admission rates from the ED increased by 53.4% (95% confidence interval [CI], P<0.001); lengths of stay decreased by 15.1% (95% CI, P<0.001); and durations of hospitalization in the pulmonology department decreased by 38.4% (95% CI, P=0.001). Concordance of diagnoses between admission and discharge decreased by 14.2% in the cardiology department (95% CI, P=0.021).
Conclusion
Lengths of stay were reduced without critical declines in diagnostic concordance rates when emergency medicine physicians, instead of IM residents in the ED, decided upon admissions of IM patients.