Somatosympathetic reflex unilateral sweating and pupillary dilatation in a paraplegic man

Somatosympathetic Vasoconstrictor Reflexes in Human Spinal Cord Injury: Responses to Innocuous and Noxious Sensory Stimulation below Lesion

It is known that the sudden increases in blood pressure associated with autonomic dysreflexia in people with spinal cord injury (SCI) are due to a spinally mediated reflex activation of sympathetic vasoconstrictor neurons supplying skeletal muscle and the gut. Apart from visceral inputs, such as those originating from a distended bladder, there is a prevailing opinion that autonomic dysreflexia can be triggered by noxious stimulation below the lesion. However, do noxious inputs really cause an increase in blood pressure in SCI? Using microelectrodes inserted into a peripheral nerve to record sympathetic nerve activity we had previously shown that selective stimulation of small-diameter afferents in muscle or skin, induced by bolus injection of hypertonic saline into the tibialis anterior muscle or the overlying skin, evokes a sustained increase in muscle sympathetic nerve activity and blood pressure and a transient increase in skin sympathetic nerve activity and decrease in skin blood flow in able-bodied subjects. We postulated that these sympathetic responses would be exaggerated in SCI, with a purely noxious stimulus causing long-lasting increases in blood pressure and long-lasting decreases in skin blood flow. Surprisingly, though, we found that intramuscular or subcutaneous injection of hypertonic saline into the leg caused negligible changes in these parameters. Conversely, weak electrical stimulation over the abdominal wall, which in able-bodied subjects is not painful and activates large-diameter cutaneous afferents, caused a marked increase in blood pressure in SCI but not in able-bodied subjects. This suggests that it is activation of large-diameter somatic afferents, not small-diameter afferents, that triggers increases in sympathetic outflow in SCI. Whether the responses to activation of large-diameter afferents reflect plastic changes in the spinal cord in SCI is unknown.

Propantheline bromide in the management of hyperhidrosis associated with spinal cord injury

OBJECTIVE

To report 2 cases in which oral propantheline reduced the discomfort associated with sweating related to spinal cord injury (SCI), and to review the literature on the management of SCI-related sweating.

CASE SUMMARIES

Case 1: A 27-year-old quadriplegic man with an American Spinal Injury Association (ASIA) Frankel class C injury to C5/C6 experienced profuse sweating and requested propantheline. He stated that he had received the medication previously and reported that propantheline 15 mg tid had controlled his sweating. Propantheline bromide was reinstituted, and within 24 hours, the patient's episodes of profuse sweating had decreased markedly in number and frequency. Case 2: A 35-year-old quadriplegic woman had an ASIA class D lesion at C3. Since her injury, she had experienced profuse sweating that worsened when she became cold and at night. She stated that her sweating was under control as long as she took propantheline. Propantheline therapy was continued and no further sweating episodes have occurred.

DATA SOURCE

A MEDLINE search was used to identify pertinent literature including reviews. Standard texts and texts referenced in the pertinent literature also were examined.

STUDY SELECTION

All available sources of information were reviewed.

DATA SYNTHESIS

The earliest case reports of systemic therapy for hyperhidrosis described the use of the anticholinergic methantheline bromide. Methantheline in combination with ergoloid mesylates also was suggested for the treatment of congenital hyperhidrosis. Local topical therapy for hyperhidrosis, such as aluminum chlorohydrate and aluminum chloride, the active ingredients in some antiperspirants, have been tried with some success. Talc, starch, and other powders have been suggested to absorb excessive sweat. Formalin and glutaraldehyde also have been used. Topical propantheline bromide has been used successfully in treating palmar and plantar hidrosis. Clonazepam has been used successfully in a case of unilateral localized hyperhidrosis. Systemic phenoxybenzamine has been used with some success and there have been attempt at other systemic therapy using mecamylamine, atropine, propoxyphenel, and methenamine. Scopolamine patches also have been used successfully in a small number of patients. Other agents that have been used include dibenamine, piperoxan, and phentolamine. Systemic propantheline also has been listed as an agent with potential efficacy in treating the profuse sweating associated with SCI, but was not recommended primarily because of adverse effects and difficulty in titrating to the lowest effective dosage. However, studies or case reports specific to the use of propantheline in patients with SCI appear to be lacking, as are reports of direct comparison between propantheline and other agents.

DISCUSSION

Concerning the mechanism of action of propantheline bromide for hyperhidrosis, it seems reasonable to attribute its effects to the drug's well-documented anticholinergic/antimuscarinic actions. At dosages used to effectively treat neurogenic bladder, propantheline bromide also should block the muscarinic receptors responsible for sweat gland stimulation. Central nervous system adverse effects should be minimal at usual clinical dosages, as propantheline does not cross the blood-brain barrier.

CONCLUSIONS

It would appear that in some patients with SCI who are subject to incidental episodes of profuse sweating, oral propantheline may offer some relief and may, in fact, be well tolerated, as in the cases described. Additionally, propantheline would seem a good therapeutic choice in SCI patients with excessive sweating and neurogenic bladder dysfunction who may derive dual benefit from the agent.