Abscess Material

Abscesses suspected of being caused by Entamoeba histolytica may be aspirated, and the material may be submitted to the laboratory. 

The last material aspirated is most likely to contain amebae. Material may be examined microscopically in wet mounts and permanent stains, and in addition, it can be cultured for amebae if bacteria are also added to the culture as described below. Abscess material is often thick and difficult to examine. It may be treated with streptokinase and streptodonase enzymes to liquefy the specimen. 

Add 1 part enzyme solution to 5 parts aspirated material. 

The sediment may be used for microscopic examinations for amebae (wet mounts and permanent stains) and for the culture of amebae. 

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While selection of antimicrobial therapy may be a major consideration in treating infectious diseases, it may not be the only therapeutic intervention. Other important therapies may include adequate hydration, ventilatory support, and other supportive medications. In addition, antimicrobials are unlikely to be effective if the process or source that leads to the infection is not controlled. Source control refers to this process and may involve removal of prosthetic materials such as catheters and infected tissue or drainage of an abscess. Source-control considerations should be a fundamental component of any infectious diseases treatment. It is also important to recognize that there may be many different antimicrobial regimens that may cure the patient. While the following therapy sections... 

Oscillating intracardiac mass on valve or supporting structures, in the path of regurgitant, or on implanted material in the absence of an alternative anatomic explanation, or Abscess, or... 

The primary goals of treatment are correction of the intraabdominal disease processes or injuries that have caused infection and drainage of collections of purulent material (abscess). A secondary objective is to resolve the infection without major organ system complications (e.g., pulmonary, hepatic, cardiovascular, or renal failure) or adverse drug effects. Ideally, the patient should be discharged from the hospital with full function for self-care and routine daily activities. 

Source control Removal of the primary cause of an infection such as contaminated prosthetic materials (e.g., catheters), necrotic tissue, or drainage of an abscess. Antimicrobials are unlikely to be effective if the process or source that led to the infection is not controlled. 

Removal of biliary tract gallstones with endoscopic retrograde cholangiopancreatography or surgery usually resolves AP and reduces the risk of recurrence. Surgery may be indicated in AP to treat pseudocyst, pancreatic abscess, and to drain the pancreatic bed if hemorrhagic or necrotic material is present. 

The goals of treatment are the correction of intraabdominal disease processes or injuries that have caused infection and the drainage of collections of purulent material (e.g., abscess). 

In developing countries many infections of the limbs result from exposure to punctures and subsequent contamination by organic material. In hospitals subcutaneous and intramuscular injections and intravenous (peripherally or centrally placed) infusions can be complicated respectively by subcutaneous or intramuscular abscesses and purulent (thrombo)phlebitis and secondary bacteraemia. 

Q12 Irritation and damage to other structures in the abdomen may occur if the diverticulitis is not treated. Abdominal muscles may go into painful spasm and a minority of patients might have rectal bleeding. A major problem could be development of an intestinal obstruction or an abscess in the wall of the intestine. The abscess may eventually cause perforation of the intestinal wall leakage of infected material into the peritoneal cavity and then infection of the peritoneal membranes (peritonitis) may occur. Peritonitis is a very serious condition. 

In the course of the rare systemic gas gangrene caused by Clostridium perfringens (gram-positive, anaerobic bacterium), severe clostridial hepatitis may ensue. Necrotic foci, abscesses and aerogenesis develop. The pathogens can be cultivated from biopsy material. A major harmful factor is the respective exotoxin, which sometimes causes pronounced haemolytic icterus. (121)... 

It is probable that antibiotics will reach the interior of those abscesses which are still relatively small and have only existed for a short period of time. In these cases, too, the spectrum of aerobic and anaerobic bacteria should initially be covered non-specifically by the above-mentioned combination of antibiotics. At the same time, the presence of an amoebic abscess or echinococcosis should be ruled out serologically (as quickly as possible) and aspirated material collected for bacterial and mycotic testing. Depending on the results, the respective antibiotic (and possibly fungistatic) therapy is effected. After 2-3 (-4) days, the efficacy of this targeted treatment is reviewed clinically and biochemically as well as ultrasonographically. If the treatment is considered to have been effective, it is continued until obliteration of the abscess foci is achieved. (12, 29,53, 60, 64, 74, 91, 97, 113)... 

It has been suggested that the development of a sterile abscess represents an idiosyncratic reaction of some individuals, perhaps genetically determined, which causes a granulomatous response to antigens, irrespective of the location of the vaccine (36). Others maintain that it is caused by a contaminated needle track or to vaccine material coating the outside of the needle, resulting from the lack of a proper injection technique. 

Even when the pharmacokinetic parameters of a drug are such to suggest that it will reach the site of the infection, local factors can influence its antimicrobial activity. Aminoglycosides are ineffective in hyperosmolar, anaerobic acidic environments, such as the purulent environment of abscesses. Sulfonamides act by replacing para-aminobenzoic acid (PABA) in the folic acid synthetic pathway of bacteria and are ineffective in purulent material and necrotic tissue, which provide alternative sources of PABA. 

The antimicrobial activity of aminoglycosides is enhanced in an alkaline environment (pH 6-8). They also bind to and are inactivated by the nucleic acid material released by decaying white blood cells. They are, therefore, usually ineffective in the acidic, hyperosmolar, anaerobic environment of abscesses. 

In addition to the infected materials produced by the patient (e.g., blood, sputum, urine, stool, and wound or sinus drainage), other less accessible fluids or tissues must be obtained based on localized signs or symptoms (e.g., spinal fluid in meningitis and joint fluid in arthritis). Abscesses and cellulitic areas also should be aspirated. 

Computed tomographic (CT) scan is used frequently to evaluate the abdomen for the presence of an abscess and is the imaging modality of greatest value. An oral radiocontrast agent should be given to allow differentiation of the abscess from the bowel. Intravenous radiocontrast material will be taken up preferentially in the wall of the abscess, creating a unique radiographic appearance, so-called rim enhancement. 

Primary peritonitis is treated with antimicrobials and rarely requires drainage. Secondary peritonitis requires surgical correction of the underlying pathology. The drainage of the purulent material is the critical component of management of an intraabdominal abscess. Without adequate drainage of the abscess, antimicrobial therapy and fluid resuscitation can be expected to fail. 

Sarcomatous and desmoplastic neoplasms and various cysts with collagenous walls may simulate abscesses (see Figs. 20.3 IB, 20.34A, and 20.39). These tumors may be distinguished by the lack of an inflammatory component and the presence of a neoplastic component. More problematic are cysts that have ruptured and exuded material foreign to the CNS, such as colloid or squamous epithelial cells. If this material is not detectable on TI E staining within the inflammatory reaction, immunohistochemical stains for cyst wall material, such as CK stains for epithelial cells, assist the interpretation. These other lesions are sterile in situ and do not stain for microorganisms as an abscess would (see Box 20.2). 

Gross necrotic abscess filled with brown pastelike material ( anchovy j... 

The tissue reaction in vivo to implanted PHB films and medical devices was studied. In most cases, a good biocompatibility of PHB was demonstrated. In general, no acute inflammation, abscess formation, or tissue necrosis were observed in tissue surrounding of the implanted PHB materials. In addition, no tissue reactivity or cellular mobilization occurred in areas remote from the implantation site [13, 16, 31, 71]. On the one hand, it was shown that PHB elicited similar mild tissue response as PLA did [16], but on the other hand, the use of implants consisting of poly lactic acid, polyglicolic acid, and their copolymers is not without a number of sequelae related with the chronic inflammatory reactions in tissue [81-85]. 

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