GANGRENE
Definition--Types: _Dry_, _Moist_--Varieties--Gangrene primarily due to
interference with circulation: _Senile gangrene_; _Embolic
gangrene_; _Gangrene following ligation of arteries_; _Gangrene
from mechanical causes_; _Gangrene from heat, chemical agents, and
cold_; _Diabetic gangrene_; _Gangrene associated with spasm of
blood vessels_; _Raynaud's disease_; _Angio-sclerotic gangrene_;
_Gangrene from ergot_. Bacterial varieties of gangrene.
_Pathology_--clinical varieties--_Acute infective gangrene_;
_Malignant œdema_; _Acute emphysematous_ or _gas gangrene_;
_Cancrum oris_, _etc_. Bed-sores: _Acute_; _chronic_.
Gangrene or mortification is the process by which a portion of tissue
dies _en masse_, as distinguished from the molecular or cellular death
which constitutes ulceration. The dead portion is known as a _slough_.
In this chapter we shall confine our attention to the process as it
affects the limbs and superficial parts, leaving gangrene of the viscera
to be described in regional surgery.
TYPES OF GANGRENE
Two distinct types of gangrene are met with, which, from their most
obvious point of difference, are known respectively as _dry_ and
_moist_, and there are several clinical varieties of each type.
Speaking generally, it may be said that dry gangrene is essentially due
to a simple _interference with the blood supply_ of a part; while the
main factor in the production of moist gangrene is _bacterial
infection_.
The cardinal signs of gangrene are: change in the colour of the part,
coldness, loss of sensation and motor power, and, lastly, loss of
pulsation in the arteries.
#Dry Gangrene# or #Mummification# is a comparatively slow form of local
death due, as a rule, to a diminution in the arterial blood supply of
the affected part, resulting from such causes as the gradual narrowing
of the lumen of the arteries by disease of their coats, or the blocking
of the main vessel by an embolus.
As the fluids in the tissues are lost by evaporation the part becomes
dry and shrivelled, and as the skin is usually intact, infection does
not take place, or if it does, the want of moisture renders the part an
unsuitable soil, and the organisms do not readily find a footing. Any
spread of the process that may take place is chiefly influenced by the
anatomical distribution of the blocked arteries, and is arrested as soon
as it reaches an area rich in anastomotic vessels. The dead portion is
then cast off, the irritation resulting from the contact of the dead
with the still living tissue inducing the formation of granulations on
the proximal side of the junction, and these by slowly eating into the
dead portion produce a furrow--the _line of demarcation_--which
gradually deepens until complete separation is effected. As the muscles
and bones have a richer blood supply than the integument, the death of
skin and subcutaneous tissues extends higher than that of muscles and
bone, with the result that the stump left after spontaneous separation
is conical, the end of the bone projecting beyond the soft parts.
_Clinical Features._--The part undergoing mortification becomes colder
than normal, the temperature falling to that of the surrounding
atmosphere. In many instances, but not in all, the onset of the process
is accompanied by severe neuralgic pain in the part, probably due to
anæmia of the nerves, to neuritis, or to the irritation of the exposed
axis cylinders by the dead and dying tissues around them. This pain soon
ceases and gives place to a complete loss of sensation. The dead part
becomes dry, horny, shrivelled, and semi-transparent--at first of a dark
brown, but finally of a black colour, from the dissemination of blood
pigment throughout the tissues. There is no putrefaction, and therefore
no putrid odour; and the condition being non-infective, there is not
necessarily any constitutional disturbance. In itself, therefore, dry
gangrene does not involve immediate risk to life; the danger lies in the
fact that the breach of surface at the line of demarcation furnishes a
possible means of entrance for bacteria, which may lead to infective
complications.
#Moist Gangrene# is an acute process, the dead part retaining its fluids
and so affording a favourable soil for the development of bacteria. The
action of the organisms and their toxins on the adjacent tissues leads
to a rapid and wide spread of the process. The skin becomes moist and
macerated, and bullæ, containing dark-coloured fluid or gases, form
under the epidermis. The putrefactive gases evolved cause the skin to
become emphysematous and crepitant and produce an offensive odour. The
tissues assume a greenish-black colour from the formation in them of a
sulphide of iron resulting from decomposition of the blood pigment.
Under certain conditions the dead part may undergo changes resembling
more closely those of ordinary post-mortem decomposition. Owing to its
nature the spread of the gangrene is seldom arrested by the natural
protective processes, and it usually continues until the condition
proves fatal from the absorption of toxins into the circulation.
The _clinical features_ vary in the different varieties of moist
gangrene, but the local results of bacterial action and the
constitutional disturbance associated with toxin absorption are present
in all; the prognosis therefore is grave in the extreme.
From what has been said, it will be gathered that in dry gangrene there
is no urgent call for operation to save the patient's life, the primary
indication being to prevent the access of bacteria to the dead part, and
especially to the surface exposed at the line of demarcation. In moist
gangrene, on the contrary, organisms having already obtained a footing,
immediate removal of the dead and dying tissues, as a rule, offers the
only hope of saving life.
VARIETIES OF GANGRENE
#Varieties of Gangrene essentially due to Interference with the
Circulation#
While the varieties of gangrene included in this group depend primarily
on interference with the circulation, it is to be borne in mind that the
clinical course of the affection may be profoundly influenced by
superadded infection with micro-organisms. Although the bacteria do not
play the most important part in producing tissue necrosis, their
subsequent introduction is an accident of such importance that it may
change the whole aspect of affairs and convert a dry form of gangrene
into one of the moist type. Moreover, the low state of vitality of the
tissues, and the extreme difficulty of securing and maintaining asepsis,
make it a sequel of great frequency.
#Senile Gangrene.#--Senile gangrene is the commonest example of local
death produced by a _gradual_ diminution in the quantity of blood
passing through the parts, as a result of arterio-sclerosis or other
chronic disease of the arteries leading to diminution of their calibre.
It is the most characteristic example of the dry type of gangrene. As
the term indicates, it occurs in old persons, but the patient's age is
to be reckoned by the condition of his arteries rather than by the
number of his years. Thus the vessels of a comparatively young man who
has suffered from syphilis and been addicted to alcohol are more liable
to atheromatous degeneration leading to this form of gangrene than are
those of a much older man who has lived a regular and abstemious life.
This form of gangrene is much more common in men than in women. While it
usually attacks only one foot, it is not uncommon for the other foot to
be affected after an interval, and in some cases it is bilateral from
the outset. It must clearly be understood that any form of gangrene may
occur in old persons, the term senile being here restricted to that
variety which results from arterio-sclerosis.
[Illustration: FIG. 20.--Senile Gangrene of the Foot, showing line of
demarcation.]
_Clinical Features._--The commonest seat of the disease is in the toes,
especially the great toe, whence it spreads up the foot to the heel, or
even to the leg (Fig. 20). There is often a history of some slight
injury preceding its onset. The vitality of the tissues is so low that
the balance between life and death may be turned by the most trivial
injury, such as a cut while paring a toe-nail or a corn, a blister
caused by an ill-fitting shoe or the contact of a hot-bottle. In some
cases the actual gangrene is determined by thrombosis of the popliteal
or tibial arteries, which are already narrowed by obliterating
endarteritis.
It is common to find that the patient has been troubled for a long time
before the onset of definite signs of gangrene, with cold feet, with
tingling and loss of feeling, or a peculiar sensation as if walking on
cotton wool.
The first evidence of the death of the part varies in different cases.
Sometimes a dark-blue spot appears on the medial side of the great toe
and gradually increases in size; or a blister containing blood-stained
fluid may form. Streaks or patches of dark-blue mottling appear higher
up on the foot or leg. In other cases a small sore surrounded by a
congested areola forms in relation to the nail and refuses to heal. Such
sores on the toes of old persons are always to be looked upon with
suspicion and treated with the greatest care; and the urine should be
examined for sugar. There is often severe, deep-seated pain of a
neuralgic character, with cramps in the limb, and these may persist long
after a line of demarcation has formed. The dying part loses sensibility
to touch and becomes cold and shrivelled.
All the physical appearances and clinical symptoms associated with dry
gangrene supervene, and the dead portion is delimited by a line of
demarcation. If this forms slowly and irregularly it indicates a very
unsatisfactory condition of the circulation; while, if it forms quickly
and decidedly, the presumption is that the circulation in the parts
above is fairly good. The separation of the dead part is always attended
with the risk of infection taking place, and should this occur, the
temperature rises and other evidences of toxæmia appear.
_Prophylaxis._--The toes and feet of old people, the condition of whose
circulation predisposes them to gangrene, should be protected from
slight injuries such as may be received while paring nails, cutting
corns, or wearing ill-fitting boots. The patient should also be warned
of the risk of exposure to cold, the use of hot-bottles, and of placing
the feet near a fire. Attempts have been made to improve the peripheral
circulation by establishing an anastomosis between the main artery of a
limb and its companion vein, so that arterial blood may reach the
peripheral capillaries--reversal of the circulation--but the clinical
results have proved disappointing. (See _Op. Surg._, p. 29.)
_Treatment._--When there is evidence that gangrene has occurred, the
first indication is to prevent infection by purifying the part, and
after careful drying to wrap it in a thick layer of absorbent and
antiseptic wool, retained in place by a loosely applied bandage. A
slight degree of elevation of the limb is an advantage, but it must not
be sufficient to diminish the amount of blood entering the part.
Hot-bottles are to be used with the utmost caution. As absolute dryness
is essential, ointments or other greasy dressings are to be avoided, as
they tend to prevent evaporation from the skin. Opium should be given
freely to alleviate pain. Stimulation is to be avoided, and the patient
should be carefully dieted.
When the gangrene is limited to the toes in old and feeble patients,
some surgeons advocate the expectant method of treatment, waiting for a
line of demarcation to form and allowing the dead part to be separated.
This takes place so slowly, however, that it necessitates the patient
being laid up for many weeks, or even months; and we agree with the
majority in advising early amputation.
In this connection it is worthy of note that there are certain points at
which gangrene naturally tends to become arrested--namely, at the highly
vascular areas in the neighbourhood of joints. Thus gangrene of the
great toe often stops when it reaches the metatarso-phalangeal joint; or
if it trespasses this limit it may be arrested either at the
tarso-metatarsal or at the ankle joint. If these be passed, it usually
spreads up the leg to just below the knee before signs of arrestment
appear. Further, it is seen from pathological specimens that the spread
is greater on the dorsal than on the plantar aspect, and that the death
of skin and subcutaneous tissues extends higher than that of bone and
muscle.
These facts furnish us with indications as to the seat and method of
amputation. Experience has proved that in senile gangrene of the lower
extremity the most reliable and satisfactory results are obtained by
amputating in the region of the knee, care being taken to perform the
operation so as to leave the prepatellar anastomosis intact by retaining
the patella in the anterior flap. The most satisfactory operation in
these cases is Gritti's supra-condylar amputation. Hæmorrhage is easily
controlled by digital pressure, and the use of a tourniquet should be
dispensed with, as the constriction of the limb is liable to interfere
with the vitality of the flaps.
When the tibial vessels can be felt pulsating at the ankle it may be
justifiable, if the patient urgently desires it, to amputate lower than
the knee; but there is considerable risk of gangrene recurring in the
stump and necessitating a second operation.
That amputation for senile gangrene performed between the ankle and the
knee seldom succeeds, is explained by the fact that the vascular
obstruction is usually in the upper part of the posterior tibial artery,
and the operation is therefore performed through tissues with an
inadequate blood supply. It is not uncommon, indeed, on amputating above
the knee, to find even the popliteal artery plugged by a clot. This
should be removed at the amputation by squeezing the vessel from above
downward by a "milking" movement, or by "catheterising the artery" with
the aid of a cannula with a terminal aperture.
It is to be borne in mind that the object of amputation in these cases
is merely to remove the gangrenous part, and so relieve the patient of
the discomfort and the risks from infection which its presence involves.
While it is true that in many of these patients the operation is borne
remarkably well, it must be borne in mind that those who suffer from
senile gangrene are of necessity bad lives, and a guarded opinion should
be expressed as to the prospects of survival. The possibility of the
disease developing in the other limb has already been referred to.
[Illustration: FIG. 21.--Embolic Gangrene of Hand and Arm.]
#Embolic Gangrene# (Fig. 21).--This is the most typical form of gangrene
resulting from the _sudden_ occlusion of the main artery of a part,
whether by the impaction of an embolus or the formation of a thrombus in
its lumen, when the collateral circulation is not sufficiently free to
maintain the vitality of the tissues.
There is sudden pain at the site of impaction of the embolus, and the
pulses beyond are lost. The limb becomes cold, numb, insensitive, and
powerless. It is often pale at first--hence the term "white gangrene"
sometimes applicable to the early appearances, which closely resemble
those presented by the limb of a corpse.
If the part is aseptic it shrivels, and presents the ordinary features
of dry gangrene. It is liable, however, especially in the lower
extremity and when the veins also are obstructed, to become infected and
to assume the characters of the moist type.
The extent of the gangrene depends upon the site of impaction of the
embolus, thus if the _abdominal aorta_ becomes suddenly occluded by an
embolus at its bifurcation, the obstruction of the iliacs and femorals
induces symmetrical gangrene of both extremities as high as the inguinal
ligaments. When gangrene follows occlusion of the _external iliac_ or of
the _femoral artery_ above the origin of its deep branch, the death of
the limb extends as high as the middle or upper third of the thigh. When
the _femoral_ below the origin of its deep branch or the _popliteal
artery_ is obstructed, the veins remaining pervious, the anastomosis
through the profunda is sufficient to maintain the vascular supply, and
gangrene does not necessarily follow. The rupture of a popliteal
aneurysm, however, by compressing the vein and the articular branches,
usually determines gangrene. When an embolus becomes impacted at the
_bifurcation of the popliteal_, if gangrene ensues it usually spreads
well up the leg.
When the _axillary artery_ is the seat of embolic impaction, and
gangrene ensues, the process usually reaches the middle of the upper
arm. Gangrene following the blocking of the _brachial_ at its
bifurcation usually extends as far as the junction of the lower and
middle thirds of the forearm.
Gangrene due to thrombosis or embolism is sometimes met with in patients
recovering from typhus, typhoid, or other fevers, such as that
associated with child-bed. It occurs in peripheral parts, such as the
toes, fingers, nose, or ears.
_Treatment._--The general treatment of embolic gangrene is the same as
that for the senile form. Success has followed opening the artery and
removing the embolus. The artery is exposed at the seat of impaction
and, having been clamped above and below, a longitudinal opening is made
and the clot carefully extracted with the aid of forceps; it is
sometimes unexpectedly long (one recorded from the femoral artery
measured nearly 34 inches); the wound in the artery is then sewn up with
fine silk soaked in paraffin. When amputation is indicated, it must be
performed sufficiently high to ensure a free vascular supply to the
flaps.
#Gangrene following Ligation of Arteries.#--After the ligation of an
artery in its continuity--for example, in the treatment of aneurysm--the
limb may for some days remain in a condition verging on gangrene, the
distal parts being cold, devoid of sensation, and powerless. As the
collateral circulation is established, the vitality of the tissues is
gradually restored and these symptoms pass off. In some cases,
however,--and especially in the lower extremity--gangrene ensues and
presents the same characters as those resulting from embolism. It tends
to be of the dry type. The occlusion of the vein as well as the artery
is not found to increase the risk of gangrene.
#Gangrene from Mechanical Constriction of the Vessels of the part.#--The
application of a bandage or plaster-of-Paris case too tightly, or of a
tourniquet for too long a time, has been known to lead to death of the
part beyond; but such cases are rare, as are also those due to the
pressure of a fractured bone or of a tumour on a large artery or vein.
When gangrene occurs from such causes, it tends to be of the moist type.
Much commoner is it to meet with localised areas of necrosis due to the
excessive _pressure of splints_ over bony prominences, such as the
lateral malleolus, the medial condyle of the humerus, or femur, or over
the dorsum of the foot. This is especially liable to occur when the
nutrition of the skin is depressed by any interference with its
nerve-supply, such as follows injuries to the spine or peripheral
nerves, disease of the brain, or acute anterior poliomyelitis. When the
splint is removed the skin pressed upon is found to be of a pale yellow
or grey colour, and is surrounded by a ring of hyperæmia. If protected
from infection, the clinical course is that of dry gangrene.
Bed-sores, which are closely allied to pressure sores, will be described
at the end of this chapter.
When a localised portion of tissue, for example, a piece of skin, is so
severely _crushed_ or _bruised_ that its blood vessels are occluded and
its structure destroyed, it dies, and, if not infected with bacteria,
dries up, and the shrivelled brown skin is slowly separated by the
growth of granulation tissue beneath and around it.
Fingers, toes, or even considerable portions of limbs may in the same
way be suddenly destroyed by severe trauma, and undergo mummification.
If organisms gain access, typical moist gangrene may ensue, or changes
similar to those of ordinary post-mortem decomposition may take place.
_Treatment._--The first indication is to exclude bacteria by purifying
the damaged part and its surroundings, and applying dry, non-irritating
dressings.
When these measures are successful, dry gangrene ensues. The raw surface
left after the separation of the dead skin may be allowed to heal by
granulation, or may be covered by skin-grafts. In the case of a finger
or a limb it is not necessary to wait until spontaneous separation takes
place, as this is often a slow process. When a well-marked line of
demarcation has formed, amputation may be performed just sufficiently
far above it to enable suitable flaps to be made.
The end of a stump, after spontaneous separation of the gangrenous
portion, requires to be trimmed, sufficient bone being removed to permit
of the soft parts coming together.
If moist gangrene supervenes, amputation must be performed without
delay, and at a higher level.
#Gangrene from Heat, Chemical Agents, and Cold.#--Severe #burns# and
#scalds# may be followed by necrosis of tissue. So long as the parts are
kept absolutely dry--as, for example, by the picric acid method of
treatment--the grossly damaged portions of tissue undergo dry gangrene;
but when wet or oily dressings are applied and organisms gain access,
moist gangrene follows.
Strong #chemical agents#, such as caustic potash, nitric or sulphuric
acid, may also induce local tissue necrosis, the general appearances of
the lesions produced being like those of severe burns. The resulting
sloughs are slow to separate, and leave deep punched-out cavities which
are long of healing.
#Carbolic Gangrene.#--Carbolic acid, even in comparatively weak
solution, is liable to induce dry gangrene when applied as a fomentation
to a finger, especially in women and children. Thrombosis occurs in the
blood vessels of the part, which at first is pale and soft, but later
becomes dark and leathery. On account of the anæsthetic action of
carbolic acid, the onset of the process is painless, and the patient
does not realise his danger. A line of demarcation soon forms, but the
dead part separates very slowly.
#Gangrene from Frost-bite.#--It is difficult to draw the line between
the third degree of chilblain and the milder forms of true frost-bite;
the difference is merely one of degree. Frost-bite affects chiefly the
toes and fingers--especially the great toe and the little finger--the
ears, and the nose. In this country it is seldom seen except in members
of the tramp class, who, in addition to being exposed to cold by
sleeping in the open air, are ill-fed and generally debilitated. The
condition usually manifests itself after the parts, having been
subjected to extreme cold, are brought into warm surroundings. The first
symptom is numbness in the part, followed by a sense of weight,
tingling, and finally by complete loss of sensation. The part attacked
becomes white and bleached-looking, feels icy cold, and is insensitive
to touch. Either immediately, or, it may be, not for several days, it
becomes discoloured and swollen, and finally contracts and shrivels.
Above the dead area the limb may be the seat of excruciating pain. The
dead portion is cast off, as in other forms of dry gangrene, by the
formation of a line of demarcation.
To prevent the occurrence of gangrene from frost-bite it is necessary to
avoid the sudden application of heat. The patient should be placed in a
cold room, and the part rubbed with snow, or put in a cold bath, and
have light friction applied to it. As the circulation is restored the
general surroundings and the local applications are gradually made
warmer. Elevation of the part, wrapping it in cotton wool, and removal
to a warmer room, are then permissible, and stimulants and warm drinks
may be given with caution. When by these means the occurrence of
gangrene is averted, recovery ensues, its onset being indicated by the
white parts assuming a livid red hue and becoming the seat of an acute
burning sensation.
A condition known as _Trench feet_ was widely prevalent amongst the
troops in France during the European War. Although allied to frost-bite,
cold appears to play a less important part in its causation than
humidity and constriction of the limbs producing ischæmia of the feet.
Changes were found in the endothelium of the blood vessels, the axis
cylinders of nerves, and the muscles. The condition does not occur in
civil life.
#Diabetic Gangrene.#--This form of gangrene is prone to occur in persons
over fifty years of age who suffer from glycosuria. The arteries are
often markedly diseased. In some cases the existence of the glycosuria
is unsuspected before the onset of the gangrene, and it is only on
examining the urine that the cause of the condition is discovered. The
gangrenous process seldom begins as suddenly as that associated with
embolism, and, like senile gangrene, which it may closely simulate in
its early stages, it not infrequently begins after a slight injury to
one of the toes. It but rarely, however, assumes the dry, shrivelling
type, as a rule being attended with swelling, œdema, and dusky redness
of the foot, and severe pain. According to Paget, the dead part remains
warm longer than in other forms of senile gangrene; there is a greater
tendency for patches of skin at some distance from the primary seat of
disease to become gangrenous, and for the death of tissue to extend
upwards in the subcutaneous planes, leaving the overlying skin
unaffected. The low vitality of the tissues favours the growth of
bacteria, and if these gain access, the gangrene assumes the characters
of the moist type and spreads rapidly.
The rules for amputation are the same as those governing the treatment
of senile gangrene, the level at which the limb is removed depending
upon whether the gangrene is of the dry or moist type. The general
treatment for diabetes must, of course, be employed whether amputation
is performed or not. Paget recommended that the dietetic treatment
should not be so rigid as in uncomplicated diabetes, and that opium
should be given freely.
The _prognosis_ even after amputation is unfavourable. In many cases the
patient dies with symptoms of diabetic coma within a few days of the
operation; or, if he survives this, he may eventually succumb to
diabetes. In others there is sloughing of the flaps and death results
from toxæmia. Occasionally the other limb becomes gangrenous. On the
other hand, the glycosuria may diminish or may even disappear after
amputation.
#Gangrene associated with Spasm of Blood Vessels.#--#Raynaud's Disease#,
or symmetrical gangrene, is supposed to be due to spasm of the
arterioles, resulting from peripheral neuritis. It occurs oftenest in
women, between the ages of eighteen and thirty, who are the subjects of
uterine disorders, anæmia, or chlorosis. Cold is an aggravating factor,
as the disease is commonest during the winter months. The digits of both
hands or the toes of both feet are simultaneously attacked, and the
disease seldom spreads beyond the phalanges or deeper than the skin.
The first evidence is that the fingers become cold, white, and
insensitive to touch and pain. These attacks of _local syncope_ recur at
varying intervals for months or even years. They last for a few minutes
or even for some hours, and as they pass off the parts become hyperæmic
and painful.
A more advanced stage of the disease is known as _local asphyxia_. The
circulation through the fingers becomes exceedingly sluggish, and the
parts assume a dull, livid hue. There is swelling and burning or
shooting pain. This may pass off in a few days, or may increase in
severity, with the formation of bullæ, and end in dry gangrene. As a
rule, the slough which forms is comparatively small and superficial,
but it may take some months to separate. The condition tends to recur in
successive winters.
The _treatment_ consists in remedying any nervous or uterine disorder
that may be present, keeping the parts warm by wrapping them in cotton
wool, and in the use of hot-air or electric baths, the parts being
immersed in water through which a constant current is passed. When
gangrene occurs, it is treated on the same lines as other forms of dry
gangrene, but if amputation is called for it is only with a view to
removing the dead part.
#Angio-sclerotic Gangrene.#--A form of gangrene due to _angio-sclerosis_
is occasionally met with in young persons, even in children. It bears
certain analogies to Raynaud's disease in that spasm of the vessels
plays a part in determining the local death.
The main arteries are narrowed by hyperplastic endarteritis followed by
thrombosis, and similar changes are found in the veins. The condition is
usually met with in the feet, but the upper extremity may be affected,
and is attended with very severe pain, rendering sleep impossible.
The patient is liable to sudden attacks of numbness, tingling and
weakness of the limbs which pass off with rest--_intermittent
claudication_. During these attacks the large arteries--femoral,
brachial, and subclavian--can be felt as firm cords, while pulsation is
lost in the peripheral vessels. Gangrene eventually ensues, is attended
with great pain and runs a slow course. It is treated on the same lines
as Raynaud's disease.
#Gangrene from Ergot.#--Gangrene may occur from interference with blood
supply, the result of tetanic contraction of the minute vessels, such as
results in ill-nourished persons who eat large quantities of coarse rye
bread contaminated with the _claviceps purpurea_ and containing the
ergot of rye. It has also occurred in the fingers of patients who have
taken ergot medicinally over long periods. The gangrene, which attacks
the toes, fingers, ears, or nose, is preceded by formication, numbness,
and pains in the parts to be affected, and is of the dry variety.
In this country it is usually met with in sailors off foreign ships,
whose dietary largely consists of rye bread. Trivial injuries may be the
starting-point, the anæsthesia produced by the ergotin preventing the
patient taking notice of them. Alcoholism is a potent predisposing
cause.
As it is impossible to predict how far the process will spread, it is
advisable to wait for the formation of a line of demarcation before
operating, and then to amputate immediately above the dead part.
BACTERIAL VARIETIES OF GANGRENE
The acute bacillary forms of gangrene all assume the moist type from the
first, and, spreading rapidly, result in extensive necrosis of tissue,
and often end fatally.
The infection is usually a mixed one in which anaërobic bacteria
predominate. The anaërobe most constantly present is the _bacillus
ærogenes capsulatus_, usually in association with other anaërobes, and
sometimes with pyogenic diplo- and streptococci. According to the mode of
action of the associated organisms and the combined effects of their
toxins on the tissues, the gangrenous process presents different
pathological and clinical features. Some combinations, for example,
result in a rapidly spreading cellulitis with early necrosis of
connective tissue accompanied by thrombosis throughout the capillary and
venous circulation of the parts implicated; other combinations cause
great œdema of the part, and others again lead to the formation of gases
in the tissues, particularly in the muscles.
These different effects do not appear to be due to a specific action of
any one of the organisms present, but to the combined effect of a
particular group living in symbiosis.
According as the cellulitic, the œdematous, or the gaseous
characteristics predominate, the clinical varieties of bacillary
gangrene may be separately described, but it must be clearly understood
that they frequently overlap and cannot always be distinguished from one
another.
#Clinical Varieties of Bacillary Gangrene.#--#Acute infective gangrene#
is the form most commonly met with in civil practice. It may follow such
trivial injuries as a pin-prick or a scratch, the signs of acute
cellulitis rapidly giving place to those of a spreading gangrene. Or it
may ensue on a severe railway, machinery, or street accident, when
lacerated and bruised tissues are contaminated with gross dirt. Often
within a few hours of the injury the whole part rapidly becomes painful,
swollen, œdematous, and tense. The skin is at first glazed, and perhaps
paler than normal, but soon assumes a dull red or purplish hue, and
bullæ form on the surface. Putrefactive gases may be evolved in the
tissues, and their presence is indicated by emphysematous crackling when
the part is handled. The spread of the disease is so rapid that its
progress is quite visible from hour to hour, and may be traced by the
occurrence of red lines along the course of the lymphatics of the limb.
In the most acute cases the death of the affected part takes place so
rapidly that the local changes indicative of gangrene have not time to
occur, and the fact that the part is dead may be overlooked.
[Illustration: FIG. 22.--Gangrene of Terminal Phalanx of Index-Finger,
following cellulitis of hand resulting from a scratch on the palm of the
hand.]
Rigors may occur, but the temperature is not necessarily raised--indeed,
it is sometimes subnormal. The pulse is small, feeble, rapid, and
irregular. Unless amputation is promptly performed, death usually
follows within thirty-six or forty-eight hours. Even early operation
does not always avert the fatal issue, because the quantity of toxin
absorbed and its extreme virulence are often more than even a robust
subject can outlive.
_Treatment._--Every effort must be made to purify all such wounds as are
contaminated by earth, street dust, stable refuse, or other forms of
gross dirt. Devitalised and contaminated tissue is removed with the
knife or scissors and the wound purified with antiseptics of the
chlorine group or with hydrogen peroxide. If there is a reasonable
prospect that infection has been overcome, the wound may be at once
sutured, but if this is doubtful it is left open and packed or
irrigated.
When acute gangrene has set in no treatment short of amputation is of
any avail, and the sooner this is done, the greater is the hope of
saving the patient. The limb must be amputated well beyond the apparent
limits of the infected area, and stringent precautions must be taken to
avoid discharge from the already gangrenous area reaching the operation
wound. An assistant or nurse, who is to take no other part in the
operation, is told off to carry out the preliminary purification, and to
hold the limb during the operation.
#Malignant Œdema.#--This form of acute gangrene has been defined as
"a spreading inflammatory œdema attended with emphysema, and ultimately
followed by gangrene of the skin and adjacent parts." The predominant
organism is the _bacillus of malignant œdema_ or _vibrion septique_ of
Pasteur, which is found in garden soil, dung, and various putrefying
substances. It is anaërobic, and occurs as long, thick rods with
somewhat rounded ends and several laterally placed flagella. Spores,
which have a high power of resistance, form in the centre of the rods,
and bulge out the sides so as to give the organisms a spindle-shaped
outline. Other pathogenic organisms are also present and aid the
specific bacillus in its action.
At the bedside it is difficult, if not impossible, to distinguish it
from acute infective gangrene. Both follow on the same kinds of injury
and run an exceedingly rapid course. In malignant œdema, however, the
incidence of the disease is mainly on the superficial parts, which
become œdematous and emphysematous, and acquire a marbled appearance
with the veins clearly outlined. Early disappearance of sensation is a
particularly grave symptom. Bullæ form on the skin, and the tissues
have "a peculiar heavy but not putrid odour." The constitutional effects
are extremely severe, and death may ensue within a few hours.
#Acute Emphysematous# or #Gas Gangrene# was prevalent in certain areas
at various periods during the European War. It follows infection of
lacerated wounds with the _bacillus ærogenes capsulatus_, usually in
combination with other anaërobes, and its main incidence is on the
muscles, which rapidly become infiltrated with gas that spreads
throughout the whole extent of the muscle, disintegrating its fibres and
leading to necrosis. The gangrenous process spreads with appalling
rapidity, the limb becoming enormously swollen, painful, and crepitant
or even tympanitic. Patches of coppery or purple colour appear on the
skin, and bullæ containing blood-stained serum form on the surface. The
toxæmia is profound, and the face and lips assume a characteristic
cyanosis. The condition is attended with a high mortality. Only in the
early stages and when the infection is limited are local measures
successful in arresting the spread; in more severe cases amputation is
the only means of saving life.
#Cancrum Oris# or #Noma#.--This disease is believed to be due to a
specific bacillus, which occurs in long delicate rods, and is chiefly
found at the margin of the gangrenous area. It is prone to attack
unhealthy children from two to five years of age, especially during
their convalescence from such diseases as measles, scarlet fever, or
typhoid, but may attack adults when they are debilitated. It is most
common in the mouth, but sometimes occurs on the vulva. In the mouth it
begins as an ulcerative stomatitis, more especially affecting the gums
or inner aspect of the cheek. The child lies prostrated, and from the
open mouth foul-smelling saliva, streaked with blood, escapes; the face
is of an ashy-grey colour, the lips dark and swollen. On the inner
aspect of the cheek is a deeply ulcerated surface, with sloughy shreds
of dark-brown or black tissue covering its base; the edges are
irregular, firm, and swollen, and the surrounding mucous membrane is
infiltrated and œdematous. In the course of a few hours a dark spot
appears on the outer aspect of the cheek, and rapidly increases in size;
towards the centre it is black, shading off through blue and grey into a
dark-red area which extends over the cheek (Fig. 23). The tissue
implicated is at first firm and indurated, but as it loses its vitality
it becomes doughy and sodden. Finally a slough forms, and, when it
separates, the cheek is perforated.
Meanwhile the process spreads inside the mouth, and the gums, the floor
of the mouth, or even the jaws, may become gangrenous and the teeth fall
out. The constitutional disturbance is severe, the temperature raised,
and the pulse feeble and rapid.
The extremely fœtid odour which pervades the room or even the house the
patient occupies, is usually sufficient to suggest the diagnosis of
cancrum oris. The odour must not be mistaken for that due to
decomposition of sordes on the teeth and gums of a debilitated patient.
The _prognosis_ is always grave in the extreme, the main risks being
general toxæmia and septic pneumonia. When recovery takes place there is
serious deformity, and considerable portions of the jaws may be lost by
necrosis.
[Illustration: FIG. 23.--Cancrum oris.
(From a photograph lent by Sir George T. Beatson.)]
_Treatment._--The only satisfactory treatment is thorough removal under
an anæsthetic of all the sloughy tissue, with the surrounding zone in
which the organisms are active. This is most efficiently accomplished by
the knife or scissors, cutting until the tissue bleeds freely, after
which the raw surface is painted with undiluted carbolic acid and
dressed with iodoform gauze. It may be necessary to remove large pieces
of bone when the necrotic process has implicated the jaws. The mouth
must be constantly sprayed with peroxide of hydrogen, and washed out
with a disinfectant and deodorant lotion, such as Condy's fluid. The
patient's general condition calls for free stimulation.
The deformity resulting from these necessarily heroic measures is not so
great as might be expected, and can be further diminished by plastic
operations, which should be undertaken before cicatricial contraction
has occurred.
BED-SORES
Bed-sores are most frequently met with in old and debilitated patients,
or in those whose tissues are devitalised by acute or chronic diseases
associated with stagnation of blood in the peripheral veins. Any
interference with the nerve-supply of the skin, whether from injury or
disease of the central nervous system or of the peripheral nerves,
strongly predisposes to the formation of bed-sores. Prolonged and
excessive pressure over a bony prominence, especially if the parts be
moist with skin secretions, urine, or wound discharges, determines the
formation of a sore. Excoriations, which may develop into true
bed-sores, sometimes form where two skin surfaces remain constantly
apposed, as in the region of the scrotum or labium, under pendulous
mammæ, or between fingers or toes confined in a splint.
[Illustration: FIG. 24.--Acute Bed-Sores over Right Buttock.]
_Clinical Features._--Two clinical varieties are met with--the acute
and the chronic bed-sore.
The _acute_ bed-sore usually occurs over the sacrum or buttock. It
develops rapidly after spinal injuries and in the course of certain
brain diseases. The part affected becomes red and congested, while the
surrounding parts are œdematous and swollen, blisters form, and the skin
loses its vitality (Fig. 24).
In advanced cases of general paralysis of the insane, a peculiar form of
acute bed-sore beginning as a blister, and passing on to the formation
of a black, dry eschar, which slowly separates, occurs on such parts as
the medial side of the knee, the angle of the scapula, and the heel.
The _chronic_ bed-sore begins as a dusky reddish purple patch, which
gradually becomes darker till it is almost black. The parts around are
œdematous, and a blister may form. This bursts and exposes the papillæ
of the skin, which are of a greenish hue. A tough greyish-black slough
forms, and is slowly separated. It is not uncommon for the gangrenous
area to continue to spread both in width and in depth till it reaches
the periosteum or bone. Bed-sores over the sacrum sometimes implicate
the vertebral canal and lead to spinal meningitis, which usually proves
fatal.
In old and debilitated patients the septic absorption taking place from
a bed-sore often proves a serious complication of other surgical
conditions. From this cause, for example, old people may succumb during
the treatment of a fractured thigh.
The granulating surface left on the separation of the slough tends to
heal comparatively rapidly.
_Prevention of Bed-sores._--The first essential in the prevention of
bed-sores is the regular changing of the patient's position, so that no
one part of the body is continuously pressed upon for any length of
time. Ring-pads of wool, air-cushions, or water-beds are necessary to
remove pressure from prominent parts. Absolute dryness of the skin is
all-important. At least once a day, the sacrum, buttocks,
shoulder-blades, heels, elbows, malleoli, or other parts exposed to
pressure, must be sponged with soap and water, thoroughly dried, and
then rubbed with methylated spirit, which is allowed to dry on the skin.
Dusting the part with boracic acid powder not only keeps it dry, but
prevents the development of bacteria in the skin secretions.
In operation cases, care must be taken that irritating chemicals used to
purify the skin do not collect under the patient and remain in contact
with the skin of the sacrum and buttocks during the time he is on the
operating-table. There is reason to believe that the so-called
"post-operation bed-sore" may be due to such causes. A similar result
has been known to follow soiling of the sheets by the escape of a
turpentine enema.
_Treatment._--Once a bed-sore has formed, every effort must be made to
prevent its spread. Alcohol is used to cleanse the broken surface, and
dry absorbent dressings are applied and frequently changed. It is
sometimes found necessary to employ moist or oily substances, such as
boracic poultices, eucalyptus ointment, or balsam of Peru, to facilitate
the separation of sloughs, or to promote the growth of granulations. In
patients who are not extremely debilitated the slough may be excised,
the raw surface scraped, and then painted with iodine.
Skin-grafting is sometimes useful in covering in the large raw surface
left after separation or removal of sloughs.