Subphrenic Abscess

AUTHOR: Glenn G. Fort, MD, MPH

Definition

A localized accumulation of infected fluid, often encapsulated, located under the diaphragm and may also involve the liver and spleen

Synonyms

Subdiaphragmatic abscess

Infradiaphragmatic abscess

ICD-10CM CODES
K65.1		Peritoneal abscess
K68.11		Postprocedural retroperitoneal abscess

Epidemiology & Demographics

Incidence

Not well known but intraabdominal abscess occurs in 1% to 2% of all cases of abdominal surgery. It increases to 10% to 30% in cases with preoperative perforation of a hollow viscus, spillage of fecal material into peritoneum, or intestinal ischemia.

Risk Factors

Abdominal surgery, especially with accidental viscus perforation
Peptic ulcer perforation
Appendiceal perforation
Diverticulitis with perforation
Mesenteric ischemia with bowel infarction
Abdominal trauma especially penetrating trauma
Foreign body ingestion with subsequent viscus perforation

Physical Findings & Clinical Presentation

Constitutional symptoms include:
1. Fever, malaise, or chills
2. Cough, increased respiratory rate with shallow or grunting respiration
3. Shoulder-tip pain on affected side (referred pain)
Physical findings can include:
1. Dullness to percussion on affected side
2. Diminished or absent breath sounds on affected side
3. Tenderness over the eighth to eleventh ribs

Etiology

Infection is usually polymicrobial: Aerobic gram-negative rods, most commonly Escherichia coli, Klebsiella species, Enterobacter species, and Pseudomonas aeruginosa, and gram-positive cocci: Streptococcus viridans, enterococci, and Staphylococcus aureus, and anaerobes (found in 60% to 70% of cases) such as Bacteroides fragilis and Clostridia species.

Diagnosis ⬆ ⬇

Differential Diagnosis

Liver abscess
Subhepatic abscess
Lesser sac abscess
Empyema of the lung
Diaphragmatic hernia

Workup

Should be started in patients with recent abdominal surgery (weeks to months) with the constitutional symptoms and physical findings mentioned above

Laboratory Tests

Complete blood count with differential may show an elevated white blood count with left shift.
Blood cultures may be positive in up to 50% of the cases.
Gram stain and culture, aerobically and anaerobically, of any aspiration procedure.

Imaging Studies

Plain x-ray films can suggest the location of the abscess in about 50% of the cases and can demonstrate elevation of the hemidiaphragm and/or subphrenic air-fluid level.
Ultrasonography and CT (Fig. E1) are more sensitive.
Other options include leukocyte tagged with gallium 67 and indium 111 scans and MRI.

Figure E1 Subphrenic abscess.

A postoperative abscess (Ab) is seen as a fluid collection between the diaphragm and the liver. Mass impression on the liver is evidence of fluid loculation. An air-fluid level (arrow) is evident, caused by gas-producing Escherichia coli. This abscess was successfully treated using percutaneous catheter drainage guided by computed tomography.

From Webb WR et al: Fundamentals of body CT, ed 4, Philadelphia, 2015, Saunders.

Treatment ⬆ ⬇

Includes source control with either percutaneous drainage or surgery and intravenous antibiotics:

Percutaneous drainage via interventional radiology:
1. Percutaneous drainage ¹ with catheter placement remains the preferred treatment despite the fact that the subphrenic location can be problematic for imaging-guided percutaneous drainage.
2. Approaches include subcostal approach or intercostal approach. The intercostal approach is associated with a higher risk for pleural complications, but these tend to be minor.²
3. Radiographic modalities used include ultrasonography, CT, and fluoroscopy.
4. Complications of drainage procedures can include pleural effusion, pneumothorax, or empyema.
Surgery: May be required in recurrence of abscess or due to multiple abscesses not amenable to percutaneous drainage procedure
Antibiotics: Broad-spectrum antibiotics should be used to cover gram-negative rods, gram-positive bacteria, and anaerobes until cultures are resulted and should be continued at least 4 to 7 days after adequate drainage procedure. Examples include:
1. Piperacillin/tazobactam 3.375 g IV q6h or 4.5 g IV q8h
2. Meropenem 1 g IV q8h or imipenem 0.5 to 1 g IV q6h
3. Ciprofloxacin IV 400 mg IV q12h plus IV metronidazole 500 mg IV q8h for penicillin allergic patients

Referral

Interventional radiology
General surgery
Infectious diseases

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Basic Information ⬇

Diagnosis ⬆ ⬇

Treatment ⬆ ⬇

Pearls & Considerations ⬆ ⬇

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