eMedicine Specialties > Emergency Medicine > Gastrointestinal

Perirectal Abscess: Treatment & Medication

Author: Drew Evan Fenton, MD, Hospitalist, Our Health Care Consultants
Contributor Information and Disclosures

Updated: Nov 20, 2009

Treatment

Emergency Department Care

The isolated perianal abscess that is not associated with deeper, perirectal abscesses is the only type of anorectal abscess that can be adequately treated in an ED setting and is very rare.

Perirectal abscess must be treated in the operating suite, where optimal anesthesia can be achieved and the abscess and any fistula or other complication may be treated definitively. The "point" of a deep abscess must not be mistaken for a superficial perianal abscess. Inadequate ED debridement of a perirectal abscess may result in increased morbidity and even mortality. ED debridement of perirectal abscesses should not be performed. Because the ED lacks adequate anesthesia, ED treatment of perirectal abscesses is inhumane.

A simple (and, by definition, superficial) perianal abscess may be incised and drained in the ED. Adequate analgesia should be obtained by using the steps discussed in Procedures. Conscious sedation may be considered for pain control and to make the procedure as humane as possible. The patient may be discharged home after appropriate wound care with instructions for Sitz baths and routine follow-up care.

Superficial perianal abscesses are uncommon; thus, the provider should err on the side of assuming a deeper process exists if the diagnosis is in doubt.

• As an example, optimal treatment of ischiorectal abscesses is incision and drainage often followed by fistulotomy under general anesthesia in the operating suite.  
  • The performance of an extensive and complete surgical procedure by a consultant with accurate anatomical knowledge of the region is imperative to avoid serious complications. Such treatment results in a lower recurrence rate.
  • The need for the routine use of antibiotics has not been established. Intravenous antibiotics may be used as preventive or therapeutic measures in patients who are immunocompromised, in those who appear septic, or in those who have heart valve abnormalities or prostheses.
  • Ascertain tetanus immunity. When acceptable immunity cannot be established, follow the currently recommended guidelines for high-risk wounds.
• The goal in treating any abscess is to make an incision to surgically release pus and to remove any dead tissue, and then to keep the surgical incision open by the use of a drain, either (1) a Penrose drain, which may be sutured to the incisional margin and later removed, or (2) iodoform gauze stripping. In the case of perianal abscess, the procedure involves sterile preparation, adequate analgesia, incision and drainage often facilitated by irrigation of the abscess cavity, blunt disruption of any loculations (a gloved fingertip is ideal for this), debridement of any accessible necrotic tissue, and placement of a drain.
  • Do not pack the abscess full of iodoform gauze. The intent is to keep the surgical incision open so that pus and other material can drain. If iodoform gauze stripping is used, using a limited amount of gauze is important, that is, just enough to keep the wound open. Packing the wound full of iodoform gauze does not improve the outcome, and, in fact, it may worsen the prognosis by creating a large foreign body that may become a nidus of infection. This nidus could perpetuate the infection and cause the abscess to enlarge, spread to other areas, erode into vessels or into the peritoneal cavity, and, occasionally, it could cause sepsis and death.
  • In one pediatric case, an incision and drainage (I&D) and packing was performed on a large perirectal abscess in the ED. This packing was left in the wound for days. Shortly thereafter, sepsis and seeding of the myocardium developed with a resultant myocardial abscess. This myocardial abscess eventually ruptured into the pericardial sac, causing tamponade and sudden death.

Consultations

• When the diagnosis of perirectal abscess is made or is being entertained, expeditious consultation with a surgeon is mandatory.
  • Timely and appropriate operative treatment prevents more serious complications such as extension of the abscess or serious systemic infection.
  • The appropriate surgical treatment of perirectal abscess is complex and painful and therefore should not be undertaken in the ED. General or spinal anesthesia is necessary to obtain the appropriate anesthetic result.
  • A newer technique includes endoscopic ultrasonographic-guided drainage of deep pelvic abscesses with stent placement for drainage of pus. In one study, this technique successfully treated most patients who underwent this treatment, requiring no further intervention. 

Medication

Antibiotics are unnecessary in otherwise healthy individuals. The practitioner should provide appropriate empiric intravenous antibiotic coverage for patients who are elderly or immunosuppressed, patients who have comorbidities, patients with a heart valve abnormality or prosthetic valve likely to benefit from antibiotic prophylaxis, or those in whom infection has become systemic. Predisposing or comorbid factors may guide empiric antibiotic selection.

Analgesia is necessary for pain control and may be given orally or via an intravenous route, in conjunction with anesthetics if needle aspiration or I&D of an abscess is performed.

Anxiolytics may help certain patients who are apprehensive about needle aspiration, I&D, imaging studies, or surgery.

Antibiotics

Appropriate antibiotic coverage should be given intravenously preoperatively and postoperatively, either based on Gram stain or an empiric basis, as a preventive measure, for elderly patients, patients with immunosuppression, patients with heart valve abnormality or prosthesis, and those with comorbid states.

Ampicillin and sulbactam (Unasyn)

Drug combination of beta-lactamase inhibitor with ampicillin. Interferes with bacterial cell wall synthesis during active replication, causing bactericidal activity against susceptible organisms. Alternative to amoxicillin when unable to take medication PO.
Covers skin, enteric flora, and anaerobes. Not ideal for nosocomial pathogens.

Imipenem cilastatin (Primaxin)

Should be used for more severely ill ICU patients empirically. Pus and/or blood culture and sensitivity results, once available, should guide antibiotic selection. Predisposing and comorbid diseases may also guide empiric antibiotic selection.

Ampicillin (Marcillin, Omnipen, Polycillin)

Broad-spectrum penicillin. Interferes with bacterial cell wall synthesis during active replication, causing bactericidal activity against susceptible organisms. Alternative to amoxicillin when unable to take medication PO.
Those with prosthetic heart valves at risk for endocarditis should receive IV prophylactic antibiotics prior to any procedure. Ampicillin IV should be used, unless the patient is penicillin allergic, in which case cefazolin or clindamycin are appropriate choices.

Cefazolin (Ancef, Kefzol, Zolicef)

First-generation semisynthetic cephalosporin that by binding to 1 or more penicillin-binding proteins arrests bacterial cell wall synthesis and inhibits bacterial replication. Poor capacity to cross blood-brain barrier. Primarily active against skin flora, including S aureus. Typically used alone for skin and skin-structure coverage. Regimens for IV and IM dosing are similar. Primarily active against skin flora, including S aureus. Use in penicillin-allergic patients with prosthetic heart valves at risk for endocarditis.

Clindamycin (Cleocin)

Semisynthetic antibiotic produced by 7(S)-chloro-substitution of 7(R)-hydroxyl group of parent compound lincomycin. Inhibits bacterial growth, possibly by blocking dissociation of peptidyl tRNA from ribosomes, causing RNA-dependent protein synthesis to arrest. Widely distributes in the body without penetration of CNS. Protein bound and excreted by the liver and kidneys.
Use in penicillin-allergic patients with prosthetic heart valves at risk for endocarditis.

Anesthetics

These agents may help to blunt the pain of a diagnostic needle aspiration but is only partially effective.

Lidocaine 1% (Xylocaine)

Decreases permeability to sodium ions in neuronal membranes. This results in the inhibition of depolarization, blocking the transmission of nerve impulses. Ethylene chloride may be used in conjunction with lidocaine to blunt the pain of a diagnostic needle aspiration but is only partially effective. It should be sprayed over the area to be aspirated immediately prior to aspiration.

Pain medication

Pain control is essential to quality patient care. Analgesics ensure patient comfort, promote pulmonary toilet, and have sedating properties, which are beneficial for patients who experience pain. These agents are used for comfort and sedation and to blunt discomfort of diagnostic needle aspiration.

Meperidine (Demerol)

Analgesic with multiple actions similar to those of morphine; may produce less constipation, smooth muscle spasm, and depression of cough reflex than similar analgesic doses of morphine. May use in combination with promethazine to provide synergistic effect.

Antiemetics

These agents are used to treat emesis.

Promethazine (Phenergan)

Antidopaminergic agent effective in treating emesis. Blocks postsynaptic mesolimbic dopaminergic receptors in brain and reduces stimuli to brainstem reticular system. May use in combination with meperidine to provide synergistic effect.

Benzodiazepines

By binding to specific receptor sites these agents appear to potentiate the effects of γ -aminobutyric acid (GABA) and to facilitate inhibitory GABA neurotransmission and other inhibitory transmitters. Benzodiazepines are anxiolytics that may help patients apprehensive about needle aspiration, imaging studies, or surgery. Conscious sedatives may be considered by the emergency physician with equipment and experience necessary to manage the patient's airway if spontaneous ventilation become compromised.

Midazolam (Versed)

Shorter-acting benzodiazepine sedative-hypnotic useful in patients who require acute and/or short-term sedation. Midazolam is also useful for its amnestic effects.

Lorazepam (Ativan)

Sedative hypnotic with short onset of effects and relatively long half-life.
By increasing the action of GABA, which is a major inhibitory neurotransmitter in the brain, may depress all levels of CNS, including limbic and reticular formation.
When patient needs to be sedated for longer than 24-h period, this medication is excellent.

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