CHAPTER XI

LIVER ABSCESS

HISTORY AND GEOGRAPHICAL DISTRIBUTION

=History.=—Although Hippocrates noted the method of evacuating abscess of the liver by caustics there was very little known about the condition until during the last century.

The history in connection with the finding of amoebae in liver abscesses is of very recent date (1887) and is taken up under the history of amoebic dysentery.

=Geographical Distribution.=—Concisely one may state that the distribution of liver abscess is in relation to the existence of amoebic dysentery. It is particularly prevalent in those centers of amoebic infection where there are many white men having little knowledge of the conditions necessary for the maintenance of health in the tropics.

In liver abscess, as with blackwater fever, it is education rather than acclimatization that brings about a diminution of these tropical diseases.

For several years subsequent to the American occupation of the Philippines amoebic dysentery and liver abscess were common but in more recent years liver abscess has become rare in Americans and amoebic dysentery much reduced in prevalence.

More temperate living results in less storing up of fat in the liver and an organ more resistant to infection.

ETIOLOGY AND EPIDEMIOLOGY

=Etiology.=—The dislodgment of amoebae-containing material from amoebic intestinal ulcerations and the plugging of the portal capillaries by such emboli give us the starting point of a liver abscess. The exciting cause is _Entamoeba histolytica_ which in the liver continues the same production of a gelatinous necrosis as is carried on in the submucosa of the large intestine or appendix.

This pathogenic amoeba is fully described under amoebic dysentery.

As to obtaining a history of amoebic dysentery in liver abscess cases we have the following statistics:

500 cases with dysentery findings in 60% (Kartulis). 444 cases with dysentery findings in 59% (Zancarol). 500 cases with dysentery findings in 85% (Kelsch and Kiener). 63 cases with dysentery findings in 90.5% (Rogers). 38 cases with dysentery findings in 85% (Seamen’s hospital autopsies).

Amoebic liver abscess is exceedingly rare among children and probably 10 times less common among women than men.

Of 40 cases of liver abscess Waring noted intemperance in 67.5% and authorities generally insist upon the importance of the abuse of alcohol as a predisposing factor.

Natives of India very rarely develop liver abscess but it has been noted that when they begin to follow the customs of Europeans, as to eating and drinking, such lesions become more common in them.

As to the proportion of cases of amoebic dysentery which give rise to liver abscess only the statistics of those who have differentiated between bacillary and amoebic dysentery are of any value. Such statistics would indicate that about 20% of the cases of amoebic dysentery are complicated by liver abscess.

Liver abscess may be present without demonstrable lesions in the large intestines, such lesions having healed or the intestinal involvement having been so slight as not to have caused other than microscopic changes.

It is a well-known fact that liver abscess may set in years after a patient has left the tropics and years after the occurrence of any dysenteric manifestations.

PATHOLOGY

There seems little doubt but that the amoebae in the thrombosed terminals of the portal vein are carried by way of the upward current into the liver where they lodge in the liver capillaries, Councilman and Lafleur having found amoebae in such emboli.

Another view is that the amoebae may wander across the abdominal cavity and enter the liver in this way. This seems as improbable as that view which considers a possible entrance by way of the bile duct. Bile is toxic to amoebae and it would be difficult to explain their presence in the small intestines.

In 639 cases Roux found the abscess in the right lobe in 70% of the cases.

Other statistics give about 75% for the right lobe, 10% for the left lobe, 4% for the lobus Spigelii and in about 10% of cases abscesses are found in both right and left lobes.

In 562 cases Zancarol found a single abscess in 60% of the cases.

In 288 cases Waring found a single abscess in 61.5%, double abscesses in 11.5% and multiple abscesses in 27%. The favorite site of liver abscess is the superior and posterior part of the right lobe and near its surface.

The abscesses vary enormously in size, some being no larger than a walnut while others may contain a quart or more of pus, exceptionally as much as a gallon. The pus is typically of a chocolate color and contains degenerated liver cells, granular débris and often haematoidin and Charcot-Leyden crystals. There is an absence of polymorphonuclears. It may however be creamy in color.

In Strong’s cases about 50% of the abscesses showed bacteria upon culturing, the organisms noted being staphylococci, streptococci, _B. coli_ and _B. pyocyaneus_.

The walls of liver abscesses are rather shaggy and the amoebae are found deeply located.

It is probable that the necrotic process, set up by the amoebae, begins in the interlobular capillaries although it may at times begin within the lobule.

Microscopically, the necrotic abscess wall shows amoebae in its depths but necrosis of the surrounding tissue beyond the zone of the amoebae is noticeable which would suggest the elimination by the amoebae of some toxic substance. There is an absence of polymorphonuclear infiltration around the abscess.

Surrounding the abscess wall there is a zone of marked hyperaemia. Amoebae may be found in this area as well as in the abscess wall.

If the liver abscess is not treated by emetine or with this drug and some surgical procedure the tendency is for rupture to occur and Cyr’s statistics show that of 159 cases rupture occurred as follows: lungs 59, pleural cavity 31, peritoneal cavity 39, intestines 8, stomach 8, vena cava 3, kidneys 2, bile ducts 4, pericardium 1 and externally 2.

SYMPTOMATOLOGY

Although the statistics would indicate that a history of amoebic dysentery has been obtained in only from 60 to 90% of cases of liver abscess, yet, when we consider that amoebic lesions of the large intestines have been frequently noted at autopsy in those who had never shown symptoms of dysentery during life, we are forced to believe that amoebic lesions of the appendix or large intestines are necessary factors in the production of liver abscess. Consequently, a history of amoebic dysentery is one of the most important points to consider in the making of a diagnosis of tropical liver abscess.

=Tropical Liver.=—There is also much evidence to be obtained from statistics and otherwise to support the view that the amoebic infection of the liver is only possible in a person whose liver has been functionally impaired. To this condition the designation tropical congestion of the liver or simply tropical liver has been applied. There is much to support the view that, in the tropics, the intestines and liver take the place of the thoracic organs in being subject to congestion. In temperate climates excesses and exposure to debilitating influences result in coryza or pneumonia. In the tropics we have diarrhoea and congestion of the liver. Tropical liver is recognized by vague digestive troubles, high-colored urine, loss of energy, irritability, with a sensation of fullness in the region of the liver which is generally described by the patient’s statement that he feels his liver. There may be pain referred to the right shoulder and the liver may be tender on palpation.

By the discontinuance of alcohol and highly spiced foods, with treatment by phosphate of soda or sodium sulphate, together with general care of the health, the patient may recover completely.

Rogers recognizes a condition which he terms the _pre-suppurative stage of amoebic hepatitis_ in which the amoebae from dysenteric lesions have lodged in the portal terminals of the liver but in which abscess formation has not taken place.

At this stage we have a leucocytosis in which the polymorphonuclears are but little increased in percentage with a low remittent fever. At this time Rogers considers that the disease may be cured by emetine or ipecac and liver abscess avoided.

=A Typical Case of Liver Abscess.=—Following a case of amoebic dysentery, during the period of convalescence or subsequently, a rather irregular type of fever is noted, which shows an evening rise with sweatings which tend to become colliquative. From a marked feeling of weight in the region of the liver there may later develop tenderness or pain upon palpation of the liver. Of importance is the fact that there is no associated splenic enlargement. In the majority of cases the right side of the liver enlarges in an upward direction. A tape-measure will often show enlargement of the right side. Pain referred to the right shoulder is often complained of when the abscess is located in the upper convex part of the liver but, when nearer the inferior concave surface, there may be pain referred to the region of the appendix. When located in the left lobe the symptoms may be considered as of gastric origin.

The upward enlargement of the liver as shown by X-rays is of great value in diagnosis, but an abscess located in the center of the liver is not indicated by such rays.

There is a marked tendency to splint the liver so that the patient tends to lie towards the right side and when walking applies his right arm and forearm to his side, which led Koch to remark, “It is as if he carried his abscess under his arm.” The right rectus often shows rigidity.

Auscultation of the base of the right lung reveals a moist crepitation which, together with a dry cough (tussis hepatica), the fever, evening sweats, anaemia and emaciation, may suggest tuberculosis. The respirations are shallow as deep inspiration tends to cause pain. It must be remembered that cases of liver abscess have been reported where there were practically no symptoms.

Insomnia is a marked feature in many cases. Jaundice is rare, but an earthy color or subicteroid tinging is often noted. The superficial veins may be enlarged.

The urine is scanty and high-coloured, frequently with a marked increase in the ammonia nitrogen. Urobilin may be present in considerable amount.

There is a rather constant but low leucocytosis of from 12 to 20 thousand, which shows only about 70% of polymorphonuclears with an increase in large mononuclears up to 10 to 15%.

The final proof is the obtaining of the chocolate-coloured or anchovy sauce-like pus by exploratory puncture.

[Illustration: FIG. 61.—Temperature chart of liver abscess.]

This pus does not contain pus cells but only granular débris, cholesterin crystals and is often bacteriologically sterile. The amoebae, being in the abscess wall, are not apt to be found when pus is at first withdrawn. Owing to the tendency of liver abscess to rupture into the lungs the first indication of the true nature of a prolonged hectic fever may be obtained when the characteristic pus is expectorated by the patient.

Attended with progressive emaciation and exhaustion the patient, as a rule, after a prolonged illness, dies, unless operative procedures cure him or some intercurrent disease brings about his death.

Symptoms in Detail

_Onset and the Fever Chart._—The onset is at times so insidious that there may be no symptoms and yet a liver abscess be found at autopsy. Usually following convalescence after amoebic dysentery an irregular fever sets in which becomes hectic in character. Profuse sweats accompany the evening rise. The morning temperature is frequently normal and there may be frequent apyretic intervals.

_The Respiratory System._—Crepitation at the right base, a dry cough (tussis hepatica) and shallow respirations are features of the disease.

_The Nervous System._—Pains in the right shoulder are connected with irritation of the branches of the phrenic nerve.

The patient is irritable and often complains of insomnia.

The right rectus tends to be somewhat rigid and decubitus is dorsal or toward the right side.

_The Liver and Spleen._—The liver is tender and as the abscess in nine-tenths of the cases is located in the right lobe and generally toward the upper convex surface we have an enlargement upward. There is very rarely any jaundice.

The urine shows an excess of urobilin and of nitrogen eliminated as ammonia. When the abscess is in the left lobe the condition is apt to be considered as some gastric disturbance. The spleen, as a rule, shows no enlargement.

_Examination of the Blood._—There is usually a moderate leucocytosis with normal polymorphonuclear percentage and increase in the large mononuclears.

[Illustration: FIG. 62.—Liver abscess. X-ray photograph taken from the side and showing upward enlargement of liver. (Ruge and zur Verth after Béclére.)]

DIAGNOSIS

=Clinical Diagnosis.=—Of greatest importance is a history of a previous dysentery although it must be remembered that liver abscess may appear in one who has never had dysenteric symptoms. Fever of a hectic type with crepitation at right base, pain and upward enlargement of the liver are most significant.

The X-ray may confirm the diagnosis of upward enlargement which may be as high as the angle of the scapula. The majority of conditions causing enlargement of the liver give a downward enlargement.

The amelioration of symptoms by giving emetine hypodermically for two or three days is diagnostically exceedingly important.

Syphilitic gummata may give the picture of liver abscess, especially as regards the fever and loss of weight. Iodide of potash is said to be of use in differentiating, as it controls the fever of syphilis. The gummatous enlargement, however, is irregular and projects downward.

Suppurative pylephlebitis generally arises from infections of the colon or appendix. This condition as well as pyaemic (multiple) abscesses of the liver is apt to show jaundice.

In suppurative cholangitis and cholecystitis we get a history of biliary colic, jaundice and usually a marked point of tenderness at the tip of the ninth rib and a tumor in the region of the gall bladder. Abscess of the left lobe may give the symptoms of gastric trouble.

In differentiating empyema we usually have a history of pleurisy or pneumonia.

Suppurating hydatid cyst which may be confused with liver abscess is most surely differentiated by finding echinococcus hooklets.

Then too the complement fixation test for hydatid disease will differentiate.

Tuberculosis is often thought of, particularly when a liver abscess ruptures through the lungs. Malaria is also usually suspected. Abscess in the kidney or perinephritic region may be very confusing. In an abscess of the abdominal wall an exploring needle does not move up and down with respiration as it does when penetrating a liver abscess cavity.

=Laboratory Diagnosis.=—The chocolate-colored pus of a liver abscess, when there has been no bacterial contamination, shows an absence of polymorphonuclears and does not at first show amoebae. These appear in the pus coming from the drainage tube about the third day. Cholesterin and haematoidin crystals may be found in the granular débris of a fresh drop of pus used for examination for amoebae.

Liver abscess usually shows a moderate leucocytosis with a normal polymorphonuclear percentage and an increase of large mononuclears and transitionals to about 12 to 20%.

According to Schilling-Torgau we may have a perfectly normal white count and polymorphonuclear percentage and yet have evidence of the presence of liver abscess in his modification of Arneth’s index, so that in an apparently normal differential count we may find that ½ or more of the polymorphonuclears are of a less mature type and in cases where there are many immature polymorphonuclears we have indications which force a very cautious or unfavorable prognosis.

Thus a differential count of 33% band-form polymorphonuclears and 39% of normal nucleated ones would make us give a cautious prognosis, while one with 1% myelocytes, 22.5% immature polymorphonuclears, 21% band-form nucleated ones and 30% of normal ones would make for a very bad prognosis. We have a displacement to the left. Normally there are 63% of normal polymorphonuclears, 4% of band-form and no immature ones or myelocytes.

One may find an iodophilia in liver abscess.

Of the functional liver tests we may determine the ammonia quotient, the percentage of N eliminated as ammonia being increased in abscess of the liver. The same is true of the lipase test. Probably the most specific test for disturbances of the hepatic function is that for urobilinogen. The test is made by adding 5 to 10 drops of Ehrlich’s aldehyde reagent to 5 cc. of perfectly fresh urine when a positive reaction gives a fine cherry-red color.

PROPHYLAXIS AND TREATMENT

=Prophylaxis.=—The prophylaxis is the same as that for amoebic dysentery plus avoidance of anything which reduces the functional power of the liver, such as overfeeding, alcoholic excesses, etc.

It is well to remember that abscesses may occur months or even two or three years after an attack of amoebic dysentery, consequently it is well to give a grain of emetine on two or three successive days of each month following an acute attack.

=Treatment.=—Leaving out of consideration the pre-suppurative stage of amoebic hepatitis which, according to many authorities, responds to injections of emetine, it may be stated that the treatment of liver abscess is entirely surgical and such treatment should be instituted the moment the diagnosis is made. The earlier a liver abscess is drained the less run down will be the patient, the more rapid the convalescence and the better the prognosis.

Until recently surgical authorities condemned severely the trocar and cannula method of operation, but with the introduction of emetine there are now those who believe that such a procedure may suffice and a more radical operation not be necessitated.

Prior to introducing the trocar and cannula the usual procedure is to use an aspirating needle of about ⅛ inch bore and 3½ inch length. If the needle happens to be longer it should not be passed deeper than 3½ inches, in a person with a 32-inch chest, in order surely to avoid the vena cava. If there are no distinct localizing signs the needle should first be introduced in the eighth or ninth interspaces in the anterior axillary line and pushed backward, inward and slightly upward. Manson recommends at least 6 punctures before abandoning exploration. Cantlie does not think that a moderate degree of haemorrhage from the puncture of the liver will do harm in a case which is simply a liver congestion. One should always be ready to operate in case pus be found in the exploring needle. Leaving the needle in situ a small skin incision is made and a 4 or 5 inch by ⅜ inch trocar and cannula introduced along the line of the needle. Withdrawing the trocar some of the pus is allowed to escape through the cannula and there is then introduced a 6 × ½ inch piece of strong rubber drainage tubing, one end of which has lateral fenestrations but a closed tip in order that a long steel pin may put the tubing on the stretch so that it passes the smaller lumen of the cannula.

The cannula is then slipped out over the tubing and the external stretched end of the tubing released so that the contracting rubber fills the puncture. The steel pin used for introducing the rubber tube is then withdrawn and the tubing transfixed close to the skin with a safety pin.

After the cavity has drained of pus a dressing is applied. There are some who advocate aspiration alone without subsequent drainage. The dressing should be changed frequently and a connecting tube, draining into an antiseptic-containing bottle, should be attached to the tube in the cavity in order to obtain a syphoning action. Some aspirate and inject into the cavity about 2 ounces of 1 to 1000 emetine solution.

Some report favorably from the use of 1 to 1000 quinine irrigations. At present the hypodermic use of emetine will probably obviate the necessity of any irrigation.

There are those who think that a preliminary aspiration, followed by incision, after a few days of improvement in general condition, is the best method in serious cases.

It is usual to recommend a general anaesthetic when introducing the aspirating syringe or trocar and cannula. Local anaesthesia with quinine and urea hydrochloride, however, will usually suffice and lessen the dangers of shock in bad cases. Rib resections and even intra-abdominal procedures are best done under local anaesthesia provided the operator is familiar with the technic.

Newman has recently warned against the use of the small aspirator for diagnosis, pointing out that it is unreliable and that the diagnosis should be made by other diagnostic aids, including hypodermic use of emetine. He notes the occurrence of death from internal haemorrhage, the interference of the needle with the surgical incision and, further, the obscuration of the field of operation by pus where no adhesions exist and, finally, the danger of general peritoneal infection from a leak. He notes that the cavity may be under tension and that the pus may force itself along the track of the needle. He recommends incision and packing with gauze where adhesions do not exist and the exploration of the liver with dressing forceps instead of cutting into the liver with the knife.

USUAL OPERATION FOR LIVER ABSCESS

Either a vertical incision about the middle of the right rectus (Bevan) or a Kocher incision, parallel with the costal margin, may be used. The latter incision favors hernia if prolonged drainage is required. The hand is introduced into the abdominal cavity and the liver palpated. Often the borders of the site of a liver abscess give a hard feeling on palpation. If adhesions are not present the area should be packed off with gauze and the cavity opened by a dressing forceps, haemostat or thermo-cautery. It is often advisable to introduce a trocar and cannula and to drain off the excess of pus.

Where the abscess is situated far back or high up in the liver the transpleural route is to be preferred to the abdominal one. Make a 3 or 4 inch incision over the 9th rib with its center in the line of the angle of the scapula. Excise about 2 inches of rib subperiosteally. An assistant presses a roll of gauze against the tissues above the line of incision to prevent air entering the pleural cavity. Later the upper flap may be sutured to the endothoracic fascia. Even if the pleural cavity should be opened and air enter no serious result will follow although it is an accident to be avoided if possible. The diaphragm is now cut through and the liver exposed and after packing gauze around the area to be opened, the abscess cavity is entered and drained as previously described.

McDill prefers to resect 2 or 3 inches of both 9th and 10th ribs in the midaxillary line. The muscle wounds made in resection are then closed by catgut. This movable wall is now forced against the diaphragm with a roll of gauze pressed inward by an assistant. A 3-inch incision is now made through this bone-free wall near the upper border of the 11th rib, going through diaphragm and exposing the liver. The edges of the wound in the thoracic wall and diaphragm are now clamped together by haemostats to close off the pleural cavity. Later catgut sutures are substituted for the forceps. The liver often bulges into the wound. Finding the abscess by a palpating finger as a rather firm area in a less resistant liver surface we introduce a forceps or aspirating needle or trocar and proceed as above noted.

There are indications that the use of emetine subcutaneously may make the more radical operations unnecessary. In a recent symposium on liver abscess many of the papers would indicate a preference for aspiration without drainage coupled with emetine subcutaneously.

Rogers, in a recent article, notes that a case of liver abscess was cured by emetine without any form of operation. Recent experience, however, would indicate that it is necessary to evacuate the pus to effect a cure.

SECTION II

DISEASES DUE TO BACTERIA

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