Tuesday, June 18, 2013

Compensatory Hyperhidrosis

The most well-documented symptom of corposcindosis is “compensatory hyperhidrosis”. While patients cannot sweat at all above the nipple line, they tend to sweat profusely on the rest of the body.

Compensatory Hyperhidrosis
The most common areas for compensatory hyperhidrosis are the abdomen, lower back, crotch, and the backs of the legs. Complaints of soaked underwear or shirts are common. Patients report sweating at lower temperatures than before surgery, greater volumes of perspiration, and longer times waiting for sweating to stop.

Mechanism for Compensatory Hyperhidrosis

Compensatory hyperhidrosis is also referred to as “compensatory sweating” and “reflex sweating”. The mechanism of this surgically-induced excessive lower body sweating is “poorly understood” (Kopelman et al. 2000). Some hypotheses have been advanced:

The "compensatory cooling" hypothesis

The body cannot sweat on part of the body, so it compensates for the loss of evaporative cooling in that area by creating more evaporative cooling in another area.

Given the nature of the autonomic nervous system to maintain homeostasis by compensating in response to stressors, this hypothesis has an immediate plausibility. However, under this hypothesis, simply wetting the head and shoulders with water (imitating the lost sweating) would be expected to relieve compensatory hyperhidrosis. Several ETS patients have reported that compensatory hyperhidrosis occurs regardless of putting water on the head and shoulders.

The "reflex" hypothesis

Nerve impulses from the lower body travel upwards along the sympathetic chain and encounter dead ends and scar tissue, which causes a rebounding or reflexive signal to be sent back down the chain, stimulating excessive lower-body sweating.
The CS model generates a third hypothesis that may explain or at least contribute to the phenomenon:

The “false message” hypothesis

“The local and mean skin temperature are important for providing sensory input [to the control center]” (Kenney). Recall that thermoreceptors located in the denerved area are surrounded by skin that is up to 12 degrees F hotter than normal (see Gyftokostas et al. 1992). Messages about environment temperature are exaggerated, leading to exaggerated sweating response.
We call for more empirical research on total body sweating, and the etiology of compensatory hyperhidrosis. Patients should be warned about compensatory hyperhidrosis.

Total Body Perspiration

While historically used to treat a variety of complaints, currently the most common indication for ETS surgery is “hyperhidrosis”, that is excessive sweating. Patient consent is ordinarily premised around a desire to “reduce” the excessive sweating. (see Addenbrooke consent form). A natural curiosity would lead us to wonder whether the surgery actually reduced the total amount of sweating, or in fact increased it. Thusfar, only one study has attempted to answer that question.
“The effect of upper dorsal thoracoscopic sympathectomy on the total amount of body perspiration.” (Kopelman et al. 2000)
By 2000, Israeli surgeons Hashmonai, Kopelman and colleagues had noticed that “compensatory hyperhidrosis is a disturbing sequela of this operation”. (Kopelman et al. 2000, emphasis added). They conducted a very straightforward test on their ETS patients. They weighed the subjects, then sent them into the sauna to sweat for 10 minutes, then weighed them again to see how much water had been lost. This process was done before and after surgery.
“The amount of perspiration induced by the sauna bath ranged from 60 to 480 g, with a mean value of 185.29 +/- 125.80 g, before the operation, and from 60 to 540 g, with a mean value of 265.88 +/- 154.05 g, after the operation (P = 0.0113).” (Kopelman et al. 2000).
Total body sweating has increased 43% on average.

Let’s see what these numbers actually describe. Body sweating has been divided into two distinct regions, an upper region comprising about 1/3 of total body surface which can no longer sweat at all, and a lower region comprising the remaining 2/3 of total body surface which now sweats so hyperactively that total body sweating is 43% higher than it was initially. Since the 43% total increase is being generated by only 67% of the body surface, that part of the body must have increased its sweating by 113%. (67% x 213% = 143%). In other words, the lower body now sweats more than twice as much as it did before surgery.

Thus Koppelman casts serious doubt on the efficacy of ETS as hyperhidrosis treatment. If the goal is reduced sweating, thoracic sympathectomy is highly unlikely to achieve that. Research on total body sweating is called for. Patients should be warned that total body sweating is expected to go up, not down.