An
abscess is a collection of
pusPus is a whitish-yellow, yellow or yellow-brown exudate produced by vertebrates during inflammatory pyogenic bacterial infections. An accumulation of pus in an enclosed tissue space is known as an abscess, while a visible collection of pus within or beneath the epidermis is known as a pustule or...
(dead neutrophils) that has accumulated in a cavity formed by the tissue on the basis of an
infectiousAn infection is the detrimental colonization of a host organism by a foreign species. In an infection, the infecting organism seeks to utilize the host's resources to multiply, usually at the expense of the host. The infecting organism, or pathogen, interferes with the normal functioning of the...
process (usually caused by bacteria or parasites) or other foreign materials (e.g. splinters, bullet wounds, or injecting needles). It is a
defensive reactionAn immune system is a system of biological structures and processes within an organism that protects against disease by identifying and killing pathogens and tumour cells. It detects a wide variety of agents, from viruses to parasitic worms, and needs to distinguish them from the organism's own...
of the tissue to prevent the spread of infectious materials to other parts of the body.
The organisms or foreign materials kill the local
cellThe cell is the basic structural and functional unit of all known living organisms. It is the smallest unit of an organism that is classified as living, and is often called the building block of life. The Alberts text discusses how the "cellular building blocks" move to shape developing embryos...
s, resulting in the release of
cytokineCytokines are any of a number of substances that are secreted by specific cells of the immune system which carry signals locally between cells, and thus have an effect on other cells. They are a category of signaling molecules that are used extensively in cellular communication. They are proteins,...
s. The cytokines trigger an
inflammatory responseInflammation is the complex biological response of vascular tissues to harmful stimuli, such as pathogens, damaged cells, or irritants. Inflammation is a protective attempt by the organism to remove the injurious stimuli as well as initiate the healing process for the tissue. Inflammation is not a...
, which draws large numbers of
white blood cellWhite blood cells , or leukocytes , are cells of the immune system defending the body against both infectious disease and foreign materials. Five different and diverse types of leukocytes exist, but they are all produced and derived from a multipotent cell in the bone marrow known as a...
s to the area and increases the regional
bloodBlood is a specialized bodily fluid that delivers necessary substances to the body's cells — such as nutrients and oxygen — and transports waste products away from those same cells....
flow.
The final structure of the abscess is an abscess wall, or capsule, that is formed by the adjacent healthy cells in an attempt to keep the pus from infecting neighboring structures. However, such encapsulation tends to prevent immune cells from attacking bacteria in the pus, or from reaching the causative organism or foreign object.
Abscesses must be differentiated from
empyemaPleural empyema is an accumulation of pus in the pleural cavity. Most pleural empyemas arise from an infection within the lung , often associated with parapneumonic effusions. There are three stages: exudative, fibrinopurulent and organizing. In the exudative stage, the pus accumulates...
s, which are accumulations of pus in a preexisting rather than a newly formed anatomical cavity.
Manifestations
The cardinal symptoms and signs of any kind of inflammatory process are redness (rubor), heat (calor), swelling (tumor), pain (dolor) and loss of function. Abscesses may occur in any kind of solid tissue but most frequently on skin surface (where they may be superficial pustules (
boilBoil is a skin disease caused by the infection of hair follicles, resulting in the localized accumulation of pus and dead tissue. Individual boils can cluster together and form an interconnected network of boils called carbuncles....
s) or deep skin abscesses), in the lungs,
brainBrain abscess is an abscess caused by inflammation and collection of infected material, coming from local or remote infectious sources, within the brain tissue...
,
teethA tooth abscess or root abscess is pus enclosed in the tissues of the jaw bone at the tip of an infected tooth. Usually the abscess originates from a bacterial infection that has accumulated in the soft pulp of the tooth....
, kidneys and tonsils. Major complications are spreading of the abscess material to adjacent or remote tissues and extensive regional tissue death (
gangreneGangrene is a complication of necrosis or cell death characterized by the decay of body tissues, which become black and malodorous. It is caused by infection or ischemia, such as from thrombosis. It is usually the result of critically insufficient blood supply and is often associated with...
). Abscesses in most parts of the body rarely heal themselves, so prompt medical attention is indicated at the first suspicion of an abscess.
An abscess could potentially be fatal (although this is rare) if it compresses vital structures such as the
tracheaThe trachea, or windpipe, is a tube that connects to the pharynx or larynx, allowing the passage of air to the lungs. It is lined with pseudostratified ciliated columnar epithelium cells with mucosal goblet cells which produce mucus...
in the context of a deep neck abscess.
Treatment
Wound abscesses do not generally need to be treated with antibiotics, but they will require surgical intervention,
debridementDebridement is the medical removal of a patient's dead, damaged, or infected tissue to improve the healing potential of the remaining healthy tissue...
and
curettageCurettage, in surgery, is the use of a curette to remove tissue by scraping or scooping. It may be used to obtain a biopsy of a mass to determine if it is a granuloma, neoplasm, or some other tumor. It is often employed prior to definitive excisional surgery to more precisely delineate the extent...
.
Incision and drainage
The abscess should be inspected to identify if foreign objects are a cause, which may require their removal. If foreign objects are not the cause, a doctor will incise and drain the abscess and prescribe painkillers and possibly antibiotics.
SurgicalSurgery is a medical specialty that uses operative manual and instrumental techniques on a patient to investigate and/or treat a pathological condition such as disease or injury, to help improve bodily function or appearance, or sometimes for some other reason...
drainage of the abscess (e.g.
lancingIncision and drainage and clinical lancing are minor surgical procedures to release pus or pressure built up under the skin, such as from an abscess, boil, or infected paranasal sinus...
) is usually indicated once the abscess has developed from a harder serous inflammation to a softer
pusPus is a whitish-yellow, yellow or yellow-brown exudate produced by vertebrates during inflammatory pyogenic bacterial infections. An accumulation of pus in an enclosed tissue space is known as an abscess, while a visible collection of pus within or beneath the epidermis is known as a pustule or...
stage. This is expressed in the
LatinLatin is an Italic language originally spoken in Latium and Ancient Rome. Through the Roman conquest, Latin spread throughout the Mediterranean and a large part of Europe...
medical
aphorismThe word aphorism denotes an original thought, spoken or written in a laconic and easily memorable form....
:
Ubi pus, ibi evacuaUbi pus, ibi evacua is a Latin aphorism or adage, often cited in medicine, that literally means: "where there is pus, there evacuate it". It refers to what clinicians should do when there is a collection of pus in the body; that is, to create an opening for it to evacuate.Examples include what an...
.
In critical areas where surgery presents a high risk, it may be delayed or used as a last resort. The drainage of a lung abscess may be performed by positioning the patient in a way that enables the contents to be discharged via the
respiratory tractIn humans the respiratory tract is the part of the anatomy that has to do with the process of respiration.The respiratory tract is divided into 3 segments:*Upper respiratory tract: nose and nasal passages, paranasal sinuses, and throat or pharynx...
. Warm compresses and elevation of the limb may be beneficial for a skin abscess.
Packing
In North America, after drainage, an abscess cavity is often packed. There however is no evidence to support this practice and it may in fact delay healing. To try to answer this question more definitely a randomized double blinded study was started in September 2008 and is ongoing as of December 2008. A small pilot study has found no benefit from packing of simple cutaneous abscesses.
Primary closure
Primary closure has been successful when combined with
curettageCurettage, in surgery, is the use of a curette to remove tissue by scraping or scooping. It may be used to obtain a biopsy of a mass to determine if it is a granuloma, neoplasm, or some other tumor. It is often employed prior to definitive excisional surgery to more precisely delineate the extent...
and antibiotics or with curettage alone. However, another
randomized controlled trialA randomized controlled trial is a type of scientific experiment most commonly used in testing the efficacy or effectiveness of healthcare services or health technologies . RCTs are also employed in other research areas, such as judicial, educational, and social research...
found primary closure led to 35% failing to heal primarily and primary closure longer median number of days to closure (8.9 versus 7.8).
In anorectal abscesses, primary closure healed faster, but 25% of abscesses healed by secondary intention and recurrence was higher.
Antibiotics
As
Staphylococcus aureusStaphylococcus aureus is the most common cause of staph infections. It is a spherical bacterium, frequently part of the skin flora found in the nose and on skin. About 20% of the population are long-term carriers of S. aureus. S...
bacteriaThe bacteria are a large group of unicellular microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals...
is a common cause, an anti-staphylococcus antibiotic such as
flucloxacillinFlucloxacillin or floxacillin is a narrow spectrum beta-lactam antibiotic of the penicillin class. It is used to treat infections caused by susceptible Gram-positive bacteria. Unlike other penicillins, flucloxacillin has activity against beta-lactamase-producing organisms such as Staphylococcus...
or
dicloxacillinDicloxacillin is a narrow spectrum beta-lactam antibiotic of the penicillin class. It is used to treat infections caused by susceptible Gram-positive bacteria. Notably, it is active against beta-lactamase-producing organisms such as Staphylococcus aureus, which would otherwise be resistant to most...
is used. With the emergence of community-acquired methicillin-resistant staphylococcus aureus MRSA, these traditional antibiotics may be ineffective; alternative antibiotics effective against community-acquired MRSA often include
clindamycinClindamycin is a lincosamide antibiotic. It is usually used to treat infections with anaerobic bacteria but can also be used to treat some protozoal diseases, such as malaria...
, trimethoprim-sulfamethoxazole, and
doxycyclineDoxycycline is a member of the tetracycline antibiotics group and is commonly used to treat a variety of infections. Doxycycline is a semi-synthetic tetracycline invented and clinically developed in the early 1960s by Pfizer Inc. and marketed under the brand name Vibramycin. Vibramycin received...
. These antibiotics may also be prescribed to patients with a documented allergy to penicillin. (If the condition is thought to be cellulitis rather than abscess, consideration should be given to possibility of strep species as cause that are still sensitive to traditional anti-staphylococcus agents such as dicloxacillin or cephalexin in patients able to tolerate penicillin). It is important to note that
antibioticIn common usage, an antibiotic is a substance or compound that kills or inhibits the growth of bacteria...
therapy alone without surgical drainage of the abscess is seldom effective due to antibiotics often being unable to get into the abscess and their ineffectiveness at low
pHpH is a measure of the acidity or basicity of a solution. It is defined as the cologarithm of the activity of dissolved hydrogen ions . Hydrogen ion activity coefficients cannot be measured experimentally, so they are based on theoretical calculations...
levels. Whilst most medical texts advocate surgical incision some medical doctors will treat small abscesses conservatively with antibiotics.
Recurrent infections
Recurrent abscesses are often caused by community-acquired MRSA. While resistant to most beta lactam antibiotics commonly used for skin infections, it remains sensitive to alternative antibiotics, e.g., clindamycin (Cleocin), trimethoprim-sulfamethoxazole (Bactrim), and doxycycline (unlike hospital-acquired MRSA that may only be sensitive to vancomycin IV).
To prevent recurrent infections due to
StaphylococcusStaphylococcus is a genus of Gram-positive bacteria. Under the microscope they appear round , and form in grape-like clusters....
, consider the following measures:
- Topical mupirocin
Mupirocin is an antibiotic originally isolated from Pseudomonas fluorescens NCIMB 10586, developed by Beecham.
...
applied to the nares. In this randomized controlled trialA randomized controlled trial is a type of scientific experiment most commonly used in testing the efficacy or effectiveness of healthcare services or health technologies . RCTs are also employed in other research areas, such as judicial, educational, and social research...
, patients used nasal mupirocin twice daily 5 days a month for 1 year.
- Chlorhexidine baths, In a randomized controlled trial
A randomized controlled trial is a type of scientific experiment most commonly used in testing the efficacy or effectiveness of healthcare services or health technologies . RCTs are also employed in other research areas, such as judicial, educational, and social research...
, nasal recolonization with S. aureus occurred at 12 weeks in 24% of nursing home residents receiving mupirocin ointment alone (6/25) and in 15% of residents receiving mupirocin ointment plus chlorhexidine baths daily for the first three days of mupirocin treatment (4/27). Although these results did not reach statistical significanceIn statistics, a result is called statistically significant if it is unlikely to have occurred by chance. The phrase test of significance was coined by Ronald Fisher....
, the baths are an easy treatment.
Magnesium sulfate paste
Historically abscesses as well as boils and many other collections of pus have been treated via application of
magnesium sulfateMagnesium sulfate is a chemical compound containing magnesium and sulfur, with the formula MgSO4. In its hydrated form the pH is 6.0 . It is often encountered as the heptahydrate, MgSO4·7H2O, commonly called Epsom salt. Anhydrous magnesium sulfate is used as a...
paste. This works by drawing the infected pus to the surface of the skin before rupturing and leaking out, after this the body will usually repair the old infected cavity. Magnesium sulfate is therefore best applied at night with a sterile dressing covering it, the rupture itself is not painful but the drawing up may be uncomfortable. Magnesium sulfate paste is considered a "home remedy" and is not necessarily an effective or accepted medical treatment.
Perianal abscess
Perianal abscesses can be seen in patients with for example
inflammatory bowel diseaseIn medicine, inflammatory bowel disease is a group of inflammatory conditions of the colon and small intestine. The major types of IBD are Crohn's disease and ulcerative colitis..-Forms:...
(such as
Crohn's diseaseCrohn's disease is an inflammatory disease of the intestines that may affect any part of the gastrointestinal tract from anus to mouth, causing a wide variety of symptoms...
) or diabetes. Often the abscess will start as an internal wound caused by ulceration or hard stool. This wound typically becomes infected as a result of the normal presence of feces in the rectal area, and then develops into an abscess. This often presents itself as a lump of tissue near the
anusThe anus is an opening at the opposite end of an animal's digestive tract from the mouth. Its function is to expel feces, unwanted semi-solid matter produced during digestion, which, depending on the type of animal, may be one or more of: matter which the animal cannot digest, such as bones; food...
which grows larger and more painful with the passage of time.
Like other abscesses, perianal abscesses may require prompt medical treatment, such as an incision and debridement or lancing.
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