Clinical and laboratory features distinguishing between Deinagkistrodon acutus and Daboia siamensis envenomation

 

Hung-Yuan Su^1  2, Shih-Wei Huang³, Yan-Chiao Mao⁴, Ming-Wen Liu³, Kuo-Hsin Lee^1  2, Pei-Fang Lai³, Ming-Jen Tsai⁵

 

1 Department of Emergency Medicine, E-Da Hospital and I-Shou University, Kaohsiung, Taiwan

2 The School of Chinese Medicine for Post Baccalaureate, I-Shou University, Kaohsiung, Taiwan

3 Department of Emergency Medicine, Buddhist Tzu Chi General Hospital, Hualien, Taiwan

4 Division of Clinical Toxicology, Department of Emergency Medicine, Taichung Veterans General Hospital, Taichung, Taiwan

5 Department of Emergency Medicine, Ditmanson Medical Foundation Chia-Yi Christian Hospital, No. 539, Zhongxiao Road, East District, Chiayi City 600, Taiwan

 

ABSTRACT

Background:

There are 6 species of venomous snakes in Taiwan. Two of them, Deinagkistrodon acutus (D. acutus) and Daboia siamensis (D. siamensis), can cause significant coagulopathy. However, a significant proportion of patients with snakebites cannot identify the correct snake species after envenomation, which hampers the application of antivenom. Hence, the differential diagnosis between the two snakebites by clinical presentations is important. This study aims to compare their clinical and laboratory features for the purpose of differential diagnosis between the two snakebites.

 

Methods:

We retrospectively reviewed the medical records of patients who arrived at the emergency department due to D. acutus or D. siamensis envenomation, between 2003 and 2016, in one medical center in eastern Taiwan. Since these snakebites are rare, we also included 3 cases reported from another hospital in central Taiwan.

 

Results:

In total, 15 patients bitten by D. acutus and 12 patients by D. siamensis were analyzed. Hemorrhagic bulla formation and the need for surgical intervention only presented for D. acutus envenomation cases (Both 53.3% vs. 0.0%, P=0.003). As to laboratory features, lower platelet counts (20.0 × 10³/μL [interquartile range, 14-66 × 10³/μL] vs. 149.0 × 10³/μL [102.3-274.3 × 10³/μL], P = 0.001), lower D-dimer level (1423.4 μg/L [713.4-4212.3 μg/L] vs. 12,500.0 μg/L [2351.4-200,000 μg/L], P = 0.008), higher proportion of patients with moderate-to-severe thrombocytopenia (platelet count < 100 × 10³/μL) (80% vs. 16.7%, odds ratio (OR) = 20.0, 95% CI, 2.77-144.31; P = 0.002), and lower proportion of patients with extremely high D-dimer (> 5000 ng/mL) (16.7% vs. 66.7%, adjusted OR = 0.1 (95% CI, 0.01-0.69; P = 0.036) were found among cases of D. acutus envenomation compared to D. siamensis envenomation. The combination of hemorrhagic bulla, thrombocytopenia, and a lack of extremely high D-dimer had good discriminatory power (area under the curve (AUC) = 0.965; 95% CI, 0.904-1.00) for distinguishing D. acutus from D. siamensis envenomation.

 

Conclusions:

The presentation of moderate to severe thrombocytopenia (platelet count < 100 × 10³/μL) and hemorrhagic bulla formation may indicate D. acutus envenomation. However, the envenomed patient with extremely high D-dimer levels may indicate a D. siamensis envenomation. These findings may help diagnose and select the right antivenom in patients with unknown snakebites who present significant coagulopathy.

 

Keywords: Coagulopathy; Deinagkistrodon acutus; Daboia siamensis; Snakebite; Thrombocytopenia

 

Received: August 27, 2018.

Accepted: December 06, 2018.

Published: December 27, 2018.

 

Correspondence: tshi33@gmail.com

 

Authors’ contributions

The first two authors, HUS and SWH interpreted the clinical findings and drafted the manuscript. The third authors, YCM provide detailed data collection from Taichung Veteran General Hospital and provided professional opinion. The fourth and sixth authors, MWL and PFL provided data collection from Hualien Tzu Chi Medical center and professional opinion. The fifth author KHL provide professional opinion and help revised the manuscript. The correspondent author MJT designed this study, interpreted the clinical findings and revised the manuscript. All authors read and approved the final manuscript.

 

Competing interests

The authors declare that they have no competing interests.