Alexis Thomson and Alexander Miles - Manual of Surgery

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The vaccine treatment has been successfully employed in various
tuberculous lesions, in pyogenic infections such as acne, boils,
sycosis, streptococcal, pneumococcal, and gonococcal conditions, in
infections of the accessory air sinuses, and in other diseases caused by
bacteria.

PYOGENIC BACTERIA

From the point of view of the surgeon the most important varieties of
micro-organisms are those that cause inflammation and suppuration--the
_pyogenic bacteria_. This group includes a great many species, and these
are so widely distributed that they are to be met with under all
conditions of everyday life.

The nature of the inflammatory and suppurative processes will be
considered in detail later; suffice it here to say that they are brought
about by the action of one or other of the organisms that we have now to
consider.

It is found that the _staphylococci_, which cluster into groups, tend to
produce localised lesions; while the chain-forms--_streptococci_--give
rise to diffuse, spreading conditions. Many varieties of pyogenic
bacteria have now been differentiated, the best known being the
staphylococcus aureus, the streptococcus, and the bacillus coli
communis.

[Illustration: FIG. 2.--Staphylococcus aureus in Pus from case of
Osteomyelitis. x 1000 diam. Gram's stain.]

_Staphylococcus Aureus._--This is the commonest organism found in
localised inflammatory and suppurative conditions. It varies greatly in
its virulence, and is found in such widely different conditions as skin
pustules, boils, carbuncles, and some acute inflammations of bone. As
seen by the microscope it occurs in grape-like clusters, fission of the
individual cells taking place irregularly (Fig. 2). When grown in
artificial media, the colonies assume an orange-yellow colour--hence the
name _aureus_. It is of high vitality and resists more prolonged
exposure to high temperatures than most non-sporing bacteria. It is
capable of lying latent in the tissues for long periods, for example, in
the marrow of long bones, and of again becoming active and causing a
fresh outbreak of suppuration. This organism is widely distributed: it
is found on the skin, in the mouth, and in other situations in the body,
and as it is present in the dust of the air and on all objects upon
which dust has settled, it is a continual source of infection unless
means are taken to exclude it from wounds.

The _staphylococcus albus_ is much less common than the aureus, but has
the same properties and characters, save that its growth on artificial
media assumes a white colour. It is the common cause of stitch
abscesses, the skin being its normal habitat.

[Illustration: FIG. 3.--Streptococci in Pus from an acute abscess in
subcutaneous tissue. x 1000 diam. Gram's stain.]

_Streptococcus Pyogenes._--This organism also varies greatly in its
virulence; in some instances--for example in erysipelas--it causes a
sharp attack of acute spreading inflammation, which soon subsides
without showing any tendency to end in suppuration; under other
conditions it gives rise to a generalised infection which rapidly proves
fatal. The streptococcus has less capacity of liquefying the tissues
than the staphylococcus, so that pus formation takes place more slowly.
At the same time its products are very potent in destroying the tissues
in their vicinity, and so interfering with the exudation of leucocytes
which would otherwise exercise their protective influence. Streptococci
invade the lymph spaces, and are associated with acute spreading
conditions such as phlegmonous or erysipelatous inflammations and
suppurations, lymphangitis and suppuration in lymph glands, and
inflammation of serous and synovial membranes, also with a form of
pneumonia which is prone to follow on severe operations in the mouth and
throat. Streptococci are also concerned in the production of spreading
gangrene and pyaemia.

Division takes place in one axis, so that chains of varying length are
formed (Fig. 3). It is less easily cultivated by artificial media than
the staphylococcus; it forms a whitish growth.

[Illustration: FIG. 4.--Bacillus coli communis in Urine, from a case of
Cystitis. x 1000 diam. Leishman's stain.]

_Bacillus Coli Communis._--This organism, which is a normal inhabitant
of the intestinal tract, shows a great tendency to invade any organ or
tissue whose vitality is lowered. It is causatively associated with such
conditions as peritonitis and peritoneal suppuration resulting from
strangulated hernia, appendicitis, or perforation in any part of the
alimentary canal. In cystitis, pyelitis, abscess of the kidney,
suppuration in the bile-ducts or liver, and in many other abdominal
conditions, it plays a most important part. The discharge from wounds
infected by this organism has usually a foetid, or even a faecal odour,
and often contains gases resulting from putrefaction.

It is a small rod-shaped organism with short flagellae, which render it
motile (Fig. 4). It closely resembles the typhoid bacillus, but is
distinguished from it by its behaviour in artificial culture media.

[Illustration: FIG. 5.--Fraenkel's Pneumococci in Pus from Empyema
following Pneumonia. x 100 diam. Stained with Muir's capsule stain.]

_Pneumo-bacteria._--Two forms of organism associated with
pneumonia--_Fraenkel's pneumococcus_ (one of the diplococci) (Fig. 5)
and _Friedlander's pneumo-bacillus_ (a short rod-shaped form)--are
frequently met with in inflammations of the serous and synovial
membranes, in suppuration in the liver, and in various other
inflammatory and suppurative conditions.

_Bacillus Typhosus._--This organism has been found in pure culture in
suppurative conditions of bone, of cellular tissue, and of internal
organs, especially during convalescence from typhoid fever. Like the
staphylococcus, it is capable of lying latent in the tissues for long
periods.

_Other Pyogenic Bacteria._--It is not necessary to do more than name
some of the other organisms that are known to be pyogenic, such as the
bacillus pyocyaneus, which is found in green and blue pus, the
micrococcus tetragenus, the gonococcus, actinomyces, the glanders
bacillus, and the tubercle bacillus. Most of these will receive further
mention in connection with the diseases to which they give rise.

#Leucocytosis.#--Most bacterial diseases, as well as certain other
pathological conditions, are associated with an increase in the number
of leucocytes in the blood throughout the circulatory system. This
condition of the blood, which is known as _leucocytosis_, is believed to
be due to an excessive output and rapid formation of leucocytes by the
bone marrow, and it probably has as its object the arrest and
destruction of the invading organisms or toxins. To increase the
resisting power of the system to pathogenic organisms, an artificial
leucocytosis may be induced by subcutaneous injection of a solution of
nucleinate of soda (16 minims of a 5 per cent. solution).

The _normal_ number of leucocytes per cubic millimetre varies in
different individuals, and in the same individual under different
conditions, from 5000 to 10,000: 7500 is a normal average, and anything
above 12,000 is considered abnormal. When leucocytosis is present, the
number may range from 12,000 to 30,000 or even higher; 40,000 is looked
upon as a high degree of leucocytosis. According to Ehrlich, the
following may be taken as the standard proportion of the various forms
of leucocytes in normal blood: polynuclear neutrophile leucocytes, 70 to
72 per cent.; lymphocytes, 22 to 25 per cent.; eosinophile cells, 2 to 4
per cent.; large mononuclear and transitional leucocytes, 2 to 4 per
cent.; mast-cells, 0.5 to 2 per cent.

In estimating the clinical importance of a leucocytosis, it is not
sufficient merely to count the aggregate number of leucocytes present. A
differential count must be made to determine which variety of cells is
in excess. In the majority of surgical affections it is chiefly the
granular polymorpho-nuclear neutrophile leucocytes that are in excess
(_ordinary leucocytosis_). In some cases, and particularly in parasitic
diseases such as trichiniasis and hydatid disease, the eosinophile
leucocytes also show a proportionate increase (_eosinophilia_). The term
_lymphocytosis_ is applied when there is an increase in the number of
circulating lymphocytes, as occurs, for example, in lymphatic leucaemia,
and in certain cases of syphilis.

Leucocytosis is met with in nearly all acute infective diseases, and in
acute pyogenic inflammatory affections, particularly in those attended
with suppuration. In exceptionally acute septic conditions the extreme
virulence of the toxins may prevent the leucocytes reacting, and
leucocytosis may be absent. The absence of leucocytosis in a disease in
which it is usually present is therefore to be looked upon as a grave
omen, particularly when the general symptoms are severe. In some cases
of malignant disease the number of leucocytes is increased to 15,000 or
20,000. A few hours after a severe haemorrhage also there is usually a
leucocytosis of from 15,000 to 30,000, which lasts for three or four
days (Lyon). In cases of haemorrhage the leucocytosis is increased by
infusion of fluids into the circulation. After all operations there is
at least a transient leucocytosis (_post-operative leucocytosis_)
(F. I. Dawson).

The leucocytosis begins soon after the infection manifests itself--for
example, by shivering, rigor, or rise of temperature. The number of
leucocytes rises somewhat rapidly, increases while the condition is
progressing, and remains high during the febrile period, but there is no
constant correspondence between the number of leucocytes and the height
of the temperature. The arrest of the inflammation and its resolution
are accompanied by a fall in the number of leucocytes, while the
occurrence of suppuration is attended with a further increase in their
number.

In interpreting the "blood count," it is to be kept in mind that a
_physiological leucocytosis_ occurs within three or four hours of taking
a meal, especially one rich in proteins, from 1500 to 2000 being added
to the normal number. In this _digestion leucocytosis_ the increase is
chiefly in the polynuclear neutrophile leucocytes. Immediately before
and after delivery, particularly in primiparae, there is usually a
moderate degree of leucocytosis. If the labour is normal and the
puerperium uncomplicated, the number of leucocytes regains the normal in
about a week. Lactation has no appreciable effect on the number of
leucocytes. In new-born infants the leucocyte count is abnormally high,
ranging from 15,000 to 20,000. In children under one year of age, the
normal average is from 10,000 to 20,000.

_Absence of Leucocytosis--Leucopenia._--In certain infective diseases
the number of leucocytes in the circulating blood is abnormally
low--3000 or 4000--and this condition is known as _leucopenia_. It
occurs in typhoid fever, especially in the later stages of the disease,
in tuberculous lesions unaccompanied by suppuration, in malaria, and in
most cases of uncomplicated influenza. The occurrence of leucocytosis in
any of these conditions is to be looked upon as an indication that a
mixed infection has taken place, and that some suppurative process is
present.

The absence of leucocytosis in some cases of virulent septic poisoning
has already been referred to.

It will be evident that too much reliance must not be placed upon a
single observation, particularly in emergency cases. Whenever possible,
a series of observations should be made, the blood being examined about
four hours after meals, and about the same hour each day.

The clinical significance of the blood count in individual diseases will
be further referred to.

_The Iodine or Glycogen Reaction._--The leucocyte count may be
supplemented by staining films of the blood with a watery solution of
iodine and potassium iodide. In all advancing purulent conditions, in
septic poisonings, in pneumonia, and in cancerous growths associated
with ulceration, a certain number of the polynuclear leucocytes are
stained a brown or reddish-brown colour, due to the action of the iodine
on some substance in the cells of the nature of glycogen. This reaction
is absent in serous effusions, in unmixed tuberculous infections, in
uncomplicated typhoid fever, and in the early stages of cancerous
growths.

CHAPTER III

INFLAMMATION

Definition--Nature of inflammation from surgical point of
view--Sequence of changes in bacterial inflammation--Clinical
aspects of inflammation--General principles of treatment--Chronic
inflammation.

Inflammation may be defined as the series of vital changes that occurs
in the tissues in response to irritation. These changes represent the
reaction of the tissue elements to the irritant, and constitute the
attempt made by nature to arrest or to limit its injurious effects, and
to repair the damage done by it.

The phenomena which characterise the inflammatory reaction can be
induced by any form of irritation--such, for example, as mechanical
injury, the application of heat or of chemical substances, or the action
of pathogenic bacteria and their toxins--and they are essentially
similar in kind whatever the irritant may be. The extent to which the
process may go, however, and its effects on the part implicated and on
the system as a whole, vary with different irritants and with the
intensity and duration of their action. A mechanical, a thermal, or a
chemical irritant, acting alone, induces a degree of reaction directly
proportionate to its physical properties, and so long as it does not
completely destroy the vitality of the part involved, the changes in the
tissues are chiefly directed towards repairing the damage done to the
part, and the inflammatory reaction is not only compatible with the
occurrence of ideal repair, but may be looked upon as an integral step
in the reparative process.

The irritation caused by infection with bacteria, on the other hand, is
cumulative, as the organisms not only multiply in the tissues, but in
addition produce chemical poisons (toxins) which aggravate the
irritative effects. The resulting reaction is correspondingly
progressive, and has as its primary object the expulsion of the irritant
and the limitation of its action. If the natural protective effort is
successful, the resulting tissue changes subserve the process of repair,
but if the bacteria gain the upper hand in the struggle, the
inflammatory reaction becomes more intense, certain of the tissue
elements succumb, and the process for the time being is a destructive
one. During the stage of bacterial inflammation, reparative processes
are in abeyance, and it is only after the inflammation has been allayed,
either by natural means or by the aid of the surgeon, that repair takes
place.

In applying the antiseptic principle to the treatment of wounds, our
main object is to exclude or to eliminate the bacterial factor, and so
to prevent the inflammatory reaction going beyond the stage in which it
is protective, and just in proportion as we succeed in attaining this
object, do we favour the occurrence of ideal repair.

#Sequence of Changes in Bacterial Inflammation.#--As the form of
inflammation with which we are most concerned is that due to the action
of bacteria, in describing the process by which the protective influence
of the inflammatory reaction is brought into play, we shall assume the
presence of a bacterial irritant.

The introduction of a colony of micro-organisms is quickly followed by
an accumulation of wandering cells, and proliferation of
connective-tissue cells in the tissues at the site of infection. The
various cells are attracted to the bacteria by a peculiar chemical or
biological power known as _chemotaxis_, which seems to result from
variations in the surface tension of different varieties of cells,
probably caused by some substance produced by the micro-organisms.
Changes in the blood vessels then ensue, the arteries becoming dilated
and the rate of the current in them being for a time increased--_active
hyperaemia_. Soon, however, the rate of the blood flow becomes slower
than normal, and in course of time the current may cease (_stasis_), and
the blood in the vessels may even coagulate (_thrombosis_). Coincidently
with these changes in the vessels, the leucocytes in the blood of the
inflamed part rapidly increase in number, and they become viscous and
adhere to the vessel wall, where they may accumulate in large numbers.
In course of time the leucocytes pass through the vessel
wall--_emigration of leucocytes_--and move towards the seat of
infection, giving rise to a marked degree of _local leucocytosis_.
Through the openings by which the leucocytes have escaped from the
vessels, red corpuscles may be passively extruded--_diapedesis of red
corpuscles_. These processes are accompanied by changes in the
endothelium of the vessel walls, which result in an increased formation
of lymph, which transudes into the meshes of the connective tissue
giving rise to an _inflammatory oedema_, or, if the inflammation is on a
free surface, forming an _inflammatory exudate_. The quantity and
characters of this exudate vary in different parts of the body, and
according to the nature, virulence, and location of the organisms
causing the inflammation. Thus it may be _serous_, as in some forms of
synovitis; _sero-fibrinous_, as in certain varieties of peritonitis, the
fibrin tending to limit the spread of the inflammation by forming
adhesions; _croupous_, when it coagulates on a free surface and forms a
false membrane, as in diphtheria; _haemorrhagic_ when mixed with blood;
or _purulent_, when suppuration has occurred. The protective effects of
the inflammatory reaction depend for the most part upon the transudation
of lymph and the emigration of leucocytes. The lymph contains the
opsonins which act on the bacteria and render them less able to resist
the attack of the phagocytes, as well as the various protective
antibodies which neutralise the toxins. The polymorph leucocytes are the
principal agents in the process of phagocytosis (p. 22), and together
with the other forms of phagocytes they ingest and destroy the bacteria.

If the attempt to repel the invading organisms is successful, the
irritant effects are overcome, the inflammation is arrested, and
_resolution_ is said to take place.

Certain of the vascular and cellular changes are now utilised to restore
the condition to the normal, and _repair_ ensues after the manner
already described. In certain situations, notably in tendon sheaths, in
the cavities of joints, and in the interior of serous cavities, for
example the pleura and peritoneum, the restoration to the normal is not
perfect, adhesions forming between the opposing surfaces.

If, however, the reaction induced by the infection is insufficient to
check the growth and spread of the organisms, or to inhibit their toxin
production, local necrosis of tissue may take place, either in the form
of suppuration or of gangrene, or the toxins absorbed into the
circulation may produce blood-poisoning, which may even prove fatal.

#Clinical Aspects of Inflammation.#--It must clearly be understood that
inflammation is not to be looked upon as a disease in itself, but rather
as an evidence of some infective process going on in the tissues in
which it occurs, and of an effort on the part of these tissues to
overcome the invading organisms and their products. The chief danger to
the patient lies, not in the reactive changes that constitute the
inflammatory process, but in the fact that he is liable to be poisoned
by the toxins of the bacteria at work in the inflamed area.

Since the days of Celsus (first century A.D.), heat, redness, swelling,
and pain have been recognised as cardinal signs of inflammation, and to
these may be added, interference with function in the inflamed part, and
general constitutional disturbance. Variations in these signs and
symptoms depend upon the acuteness of the condition, the nature of the
causative organism and of the tissue attacked, the situation of the part
in relation to the surface, and other factors.

The _heat_ of the inflamed part is to be attributed to the increased
quantity of blood present in it, and the more superficial the affected
area the more readily is the local increase of temperature detected by
the hand. This clinical point is best tested by placing the palm of the
hand and fingers for a few seconds alternately over an uninflamed and an
inflamed area, otherwise under similar conditions as to coverings and
exposure. In this way even slight differences may be recognised.

_Redness_, similarly, is due to the increased afflux of blood to the
inflamed part. The shade of colour varies with the stage of the
inflammation, being lighter and brighter in the early, hyperaemic stages,
and darker and duskier when the blood flow is slowed or when stasis has
occurred and the oxygenation of the blood is defective. In the
thrombotic stage the part may assume a purplish hue.

The _swelling_ is partly due to the increased amount of blood in the
affected part and to the accumulation of leucocytes and proliferated
tissue cells, but chiefly to the exudate in the connective
tissue--_inflammatory oedema_. The more open the structure of the tissue
of the part, the greater is the amount of swelling--witness the marked
degree of oedema that occurs in such parts as the scrotum or the eyelids.

_Pain_ is a symptom seldom absent in inflammation. _Tenderness_--that
is, pain elicited on pressure--is one of the most valuable diagnostic
signs we possess, and is often present before pain is experienced by the
patient. That the area of tenderness corresponds to the area of
inflammation is almost an axiom of surgery. Pain and tenderness are due
to the irritation of nerve filaments of the part, rendered all the more
sensitive by the abnormal conditions of their blood supply. In
inflammatory conditions of internal organs, for example the abdominal
viscera, the pain is frequently referred to other parts, usually to an
area supplied by branches from the same segment of the cord as that
supplying the inflamed part.

For purposes of diagnosis, attention should be paid to the terms in
which the patient describes his pain. For example, the pain caused by
an inflammation of the skin is usually described as of a _burning_ or
_itching_ character; that of inflammation in dense tissues like
periosteum or bone, or in encapsuled organs, as _dull_, _boring_, or
_aching_. When inflammation is passing on to suppuration the pain
assumes a _throbbing_ character, and as the pus reaches the surface, or
"points," as it is called, sharp, _darting_, or _lancinating_ pains are
experienced. Inflammation involving a nerve-trunk may cause a _boring_
or a _tingling_ pain; while the implication of a serous membrane such as
the pleura or peritoneum gives rise to a pain of a sharp, _stabbing_
character.

_Interference with the function_ of the inflamed part is always present
to a greater or less extent.

#Constitutional Disturbances.#--Under the term constitutional
disturbances are included the presence of fever or elevation of
temperature; certain changes in the pulse rate and the respiration;
gastro-intestinal and urinary disturbances; and derangements of the
central nervous system. These are all due to the absorption of toxins
into the general circulation.

_Temperature._--A marked rise of temperature is one of the most constant
and important concomitants of acute inflammatory conditions, and the
temperature chart forms a fairly reliable index of the state of the
patient. The toxins interfere with the nerve-centres in the medulla that
regulate the balance between the production and the loss of body heat.

Clinically the temperature is estimated by means of a self-registering
thermometer placed, for from one to five minutes, in close contact with
the skin in the axilla, or in the mouth. Sometimes the thermometer is
inserted into the rectum, where, however, the temperature is normally
3/4 F. higher than in the axilla.

_In health_ the temperature of the body is maintained at a mean of about
98.4 F. (37 C.) by the heat-regulating mechanism. It varies from hour
to hour even in health, reaching its maximum between four and eight in
the evening, when it may rise to 99 F., and is at its lowest between
four and six in the morning, when it may be about 97 F.

The temperature is more easily disturbed in children than in adults, and
may become markedly elevated (104 or 105 F.) from comparatively slight
causes; in the aged it is less liable to change, so that a rise to 103
or 104 F. is to be looked upon as indicating a high state of fever.

A sudden rise of temperature is usually associated with a feeling of
chilliness down the back and in the limbs, which may be so marked that
the patient shivers violently, while the skin becomes cold, pale, and
shrivelled--_cutis anserina_. This is a nervous reaction due to a want
of correspondence between the internal and the surface temperature of
the body, and is known clinically as a _rigor_. When the temperature
rises gradually the chill is usually slight and may be unobserved. Even
during the cold stage, however, the internal temperature is already
raised, and by the time the chill has passed off its maximum has been
reached.