[L. abscessus, a going away, departure]
A localized collection of pus in any body part, resulting from invasion of a pyogenic bacterium or other pathogen. Staphylococcus aureus, e.g., methicillin-resistant S. aureus (MRSA), is a common cause. The abscess is surrounded by a membrane of variable strength created by macrophages, fibrin, and granulation tissue. Abscesses can disrupt function in adjacent tissues and can be life threatening in some circumstances, e.g., in the lung or within the peritoneal cavity.

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ANTECUBITAL ABSCESS Antecubital abscess opened to allow drainage of infection; SEE: inflammation; SEE: pus; SEE: suppuration
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INTRA-ABDOMINAL ABSCESS CT scan shows abscess between stomach and spleen (Courtesy of Harvey Hatch, MD, Curry General Hospital)

acute abscess

An abscess associated with significant inflammation, producing intense heat, redness, swelling, and throbbing pain. The tissue over the abscess becomes elevated, soft, and eventually unstable (fluctuant) and discolored as the abscess comes to a head. An abscess can rupture spontaneously or be drained via an incision. If it is left untreated, the invading pathogens may spread to adjacent tissues or to other parts of the body through the bloodstream. Appearance of or increase in fever may indicate sepsis.

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ACUTE ABSCESS Acute abscess of the skin with surrounding cellulitis

alveolar abscess

An abscess around the root of a tooth in the alveolar cavity. It is usually the result of necrosis and infection of dental pulp following the occurrence of dental caries.
SEE: periapical abscess

amebic abscess

An abscess, typically in the liver, caused by Entamoeba histolytica.
SYN: SEE: endamebic abscess

anorectal abscess

An abscess in the ischiorectal fossa. It occurs in patients with Crohn disease, diabetes mellitus, or anal fissures more often than in others. Incision, drainage, and antibiotics usually provide effective treatment.
SYN: SEE: rectal abscess;
SYN: SEE: ischiorectal abscess

apical abscess

1. An abscess at the apex of a lung. SEE: 2. Periapical abscess.

appendicular abscess

An abscess around an inflamed or ruptured vermiform appendix.

axillary abscess

An abscess or multiple abscesses in the axilla, e.g., in patients with hidradenitis suppurativa.

Bartholin abscess

SEE: Bartholin, Caspar (the younger)

Bezold abscess

SEE: Bezold, Friedrich

bicameral abscess

An abscess with two pockets.

bile duct abscess

An abscess of the bile duct.
SYN: SEE: cholangitic abscess

biliary abscess

An abscess of the gallbladder. It is an infrequent complication of cholangitis or obstruction of the bile duct.

bone abscess

SEE: Brodie abscess.

brain abscess

An intracranial abscess involving the brain or its membranes. It is seldom primary but usually occurs secondary to infections of the middle ear, nasal sinuses, face, or skull or from contamination from penetrating wounds or skull fractures. It may also have a metastatic origin arising from septic foci in the lungs (as in bronchiectasis, empyema, lung abscess), in bone (as in osteomyelitis), or in the heart (as in endocarditis). Infection of nerve tissue by the invading organism results in necrosis and liquefaction of the tissue, with edema of surrounding tissues. Brain abscesses may be acute, subacute, or chronic. Their clinical manifestations depend on the part of the brain involved, the size of the abscess, the virulence of the infecting organism, and other factors.
SYN: SEE: cerebral abscess; SEE: intracranial abscess

Symptoms may include headache, fever, vomiting, malaise, irritability, seizures, or paralysis.

The usual treatment is chemotherapy. Surgical drainage may be required.

breast abscess

SEE: Mammary abscess.

Brodie abscess

SEE: Brodie, Sir Benjamin Collins

bursal abscess

An abscess in a bursa.

canalicular abscess

A breast abscess that discharges into the milk ducts.

caseous abscess

An abscess in which the pus has a cheesy appearance.

cerebral abscess

SEE: Brain abscess.

cholangitic abscess

SEE: Biliary abscess.

chronic abscess

An abscess containing pus but without signs of inflammation. It usually develops slowly as a result of liquefaction of tuberculous tissue. It may occur anywhere in or on the body but more frequently is found in the spine, hips, genitourinary tract, and lymph glands. Symptoms may be very mild. Pain, when present, is caused by pressure on surrounding parts; tenderness is often absent. Chronic septic changes accompanied by afternoon fever may occur. Amyloid disease may develop if the abscess persists for a prolonged period.
SYN: SEE: cold abscess

circumtonsillar abscess

SEE: Peritonsillar abscess.

cold abscess

SEE: Chronic abscess.

collar-button abscesses

Two pus-containing cavities, one larger than the other, connected by a narrow channel.

dental abscess

An acute inflammatory infection within the maxilla or mandible.
SEE: periapical abscess; SEE: periodontal abscess

dentoalveolar abscess

SEE: Periapical abscess.

diffuse abscess

An abscess not circumscribed by a well-defined capsule.

dry abscess

An abscess that disappears without pointing or breaking.

embolic abscess

SEE: Metastatic abscess.

emphysematous abscess

An abscess containing air or gas, produced by organisms such as Clostridium perfringens.
SYN: SEE: gas abscess; SEE: tympanitic abscess

endamebic abscess

SEE: Amebic abscess.

epidural abscess

SEE: Extradural abscess.

extradural abscess

An abscess on the dura mater that is an occasional cause of back pain in febrile patients, usually in those who inject drugs.
SYN: SEE: epidural abscess

fecal abscess

An abscess containing both pus and stool.
SYN: SEE: stercoraceous abscess; SEE: stercoral abscess

filarial abscess

An abscess caused by parasitic infection with microfilariae.

follicular abscess

An abscess in a follicle.

fungal abscess

An abscess caused by a fungus, as in the syndrome mycetoma.
SYN: SEE: mycotic abscess

gas abscess

SEE: Emphysematous abscess.

gingival abscess

An abscess of the gum.

helminthic abscess

SEE: Worm abscess.

hemorrhagic abscess

An abscess containing blood.

hepatic abscess

SEE: Liver abscess.

hot abscess

SEE: Acute abscess.

hypostatic abscess

SEE: Metastatic abscess.

idiopathic abscess

An abscess of unknown cause.

iliac abscess

An abscess in the iliac region.

iliopsoas abscess

An abscess in the psoas and iliacus muscles. It typically results from a local or regional spread of an intestinal or renal abscess or from a blood-borne infection, e.g., after a drug injection.
SYN: SEE: psoas abscess

intracranial abscess

SEE: Brain abscess.

intradural abscess

An abscess within the layers of the dura mater.

intraperitoneal abscess

SEE: Peritoneal abscess.

ischiorectal abscess

SEE: Anorectal abscess.

kidney abscess

An abscess in the kidney, typically following pyelonephritis or a blood-borne infection. The most common causative organisms are gram-negative bacteria from the lower urinary tract that spread to the kidneys and Staphylococcus aureus from a blood-borne infection. Immunocompromised patients may develop abscesses caused by Nocardia, Candida, or Aspergillus. Occasionally, Mycobacterium tuberculosis and Echinococcus are responsible agents.
SYN: SEE: renal

Antimicrobial agents are used in combination with surgical drainage. Occasionally, nephrectomy or retroperitoneal exploration is required.

lacrimal abscess

An abscess in a lacrimal gland or in a lacrimal duct.

lateral alveolar abscess

An abscess occurring in periodontal tissue.

liver abscess

An abscess in the liver caused by pathogenic organisms such as those of species of Bacteroides, Streptococcus, Staphylococcus, or Entamoeba histolytica.

The patient generally has high fevers; sweats and chills; and an enlarged, painful, tender liver. Pus may be obtained by aspiration.

Embolic (multiple) abscesses are generally fatal. Liver abscesses may heal after they have been removed and treated with antibiotics.

SEE: hepatic abscess

lumbar abscess

An abscess in the lumbar region.

lung abscess

An abscess in lung tissue, caused by anaerobic bacteria such as Staphylococcus aureus or Nocardia species.

lymphatic abscess

An abscess of a lymph node.

mammary abscess

An abscess in the female breast, esp. one involving the glandular tissue. It usually occurs during lactation or weaning.
SYN: SEE: breast abscess

mastoid abscess

An abscess of the mastoid portion of the temporal bone.

metastatic abscess

A secondary abscess at a distance from the focus of infection.
SYN: SEE: embolic abscess; SEE: hypostatic abscess; SEE: wandering abscess

miliary abscesses

Multiple small embolic abscesses.

milk abscess

A mammary abscess during lactation.

mycotic abscess

SEE: Fungal abscess.

nocardial abscess

An abscess caused by the genus Nocardia, e.g., in the lung.

orbital abscess

An abscess in the orbit of the eye.

palatal abscess

An abscess in a maxillary tooth, erupting toward the palate.

palmar abscess

An abscess in the tissues of the palm of the hand.

pancreatic abscess

An abscess of pancreatic tissue, usually as a complication of acute pancreatitis or abdominal surgery.

parafrenal abscess

An abscess on the side of the frenulum of the penis.

parametric abscess

An abscess between the folds of the broad ligaments of the uterus.

paranephric abscess

An abscess in the tissues around the kidney.
SYN: SEE: perinephric abscess

parapancreatic abscess

An abscess in the tissues adjacent to the pancreas.
SYN: SEE: peripancreatic abscess

parietal abscess

A periodontal abscess arising in the periodontal tissue other than the orifice through which the vascular supply enters the dental pulp.

parotid abscess

An abscess of the parotid gland.

pelvic abscess

An abscess of the pelvic peritoneum, esp. in the pouch of Douglas. It may arise as a complication of a sexually transmitted disease or diverticulitis.

perianal abscess

An abscess of the skin around the anus. It usually results from obstruction of intestinal crypts and subsequent fistula formation in the skin.
SYN: SEE: periproctic abscess

periapical abscess

An abscess at the apex of a tooth, usually resulting from dental caries or tooth trauma. It may be classified further as an acute periapical abscess, a chronic periapical abscess, a periapical granuloma, or a radicular cyst.
SYN: SEE: apical abscess (2); SEE: dentoalveolar abscess

pericemental abscess

An alveolar abscess not involving the apex of a tooth.

pericoronal abscess

SEE: Pericoronitis.

peridental abscess

An abscess of periodontal tissue.

perinephric abscess

SEE: Paranephric abscess.

periodontal abscess

An acute or chronic abscess found in the gingiva, periodontal pockets, or periodontal ligament.

peripancreatic abscess

SEE: Parapancreatic abscess.

peripleuritic abscess

An abscess in the tissue surrounding the parietal pleura.

periproctic abscess

SEE: Perianal abscess.

peritoneal abscess

An abscess within the peritoneal cavity usually following peritonitis. It is usually caused by enteric bacteria, e.g., Escherichia coli, enterococci, or Klebsiella.
SYN: SEE: intraperitoneal abscess

peritonsillar abscess

An abscess of the tissue around the tonsillar capsule. Needle aspiration of the abscess, with subsequent antibiotic therapy, is an effective treatment in 90% of cases.
SYN: SEE: circumtonsillar abscess

periureteral abscess

An abscess in the tissue around a ureter.

periurethral abscess

An abscess in tissue surrounding the urethra.

perivesical abscess

An abscess in tissue around the urinary bladder.

pneumococcic abscess

An abscess due to infection with pneumococci (Streptococcus pneumoniae).

prelacrimal abscess

An abscess of the lacrimal sac, producing an inflamed, tender swelling at the inner canthus of the eye.

premammary abscess

A subcutaneous or subareolar abscess of the mammary gland.

prostatic abscess

An abscess within the prostate gland.

protozoal abscess

An abscess caused by a protozoon.

psoas abscess

SEE: Iliopsoas abscess.

pulp abscess

1. An abscess in the pulp chamber of a tooth.
2. An abscess of the tissues of the pulp of a finger.

pyemic abscess

A metastatic abscess, usually multiple, caused bypyogenic organisms.

rectal abscess

SEE: Anorectal abscess.

renal abscess

SEE: Kidney abscess.

retrocecal abscess

An abscess located behind the cecum. It is an occasional, severe complication of a ruptured appendix or Crohn disease.

retromammary abscess

An abscess between the mammary gland and the chest wall.

retroperitoneal abscess

An abscess located between the peritoneum and the posterior abdominal wall. It may arise from an abscess in the kidney or from the spread of an intraperitoneal infection posteriorly.

retropharyngeal abscess

An abscess of the lymph nodes in the walls of the pharynx. It sometimes simulates diphtheritic pharyngitis.

Staphylococcus aureus and group A beta-hemolytic streptococcus are the most common pathogens.

Typically, a history of pharyngitis is elicited. This is followed by high fever, dysphagia, and refusal to eat. The condition progresses to respiratory distress with hyperextension of the head (“sniffing position”), tachypnea, labored breathing, and drooling. An exquisitely tender bulge in the pharyngeal wall is usually evident.

A retropharyngeal abscess, if fluctuant, should be treated with incision and drainage. If it is recognized before becoming fluctuant, the abscess should be treated with antibiotics, intravenously administered if the patient is unable to swallow.

retrovesical abscess

An abscess behind the bladder.

root abscess

A colloquial and veterinary term for periapical abscess.

runaround abscess

A colloquial term for a bacterial infection that surrounds a fingernail; a paronychia.

sacrococcygeal abscess

An abscess over the sacrum and coccyx.

septicemic abscess

An abscess resulting from septicemia.

spermatic abscess

An abscess of the seminiferous tubules.

spinal abscess

An abscess resulting from necrosis of a vertebra.

splenic abscess

An abscess of the spleen. It may arise either from the spread of infection from a neighboring organ (such as a diverticular abscess or a ruptured gastric ulcer) or from hematogenous spread in patients with infective endocarditis.

stercoraceous abscess

SEE: Fecal abscess

stercoral abscess

SEE: Fecal abscess.

sterile abscess

An abscess from which microorganisms cannot be cultivated, such as an occasional complication of an intramuscular injection.

stitch abscess

An abscess formed around a stitch or suture.

streptococcal abscess

An abscess caused by streptococci.

subaponeurotic abscess

An abscess beneath an aponeurosis or fascia.

subarachnoid abscess

An abscess of the midlayer of the covering of the brain and spinal cord.

subareolar abscess

An abscess underneath the areola of the mammary gland, sometimes draining through the nipple.

subdiaphragmatic abscess

An abscess beneath the diaphragm, e.g., a hepatic, splenic, or interperitoneal abscess.
SYN: SEE: subphrenic abscess

subdural abscess

An abscess beneath the dura of the brain or spinal cord.

subfascial abscess

An abscess beneath the fascia.

subgaleal abscess

An abscess beneath the galea aponeurotica (the epicranial aponeurosis).

subpectoral abscess

An abscess beneath the pectoral muscles.

subperiosteal abscess

A bone abscess below the periosteum.

subperitoneal abscess

An abscess between the parietal peritoneum and the abdominal wall.

subphrenic abscess

SEE: Subdiaphragmatic abscess.

subscapular abscess

An abscess between the serratus anterior muscle and the posterior thoracic wall.

subungual abscess

An abscess beneath the fingernail. It may follow injury from a pin, needle, or splinter.

sudoriparous abscess

An abscess of a sweat gland.

suprahepatic abscess

An abscess in the suspensory ligament between the liver and the diaphragm.

syphilitic abscess

An abscess occurring in the tertiary stage of syphilis, esp. in bone.

thecal abscess

A spinal epidural abscess.

thymus abscess

An abscess of the thymus.

tonsillar abscess

Acute suppurative tonsillitis.

tooth abscess

SEE: Alveolar abscess.

tropical abscess

An amebic abscess of the liver.

tuberculous abscess

SEE: Chronic abscess.

tubo-ovarian abscess

An abscess involving both the fallopian tubes and the ovaries. It is typically transmitted sexually.

tympanitic abscess

SEE: Emphysematous abscess.

tympanocervical abscess

An abscess arising in the tympanum and extending to the neck.

tympanomastoid abscess

An abscess of both the tympanum and the mastoid.

urethral abscess

An abscess in the urethra.

urinary abscess

An abscess caused by escape of urine into surrounding tissues.

urinous abscess

An abscess that contains pus and urine.

verminous abscess

SEE: Worm abscess.

wandering abscess

SEE: Metastatic abscess.

warm abscess

SEE: Acute abscess.

worm abscess

An abscess caused by or containing insect larvae, worms, or other animal parasites.
SYN: SEE: helminthic; SEE: verminous abscess