[07.13] Intra Abdominal Infections and Abscess V2.pdf

Parietal peritoneum

What is the name of the continuous serous membrane that lines the abdominal cavity?

Visceral peritoneum

What is the name of the continuous serous membrane that lines the intraperitoneal organs?

Mesentery

What is the term for the structure formed where the peritoneum doubles over itself?

Peritoneal cavity

What is the space between the parietal and visceral peritoneum called?

Protein < 30 g/L

What is the normal protein concentration threshold in peritoneal serous fluid?

Albumin

What is the primary protein component found in normal peritoneal fluid?

WBC < 300 cells per microliter

What is the normal white blood cell count threshold in the peritoneal cavity?

Mononuclear cells

What is the predominant type of white blood cell in normal peritoneal fluid?

Polymorphonuclear neutrophils (PMNs)

Which cells show an early influx during the inflammatory process of peritonitis?

Subphrenic spaces

Which compartmentalized spaces are separated by the falciform ligament?

Falciform ligament

What structure limits the spread of infection between the left and right subphrenic spaces?

Suprapelvic spaces

What is the lowest point of the abdominal cavity for a patient in the recumbent position?

Pancreas (anterior), Duodenum, Ascending and descending colon, Kidneys (posterior), Ureters, and Adrenals

List the seven retroperitoneal organs identified in the sources.

Liver, Stomach, Gallbladder, Spleen, Jejunum, Ileum, Transverse and Sigmoid colon, Cecum, and Appendix

List the ten intraperitoneal organs identified in the sources.

Retroperitoneal space

If a tumor of the right kidney ruptures, into which compartment will the contents spill rather than the peritoneal cavity?

Disruption of the normal anatomic barrier

What is the general cause of intra-abdominal infections?

Tumor, inflammation, or ischemia

List three factors that can lead to a "weak bowel" and subsequent barrier disruption.

Ulcer, diverticulum, or appendix

List three common sources of an anatomical rupture leading to infection.

Pancreatitis

Which condition causes adjacent inflammation via an enzyme leak?

Pelvic Inflammatory Disease (PID)

Which condition causes adjacent inflammation via an organism leak?

Peritonitis and Abscess formation

What are the two primary stages of intra-abdominal infection?

Primary Bacterial Peritonitis (PBP)

Which type of peritonitis occurs spontaneously without an apparent source of infection?

Secondary bacterial peritonitis

Which type of peritonitis is caused by bacterial spillage from a ruptured intra-abdominal viscus?

Liver cirrhosis

What is the most common underlying cause, linked to less than 10 percent of cases, of Primary Bacterial Peritonitis?

Metastatic malignant disease, active hepatitis, congestive heart failure, and SLE

List four non-cirrhotic conditions associated with Primary Bacterial Peritonitis.

Portal hypertension and altered liver function

Pathogenesis of PBP is primarily driven by which two consequences of liver disease?

Increased bacterial translocation through the intestinal wall

Dysfunctional immunity in PBP leads to what specific bacterial movement?

Bacterial overgrowth in the intestines

Decreased bacterial clearance in the liver leads to what condition in the gut?

Hypersplenism, altered bile composition, decreased motility, and decreased gastric acid

List four physiological changes that contribute to bacterial overgrowth in PBP.

Pancytopenia

What blood condition results from hypersplenism and further decreases bacterial clearance?

Loosening of tight junctions

What structural change in the intestinal wall allows for bacterial leakage in PBP?

Fever, ascites, and acute abdominal pain

What are the three hallmark clinical manifestations of Primary Bacterial Peritonitis?

Ascites

Which clinical feature usually happens before the onset of peritonitis in PBP?

Fatigue, malaise, and encephalopathy

List three systemic symptoms associated with PBP.

Ascitic fluid PMN count > 250 cells per microliter

What is the diagnostic threshold for neutrophils in the peritoneal fluid for PBP?

E. coli

What is the most common aerobic microorganism found in Primary Bacterial Peritonitis?

Strep, Enterococci, and Pneumococci

List three types of Gram-positive organisms commonly found in PBP.

Single specimen isolated

What is the characteristic culture finding for PBP compared to secondary peritonitis?

Anaerobes

The presence of which type of bacteria in a mixed flora culture suggests secondary peritonitis rather than PBP?

ESBL-producing Enterobacteriaceae

What specific type of resistant bacteria is a growing concern in PBP flora?

Nosocomial origin, long-term quinolone prophylaxis, and recent beta-lactam use

List three risk factors for the development of antimicrobial resistance in PBP.

Muscle guarding, tenderness, and rebound tenderness

What are the three classic physical examination findings of peritoneal irritation?

Rebound tenderness

Which physical sign is specifically caused by the inflamed peritoneum being suddenly released?

Rovsing’s Sign

What is the term for pain elicited on the right side when pressure is applied to the left lower abdomen?

Dermatomes

The localization of Rovsing’s Sign is due to the distribution of what?

Low yield of organisms

Why is isolation of the causative agent difficult in PBP cases?

10 ml

How much peritoneal fluid should be inoculated into a blood culture bottle to improve isolation yield?

Blood culture

Besides ascitic fluid culture, what other diagnostic test must be done due to the occurrence of bacteremia?

Gram-positive and Gram-negative bacteria

Empiric antibiotic therapy for PBP must cover which two broad groups of bacteria?

Cefotaxime

Which third-generation cephalosporin is a common empiric option for PBP?

Piperacillin-tazobactam

Which broad-spectrum penicillin and beta-lactamase inhibitor combination is used for PBP?

Imipenem

Which carbapenem is referred to as the "silver bullet" for severe PBP illness or resistant organisms?

Anaerobic coverage

Which type of antibiotic coverage is notably not required for the treatment of PBP?

72 hours

Within how many hours do patients with PBP usually respond to treatment?

Quinolones

Which class of antibiotics is recommended for long-term secondary prophylaxis of PBP?

70%

What is the estimated recurrence risk of PBP within one year without prophylaxis?

Bacteremia and sepsis

Early death in untreated secondary peritonitis is often caused by what?

Potent endotoxins

What specific bacterial component of Gram-negative bacilli drives sepsis in secondary peritonitis?

Chemical Irritation

What is the initial cause of peritonitis in an upper GI perforation, such as a ruptured gastric ulcer?

Below the ligament of Treitz

Perforation below which anatomical landmark results in very high bacterial contamination?

Anaerobes (~99.9%)

What type of bacteria predominates in the normal colonic flora?

Near-neutral (pH 7 to 8)

What is the typical pH of colonic luminal contents?

Epigastric pain

Where is pain usually first felt in a ruptured gastric ulcer?

Periumbilical pain

Where does pain typically start in cases of appendicitis?

Nausea

What common systemic symptom often accompanies the initial periumbilical pain of appendicitis?

Right Lower Quadrant (RLQ)

Where does appendicitis pain eventually localize?

Lying immobile with knees drawn up

What is the characteristic physical posture of a patient with spreading peritonitis?

Coughing or sneezing

What two actions cause sharp, agonizing pain in patients with peritonitis because they stretch the peritoneum?

Marked leukocytosis

What is the characteristic laboratory finding in the blood for secondary peritonitis?

E. coli and Bacteroides fragilis

What are the two most common microorganisms isolated in secondary peritonitis?

Antifungal therapy

What should be added to the treatment plan for secondary peritonitis if Candida is identified?

Linezolid

Which antibiotic is used to treat VRE if it is identified in secondary peritonitis?

Staphylococcal species

Which organisms are more commonly found in post-surgical peritonitis cases that resemble PBP?

CT Scan

Which imaging modality is commonly used for secondary peritonitis, although often bypassed if the patient is unstable?

Surgery

What is the primary lifesaving treatment for secondary peritonitis?

Gram-negative bacilli and anaerobes

Which two groups of organisms are the primary targets of antimicrobial treatment in secondary peritonitis?

Metronidazole

Which specific antibiotic is added to regimens like levofloxacin or ceftriaxone to cover anaerobes?

Continuous Ambulatory Peritoneal Dialysis

What does the acronym CAPD stand for?

Osmosis and Diffusion

By what two processes are excess water and solutes removed during peritoneal dialysis?

Skin organisms migrating along the catheter

What is the primary route of infection for CAPD peritonitis?

Coagulase (-) Staphylococcus spp. (e.g., S. epidermidis)

Which group of organisms causes more than 45 percent of CAPD peritonitis cases?

Monomicrobial (single organism)

Is CAPD peritonitis usually monomicrobial or multimicrobial?

Cloudy dialysate fluid

What is a classic clinical presentation of the fluid in CAPD peritonitis?

Centrifugation

What laboratory process is performed on several liters of dialysate fluid to improve culture yield?

Cefazolin

Which first-generation cephalosporin is used for Gram-positive coverage in CAPD peritonitis?

Ceftazidime

Which third-generation cephalosporin is used for Gram-negative coverage in CAPD peritonitis?

Vancomycin

Which antibiotic is substituted for Cefazolin if MRSA is suspected?

Intraperitoneally

How are loading doses of antibiotics often administered in CAPD patients?

Intraperitoneal (75%) and Visceral (25%)

What are the two general kinds of intra-abdominal abscesses and their relative frequencies?

Liver (50%)

What is the most common site for a visceral abscess?

Both a disease state and a host response

Is an abscess formation considered a disease state or a host response?

Encapsulation to prevent overt infection

How does the formation of an abscess serve as a host response?

Sepsis

What systemic condition occurs when an intra-abdominal abscess bursts?

10^11 per gram of feces

What is the normal concentration of Bacteroides fragilis in human stool?

Up to 60%

What is the mortality rate if an intraperitoneal abscess is left untreated?

Gram-negative pleomorphic anaerobe

What are the Gram stain, shape, and oxygen requirements of Bacteroides fragilis?

Capsule

What is the primary virulence factor of Bacteroides fragilis that allows it to remain intact despite host immune responses?

Bile resistant

Is B. fragilis bile-sensitive or bile-resistant?

Development of gut-associated lymphoid tissues (GALT)

B. fragilis is a commensal that is essential for the development of what?

Polysaccharide A (PSA)

What specific capsule complex of B. fragilis is processed by dendritic cells to develop a mature immune system?