Sandbox:Aditya

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]Associate Editor(s)-in-Chief: Aditya Ganti M.B.B.S. [2]

Synonyms and keywords:

Overview

An appendicular abscess is unusual and rare entity and a life threatening complication of acute appendicitis. It is seen in 2-7% of population presenting with appendicitis.

Pathophysiology

The eight functional compartments in the peritoneal cavity include the following:

• Pelvis
• Right paracolic gutter
• Left paracolic gutter
• Right infradiaphragmatic space
• Left infradiaphragmatic space
• Lesser sac
• Hepatorenal space (Morrison space)
• Interloop spaces between small intestine loops

Periappendiceal abscesses from a perforated appendix may develop in the right lower quadrant.

Transmission

The abscesses usually contain a mixture of aerobic and anaerobic bacteria from the gastrointestinal tract.

Differentiating appendicular abscess from other abscess

Disease	Differentiating Signs and symptoms	Specific Lab tests
Acute mesenteric adenitis	Usually presents in children with a recent history of upper respiratory infection. Diffuse abdominal pain with tenderness not localized to the right lower quadrant. Guarding without rigidity Generalized lymphadenopathy is present.	Relative lymphocytosis in WBC differential counts is suggestive. Negative ultrasound or CT findings help exclude other diagnoses.
Intussusception
Crohn's disease
Viral gastroenteritis	Common in children; caused by viruses, bacteria, or toxin. Characterized by profuse watery diarrhea, nausea, and vomiting. Crampy abdominal pain often precedes the diarrhea, and no localizing signs are present. Typhoid fever, with intestinal perforation may cause localized abdominal pain and/or generalized and rebound tenderness, associated maculopapular rash, inappropriate bradycardia, and leukopenia will differentiate from appendicular abscess
Meckel diverticulitis
Peptic ulcer disease
Cholecystitis
Urinary tract infection
Right side ureteric stone
Pelvic inflammatory disease
Ectopic pregnancy
Ovarian torsion

Epidemiology and Demographics

The lifetime risk of appendicitis is 8.6 % for males and 6.7 % for females; however, the risk of undergoing appendectomy is much lower for males than for females (12 vs. 23 %) and it occurs most often between the ages of 10 and 30, with a male:female ratio of approximately 1.4:1.

Diagnosis

History

The key to an efficient and accurate diagnosis is a detailed and thorough history. The following information should be obtained:

• Onset, location, radiation, and duration of pain;
• Aggravating or relieving factors;
• Severity of pain (constant or intermittent);
• Characteristics of the pain;
• History of the pain;
• Association with nausea, vomiting, anorexia, or diarrhea;
• Time of last bowel movement; and
• Recent use of analgesics, narcotics, or antibiotics.

Treatment

No universal standard treatment exists for appendicitis complicated by abscess. The preferred treatment includes non-operative management such as drainage and broad spectrum IV antibiotics followed by interval appendectomy with high success rates up to 97% and low incidences of complications.

Medical Therapy

Antibiotic therapy must have broad spectrum activity towards both gram-negative and anaerobic pathogens.

Empiric therapy

Monotherapy with a beta-lactam/beta-lactamase inhibitor:

• Ampicillin-sulbactam :3 g IV every six hours
• Ticarcillin-clavulanate :3 g IV every four hours
• Piperacillin-tazobactam :3 g or 4.5 g IV every six hours

Combination third generation cephalosporins PLUS metronidazole

• Ceftriaxone  : 1 g IV every 24 hours (plus)
• metronidazole : 500 mg IV every eight hours.

Alternative empiric regimens

Combination fluoroquinolone◊ PLUS metronidazole:

• Ciprofloxacin (or) : 400 mg IV every 12 hours
• Levofloxacin (plus) : 500 or 750 mg IV once daily
• Metronidazole  : 500 mg IV every eight hours

Monotherapy with a carbapenem

• Imipenem-cilastatin : 500 mg IV every six hours
• Meropenem  : 1 g IV every eight hours
• Doripenem  : 500 mg IV every eight hours
• Ertapenem  : 1 g IV once daily

Surgery

Emergency appendectomy Indicated in the treatment of

• Perforated appendicitis, especially in patients with life-threatening signs of peritonitis,
• In patients with a large appendiceal abscess,
• In patients with an extraluminal appendicolith.

Percutaneous drainage

• Percutaneous drainage can be performed under US or CT guidance, using either the Seldinger or trocar technique.
• US is limited if the abscess is small, obscured by other structures, or if precise placement is required because of nearby vessels or organs. In these cases, CT is the optimal imaging modality.<ref>
• When an abscess is deep in the pelvis, depending on the specific location of the fluid collection, access may be obtained via transgluteal, transvaginal, or transrectal approaches.
• If the fluid collection is sterile, a transgluteal approach is preferred because it allows for sterile technique.<REF>

Antero-superior to the bladder

• The patient is first placed supine on the CT table for a percutaneous anterior approach to the abscess.
• Localization scan using CT allows us for selecting a safe window of access into the collection.
• A coaxial micropuncture introducer set is advanced into the abscess under CT guidance.
• An Amplatz guidewire as advanced through the sheath and coiled within the abscess.
• After serial dilatation of the tract with a dilator, an pigtail drain is advanced over the guidewire and deployed.
• A final CT scan confirmed appropriate positioning of the catheter.

Abscess between the bladder and rectum

• The patient is placed in the prone position on the CT table for a posterior transgluteal approach.
• The micropuncture introducer set was advanced as medially as possible within the greater sciatic foramen to avoid vessels and the sciatic nerve.
• An pigtail drain was advanced into the abscess by employing the same technique for the anterior abscess.