Measuring pain intensity in patients with latrodectism: The visual analog scale (VAS)

• Published in: Clinical toxicology (Philadelphia, Pa.) Pa.), 2005-10, Vol.43 (6), p.707-708
• Main Authors: Gonzales, V A, Vazquez, I M, Robles, G D, Stanford, C F, Bogdan, G M, Garcia-Ubbelohde, W
• Format: Article
• Language: English
• ISSN: 1556-3650

Widow spider envenomation may cause an array of clinical effects, the hallmark of which is intense pain. Often, response to treatment must be judged by perceived changes in pain intensity due to lack of a reliable set of abnormal clinical findings. This study was conducted to quantify pain intensity in patients with latrodectism using the VAS. As part of a clinical trial, adult patients diagnosed with latrodectism and not treated with analgesics received a 5 to 10-min infusion of investigational Latrodectus antivenom (AV). If sufficient clinical improvement was not achieved, additional doses were infused at 30 and 60 min. Patients completed a VAS for pain before AV (0 min), at the end of Dose 1 (30 min), and at the end of observation (240 min). VAS score was the distance along a 10 cm line to the patient's mark with left side = "no pain" and right side = "worst possible pain". Vital signs (SBP, DBP, HR, RR) were also measured. VAS scores and vital signs were compared across time using RM ANOVAs (p22, 48%), generalized diaphoresis (48%), nausea/vomiting (29%), and tachycardia (HR greater than or equal to 100, 19%). At the end of Dose 1, there were significant decreases in mean VAS (3.3 plus or minus 2.3 cm = mild pain, p