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The autonomic nervous system in pruritus ani
The PERIANAL
Autonomic Nervous Pruritus Ani SKIN
TEMPERATURES IN CONTROL
Svstem
in
’
AFTER SYMPATHETIC SUBJECTS
BLOCK
CALEB SMITH, M.D., Wilmington, Delaware, GEORGE M. MALKIEWICZ, M.D. (By Invitation), Trenton, New Jerse_v, AND GEORGE Y. MASSENBERG, JR., M.D. (By Invitation), Macon, Georgia prevrous communications1~2 the rehef of severe intractabIe pruritus ani by sympathectomy of the superior hypogastric pIexus (presacra1 neurectomy) was reported. Three cases were cited, one persona1 and two of patients operated upon by Cotte of France who introduced presacral neurectomy as an operation. Reference was made to demonstrating the roIe pIayed by the sympathetic nervous system in pruritus ani on the basis of a faI1 in periana1 skin temperatures greater than that shown by a smaI1 number of contro1 subjects after block of the superior hypogastric plexus by a IocaI anesthetic, as we11 as on the basis of reIief of itching by such a bIock. The purpose of this article is to present a study of the effects of block of the sympathetic nervous system at various IeveIs on periana1 skin temperatures in contro1 subjects, a study that has not been made previousIy as far as we can ascertain. It is hoped that the resuIts, in addition to offering an interesting commentary on our knowledge of the physioIogy of the rectum and anus, wiI1 serve as a basis for judging the effects of simiIar bIocks on periana1 skin temperatures in patients with pruritus ani and thereby aid in demonstrating the roIe pIayed by the sympathetic nervous system in this syndrome.
I
N
METHODSAND
MATERIALS
AI1 subjects studied were either normal maIes or maIe patients with uncompIicated interna hemorrhoids. The temperature of the periana1 skin in each quadrant within the pigmented border was taken with a standard thermocoupIe* in an air-conditioned room with a reIativeIy stabIe temperature around 72O~. The * U. M. A., Inc., New York,N. Y.
patients were pIaced on an operating tabIe in the prone position and covered onIy with a short hospita1 gown. The buttocks were taped apart, thus exposing the anus and periana1 skin to the air. Forearms and legs were not covered. The room temperature was checked at the beginning and end of each study. The subjects were divided into four groups, as foIIows: Group I: periana1 skin temperatures were taken on three subjects after exposure of the anus to room temperature for a period of twenty minutes and again after exposure for forty minutes. No bIock of the sympathetic nervous system was done. Group II: perianal skin temperatures were taken on five subjects after exposure of the anus to room temperature for a period of twenty minutes. A spina anesthetic to the IeveI of SI was then administered. The anus was exposed to room temperature for a further period of twenty minutes, after which periana1 skin temperatures were again taken. Group III: periana1 skin temperatures were taken on five subjects after exposure of the anus to room temperature for a period of twenty minutes. A bIock of the superior hypogastric plexus3 was then done using a I per cent soIution of metycaine@ hydrochIoride. The anus was exposed to room temperature for a further period of twenty minutes, after which skin temperatures were again taken. Group IV: periana1 skin temperatures were taken on five subjects after exposure of the anus to room temperature for a period of twenty minutes. A spina anesthetic to the IeveI of DI I was then administered. The anus was exposed to room temperature for a further period of twenty minutes, after which perianal skin temperatures were again taken.
Autonomic
Nervous
System
RIZSULTS
perature below that of the body: Perianal skin temperatures after sympathetic bloch fall while those of the skin elsewhere rise. In 1933 Salvyer and Schlossberg’ shoned that in cats exposed to an environmental tempcra-
Figure I depicts the changes in perianal skin temperature for each group. without sympathetic Group I (exposure blocki showed an average rise in perianal skin temperature of O.2’F. The maximum change in an\ case \vas a rise of r.I°F. In one case there was no change. Group II (exposure after spinal anesthesia to S I) showed an average faII in skin temperature of 0.9’~. The maximum change in any one case was a faII of 1.2’~. The minimum change in any one case was a rise of O.S’F. Group III (exposure after bIock of the superior hypogastric plexus) showed an average fall of 1.2’~. The maximum change in any one case was a fall of 1.8”~. The minimum change in any one case was a fal1 of O._$‘F. Group IV (exposure after spina anesthesia to Dr I) showed an average faI1 of 1.6’~. The maximum change in any one case was a faI1 of 3.0’~. The minimum change in any one case was a fall of 0.8’F. Table I summarizes the changes in perianal skin temperature in each group. The values in each group were obtained by averaging the quadrant temperatures for each subject and then averaging the vaIues thus obtained.
91° 1 10 5 Kinutes After
Type
of Block
Exposure Spinal SI Superior hypogastric SpinaI DI I
plexus
SKIN
15
Injection
20
skin temperatures of nervous system at various
FIG. I. The effect on perianal
bIock of the sympathetic Ievels.
ture we11 below that of their body, the rectal temperatures rose. If, however, the animals were subjected to spina anesthesia prior to exposure, the rectal temperatures feI1. Our data indicate that periana1 skin tempera-
TABLE PERIANAL
Ani
in Pruritis
TEMPERATURES
I IN
“NORMAL”
After 20 min. Exposure (OF.)
20 min. after Block (Or.1
92.8 93.5 92.7 93.0
93.0* 92.7 91.5 9’ .4
SUBJECTS
Average Change ?F.)
hlaximum Change (OF.)
0. 2
i
Minimum Change (,“P.)
I.1
-0.')
-1.2
-1.2
_
-1.6
-3.0
1.8
* No bIock; exposure only. COMMENTS
tures in man when exposed to an environmenta temperature beIow body temperature tend to foIIow the pattern of rectal temperatures in cats, with and without spina anesthesia. These findings suggest that in man the sympathetic innervation of the perianat skin within the pigmented border follows the physioIogic pattern of the rectum rather than that of the skin of the remainder of the body. Several objections to these da.ta can be made. The changes in temperature were smaI1. Studies conducted in a room with a controlled
These data indicate that periana1 skin temperatures do not foIIow the usual pattern for skin temperatures after bIock of the sympathetic nervous system when the patient is exposed to an environmental temperature below body temperature. In fact., perianaI skin temperatures after bIock of the sympathetic nervous system foIIow a pattern diamctricaIIy opposed to that shown by skin temperatures eIsewhere on the body when the subject is exposed to an environmenta tem791
Smith,
MaIkiewicz
and
temperature much Iower than that used by us might be more significant. Such conditions were unfortunateIy not avaiIabIe to us. Skin temperatures are not as reIiabIe as those taken beneath the skin, a method, aIso unfortunateIy, not available to us. It could further be argued that a11 changes were due to heat radiation. However, in the contro1 cases, admittedIy a smaI1 group, there was a sIight rise in perianal skin temperatures, whereas in those subjects undergoing a bloc’k of the sympathetic nervous system there was a uniform faII in perianal skin temperatures. The faII was most evident in those subjected to a spina anesthetic to the IeveI of DI I, a reasonabIe finding when it is recaIIed that the sympathetic innervation of the rectum begins to arise at this IeveI. The authors believe that the data show a definite trend of changes in periana1 skin temperatures after bIock of the sympathetic nervous system. The thesis that this syndrome has the characteristics of a causaIgia state is supported by these data together with our previous findin cases ings*,” that periana1 skin temperatures of severe intractabIe pruritus ani feI1 to a greater degree that did those of contro1 subjects after sympathetic bIock, and that three patients with severe intractabIe pruritus ani were reIieved by presacra1 neurectomy. Currently there are two theories concerning the etioIogy of so-caIIed idiopathic pruritus ani. The first, the psychiatric theory, has been abIy presented by MacaIpine5 of St. BarthoIomew’s HospitaI, London. AIso, it has been shown experimentaIIy that emotiona stress can Iower the threshoId to itch sensation,6 thus favoring the buiIding up of a vicious cycIe. In our opinion, however, it has not been demonstrated that emotiona stress can induce the itching primariIy without the aid of other factors such as IocaI irritation. In the second theory, pruritus ani is regarded as a causaIgia state and the reIationship of the sympathetic nervous system to causaIgia has Iong been established. WiIson and Bruce’ take note of two types of causaIgia. One foIIows injury to a nerve trunk. The other form of causaIgia, the one with which we are concerned, is caused by some disturbance of metaboIism due to edema, ischemia or injury to the nerve endings. At this point it is we11 to recaI1 that there are two types of itch sensation6 and both are somehow reIated to pain. The first type is
Massenberg
physioIogic itching which arises in response to weak stimuli of everyday Iife. This type is termed epicritic, or first itch or pain. It is sharply IocaIized, of short duration, attended by IittIe discomfort, conducted by myeIinated fibers of 3 to IO microns at a rate of 20 to 30 meters per second, and is carried in the posterior tracts of the spina cord. The second type of itching is pathoIogic itching evoked by morbid stimuIi or is of such intensity that it causes disturbances of weIIbeing. This type is termed protopathic, or second itch or pain. It is poorIy Iocalized, persistent, associated with burning or marked discomfort, conducted by unmyeIinated fibers of 5 microns at a rate of I meter per second, and is carried in the anteroIatera1 tracts of the spinal cord. This type of itching characterizes severe intractabIe pruritus ani. In the light of our present knowIedge of itch sensation it is interesting to consider the effects of scratching on pruritus ani. ProctoIogists, of course, have known about this pernicious effect for a long time, but largely on an empirica basis. A patient with pruritus ani has a natura1 urge to try to reIieve his unpIeasant, protopathic, burning itching by scratching which overcomes in his consciousness temporariIy the protopathic itch by replacing it with the epicritic type which is Iess unpIeasant, sharper and more painfu1. In reality, however, the more unpIeasant protopathic itch persists during the scratching and is actuaIIy re-enforced by an afterdischarge of stimuli by the induction of the epicritic itch or pain that scratching causes. Herein Iies an important means of perpetuating pruritus ani. In the causalgia theory of pruritus ani any irritative Iesion of the anorecta1 region can set up pathoIogic itching. In the earIy stages of the syndrome remova of the irritating lesion resuIts in cure, a fact Iong recognized by proctoIogists. If, however, the syndrome persists for a Iong time, it may become so we11 estabIished as a causalgia state that remova of the irritating Iesion wiI1 not reIieve it; this state of affairs also is recognized by many proctoIogists. Also, in cases of Iong-standing, the irritating Iesion may have disappeared whiIe the we11 estabIished causalgia state persists, appearing thus to be without cause. Such a sequence of events is we11 recognized in causalgia in other parts of the body and caIIs to mind the so792
Autonomic
Nervous
System
‘933. 5. MACALIYNE, I. Pruritus ani; a psychiatric study. Psychosom. Med., rg: 499-$o8, 1953. 6. MESCON, H. and MOKETTI, G. Pruritus~---newer concepts of mechanism and treatment. I’ennsJ-l-lt!&U lkf. J., 58: 399-402, 1955. 7. WILSON, S. A. K. :md BKLCE, A. N. Neurology, 2nd ed., pp. 318~-319.&himore, 1955. Williams & Wilkins Co. DISCUSSIOIi
DURAND
SMITH (Chicago, III.): When one is asked to discuss a presentation whicfr is not too familiar, and especially if the data do not foIlow standard or orthodox patterns, he is more likely to be critical in his approach and to view the results with suspicion. This was my first reaction. The studies which Dr. Smith and his associates
presented cover two very complex subjects which are not too well understood, which are stiJ1 controversial in spite of voluminous research, and which will require further investigation. These subjects are the control of body temperature and pruritus ani. Body temperature is controlIed by the autonomic nervous system. The capacity to maintain normal body temperature is lost following destruction of the hypothalamus, is greatly disturbed by the transection of the cervical spinal cord and is altered in certain procedures in which specific pathways are blocked. The neural regulation of body temperature is effected through end organs in blood vessels, sweat glands, interna organs (through metabolic processes) and the glands of internal secretion. Since many factors influence changes in body temperature, these organs are subject to rather constant excitation and inhibitory impulses from higher centers. It is the disturbance of conduction of these impulses, specificalIy blocking of the sympathetic chain at the IeveI of the superior hypogastric plexus, with resultant changes in periana1 skin temperatures that forms the basis of this presentation. The subject of pruritus ani is far too complex to discuss, but the initiation and mediation of the itch impulse is pertinent to this discussion. Itching arises exclusively in the epidermis or the corresponding epithelial layer of the transitional mucous membrane through one of three ramifying axons in the skin, e.g., the sympathetic, t,he antidromic vasodilator and the protopathic sensory system, all consisting of smaIl unmyelinated fibers and aI1 mediating diffuse effects by means of axon reflex imp&es and in turn mediated by the slowIy conducting C fibers of Gasser and Erlanger of peripheral nerves. When these peripheral pain nerves discharge into the cord at low frequency,
CONCLUSIONS
Perianal skin temperatures faI1 after an appropriate block of the sympathetic nervous system when the subject is exposed to an environmental temperature beIow that of the body. Such a response is similar to that of the rectum under the same conditions and is diametricahy opposed to the response of the skin of the remainder of the body. The concept of severe intractabIe pruritus ani as a causalgia state and the relationship of the autonomic nervous system to this syndrome have been discussed. REFERENCES
severe
t-l. and
pruritus
G. M. Relief of presacra1 neurectomy.
MALKIEWICZ,
ani
by
Ani
homeostasis in normal, sympathectomized and ergotamized animals. I. The effects of high and low temperatures. Am. J. t’htG)l., IO&: 172-183,
called neurogenic type of pruritus ani in which there are no abnormal findings in the anorectal region. ProctoIogists, as well as dermatoIogists and have Iong recognized that the psychiatrists, outlook for relief is poorer in cases of Iongstanding pruritus ani. The same observation has been made in causalgia states eIsewhere in the body. Since the concept of pruritus ani as a causalgia state is still a theory, interruption of the sympathetic nervous system for its relief cannot be regarded as a generally accepted therapeutic measure. The concept is, nonetheless, an interesting and promising one which warrants further study. At present it also seems reasonabIe not onIy to continue our long-established practice of removing irritative Iesions of the anorectal region in cases of pruritus ani as early as possible, but aIso to investigate the role played by the sympathetic nervous system in severe intractable cases of pruritus ani by blocking the superior hypogastric plexus of the sympathetic nervous system with a IocaI anesthetic. Temporary reIief of itching after such a block suggests that a causalgia state exists. As in the case of early causalgia in other parts of the body, repeated bIocks may effect permanent remission of symptoms.
1. SMITH, C.
in Pruritis
U. S. Ahned Forces M. 2.,-j: 894-897, 1954. 2. SMITH.C. H. and MALKIEWICZ. G. M. Role of the autonomic nervous system in intense pruritus ani. J. Internat. Coil. Surgeons (in press). 3. FLOTHOW, P. G. ReIief of peIvic pain. South. Surgeon, 4: 36-43, 1935. 4. SAWYER, M. E. M. and SCHLOSSBERG,T. Studies of
793
Smith,
MaIkiewicz
and Massenberg
circuits of internuncia1 neurons are established with a consequent patterned discharge up the spinothalamic tracts. Any disturbance or alteration aIong any portion of the transmitting system wiI1 affect or remove the sensation of itching. A depression of the synaptic transmission of impulses through sympathetic ganglia will aIso affect itching and this is probably the explanation for the results cIaimed by the authors. Just why presacral neurectomy relieves periana1 itching cannot be explained logically. This procedure does not affect compIete sympathetic denervation of the pelvic viscera since the sacral and the more caudal lumbar sympathetic rami join the pelvic plexuses directIy. It probably interrupts al1 the visceral afferent hbers associated with the sympathetic nerves that reach the pelvic viscera, but does not bIock parasympathetic visceral afferent impulses. Relative to the data presented by the authors I wouId like to point out first that if the average of a11 eighteen cases is taken, instead of three, the average temperature twenty minutes after-exposure is 93'F. Hence there wouId then be no change in Group I. AIso, there would be a drop of onIy 0.3'F., and a fall of 1.5~and Ih'F. in Groups III and IV. We attempted to confirm the findings as reported by the authors. Six patients were given spina anesthetics to the Ievel of T8 (Alberts, persona communication). In all six there was no change in rectal temperature. In three cases there was a rise of I’C. in the perianal skin, and in the other three there was only a shght perceptible rise. No decrease in the perianal skin temperature was noted. Two patients were tested under caudaI anesthesia, In one case in which the room temperature was 72'~.there was a decrease in the rectal temperature of o.~~F., in the thighs I.~~F., and a fall of I,~~F. in the perianal skin. In the other case tested at a room temperature of 85'F.there was a rise of perianaI skin temperature of Z'F.and I.~'F. rise in the skin temperature of the thighs.
Perhaps the difference in skin temperature findings may be due to a difference of environmental temperatures. This is in keeping with the work done on sympathectomized cats by Sawyer and Schlossberg which was referred to in the paper under discussion. The body temperatures feJ1 when the environmenta temperatures were Iow and rose when the outside temperatures were high. Without the governing control of the sympathetic nervous system the body temperatures may not be stabIe but may respond to environmental temperature changes. There is a great dea1 of local variation of the perianal skin. As much as I degree change may be noted in the opposite Iateral waIIs of the anal verge in the same individual SIight increase of pressure on the thermocoupIe wil1 cause a change in the recording. Since many factors may effect adversely the recording of skin temperatures, it may be diffrcuIt to arrive at accurate normals. I think further study of this problem is indicated. Presacral neurectomy is a formidable procedure, but at times intractabIe anal pruritus requires heroic measures. I am sure that there are many patients with pruritus ani who undergo abdominal surgery. PresacraI neurectomy performed on these individuals would provide information reIative to the efficacy of this procedure. I wonder how many patients have undergone this operation and with what resuIts. How long does the absence of pruritus persist? Does the temperature return to normaI? Are there any complications? Can alcohol be injected without harm in this area? Does the preoperative use of such medications as atropine, scopolamine and morphine, or epinephrine or other pressor substances influence the findings? In conclusion I wouId like to commend the authors for their presentation, not onIy for the amount of work and effort which it entailed, but also for their offering of a new approach to the problem of pruritus ani.
794
Autonomic Nervous Pruritus Ani SKIN
TEMPERATURES IN CONTROL
Svstem
in
’
AFTER SYMPATHETIC SUBJECTS
BLOCK
CALEB SMITH, M.D., Wilmington, Delaware, GEORGE M. MALKIEWICZ, M.D. (By Invitation), Trenton, New Jerse_v, AND GEORGE Y. MASSENBERG, JR., M.D. (By Invitation), Macon, Georgia prevrous communications1~2 the rehef of severe intractabIe pruritus ani by sympathectomy of the superior hypogastric pIexus (presacra1 neurectomy) was reported. Three cases were cited, one persona1 and two of patients operated upon by Cotte of France who introduced presacral neurectomy as an operation. Reference was made to demonstrating the roIe pIayed by the sympathetic nervous system in pruritus ani on the basis of a faI1 in periana1 skin temperatures greater than that shown by a smaI1 number of contro1 subjects after block of the superior hypogastric plexus by a IocaI anesthetic, as we11 as on the basis of reIief of itching by such a bIock. The purpose of this article is to present a study of the effects of block of the sympathetic nervous system at various IeveIs on periana1 skin temperatures in contro1 subjects, a study that has not been made previousIy as far as we can ascertain. It is hoped that the resuIts, in addition to offering an interesting commentary on our knowledge of the physioIogy of the rectum and anus, wiI1 serve as a basis for judging the effects of simiIar bIocks on periana1 skin temperatures in patients with pruritus ani and thereby aid in demonstrating the roIe pIayed by the sympathetic nervous system in this syndrome.
I
N
METHODSAND
MATERIALS
AI1 subjects studied were either normal maIes or maIe patients with uncompIicated interna hemorrhoids. The temperature of the periana1 skin in each quadrant within the pigmented border was taken with a standard thermocoupIe* in an air-conditioned room with a reIativeIy stabIe temperature around 72O~. The * U. M. A., Inc., New York,N. Y.
patients were pIaced on an operating tabIe in the prone position and covered onIy with a short hospita1 gown. The buttocks were taped apart, thus exposing the anus and periana1 skin to the air. Forearms and legs were not covered. The room temperature was checked at the beginning and end of each study. The subjects were divided into four groups, as foIIows: Group I: periana1 skin temperatures were taken on three subjects after exposure of the anus to room temperature for a period of twenty minutes and again after exposure for forty minutes. No bIock of the sympathetic nervous system was done. Group II: perianal skin temperatures were taken on five subjects after exposure of the anus to room temperature for a period of twenty minutes. A spina anesthetic to the IeveI of SI was then administered. The anus was exposed to room temperature for a further period of twenty minutes, after which periana1 skin temperatures were again taken. Group III: periana1 skin temperatures were taken on five subjects after exposure of the anus to room temperature for a period of twenty minutes. A bIock of the superior hypogastric plexus3 was then done using a I per cent soIution of metycaine@ hydrochIoride. The anus was exposed to room temperature for a further period of twenty minutes, after which skin temperatures were again taken. Group IV: periana1 skin temperatures were taken on five subjects after exposure of the anus to room temperature for a period of twenty minutes. A spina anesthetic to the IeveI of DI I was then administered. The anus was exposed to room temperature for a further period of twenty minutes, after which perianal skin temperatures were again taken.
Autonomic
Nervous
System
RIZSULTS
perature below that of the body: Perianal skin temperatures after sympathetic bloch fall while those of the skin elsewhere rise. In 1933 Salvyer and Schlossberg’ shoned that in cats exposed to an environmental tempcra-
Figure I depicts the changes in perianal skin temperature for each group. without sympathetic Group I (exposure blocki showed an average rise in perianal skin temperature of O.2’F. The maximum change in an\ case \vas a rise of r.I°F. In one case there was no change. Group II (exposure after spinal anesthesia to S I) showed an average faII in skin temperature of 0.9’~. The maximum change in any one case was a faII of 1.2’~. The minimum change in any one case was a rise of O.S’F. Group III (exposure after bIock of the superior hypogastric plexus) showed an average fall of 1.2’~. The maximum change in any one case was a fall of 1.8”~. The minimum change in any one case was a fal1 of O._$‘F. Group IV (exposure after spina anesthesia to Dr I) showed an average faI1 of 1.6’~. The maximum change in any one case was a faI1 of 3.0’~. The minimum change in any one case was a fall of 0.8’F. Table I summarizes the changes in perianal skin temperature in each group. The values in each group were obtained by averaging the quadrant temperatures for each subject and then averaging the vaIues thus obtained.
91° 1 10 5 Kinutes After
Type
of Block
Exposure Spinal SI Superior hypogastric SpinaI DI I
plexus
SKIN
15
Injection
20
skin temperatures of nervous system at various
FIG. I. The effect on perianal
bIock of the sympathetic Ievels.
ture we11 below that of their body, the rectal temperatures rose. If, however, the animals were subjected to spina anesthesia prior to exposure, the rectal temperatures feI1. Our data indicate that periana1 skin tempera-
TABLE PERIANAL
Ani
in Pruritis
TEMPERATURES
I IN
“NORMAL”
After 20 min. Exposure (OF.)
20 min. after Block (Or.1
92.8 93.5 92.7 93.0
93.0* 92.7 91.5 9’ .4
SUBJECTS
Average Change ?F.)
hlaximum Change (OF.)
0. 2
i
Minimum Change (,“P.)
I.1
-0.')
-1.2
-1.2
_
-1.6
-3.0
1.8
* No bIock; exposure only. COMMENTS
tures in man when exposed to an environmenta temperature beIow body temperature tend to foIIow the pattern of rectal temperatures in cats, with and without spina anesthesia. These findings suggest that in man the sympathetic innervation of the perianat skin within the pigmented border follows the physioIogic pattern of the rectum rather than that of the skin of the remainder of the body. Several objections to these da.ta can be made. The changes in temperature were smaI1. Studies conducted in a room with a controlled
These data indicate that periana1 skin temperatures do not foIIow the usual pattern for skin temperatures after bIock of the sympathetic nervous system when the patient is exposed to an environmental temperature below body temperature. In fact., perianaI skin temperatures after bIock of the sympathetic nervous system foIIow a pattern diamctricaIIy opposed to that shown by skin temperatures eIsewhere on the body when the subject is exposed to an environmenta tem791
Smith,
MaIkiewicz
and
temperature much Iower than that used by us might be more significant. Such conditions were unfortunateIy not avaiIabIe to us. Skin temperatures are not as reIiabIe as those taken beneath the skin, a method, aIso unfortunateIy, not available to us. It could further be argued that a11 changes were due to heat radiation. However, in the contro1 cases, admittedIy a smaI1 group, there was a sIight rise in perianal skin temperatures, whereas in those subjects undergoing a bloc’k of the sympathetic nervous system there was a uniform faII in perianal skin temperatures. The faII was most evident in those subjected to a spina anesthetic to the IeveI of DI I, a reasonabIe finding when it is recaIIed that the sympathetic innervation of the rectum begins to arise at this IeveI. The authors believe that the data show a definite trend of changes in periana1 skin temperatures after bIock of the sympathetic nervous system. The thesis that this syndrome has the characteristics of a causaIgia state is supported by these data together with our previous findin cases ings*,” that periana1 skin temperatures of severe intractabIe pruritus ani feI1 to a greater degree that did those of contro1 subjects after sympathetic bIock, and that three patients with severe intractabIe pruritus ani were reIieved by presacra1 neurectomy. Currently there are two theories concerning the etioIogy of so-caIIed idiopathic pruritus ani. The first, the psychiatric theory, has been abIy presented by MacaIpine5 of St. BarthoIomew’s HospitaI, London. AIso, it has been shown experimentaIIy that emotiona stress can Iower the threshoId to itch sensation,6 thus favoring the buiIding up of a vicious cycIe. In our opinion, however, it has not been demonstrated that emotiona stress can induce the itching primariIy without the aid of other factors such as IocaI irritation. In the second theory, pruritus ani is regarded as a causaIgia state and the reIationship of the sympathetic nervous system to causaIgia has Iong been established. WiIson and Bruce’ take note of two types of causaIgia. One foIIows injury to a nerve trunk. The other form of causaIgia, the one with which we are concerned, is caused by some disturbance of metaboIism due to edema, ischemia or injury to the nerve endings. At this point it is we11 to recaI1 that there are two types of itch sensation6 and both are somehow reIated to pain. The first type is
Massenberg
physioIogic itching which arises in response to weak stimuli of everyday Iife. This type is termed epicritic, or first itch or pain. It is sharply IocaIized, of short duration, attended by IittIe discomfort, conducted by myeIinated fibers of 3 to IO microns at a rate of 20 to 30 meters per second, and is carried in the posterior tracts of the spina cord. The second type of itching is pathoIogic itching evoked by morbid stimuIi or is of such intensity that it causes disturbances of weIIbeing. This type is termed protopathic, or second itch or pain. It is poorIy Iocalized, persistent, associated with burning or marked discomfort, conducted by unmyeIinated fibers of 5 microns at a rate of I meter per second, and is carried in the anteroIatera1 tracts of the spinal cord. This type of itching characterizes severe intractabIe pruritus ani. In the light of our present knowIedge of itch sensation it is interesting to consider the effects of scratching on pruritus ani. ProctoIogists, of course, have known about this pernicious effect for a long time, but largely on an empirica basis. A patient with pruritus ani has a natura1 urge to try to reIieve his unpIeasant, protopathic, burning itching by scratching which overcomes in his consciousness temporariIy the protopathic itch by replacing it with the epicritic type which is Iess unpIeasant, sharper and more painfu1. In reality, however, the more unpIeasant protopathic itch persists during the scratching and is actuaIIy re-enforced by an afterdischarge of stimuli by the induction of the epicritic itch or pain that scratching causes. Herein Iies an important means of perpetuating pruritus ani. In the causalgia theory of pruritus ani any irritative Iesion of the anorecta1 region can set up pathoIogic itching. In the earIy stages of the syndrome remova of the irritating lesion resuIts in cure, a fact Iong recognized by proctoIogists. If, however, the syndrome persists for a Iong time, it may become so we11 estabIished as a causalgia state that remova of the irritating Iesion wiI1 not reIieve it; this state of affairs also is recognized by many proctoIogists. Also, in cases of Iong-standing, the irritating Iesion may have disappeared whiIe the we11 estabIished causalgia state persists, appearing thus to be without cause. Such a sequence of events is we11 recognized in causalgia in other parts of the body and caIIs to mind the so792
Autonomic
Nervous
System
‘933. 5. MACALIYNE, I. Pruritus ani; a psychiatric study. Psychosom. Med., rg: 499-$o8, 1953. 6. MESCON, H. and MOKETTI, G. Pruritus~---newer concepts of mechanism and treatment. I’ennsJ-l-lt!&U lkf. J., 58: 399-402, 1955. 7. WILSON, S. A. K. :md BKLCE, A. N. Neurology, 2nd ed., pp. 318~-319.&himore, 1955. Williams & Wilkins Co. DISCUSSIOIi
DURAND
SMITH (Chicago, III.): When one is asked to discuss a presentation whicfr is not too familiar, and especially if the data do not foIlow standard or orthodox patterns, he is more likely to be critical in his approach and to view the results with suspicion. This was my first reaction. The studies which Dr. Smith and his associates
presented cover two very complex subjects which are not too well understood, which are stiJ1 controversial in spite of voluminous research, and which will require further investigation. These subjects are the control of body temperature and pruritus ani. Body temperature is controlIed by the autonomic nervous system. The capacity to maintain normal body temperature is lost following destruction of the hypothalamus, is greatly disturbed by the transection of the cervical spinal cord and is altered in certain procedures in which specific pathways are blocked. The neural regulation of body temperature is effected through end organs in blood vessels, sweat glands, interna organs (through metabolic processes) and the glands of internal secretion. Since many factors influence changes in body temperature, these organs are subject to rather constant excitation and inhibitory impulses from higher centers. It is the disturbance of conduction of these impulses, specificalIy blocking of the sympathetic chain at the IeveI of the superior hypogastric plexus, with resultant changes in periana1 skin temperatures that forms the basis of this presentation. The subject of pruritus ani is far too complex to discuss, but the initiation and mediation of the itch impulse is pertinent to this discussion. Itching arises exclusively in the epidermis or the corresponding epithelial layer of the transitional mucous membrane through one of three ramifying axons in the skin, e.g., the sympathetic, t,he antidromic vasodilator and the protopathic sensory system, all consisting of smaIl unmyelinated fibers and aI1 mediating diffuse effects by means of axon reflex imp&es and in turn mediated by the slowIy conducting C fibers of Gasser and Erlanger of peripheral nerves. When these peripheral pain nerves discharge into the cord at low frequency,
CONCLUSIONS
Perianal skin temperatures faI1 after an appropriate block of the sympathetic nervous system when the subject is exposed to an environmental temperature beIow that of the body. Such a response is similar to that of the rectum under the same conditions and is diametricahy opposed to the response of the skin of the remainder of the body. The concept of severe intractabIe pruritus ani as a causalgia state and the relationship of the autonomic nervous system to this syndrome have been discussed. REFERENCES
severe
t-l. and
pruritus
G. M. Relief of presacra1 neurectomy.
MALKIEWICZ,
ani
by
Ani
homeostasis in normal, sympathectomized and ergotamized animals. I. The effects of high and low temperatures. Am. J. t’htG)l., IO&: 172-183,
called neurogenic type of pruritus ani in which there are no abnormal findings in the anorectal region. ProctoIogists, as well as dermatoIogists and have Iong recognized that the psychiatrists, outlook for relief is poorer in cases of Iongstanding pruritus ani. The same observation has been made in causalgia states eIsewhere in the body. Since the concept of pruritus ani as a causalgia state is still a theory, interruption of the sympathetic nervous system for its relief cannot be regarded as a generally accepted therapeutic measure. The concept is, nonetheless, an interesting and promising one which warrants further study. At present it also seems reasonabIe not onIy to continue our long-established practice of removing irritative Iesions of the anorectal region in cases of pruritus ani as early as possible, but aIso to investigate the role played by the sympathetic nervous system in severe intractable cases of pruritus ani by blocking the superior hypogastric plexus of the sympathetic nervous system with a IocaI anesthetic. Temporary reIief of itching after such a block suggests that a causalgia state exists. As in the case of early causalgia in other parts of the body, repeated bIocks may effect permanent remission of symptoms.
1. SMITH, C.
in Pruritis
U. S. Ahned Forces M. 2.,-j: 894-897, 1954. 2. SMITH.C. H. and MALKIEWICZ. G. M. Role of the autonomic nervous system in intense pruritus ani. J. Internat. Coil. Surgeons (in press). 3. FLOTHOW, P. G. ReIief of peIvic pain. South. Surgeon, 4: 36-43, 1935. 4. SAWYER, M. E. M. and SCHLOSSBERG,T. Studies of
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and Massenberg
circuits of internuncia1 neurons are established with a consequent patterned discharge up the spinothalamic tracts. Any disturbance or alteration aIong any portion of the transmitting system wiI1 affect or remove the sensation of itching. A depression of the synaptic transmission of impulses through sympathetic ganglia will aIso affect itching and this is probably the explanation for the results cIaimed by the authors. Just why presacral neurectomy relieves periana1 itching cannot be explained logically. This procedure does not affect compIete sympathetic denervation of the pelvic viscera since the sacral and the more caudal lumbar sympathetic rami join the pelvic plexuses directIy. It probably interrupts al1 the visceral afferent hbers associated with the sympathetic nerves that reach the pelvic viscera, but does not bIock parasympathetic visceral afferent impulses. Relative to the data presented by the authors I wouId like to point out first that if the average of a11 eighteen cases is taken, instead of three, the average temperature twenty minutes after-exposure is 93'F. Hence there wouId then be no change in Group I. AIso, there would be a drop of onIy 0.3'F., and a fall of 1.5~and Ih'F. in Groups III and IV. We attempted to confirm the findings as reported by the authors. Six patients were given spina anesthetics to the Ievel of T8 (Alberts, persona communication). In all six there was no change in rectal temperature. In three cases there was a rise of I’C. in the perianal skin, and in the other three there was only a shght perceptible rise. No decrease in the perianal skin temperature was noted. Two patients were tested under caudaI anesthesia, In one case in which the room temperature was 72'~.there was a decrease in the rectal temperature of o.~~F., in the thighs I.~~F., and a fall of I,~~F. in the perianal skin. In the other case tested at a room temperature of 85'F.there was a rise of perianaI skin temperature of Z'F.and I.~'F. rise in the skin temperature of the thighs.
Perhaps the difference in skin temperature findings may be due to a difference of environmental temperatures. This is in keeping with the work done on sympathectomized cats by Sawyer and Schlossberg which was referred to in the paper under discussion. The body temperatures feJ1 when the environmenta temperatures were Iow and rose when the outside temperatures were high. Without the governing control of the sympathetic nervous system the body temperatures may not be stabIe but may respond to environmental temperature changes. There is a great dea1 of local variation of the perianal skin. As much as I degree change may be noted in the opposite Iateral waIIs of the anal verge in the same individual SIight increase of pressure on the thermocoupIe wil1 cause a change in the recording. Since many factors may effect adversely the recording of skin temperatures, it may be diffrcuIt to arrive at accurate normals. I think further study of this problem is indicated. Presacral neurectomy is a formidable procedure, but at times intractabIe anal pruritus requires heroic measures. I am sure that there are many patients with pruritus ani who undergo abdominal surgery. PresacraI neurectomy performed on these individuals would provide information reIative to the efficacy of this procedure. I wonder how many patients have undergone this operation and with what resuIts. How long does the absence of pruritus persist? Does the temperature return to normaI? Are there any complications? Can alcohol be injected without harm in this area? Does the preoperative use of such medications as atropine, scopolamine and morphine, or epinephrine or other pressor substances influence the findings? In conclusion I wouId like to commend the authors for their presentation, not onIy for the amount of work and effort which it entailed, but also for their offering of a new approach to the problem of pruritus ani.
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