BASICS
- A complicated abdominal infection below the diaphragm
- Synonym(s): sub- or infradiaphragmatic abscess
DESCRIPTION
The subphrenic space is the area directly beneath the diaphragm and above the transverse colon. Subphrenic abscesses are infected focal fluid collections as a result of direct contamination due to surgery, trauma, local disease, or inflammatory processes. ‚
EPIDEMIOLOGY
Incidence
- The specific incidence of subphrenic abscess is not well known. Abscesses occur after 1 " “2% of abdominal surgeries.
- Most subphrenic abscesses are right-sided. Structures in the left upper quadrant (spleen, ligaments) protect the left subphrenic space. When a patient is supine, bacteria may traverse the paracolic gutters into the right subdiaphragmatic area.
- Risk of subphrenic abscess increases to 10 " “30% if
- Preoperative perforation of a hollow viscus
- Significant fecal contamination of the peritoneal cavity
- Bowel ischemia
- Immunosuppression
- Delayed diagnosis and treatment of peritonitis
ETIOLOGY AND PATHOPHYSIOLOGY
- Subphrenic abscesses typically form when bowel contents are released into the peritoneal cavity.
- Subphrenic abscesses are generally polymicrobial (1):
- Microbiology is affected by exposure to the health care setting and prior antibiotic treatment, which can select for multidrug-resistant organisms (1).
- Health care " “related isolates: Enterobacter spp., P. aeruginosa, and Enterococcus spp.; community isolates: E. coli (1)
- Local macrophage response to bacteria and foreign material leads to cytokine release, inflammatory cell, and pathogen sequestration within an abscess. Fibrin and other adhesive molecules may also contribute to abscess formation within the mesentery, abdominal wall, omentum, or loops of bowel (1).
RISK FACTORS
- Abdominal surgery; inadvertent viscus perforation
- Anastomotic leak
- Peptic ulcer perforation
- Ruptured appendicitis
- Perforated diverticulitis
- Mesenteric ischemia with bowel infarction
- Penetrating abdominal trauma
- Infected pleural effusion or empyema (transdiaphragmatic seeding)
COMMONLY ASSOCIATED CONDITIONS
- Bacteremia
- Sepsis
- Multisystem organ failure
- Pleural effusion
- Fistula formation
DIAGNOSIS
Early diagnosis reduces morbidity and mortality. ‚
HISTORY
- Recent abdominal surgery (2)
- Constitutional symptoms: fever, chills, diaphoresis, malaise
- Pain symptoms: chest, shoulder (referred pain " ”Kehr sign), and/or abdominal pain
- Pain in respective upper quadrant. Pain may also be pleuritic.
- Respiratory symptoms: nonproductive cough, dyspnea
- GI symptoms: nausea, hiccups, vomiting, adynamic ileus
PHYSICAL EXAM
- Vital signs: fever, tachycardia, hypotension
- Pulmonary findings: rales at lung base; dullness to percussion at lung base; decreased breath sounds at lung base
- Abdominal findings: tenderness, guarding; peritoneal signs, palpable mass
DIFFERENTIAL DIAGNOSIS
- Liver or subhepatic abscess
- Splenic abscess
- Interloop abscess
- Empyema
- Sepsis
- Cholangitis
DIAGNOSTIC TESTS & INTERPRETATION
Initial Tests (lab, imaging)
- CBC: leukocytosis, often with left shift; anemia
- Blood cultures: Positive <50% of cases but may guide selection and duration of antibiotic therapy (3)[B].
- Abdominal radiographs may show elevation of the hemidiaphragm, subphrenic air " “fluid level, and pleural effusion.
- CT scan of the abdomen, pelvis, and lower chest with oral and IV contrast is the imaging modality of choice for intra-abdominal abscess (4).
- Aspirate abscess for Gram stain and culture to direct antimicrobial therapy.
Follow-Up Tests & Special Considerations
- After broad-spectrum antibiotic therapy has been initiated and drainage established, the patient can be expected to defervesce within 24 to 48 hours.
- If the patient fails to improve clinically, follow-up CT scan is indicated.
- Monitor vital signs and metabolic function to detect septic shock.
- Basic metabolic panel
- Liver chemistries
- May require ICU care for careful observation
TREATMENT
- Control source (percutaneous or surgical drainage of the abscess) and correct of any ongoing contamination (repair of leaking anastomosis or perforation). Keep patient NPO until source identified
- Broad-spectrum antibiotics
- Aggressive fluid resuscitation
GENERAL MEASURES
IV fluid hydration ‚
- Patients with signs of intravascular volume depletion should have rapid restoration of fluid status (3)[B].
- Administer IV fluids to euvolemic patients without evidence of volume depletion when diagnosis of intra-abdominal abscess is first suspected (3)[B].
MEDICATION
First Line
- Broad-spectrum antibiotics
- Begin antimicrobial therapy when subphrenic abscess is considered likely (or confirmed) and in patients with septic shock (3)[B].
- More than one antimicrobial drug is generally required to provide adequate coverage (5).
- Empiric treatment for intra-abdominal infection of mild to moderate severity that is not related to health care (without severe physiologic derangement, advanced age, or immunocompromised state) (3)[B].
- Empiric treatment for complicated, high-risk intra-abdominal infection not related to health care or in patients with severe physiologic derangement, advanced age, or immunocompromised state (3)[B]
- Cover patients with prior hospital exposure for multidrug-resistant organisms (1). Empiric antibiotic therapy for health care " “associated intra-abdominal infection should be guided by local microbiologic patterns and tailored based on culture results (3)[B].
- Continue antimicrobial therapy for an established complicated intra-abdominal infections for 4 to 7 days after adequate drainage if the patient has defervesced. Longer therapy is required if it is difficult to obtain adequate source control (3)[B].
- Procalcitonin levels show promise as an additional guide for the duration of antibiotic therapies (6)[A].
SURGERY/OTHER PROCEDURES
- Percutaneous drainage is the treatment of choice for stable patients (3)[B].
- US or CT guidance
- Transthoracic drainage is generally avoided because of potential seeding of the pleural space and secondary empyema formation.
- Endoscopic US-guided transgastric drainage is an emerging modality that offers enhanced visualization of the abscess and surrounding anatomy as well as potentially decreased risk of pleural seeding (7)[C].
- Surgical consultation is advisable in cases of suspected intra-abdominal abscess, especially if the patient had recent abdominal surgery. Failure of percutaneous drainage or endoscopic drainage may necessitate open surgical exploration and evacuation of abscesses (8).
ONGOING CARE
DIET
Patients without evidence of anastomotic leak, fistula, or peritonitis can typically continue a regular diet. ‚
PROGNOSIS
- Morbidity and mortality vary depending on underlying comorbidities, severity of illness, and etiology. Mortality rates up to 31% have been reported (7).
- Percutaneous drainage is curative in >85% (9).
- Recurrence rate is 1 " “10% (9).
COMPLICATIONS
- Bacteremia
- Sepsis
- Rupture of abscess (rare)
- Abscess recurrence
- Pleural effusion
- Risk of morbidity and mortality increases with multiple operations, age >50 years, and recurrent or persistent abscesses
REFERENCES
11 Mazuski ‚ JE, Solomkin ‚ JS. Intra-abdominal infections. Surg Clin North Am. 2009;89(2):421 " “437, ix.22 Tomita ‚ H, Osada ‚ S, Miya ‚ K, et al. Delayed recurrence of postoperative intra-abdominal abscess: an unusual case and review of the literature. Surg Infect (Larchmt). 2006;7(6):551 " “554.33 Solomkin ‚ JS, Mazuski ‚ JE, Bradley ‚ JS, et al. Diagnosis and management of complicated intra-abdominal infection in adults and children: guidelines by the Surgical Infection Society and the Infectious Diseases Society of America. Clin Infect Dis. 2010;50(2):133 " “164.44 Rosen ‚ MP, Bree ‚ RL, Foley ‚ WD, et al. Acute Abdominal Pain and Fever or Suspected Abdominal Abscess. Reston, VA: American College of Radiology; 2006:7.55 Wong ‚ PF, Gilliam ‚ AD, Kumar ‚ S, et al. Antibiotic regimens for secondary peritonitis of gastrointestinal origin in adults. Cochrane Database Syst Rev. 2005;(2):CD004539.66 Agarwal ‚ R, Schwartz ‚ DN. Procalcitonin to guide duration of antimicrobial therapy in intensive care units: a systematic review. Clin Infect Dis. 2011;53(4):379 " “387.77 Seewald ‚ S, Brand ‚ B, Omar ‚ S, et al. EUS-guided drainage of subphrenic abscesses. Gastrointest Endosc. 2004;59(4):578 " “580.88 Singh ‚ S, Khardori ‚ NM. Intra-abdominal and pelvic emergencies. Med Clin North Am. 2012;96(6):1171 " “1191.99 Akinci ‚ D, Akhan ‚ O, Ozmen ‚ MN, et al. Percutaneous drainage of 300 intraperitoneal abscesses with long-term follow-up. Cardiovasc Intervent Radiol. 2005;28(6):744 " “750.
CODES
ICD10
- K65.1 Peritoneal abscess
- T81.4XXA Infection following a procedure, initial encounter
ICD9
- 567.22 Peritoneal abscess
- 998.59 Other postoperative infection
SNOMED
- subdiaphragmatic abscess (disorder)
- Postoperative subphrenic abscess (disorder)
CLINICAL PEARLS
- Subphrenic abscesses are due to contamination of the sterile peritoneal cavity with GI tract bacteria.
- Proper management involves determining the source of the infection, identifying the microbial etiology, draining the abscess, treating with broad-spectrum antibiotics, and providing hemodynamic support.
- Early consultation with an interventional radiologist is recommended to facilitate percutaneous drainage. Surgery consultation is also recommended if the patient had recent abdominal surgery.