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CHAPTER IV

SUPPURATION


Definition--Pus--_Varieties_--Acute circumscribed abscess--_Acute

   suppuration in a wound_--_Acute Suppuration in a mucous
   membrane_--Diffuse cellulitis and diffuse suppuration--
   _Whitlow_--_Suppurative cellulitis in different situations_--Chronic
   suppuration--Sinus, Fistula--Constitutional manifestations of
   pyogenic infection--_Sapraemia_--_Septicaemia_--_Pyaemia_.

Suppuration, or the formation of pus, is one of the results of the action of bacteria on the tissues. The invading organism is usually one of the staphylococci, less frequently a streptococcus, and still less frequently one of the other bacteria capable of producing pus, such as the bacillus coli communis, the gonococcus, the pneumococcus, or the typhoid bacillus.

So long as the tissues are in a healthy condition they are able to withstand the attacks of moderate numbers of pyogenic bacteria of ordinary virulence, but when devitalised by disease, by injury, or by inflammation due to the action of other pathogenic organisms, suppuration ensues.

It would appear, for example, that pyogenic organisms can pass through the healthy urinary tract without doing any damage, but if the pelvis of the kidney, the ureter, or the bladder is the seat of stone, they give rise to suppuration. Similarly, a calculus in one of the salivary ducts frequently results in an abscess forming in the floor of the mouth. When the lumen of a tubular organ, such as the appendix or the Fallopian tube is blocked also, the action of pyogenic organisms is favoured and suppuration ensues.

  1. Pus.#--The fluid resulting from the process of suppuration is known

as _pus_. In its typical form it is a yellowish creamy substance, of alkaline reaction, with a specific gravity of about 1030, and it has a peculiar mawkish odour. If allowed to stand in a test-tube it does not coagulate, but separates into two layers: the upper, transparent, straw-coloured fluid, the _liquor puris_ or pus serum, closely resembling blood serum in its composition, but containing less protein and more cholestrol; it also contains leucin, tyrosin, and certain albumoses which prevent coagulation.

The layer at the bottom of the tube consists for the most part of polymorph leucocytes, and proliferated connective tissue and endothelial cells (_pus corpuscles_). Other forms of leucocytes may be present, especially in long-standing suppurations; and there are usually some red corpuscles, dead bacteria, fat cells and shreds of tissue, cholestrol crystals, and other detritus in the deposit.

If a film of fresh pus is examined under the microscope, the pus cells are seen to have a well-defined rounded outline, and to contain a finely granular protoplasm and a multi-partite nucleus; if still warm, the cells may exhibit amoeboid movement. In stained films the nuclei take the stain well. In older pus cells the outline is irregular, the protoplasm coarsely granular, and the nuclei disintegrated, no longer taking the stain.

_Variations from Typical Pus._--Pus from old-standing sinuses is often watery in consistence (ichorous), with few cells. Where the granulations are vascular and bleed easily, it becomes sanious from admixture with red corpuscles; while, if a blood-clot be broken down and the debris mixed with the pus, it contains granules of blood pigment and is said to be "grumous." The _odour_ of pus varies with the different bacteria producing it. Pus due to ordinary pyogenic cocci has a mawkish odour; when putrefactive organisms are present it has a putrid odour; when it forms in the vicinity of the intestinal canal it usually contains the bacillus coli communis and has a faecal odour.

The _colour_ of pus also varies: when due to one or other of the varieties of the bacillus pyocyaneus, it is usually of a blue or green colour; when mixed with bile derivatives or altered blood pigment, it may be of a bright orange colour. In wounds inflicted with rough iron implements from which rust is deposited, the pus often presents the same colour.

The pus may form and collect within a circumscribed area, constituting a localised _abscess_; or it may infiltrate the tissues over a wide area--_diffuse suppuration_.


ACUTE CIRCUMSCRIBED ABSCESS

Any tissue of the body may be the seat of an acute abscess, and there are many routes by which the bacteria may gain access to the affected area. For example: an abscess in the integument or subcutaneous cellular tissue usually results from infection by organisms which have entered through a wound or abrasion of the surface, or along the ducts of the skin; an abscess in the breast from organisms which have passed along the milk ducts opening on the nipple, or along the lymphatics which accompany these. An abscess in a lymph gland is usually due to infection passing by way of the lymph channels from the area of skin or mucous membrane drained by them. Abscesses in internal organs, such as the kidney, liver, or brain, usually result from organisms carried in the blood-stream from some focus of infection elsewhere in the body.

A knowledge of the possible avenues of infection is of clinical importance, as it may enable the source of a given abscess to be traced and dealt with. In suppuration in the Fallopian tube (pyosalpynx), for example, the fact that the most common origin of the infection is in the genital passage, leads to examination for vaginal discharge; and if none is present, the abscess is probably due to infection carried in the blood-stream from some primary focus about the mouth, such as a gumboil or an infective sore throat.

The exact location of an abscess also may furnish a key to its source; in axillary abscess, for example, if the suppuration is in the lymph glands the infection has come through the afferent lymphatics; if in the cellular tissue, it has spread from the neck or chest wall; if in the hair follicles, it is a local infection through the skin.

  1. Formation of an Abscess.#--When pyogenic bacteria are introduced into

the tissue there ensues an inflammatory reaction, which is characterised by dilatation of the blood vessels, exudation of large numbers of leucocytes, and proliferation of connective-tissue cells. These wandering cells soon accumulate round the focus of infection, and form a protective barrier which tends to prevent the spread of the organisms and to restrict their field of action. Within the area thus circumscribed the struggle between the bacteria and the phagocytes takes place, and in the process toxins are formed by the organisms, a certain number of the leucocytes succumb, and, becoming degenerated, set free certain proteolytic enzymes or ferments. The toxins cause coagulation-necrosis of the tissue cells with which they come in contact, the ferments liquefy the exudate and other albuminous substances, and in this way _pus_ is formed.

If the bacteria gain the upper hand, this process of liquefaction which is characteristic of suppuration, extends into the surrounding tissues, the protective barrier of leucocytes is broken down, and the suppurative process spreads. A fresh accession of leucocytes, however, forms a new barrier, and eventually the spread is arrested, and the collection of pus so hemmed in constitutes an _abscess_.

Owing to the swelling and condensation of the parts around, the pus thus formed is under considerable pressure, and this causes it to burrow along the lines of least resistance. In the case of a subcutaneous abscess the pus usually works its way towards the surface, and "points," as it is called. Where it approaches the surface the skin becomes soft and thin, and eventually sloughs, allowing the pus to escape.

An abscess forming in the deeper planes is prevented from pointing directly to the surface by the firm fasciae and other fibrous structures. The pus therefore tends to burrow along the line of the blood vessels and in the connective-tissue septa, till it either finds a weak spot or causes a portion of fascia to undergo necrosis and so reaches the surface. Accordingly, many abscess cavities resulting from deep-seated suppuration are of irregular shape, with pouches and loculi in various directions--an arrangement which interferes with their successful treatment by incision and drainage.

The relief of tension which follows the bursting of an abscess, the removal of irritation by the escape of pus, and the casting off of bacteria and toxins, allow the tissues once more to assert themselves, and a process of repair sets in. The walls of the abscess fall in; granulation tissue grows into the space and gradually fills it; and later this is replaced by cicatricial tissue. As a result of the subsequent contraction of the cicatricial tissue, the scar is usually depressed below the level of the surrounding skin surface.

If an abscess is prevented from healing--for example, by the presence of a foreign body or a piece of necrosed bone--a sinus results, and from it pus escapes until the foreign body is removed.

  1. Clinical Features of an Acute Circumscribed Abscess.#--In the initial

stages the usual symptoms of inflammation are present. Increased elevation of temperature, with or without a rigor, progressive leucocytosis, and sweating, mark the transition between inflammation and suppuration. An increasing leucocytosis is evidence that a suppurative process is spreading.

The local symptoms vary with the seat of the abscess. When it is situated superficially--for example, in the breast tissue--the affected area is hot, the redness of inflammation gives place to a dusky purple colour, with a pale, sometimes yellow, spot where the pus is near the surface. The swelling increases in size, the firm brawny centre becomes soft, projects as a cone beyond the level of the rest of the swollen area, and is usually surrounded by a zone of induration.

By gently palpating with the finger-tips over the softened area, a fluid wave may be detected--_fluctuation_--and when present this is a certain indication of the existence of fluid in the swelling. Its recognition, however, is by no means easy, and various fallacies are to be guarded against in applying this test clinically. When, for example, the walls of the abscess are thick and rigid, or when its contents are under excessive tension, the fluid wave cannot be elicited. On the other hand, a sensation closely resembling fluctuation may often be recognised in oedematous tissues, in certain soft, solid tumours such as fatty tumours or vascular sarcomata, in aneurysm, and in a muscle when it is palpated in its transverse axis.

When pus has formed in deeper parts, and before it has reached the surface, oedema of the overlying skin is frequently present, and the skin pits on pressure.

With the formation of pus the continuous burning or boring pain of inflammation assumes a throbbing character, with occasional sharp, lancinating twinges. Should doubt remain as to the presence of pus, recourse may be had to the use of an exploring needle.

_Differential Diagnosis of Acute Abscess._--A practical difficulty which frequently arises is to decide whether or not pus has actually formed. It may be accepted as a working rule in practice that when an acute inflammation has lasted for four or five days without showing signs of abatement, suppuration has almost certainly occurred. In deep-seated suppuration, marked oedema of the skin and the occurrence of rigors and sweating may be taken to indicate the formation of pus.

There are cases on record where rapidly growing sarcomatous and angiomatous tumours, aneurysms, and the bruises that occur in haemophylics, have been mistaken for acute abscesses and incised, with disastrous results.

  1. Treatment of Acute Abscesses.#--The dictum of John Bell, "Where there

is pus, let it out," summarises the treatment of abscess. The extent and situation of the incision and the means taken to drain the cavity, however, vary with the nature, site, and relations of the abscess. In a superficial abscess, for example a bubo, or an abscess in the breast or face where a disfiguring scar is undesirable, a small puncture should be made where the pus threatens to point, and a Klapp's suction bell be applied as already described (p. 39). A drain is not necessary, and in the intervals between the applications of the bell the part is covered with a moist antiseptic dressing.

In abscesses deeply placed, as for example under the gluteal or pectoral muscles, one or more incisions should be made, and the cavity drained by glass or rubber tubes or by strips of rubber tissue.

The wound should be dressed the next day, and the tube shortened, in the case of a rubber tube, by cutting off a portion of its outer end. On the second day or later, according to circumstances, the tube is removed, and after this the dressing need not be repeated oftener than every second or third day.

Where pus has formed in relation to important structures--as, for example, in the deeper planes of the neck--_Hilton's method_ of opening the abscess may be employed. An incision is made through the skin and fascia, a grooved director is gently pushed through the deeper tissues till pus escapes along its groove, and then the track is widened by passing in a pair of dressing forceps and expanding the blades. A tube, or strip of rubber tissue, is introduced, and the subsequent treatment carried out as in other abscesses. When the drain lies in proximity to a large blood vessel, care must be taken not to leave it in position long enough to cause ulceration of the vessel wall by pressure.

In some abscesses, such as those in the vicinity of the anus, the cavity should be laid freely open in its whole extent, stuffed with iodoform or bismuth gauze, and treated by the open method.

It is seldom advisable to wash out an abscess cavity, and squeezing out the pus is also to be avoided, lest the protective zone be broken down and the infection be diffused into the surrounding tissues.

The importance of taking precautions against further infection in opening an abscess can scarcely be exaggerated, and the rapidity with which healing occurs when the access of fresh bacteria is prevented is in marked contrast to what occurs when such precautions are neglected and further infection is allowed to take place.

_Acute Suppuration in a Wound._--If in the course of an operation infection of the wound has occurred, a marked inflammatory reaction soon manifests itself, and the same changes as occur in the formation of an acute abscess take place, modified, however, by the fact that the pus can more readily reach the surface. In from twenty-four to forty-eight hours the patient is conscious of a sensation of chilliness, or may even have a rigor. At the same time he feels generally out of sorts, with impaired appetite, headache, and it may be looseness of the bowels. His temperature rises to 100 or 101 F., and the pulse quickens to 100 or 110.

On exposing the wound it is found that the parts for some distance around are red, glazed, and oedematous. The discoloration and swelling are most intense in the immediate vicinity of the wound, the edges of which are everted and moist. Any stitches that may have been introduced are tight, and the deep ones may be cutting into the tissues. There is heat, and a constant burning or throbbing pain, which is increased by pressure. If the stitches be cut, pus escapes, the wound gapes, and its surfaces are found to be inflamed and covered with pus.

The open method is the only safe means of treating such wounds. The infected surface may be sponged over with pure carbolic acid, the excess of which is washed off with absolute alcohol, and the wound either drained by tubes or packed with iodoform gauze. The practice of scraping such surfaces with the sharp spoon, squeezing or even of washing them out with antiseptic lotions, is attended with the risk of further diffusing the organisms in the tissue, and is only to be employed under exceptional circumstances. Continuous irrigation of infected wounds or their immersion in antiseptic baths is sometimes useful. The free opening up of the wound is almost immediately followed by a fall in the temperature. The surrounding inflammation subsides, the discharge of pus lessens, and healing takes place by the formation of granulation tissue--the so-called "healing by second intention."

Wound infection may take place from _catgut_ which has not been efficiently prepared. The local and general reactions may be slight, and, as a rule, do not appear for seven or eight days after the operation, and, it may be, not till after the skin edges have united. The suppuration is strictly localised to the part of the wound where catgut was employed for stitches or ligatures, and shows little tendency to spread. The infected part, however, is often long of healing. The irritation in these cases is probably due to toxins in the catgut and not to bacteria.

When suppuration occurs in connection with buried sutures of unabsorbable materials, such as silk, silkworm gut, or silver wire, it is apt to persist till the foreign material is cast off or removed.

Suppuration may occur in the track of a skin stitch, producing a _stitch abscess_. The infection may arise from the material used, especially catgut or silk, or, more frequently perhaps, from the growth of staphylococcus albus from the skin of the patient when this has been imperfectly disinfected. The formation of pus under these conditions may not be attended with any of the usual signs of suppuration, and beyond some induration around the wound and a slight tenderness on pressure there may be nothing to suggest the presence of an abscess.

_Acute Suppuration of a Mucous Membrane._--When pyogenic organisms gain access to a mucous membrane, such as that of the bladder, urethra, or middle ear, the usual phenomena of acute inflammation and suppuration ensue, followed by the discharge of pus on the free surface. It would appear that the most marked changes take place in the submucous tissue, causing the covering epithelium in places to die and leave small superficial ulcers, for example in gonorrhoeal urethritis, the cicatricial contraction of the scar subsequently leading to the formation of stricture. When mucous glands are present in the membrane, the pus is mixed with mucus--_muco-pus_.


DIFFUSE CELLULITIS AND DIFFUSE SUPPURATION

Cellulitis is an acute affection resulting from the introduction of some organism--commonly the _streptococcus pyogenes_--into the cellular connective tissue of the integument, intermuscular septa, tendon sheaths, or other structures. Infection always takes place through a breach of the surface, although this may be superficial and insignificant, such as a pin-prick, a scratch, or a crack under a nail, and the wound may have been healed for some time before the inflammation becomes manifest. The cellulitis, also, may develop at some distance from the seat of inoculation, the organisms having travelled by the lymphatics.

The virulence of the organisms, the loose, open nature of the tissues in which they develop, and the free lymphatic circulation by means of which they are spread, account for the diffuse nature of the process. Sometimes numbers of cocci are carried for a considerable distance from the primary area before they are arrested in the lymphatics, and thus several patches of inflammation may appear with healthy areas between.

The pus infiltrates the meshes of the cellular tissue, there is sloughing of considerable portions of tissue of low vitality, such as fat, fascia, or tendon, and if the process continues for some time several collections of pus may form.

_Clinical Features._--The reaction in cases of diffuse cellulitis is severe, and is usually ushered in by a distinct chill or even a rigor, while the temperature rises to 103, 104, or 105 F. The pulse is proportionately increased in frequency, and is small, feeble, and often irregular. The face is flushed, the tongue dry and brown, and the patient may become delirious, especially during the night. Leucocytosis is present in cases of moderate severity; but in severe cases the virulence of the toxins prevents reaction taking place, and leucocytosis is absent.

The local manifestations vary with the relation of the seat of the inflammation to the surface. When the superficial cellular tissue is involved, the skin assumes a dark bluish-red colour, is swollen, oedematous, and the seat of burning pain. To the touch it is firm, hot, and tender. When the primary focus is in the deeper tissues, the constitutional disturbance is aggravated, while the local signs are delayed, and only become prominent when pus forms and approaches the surface. It is not uncommon for blebs containing dark serous fluid to form on the skin. The infection frequently spreads along the line of the main lymph vessels of the part (_septic lymphangitis_) and may reach the lymph glands (_septic lymphadenitis_).

With the formation of pus the skin becomes soft and boggy at several points, and eventually breaks, giving exit to a quantity of thick grumous discharge. Sometimes several small collections under the skin fuse, and an abscess is formed in which fluctuation can be detected. Occasionally gases are evolved in the tissues, giving rise to emphysema. It is common for portions of fascia, ligaments, or tendons to slough, and this may often be recognised clinically by a peculiar crunching or grating sensation transmitted to the fingers on making firm pressure on the part.

If it is not let out by incision, the pus, travelling along the lines of least resistance, tends to point at several places on the surface, or to open into joints or other cavities.

_Prognosis._--The occurrence of _septicaemia_ is the most serious risk, and it is in cases of diffuse suppurative cellulitis that this form of blood-poisoning assumes its most aggravated forms. The toxins of the streptococci are exceedingly virulent, and induce local death of tissue so rapidly that the protective emigration of leucocytes fails to take place. In some cases the passage of masses of free cocci in the lymphatics, or of infective emboli in the blood vessels, leads to the formation of _pyogenic abscesses_ in vital organs, such as the brain, lungs, liver, kidneys, or other viscera. _Haemorrhage_ from erosion of arterial or venous trunks may take place and endanger life.

_Treatment._--The treatment of diffuse cellulitis depends to a large extent on the situation and extent of the affected area, and on the stage of the process.

_In the limbs_, for example, where the application of a constricting band is practicable, Bier's method of inducing passive hyperaemia yields excellent results. If pus is formed, one or more small incisions are made and a light moist dressing placed over the wounds to absorb the discharge, but no drain is inserted. The whole of the inflamed area should be covered with gauze wrung out of a 1 in 10 solution of ichthyol in glycerine. The dressing is changed as often as necessary, and in the intervals when the band is off, gentle active and passive movements should be carried out to prevent the formation of adhesions. After incisions have been made, we have found the _immersion_ of the limb, for a few hours at a time, in a water-bath containing warm boracic lotion or eusol a useful adjuvant to the passive hyperaemia.

_Continuous irrigation_ of the part by a slow, steady stream of lotion, at the body temperature, such as eusol, or Dakin's solution, or boracic acid, or frequent washing with peroxide of hydrogen, has been found of value.

A suitably arranged splint adds to the comfort of the patient; and the limb should be placed in the attitude which, in the event of stiffness resulting, will least interfere with its usefulness. The elbow, for example, should be flexed to a little less than a right angle; at the wrist, the hand should be dorsiflexed and the fingers flexed slightly towards the palm.

Massage, passive movement, hot and cold douching, and other measures, may be necessary to get rid of the chronic oedema, adhesions of tendons, and stiffness of joints which sometimes remain.

In situations where a constricting band cannot be applied, for example, on the trunk or the neck, Klapp's suction bells may be used, small incisions being made to admit of the escape of pus.

If these measures fail or are impracticable, it may be necessary to make one or more free incisions, and to insert drainage-tubes, portions of rubber dam, or iodoform worsted.

The general treatment of toxaemia must be carried out, and in cases due to infection by streptococci, anti-streptococcic serum may be used.

In a few cases, amputation well above the seat of disease, by removing the source of toxin production, offers the only means of saving the patient.


WHITLOW

The clinical term whitlow is applied to an acute infection, usually followed by suppuration, commonly met with in the fingers, less frequently in the toes. The point of infection is often trivial--a pin-prick, a puncture caused by a splinter of wood, a scratch, or even an imperceptible lesion of the skin.

Several varieties of whitlow are recognised, but while it is convenient to describe them separately, it is to be clearly understood that clinically they merge one into another, and it is not always possible to determine in which connective-tissue plane a given infection has originated.

_Initial Stage._--Attention is usually first attracted to the condition by a sensation of tightness in the finger and tenderness when the part is squeezed or knocked against anything. In the course of a few hours the part becomes red and swollen; there is continuous pain, which soon assumes a throbbing character, particularly when the hand is dependent, and may be so severe as to prevent sleep, and the patient may feel generally out of sorts.

If a constricting band is applied at this stage, the infection can usually be checked and the occurrence of suppuration prevented. If this fails, or if the condition is allowed to go untreated, the inflammatory reaction increases and terminates in suppuration, giving rise to one or other of the forms of whitlow to be described.

_The Purulent Blister._--In the most superficial variety, pus forms between the rete Malpighii and the stratum corneum of the skin, the latter being raised as a blister in which fluctuation can be detected (Fig. 9, a). This is commonly met with in the palm of the hand of labouring men who have recently resumed work after a spell of idleness. When the blister forms near the tip of the finger, the pus burrows under the nail--which corresponds to the stratum corneum--raising it from its bed.

There is some local heat and discoloration, and considerable pain and tenderness, but little or no constitutional disturbance. Superficial lymphangitis may extend a short distance up the forearm. By clipping away the raised epidermis, and if necessary the nail, the pus is allowed to escape, and healing speedily takes place.

_Whitlow at the Nail Fold._--This variety, which is met with among those who handle septic material, occurs in the sulcus between the nail and the skin, and is due to the introduction of infective matter at the root of the nail (Fig. 9, b). A small focus of suppuration forms under the nail, with swelling and redness of the nail fold, causing intense pain and discomfort, interfering with sleep, and producing a constitutional reaction out of all proportion to the local lesion.

To allow the pus to escape, it is necessary, under local anaesthesia, to cut away the nail fold as well as the portion of nail in the infected area, or, it may be, to remove the nail entirely. If only a small opening is made in the nail it is apt to be blocked by granulations.

[Illustration: FIG. 9.--Diagram of various forms of Whitlow.

 a = Purulent blister.
 b = Suppuration at nail fold.
 c = Subcutaneous whitlow.
 d = Whitlow in sheath of flexor tendon (e). ]

_Subcutaneous Whitlow._--In this variety the infection manifests itself as a cellulitis of the pulp of the finger (Fig. 9, c), which sometimes spreads towards the palm of the hand. The finger becomes red, swollen, and tense; there is severe throbbing pain, which is usually worst at night and prevents sleep, and the part is extremely tender on pressure. When the palm is invaded there may be marked oedema of the back of the hand, the dense integument of the palm preventing the swelling from appearing on the front. The pus may be under such tension that fluctuation cannot be detected. The patient is usually able to flex the finger to a certain extent without increasing the pain--a point which indicates that the tendon sheaths have not been invaded. The suppurative process may, however, spread to the tendon sheaths, or even to the bone. Sometimes the excessive tension and virulent toxins induce actual gangrene of the distal part, or even of the whole finger. There is considerable constitutional disturbance, the temperature often reaching 101 or 102 F.

The treatment consists in applying a constriction band and making an incision over the centre of the most tender area, care being taken to avoid opening the tendon sheath lest the infection be conveyed to it. Moist dressings should be employed while the suppuration lasts. Carbolic fomentations, however, are to be avoided on account of the risk of inducing gangrene.

_Whitlow of the Tendon Sheaths._--In this form the main incidence of the infection is on the sheaths of the flexor tendons, but it is not always possible to determine whether it started there or spread thither from the subcutaneous cellular tissue (Fig. 9, d). In some cases both connective tissue planes are involved. The affected finger becomes red, painful, and swollen, the swelling spreading to the dorsum. The involvement of the tendon sheath is usually indicated by the patient being unable to flex the finger, and by the pain being increased when he attempts to do so. On account of the anatomical arrangement of the tendon sheaths, the process may spread into the forearm--directly in the case of the thumb and little finger, and after invading the palm in the case of the other fingers--and there give rise to a diffuse cellulitis which may result in sloughing of fasciae and tendons. When the infection spreads into the common flexor sheath under the transverse carpal (anterior annular) ligament, it is not uncommon for the intercarpal and wrist joints to become implicated. Impaired movement of tendons and joints is, therefore, a common sequel to this variety of whitlow.

The _treatment_ consists in inducing passive hyperaemia by Bier's method, and, if this is done early, suppuration may be avoided. If pus forms, small incisions are made, under local anaesthesia, to relieve the tension in the sheath and to diminish the risk of the tendons sloughing. No form of drain should be inserted. In the fingers the incisions should be made in the middle line, and in the palm they should be made over the metacarpal bones to avoid the digital vessels and nerves. If pus has spread under the transverse carpal ligament, the incision must be made above the wrist. Passive movements and massage must be commenced as early as possible and be perseveringly employed to diminish the formation of adhesions and resulting stiffness.

_Subperiosteal Whitlow._--This form is usually an extension of the subcutaneous or of the thecal variety, but in some cases the inflammation begins in the periosteum--usually of the terminal phalanx. It may lead to necrosis of a portion or even of the entire phalanx. This is usually recognised by the persistence of suppuration long after the acute symptoms have passed off, and by feeling bare bone with the probe. In such cases one or more of the joints are usually implicated also, and lateral mobility and grating may be elicited. Recovery does not take place until the dead bone is removed, and the usefulness of the finger is often seriously impaired by fibrous or bony ankylosis of the interphalangeal joints. This may render amputation advisable when a stiff finger is likely to interfere with the patient's occupation.


SUPPURATIVE CELLULITIS IN DIFFERENT SITUATIONS

_Cellulitis of the forearm_ is usually a sequel to one of the deeper varieties of whitlow.

In the _region of the elbow-joint_, cellulitis is common around the olecranon. It may originate as an inflammation of the olecranon bursa, or may invade the bursa secondarily. In exceptional cases the elbow-joint is also involved.

Cellulitis of the _axilla_ may originate in suppuration in the lymph glands, following an infected wound of the hand, or it may spread from a septic wound on the chest wall or in the neck. In some cases it is impossible to discover the primary seat of infection. A firm, brawny swelling forms in the armpit and extends on to the chest wall. It is attended with great pain, which is increased on moving the arm, and there is marked constitutional disturbance. When suppuration occurs, its spread is limited by the attachments of the axillary fascia, and the pus tends to burrow on to the chest wall beneath the pectoral muscles, and upwards towards the shoulder-joint, which may become infected. When the pus forms in the axillary space, the treatment consists in making free incisions, which should be placed on the thoracic side of the axilla to avoid the axillary vessels and nerves. If the pus spreads on to the chest wall, the abscess should be opened below the clavicle by Hilton's method, and a counter opening may be made in the axilla.

Cellulitis of the _sole of the foot_ may follow whitlow of the toes.

In the _region of the ankle_ cellulitis is not common; but _around the knee_ it frequently occurs in relation to the prepatellar bursa and to the popliteal lymph glands, and may endanger the knee-joint. It is also met with in the _groin_ following on inflammation and suppuration of the inguinal glands, and cases are recorded in which the sloughing process has implicated the femoral vessels and led to secondary haemorrhage.

Cellulitis of the scalp, orbit, neck, pelvis, and perineum will be considered with the diseases of these regions.


CHRONIC SUPPURATION

While it is true that a chronic pyogenic abscess is sometimes met with--for example, in the breast and in the marrow of long bones--in the great majority of instances the formation of a chronic or cold abscess is the result of the action of the tubercle bacillus. It is therefore more convenient to study this form of suppuration with tuberculosis (p. 139).


SINUS AND FISTULA

  1. Sinus.#--A sinus is a track leading from a focus of suppuration to a

cutaneous or mucous surface. It usually represents the path by which the discharge escapes from an abscess cavity that has been prevented from closing completely, either from mechanical causes or from the persistent formation of discharge which must find an exit. A sinus is lined by granulation tissue, and when it is of long standing the opening may be dragged below the level of the surrounding skin by contraction of the scar tissue around it. As a sinus will persist until the obstacle to closure of the original abscess is removed, it is necessary that this should be sought for. It may be a foreign body, such as a piece of dead bone, an infected ligature, or a bullet, acting mechanically or by keeping up discharge, and if the body is removed the sinus usually heals. The presence of a foreign body is often suggested by a mass of redundant granulations at the mouth of the sinus. If a sinus passes through a muscle, the repeated contractions tend to prevent healing until the muscle is kept at rest by a splint, or put out of action by division of its fibres. The sinuses associated with empyema are prevented from healing by the rigidity of the chest wall, and will only close after an operation which admits of the cavity being obliterated. In any case it is necessary to disinfect the track, and, it may be, to remove the unhealthy granulations lining it, by means of the sharp spoon, or to excise it bodily. To encourage healing from the bottom the cavity should be packed with bismuth or iodoform gauze. The healing of long and tortuous sinuses is often hastened by the injection of Beck's bismuth paste (p. 145). If disfigurement is likely to follow from cicatricial contraction--for example, in a sinus over the lower jaw associated with a carious tooth--the sinus should be excised and the raw surfaces approximated with stitches.

The _tuberculous sinus_ is described under Tuberculosis.

A #fistula# is an abnormal canal passing from a mucous surface to the skin or to another mucous surface. Fistulae resulting from suppuration usually occur near the natural openings of mucous canals--for example, on the cheek, as a salivary fistula; beside the inner angle of the eye, as a lacrymal fistula; near the ear, as a mastoid fistula; or close to the anus, as a fistula-in-ano. Intestinal fistulae are sometimes met with in the abdominal wall after strangulated hernia, operations for appendicitis, tuberculous peritonitis, and other conditions. In the perineum, fistulae frequently complicate stricture of the urethra.

Fistulae also occur between the bladder and vagina (_vesico-vaginal fistula_), or between the bladder and the rectum (_recto-vesical fistula_).

The _treatment_ of these various forms of fistula will be described in the sections dealing with the regions in which they occur.

_Congenital fistulae_, such as occur in the neck from imperfect closure of branchial clefts, or in the abdomen from unobliterated foetal ducts such as the urachus or Meckel's diverticulum, will be described in their proper places.


CONSTITUTIONAL MANIFESTATIONS OF PYOGENIC INFECTION

We have here to consider under the terms Sapraemia, Septicaemia, and Pyaemia certain general effects of pyogenic infection, which, although their clinical manifestations may vary, are all associated with the action of the same forms of bacteria. They may occur separately or in combination, or one may follow on and merge into another.

  1. Sapraemia#, or septic intoxication, is the name applied to a form of

poisoning resulting from the absorption into the blood of the toxic products of pyogenic bacteria. These products, which are of the nature of alkaloids, act immediately on their entrance into the circulation, and produce effects in direct proportion to the amount absorbed. As the toxins are gradually eliminated from the body the symptoms abate, and if no more are introduced they disappear. Sapraemia in these respects, therefore, is comparable to poisoning by any other form of alkaloid, such as strychnin or morphin.

_Clinical Features._--The symptoms of sapraemia seldom manifest themselves within twenty-four hours of an operation or injury, because it takes some time for the bacteria to produce a sufficient dose of their poisons. The onset of the condition is marked by a feeling of chilliness, sometimes amounting to a rigor, and a rise of temperature to 102, 103, or 104 F., with morning remissions (Fig. 10). The heart's action is markedly depressed, and the pulse is soft and compressible. The appetite is lost, the tongue dry and covered with a thin brownish-red fur, so that it has the appearance of "dried beef." The urine is scanty and loaded with urates. In severe cases diarrhoea and vomiting of dark coffee-ground material are often prominent features. Death is usually impending when the skin becomes cold and clammy, the mucous membranes livid, the pulse feeble and fluttering, the discharges involuntary, and when a low form of muttering delirium is present.

[Illustration: FIG. 10.--Charts of Acute sapraemia from (a) case of crushed foot, and (b) case of incomplete abortion.]

A local form of septic infection is always present--it may be an abscess, an infected compound fracture, or an infection of the cavity of the uterus, for example, from a retained portion of placenta.

_Treatment._--The first indication is the immediate and complete removal of the infected material. The wound must be freely opened, all blood-clot, discharge, or necrosed tissue removed, and the area disinfected by washing with sterilised salt solution, peroxide of hydrogen, or eusol. Stronger lotions are to be avoided as being likely to depress the tissues, and so interfere with protective phagocytosis. On account of its power of neutralising toxins, iodoform is useful in these cases, and is best employed by packing the wound with iodoform gauze, and treating it by the open method, if this is possible.

The general treatment is carried out on the same lines as for other infective conditions.

  1. Chronic sapraemia or Hectic Fever.#--Hectic fever differs from acute

sapraemia merely in degree. It usually occurs in connection with tuberculous conditions, such as bone or joint disease, psoas abscess, or empyema, which have opened externally, and have thereby become infected with pyogenic organisms. It is gradual in its development, and is of a mild type throughout.

[Illustration: FIG. 11.--Chart of Hectic Fever.]

The pulse is small, feeble, and compressible, and the temperature rises in the afternoon or evening to 102 or 103 F. (Fig. 11), the cheeks becoming characteristically flushed. In the early morning the temperature falls to normal or below it, and the patient breaks into a profuse perspiration, which leaves him pale, weak, and exhausted. He becomes rapidly and markedly emaciated, even although in some cases the appetite remains good and is even voracious.

The poisons circulating in the blood produce _waxy degeneration_ in certain viscera, notably the liver, spleen, kidneys, and intestines. The process begins in the arterial walls, and spreads thence to the connective-tissue structures, causing marked enlargement of the affected organs. Albuminuria, ascites, oedema of the lower limbs, clubbing of the fingers, and diarrhoea are among the most prominent symptoms of this condition.

The _prognosis_ in hectic fever depends on the completeness with which the further absorption of toxins can be prevented. In many cases this can only be effected by an operation which provides for free drainage, and, if possible, the removal of infected tissues. The resulting wound is best treated by the open method. Even advanced waxy degeneration does not contra-indicate this line of treatment, as the diseased organs usually recover if the focus from which absorption of toxic material is taking place is completely eradicated.

[Illustration: FIG. 12.--Chart of case of Septicaemia followed by Pyaemia.]

  1. Septicaemia.#--This form of blood-poisoning is the result of the action

of pyogenic bacteria, which not only produce their toxins at the primary seat of infection, but themselves enter the blood-stream and are carried to other parts, where they settle and produce further effects.

_Clinical Features._--There may be an incubation period of some hours between the infection and the first manifestation of acute septicaemia. In such conditions as acute osteomyelitis or acute peritonitis, we see the most typical clinical pictures of this condition. The onset is marked by a chill, or a rigor, which may be repeated, while the temperature rises to 103 or 104 F., although in very severe cases the temperature may remain subnormal throughout, the virulence of the toxins preventing reaction. It is in the general appearance of the patient and in the condition of the pulse that we have our best guides as to the severity of the condition. If the pulse remains firm, full, and regular, and does not exceed 110 or even 120, while the temperature is moderately raised, the outlook is hopeful; but when the pulse becomes small and compressible, and reaches 130 or more, especially if at the same time the temperature is low, a grave prognosis is indicated. The tongue is often dry and coated with a black crust down the centre, while the sides are red. It is a good omen when the tongue becomes moist again. Thirst is most distressing, especially in septicaemia of intestinal origin. Persistent vomiting of dark-brown material is often present, and diarrhoea with blood-stained stools is not uncommon. The urine is small in amount, and contains a large proportion of urates. As the poisons accumulate, the respiration becomes shallow and laboured, the face of a dull ashy grey, the nose pinched, and the skin cold and clammy. Capillary haemorrhages sometimes take place in the skin or mucous membranes; and in a certain proportion of cases cutaneous eruptions simulating those of scarlet fever or measles appear, and are apt to lead to errors in diagnosis. In other cases there is slight jaundice. The mental state is often one of complete apathy, the patient failing to realise the gravity of his condition; sometimes there is delirium.

The _prognosis_ is always grave, and depends on the possibility of completely eradicating the focus of infection, and on the reserve force the patient has to carry him over the period during which he is eliminating the poison already circulating in his blood.

The _treatment_ is carried out on the same lines as in sapraemia, but it is less likely to be successful owing to the organisms having entered the circulation. When possible, the primary focus of infection should be dealt with.

  1. Pyaemia# is a form of blood-poisoning characterised by the development

of secondary foci of suppuration in different parts of the body. Toxins are thus introduced into the blood, not only at the primary seat of infection, but also from each of these metastatic collections. Like septicaemia, this condition is due to pyogenic bacteria, the _streptococcus pyogenes_ being the commonest organism found. The primary infection is usually in a wound--for example, a compound fracture--but cases occur in which the point of entrance of the bacteria is not discoverable. The dissemination of the organisms takes place through the medium of infected emboli which form in a thrombosed vein in the vicinity of the original lesion, and, breaking loose, are carried thence in the blood-stream. These emboli lodge in the minute vessels of the lungs, spleen, liver, kidneys, pleura, brain, synovial membranes, or cellular tissue, and the bacteria they contain give rise to secondary foci of suppuration. Secondary abscesses are thus formed in those parts, and these in turn may be the starting-point of new emboli which give rise to fresh areas of pus formation. The organs above named are the commonest situations of pyaemic abscesses, but these may also occur in the bone marrow, the substance of muscles, the heart and pericardium, lymph glands, subcutaneous tissue, or, in fact, in any tissue of the body. Organisms circulating in the blood are prone to lodge on the valves of the heart and give rise to endocarditis.

[Illustration: FIG. 13.--Chart of Pyaemia following on Acute Osteomyelitis.]

_Clinical Features._--Before antiseptic surgery was practised, pyaemia was a common complication of wounds. In the present day it is not only infinitely less common, but appears also to be of a less severe type. Its rarity and its mildness may be related as cause and effect, because it was formerly found that pyaemia contracted from a pyaemic patient was more virulent than that from other sources.

In contrast with sapraemia and septicaemia, pyaemia is late of developing, and it seldom begins within a week of the primary infection. The first sign is a feeling of chilliness, or a violent rigor lasting for perhaps half an hour, during which time the temperature rises to 103, 104, or 105 F. In the course of an hour it begins to fall again, and the patient breaks into a profuse sweat. The temperature may fall several degrees, but seldom reaches the normal. In a few days there is a second rigor with rise of temperature, and another remission, and such attacks may be repeated at diminishing intervals during the course of the illness (Figs. 12 and 13). The pulse is soft, and tends to remain abnormally rapid even when the temperature falls nearly to normal.

The face is flushed, and wears a drawn, anxious expression, and the eyes are bright. A characteristic sweetish odour, which has been compared to that of new-mown hay, can be detected in the breath and may pervade the patient. The appetite is lost; there may be sickness and vomiting and profuse diarrhoea; and the patient emaciates rapidly. The skin is continuously hot, and has often a peculiar pungent feel. Patches of erythema sometimes appear scattered over the body. The skin may assume a dull sallow or earthy hue, or a bright yellow icteric tint may appear. The conjunctivae also may be yellow. In the latter stages of the disease the pulse becomes small and fluttering; the tongue becomes dry and brown; sordes collect on the teeth; and a low muttering form of delirium supervenes.

Secondary infection of the parotid gland frequently occurs, and gives rise to a suppurative parotitis. This condition is associated with severe pain, gradually extending from behind the angle of the jaw on to the face. There is also swelling over the gland, and eventually suppuration and sloughing of the gland tissue and overlying skin.

Secondary abscesses in the lymph glands, subcutaneous tissue, or joints are often so insidious and painless in their development that they are only discovered accidentally. When the abscess is evacuated, healing often takes place with remarkable rapidity, and with little impairment of function.

The general symptoms may be simulated by an attack of malaria.

_Prognosis._--The prognosis in acute pyaemia is much less hopeless than it once was, a considerable proportion of the patients recovering. In acute cases the disease proves fatal in ten days or a fortnight, death being due to toxaemia. Chronic cases often run a long course, lasting for weeks or even months, and prove fatal from exhaustion and waxy disease following on prolonged suppuration.

_Treatment._--In such conditions as compound fractures and severe lacerated wounds, much can be done to avert the conditions which lead to pyaemia, by applying a Bier's constricting bandage as soon as there is evidence of infection having taken place, or even if there is reason to suspect that the wound is not aseptic.

If sepsis is already established, and evidence of general infection is present, the wound should be opened up sufficiently to admit of thorough disinfection and drainage, and the constricting bandage applied to aid the defensive processes going on in the tissues. If these measures fail, amputation of the limb may be the only means of preventing further dissemination of infective material from the primary source of infection.

Attempts have been made to interrupt the channel along which the infective emboli spread, by ligating or resecting the main vein of the affected part, but this is seldom feasible except in the case of the internal jugular vein for infection of the transverse sinus.

Secondary abscesses must be aspirated or opened and drained whenever possible.

The general treatment is conducted on the same lines as on other forms of pyogenic infection.