Intra-abdominal infection (IAI, also spelled intraabdominal) is a group of
infections
An infection is the invasion of tissue (biology), tissues by pathogens, their multiplication, and the reaction of host (biology), host tissues to the infectious agent and the toxins they produce. An infectious disease, also known as a transmis ...
that occur within the
abdominal cavity
The abdominal cavity is a large body cavity in humans and many other animals that contain Organ (anatomy), organs. It is a part of the abdominopelvic cavity. It is located below the thoracic cavity, and above the pelvic cavity. Its dome-shaped roo ...
. They vary from
appendicitis
Appendicitis is inflammation of the Appendix (anatomy), appendix. Symptoms commonly include right lower abdominal pain, nausea, vomiting, fever and anorexia (symptom), decreased appetite. However, approximately 40% of people do not have these t ...
to
fecal peritonitis.
[ Risk of death despite treatment is often high.]
Classifications
IAIs can be classified into uncomplicated and complicated infections. Uncomplicated infections often involved the infection of single organ and can be controlled by surgical removal of the source of infection, and antibiotics is not required after the surgery to control the infection. In complicated infections, the infection spread to a part or to the whole of the peritoneum
The peritoneum is the serous membrane forming the lining of the abdominal cavity or coelom in amniotes and some invertebrates, such as annelids. It covers most of the intra-abdominal (or coelomic) organs, and is composed of a layer of mesotheli ...
, causing peritonitis
Peritonitis is inflammation of the localized or generalized peritoneum, the lining of the inner wall of the abdomen and covering of the abdominal organs. Symptoms may include severe pain, swelling of the abdomen, fever, or weight loss. One pa ...
. Meanwhile, peritonitis can be classified into primary, secondary, and tertiary peritonitis. Primary peritonitis is the diffuse bacterial infection of the peritoneum while the integrity of the gastrointestinal tract is preserved (in cases of ascites
Ascites (; , meaning "bag" or "sac") is the abnormal build-up of fluid in the abdomen. Technically, it is more than 25 ml of fluid in the peritoneal cavity, although volumes greater than one liter may occur. Symptoms may include increased abdo ...
); secondary peritonitis is the infection of peritoneum where the integrity of gastrointestinal tract is compromised; tertiary peritonitis is reinfection of peritoneum 48 hours after apparently good surgical control of secondary peritonitis.
Signs and symptoms
Those with suspected IAIs usually have acute onset of abdominal pain with signs of local or generalised inflammation
Inflammation (from ) is part of the biological response of body tissues to harmful stimuli, such as pathogens, damaged cells, or irritants. The five cardinal signs are heat, pain, redness, swelling, and loss of function (Latin ''calor'', '' ...
s such as pain, tenderness (pain on touching), fever, tachycardia
Tachycardia, also called tachyarrhythmia, is a heart rate that exceeds the normal resting rate. In general, a resting heart rate over 100 beats per minute is accepted as tachycardia in adults. Heart rates above the resting rate may be normal ...
(increased heart rate), or tachypnea
Tachypnea, also spelt tachypnoea, is a respiratory rate greater than normal, resulting in abnormally rapid and shallow breathing.
In adult humans at rest, any respiratory rate of 1220 per minute is considered clinically normal, with tachypnea b ...
(increased breathing rate). In more severe cases, such as organ failure, signs such as hypotension
Hypotension, also known as low blood pressure, is a cardiovascular condition characterized by abnormally reduced blood pressure. Blood pressure is the force of blood pushing against the walls of the arteries as the heart pumps out blood and is ...
(low blood pressure), oliguria
Oliguria or hypouresis is the low output of urine specifically more than 80 ml/day but less than 400ml/day. The decreased output of urine may be a sign of dehydration, kidney failure, hypovolemic shock, hyperosmolar Hyperglycemic Nonketotic Syndro ...
(reduced urine output), sudden onset of altered level of consciousness
An altered level of consciousness is any measure of arousal other than normal. Level of consciousness (LOC) is a measurement of a person's arousability and responsiveness to stimuli from the environment.
A mildly depressed level of consciousn ...
, and lactic acidosis
Lactic acidosis refers to the process leading to the production of lactate by anaerobic metabolism. It increases hydrogen ion concentration tending to the state of acidemia or low pH. The result can be detected with high levels of lactate and lo ...
will appear.appendicitis
Appendicitis is inflammation of the Appendix (anatomy), appendix. Symptoms commonly include right lower abdominal pain, nausea, vomiting, fever and anorexia (symptom), decreased appetite. However, approximately 40% of people do not have these t ...
, signs such as fever, positive psoas sign
The psoas sign, also known as Cope's sign (or Cope's psoas test) or Obraztsova's sign, is a medical sign that indicates irritation to the iliopsoas group of hip flexors in the abdomen, and consequently indicates that the inflamed appendix is ret ...
, migration of pain from umbilicus to the right iliac fossa
The abdomen (colloquially called the gut, belly, tummy, midriff, tucky, or stomach) is the front part of the torso between the thorax (chest) and pelvis in humans and in other vertebrates. The area occupied by the abdomen is called the abdominal ...
increases the likelihood of the disease; while signs such as vomiting before the pain reduces its likelihood to occur.
Diagnosis
CT scan and ultrasound has been used routinely to complete the assessment of IAIs. CT scan has higher sensitivity and specificity than ultrasound to access the condition. However, CT scan poses radiation risk to the subject.
References
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General surgery