Medication Summary
Antibiotics are unnecessary in otherwise healthy individuals. The practitioner should provide appropriate empiric intravenous (IV) antibiotic coverage for patients who are elderly or immunosuppressed, patients who have comorbidities, patients with a heart valve abnormality or prosthetic valve who are likely to benefit from antibiotic prophylaxis, and patients in whom infection has become systemic.
Analgesia is necessary for pain control and may be given orally (PO) or IV, in conjunction with anesthetics if needle aspiration or incision and drainage of an abscess are performed. Anxiolytics may help certain patients who are apprehensive about needle aspiration, incision and drainage, imaging studies, or surgery.
Antibiotics
Class Summary
Appropriate IV antibiotic coverage should be provided preoperatively and postoperatively, either on the basis of Gram staining or on an empiric basis, as a preventive measure, for elderly patients, patients with immunosuppression, patients with a heart valve abnormality or prosthesis, and patients with comorbid states.
Ampicillin-sulbactam (Unasyn)
Ampicillin-sulbactam represents a combination of a beta-lactamase inhibitor with a penicillin. It interferes with bacterial cell-wall synthesis during active replication, causing bactericidal activity against susceptible organisms. It is used as an alternative to amoxicillin when a patient is unable to take medication PO. Ampicillin-sulbactam covers skin, enteric flora, and anaerobes; it is not ideal for nosocomial pathogens.
Imipenem-cilastatin (Primaxin)
Imipenem-cilastatin should be used empirically for more severely ill intensive care unit (ICU) patients. Pus or blood culture and sensitivity results, once available, should guide antibiotic selection. Predisposing and comorbid diseases may also guide empiric antibiotic selection.
Ampicillin
Ampicillin, a broad-spectrum penicillin, interferes with bacterial cell-wall synthesis during active replication, causing bactericidal activity against susceptible organisms. It is used as an alternative to amoxicillin when a patient is unable to take medication PO. Patients with prosthetic heart valves who are at risk for endocarditis should receive IV prophylactic antibiotics before any procedure. Ampicillin is preferred for this application, unless the patient is penicillin-allergic, in which case cefazolin or clindamycin is an appropriate choice.
Cefazolin
Cefazolin is a first-generation semisynthetic cephalosporin that binds to one or more penicillin-binding proteins, arresting bacterial cell wall synthesis and inhibiting bacterial replication. It has poor capacity to cross the blood-brain barrier. Cefazolin is primarily active against skin flora, including Staphylococcus aureus, and is typically used alone for skin and skin-structure coverage. Regimens for IV and intramuscular (IM) dosing are similar. This agent is used in penicillin-allergic patients with prosthetic heart valves who are at risk for endocarditis.
Clindamycin (Cleocin)
Clindamycin is a semisynthetic antibiotic produced by 7(S)-chloro-substitution of the 7(R)-hydroxyl group of the parent compound, lincomycin. It inhibits bacterial growth, possibly by blocking dissociation of peptidyl tRNA from ribosomes, causing RNA-dependent protein synthesis to arrest. Clindamycin is widely distributed in the body without penetrating the central nervous system (CNS). It is protein-bound and excreted by the liver and kidneys. This agent is used in penicillin-allergic patients with prosthetic heart valves at risk for endocarditis.
Anesthetics
Class Summary
Anesthetics may help blunt the pain of a diagnostic needle aspiration but are only partially effective.
Lidocaine 1% (Xylocaine with Epinephrine)
Lidocaine 1-2% with or without epinephrine (1:100,000 or 1:200,000 concentration) is used. Lidocaine is an amide local anesthetic used in 1-2% concentration. The 1% preparation contains 10 mg of lidocaine for each 1 mL of solution; the 2% preparation contains 20 mg of lidocaine for each 1 mL of solution. Lidocaine inhibits depolarization of type C sensory neurons by blocking sodium channels. Epinephrine prolongs the duration of the anesthetic effects from lidocaine by causing vasoconstriction of the blood vessels surrounding the nerve axons.
Lidocaine decreases permeability to sodium ions in neuronal membranes. This results in inhibition of depolarization, blocking the transmission of nerve impulses. Epinephrine prolongs the duration of the anesthetic effects from lidocaine by causing vasoconstriction of the blood vessels surrounding the nerve axons.
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 before aspiration.
Bupivacaine and epinephrine (Marcaine with Epinephrine, Vivacaine, Sensorcaine with Epinephrine)
Bupivacaine decreases permeability to sodium ions in neuronal membranes. This results in the inhibition of depolarization, blocking the transmission of nerve impulses. Epinephrine prolongs the duration of the anesthetic effects from bupivacaine by causing vasoconstriction of the blood vessels surrounding the nerve axons.
Pain Medications
Class Summary
Pain control is essential to quality patient care. Analgesics ensure patient comfort, promote pulmonary toilet, and possess sedating properties, which are beneficial for patients who experience pain. These agents are used for comfort and sedation and to blunt the discomfort of diagnostic needle aspiration.
Meperidine (Demerol, Meperitab)
Meperidine is an analgesic with multiple actions similar to those of morphine; it may produce less constipation, smooth muscle spasm, and depression of cough reflex than similar analgesic doses of morphine. Meperidine may be used in combination with promethazine to provide a synergistic effect.
Antiemetics
Class Summary
Antiemetic agents are used to treat vomiting. In combination with analgesics like meperidine, it may produce a synergistic effect.
Promethazine (Phenergan)
Promethazine is an antidopaminergic agent that is effective in treating emesis. It blocks postsynaptic mesolimbic dopaminergic receptors in the brain and reduces stimuli to the brainstem reticular system. It may be used in combination with meperidine to provide a synergistic effect.
Benzodiazepines
Class Summary
By binding to specific receptor sites, benzodiazepines appear to potentiate the effects of gamma-aminobutyric acid (GABA) and to facilitate neurotransmission of GABA and other inhibitory transmitters. These agents are anxiolytics that may help patients who are apprehensive about needle aspiration, imaging studies, or surgery. Conscious sedation may be considered by the emergency physician with equipment and experience necessary to manage the patient’s airway if spontaneous ventilation becomes compromised.
Midazolam
Midazolam is a shorter-acting benzodiazepine sedative-hypnotic that is useful in patients who require acute or short-term sedation. It is also useful for its amnestic effects.
Lorazepam (Ativan)
Lorazepam is a sedative-hypnotic that increases the action of GABA, thereby potentially depressing all levels of the CNS, including the limbic system and reticular formation. It has a short onset of effect and a relatively long half-life. When patient needs to be sedated for longer than 24 hours, this medication is excellent.
-
Illustration of major types of anorectal abscesses (submucosal type not pictured).
-
Goodsall rule for anorectal fistulas. Fistulas that exit in posterior half of rectum generally follow curved course toward posterior midline, whereas those that exit in anterior half of rectum usually follow radial course to dentate line.
-
Goodsall rule for anorectal fistulas. Note curved nature of posterior fistulas and radial (straight) orientation of anterior fistulas.
