Hyperhidrosis in Patients With Amputations-Botox

Overview

The objective is to establish and evidence base for hyperhidrosis treatment algorithm in amputees.This project will address a problem that has troubled Service members, Veterans, and civilians with amputations for decades, impacting satisfaction with prosthetic use, residual limb skin health, and negatively affecting quality of life. Prior research in this area has been limited and insufficient. We plan to conduct an open label study of Botox, up to 400 units, to treat limb hyperhidrosis in patients with amputations. The actual dose of Botox used will be based on individual results with the Iodine-Starch test to identify areas on the residual limb that are producing excessive sweat. Botulinum Toxin A (BTX-A): Botulinum toxin therapy is well-established for use in excessive sweating of several body areas (axillary, palmar, plantar, and facial) in individuals with hyperhidrosis and inadequate response to topical treatments. Extensive research has been conducted on the efficacy and safety of BTX-A for hyperhidrosis of other areas, and it has been shown to improve both objective and subjective measures of sweating, and lead to improved quality of life measures. This will be accomplished by completing the following: Test the validity of the Minor iodine-starch test in amputees. 1. Hypothesis: The iodine-starch test is a valid diagnostic tool of hyperhidrosis and can be useful for the identification of focal areas of sweating on a residual limb. 2. Treat the residual limb Hyperhidrosis with Botox, up to and limited to 400 units. Hypothesis: Treatment of residual limb Hyperhidrosis with Botox will result in improved patient reports of excessive sweating as measured by the HDSS and as measured by subjects' response to iodine-starch testing. We are confident that improving the evaluation and treatment of residual limb hyperhidrosis will reduce the secondary health consequences of amputation and will lead to improved quality of life.

Subjects who meet inclusion criteria will be given Botox injections. The maximum dose that will be used will vary from patient to patient up to 400 units. We will test the effectiveness of botulinum toxin therapy in those who fail Aluminum Chloride. Failure will be defined as a non-response (no change in HDSS), inadequate response (post-treatment HDSS of 2 or more), or intolerance to Aluminum Chloride. This would be a natural progression of interventions consistent with guidelines for other forms of hyperhidrosis. Specifically, we will study botulinum toxin type A BTX-A, brand name Botox. While there are other BTX-A products on the market, Botox is the only FDA approved toxin for the treatment of axillary hyperhidrosis. There are a few considerations to make when dosing Botox for hyperhidrosis. These include the total dose, the dose per injection site, and the distribution of injection sites. Typical doses for axillary hyperhidrosis are 50- 100 units per axilla18. However, for clinical trials used to support the FDA-approved labeling in focal spasticity, doses up to 400 units were used. There are reports of off label dosing exceeding this amount, including the case series reported by Charrow for residual limb hyperhidrosis, which used doses ranging from 300 - 500 units of Botox. There was no mention of adverse events in this series. It has been suggested that doses greater than 600 units pose a greater risk of serious adverse events including systemic weakness. Regarding dose per injection site, hyperhidrosis guidelines suggest 1 unit per site for the axilla, and 1.5 - 2 units per site for the palm or sole18. The largest case series in amputees used doses of 2-3 units per site. Regarding the distribution of injection sites, guidelines recommend injections every 1 - 2 cm in a grid-like fashion. We plan to conduct an open label study of Botox, up to 400 units, in amputees who have failed treatment with a topical antiperspirant.