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.