Appendicular abscess overview: Difference between revisions
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{{Appendicular abscess}} | {{Appendicular abscess}} | ||
{{CMG}};{{AE}}{{ADG}} | {{CMG}}; {{AE}}{{ADG}} | ||
==Overview== | ==Overview== | ||
Appendicular abscess is defined as a collection of [[pus]] resulting from [[necrosis]] of the tissue superimposed with infection in an [[Appendicitis|inflamed appendix]]. It is unusual and rare entity | Appendicular abscess is defined as a collection of [[pus]] resulting from [[necrosis]] of the [[tissue]] superimposed with [[infection]] in an [[Appendicitis|inflamed appendix]]. It is unusual and rare entity; appendicular abscess is a life-threatening complication of [[acute appendicitis]] (preoperatively) or [[appendectomy]] (postoperatively). It is observed in 2-7% of population presenting with [[appendicitis]]. Complications arise if [[appendicitis]] is not treated promptly. The [[abscess]] develops and is limited by the [[Intestines|inflamed coils of intestine]]. [[Abscess|The abscess]] can spread to [[pelvis]] leading to [[peritonitis]] if the [[abdominal wall]] is ruptured. In most of the patients, the [[Intestine|intestinal coils]] and [[omentum]] in the [[abdominal cavity]] tend to cover the [[Appendicitis|inflamed appendix]] forming an [[appendicular]] [[mass]]. <ref>{{cite book | last = Williams | first = Norman | title = Bailey & Love's short practice of surgery | publisher = CRC Press | location = Boca Raton, FLa | year = 2013 | isbn = 978-1444121285 }}</ref> | ||
==Historical | |||
[[Appendicitis]] was first | ==Historical Perspective== | ||
[[Appendicitis]] was first described by Reginald J. Fitz of Harvard University in 1886. He also coined the term [[appendix]]. Since then, the [[appendectomy]] has become one of the most common surgical procedures. The [[laparoscopic]] [[appendectomy]] was invented in the 1980s, and has led to reduced length of hospital stay a decreased risk of [[infection]], and a reduction in post-operative pain.<ref name="pmid6342553">{{cite journal |author=Williams GR |title=Presidential Address: a history of appendicitis. With anecdotes illustrating its importance |journal=[[Annals of Surgery]] |volume=197 |issue=5 |pages=495–506|pmid=6342553 |pmc=1353017 |doi= |url=http://meta.wkhealth.com/pt/pt-core/template-journal/lwwgateway/media/landingpage.htm?issn=0003-4932&volume=197&issue=5&spage=495 |accessdate=2012-08-09}}</ref> | |||
<ref name="book1">McCarty, Arthur C. "History of Appendicitis Vermiformis Its diseases and treatment." The Innominate Society http://www.innominatesociety.com/Articles/History%20of%20Appendicitis.htm (1927). APA</ref><ref name="book1">McCarty, Arthur C. "History of Appendicitis Vermiformis Its diseases and treatment." The Innominate Society http://www.innominatesociety.com/Articles/History%20of%20Appendicitis.htm (1927). APA</ref> | |||
==Classification== | ==Classification== | ||
There is no classification system established for appendicular abscess. | |||
==Pathophysiology== | ==Pathophysiology== | ||
An appendicular abscess is a complication of acute appendicitis. It is resulted due to the invasion of the appendix | An [[appendicular]] [[abscess]] is a complication of [[Appendicitis|acute appendicitis]]. It is resulted due to the invasion of the appendix by [[bacteria]] following an [[obstruction]]. The [[appendix]] exists at the junction of the [[Intestine|small and large intestine]] and is a natural habitat of wide variety of bacteria. It is, therefore, prone to develop complications when blocked. Coupled with an [[infection]], [[acute appendicitis]] can be life threatening. Other serious complications which may develop as a result of neglected [[appendicitis]] or appendicular abscess include [[gangrene]], [[appendicular]] [[Mass|masses]], [[rupture]], and [[Peritonitis|general peritoneal infections]]. Obstruction of the tubular space inside the [[appendix]] is the main inciting event, this initial problem leads to the [[inflammation]] of the appendix, [[obstruction]] of the [[blood vessels]] supplying it, and finally infection. [[Inflammation|Inflammatory mediators]] along with various [[bacterial]] [[toxins]] and [[proteolytic]] [[enzymes]] from the [[neutrophils]] are released, resulting in the formation of an [[abscess]] in the appendix.<ref name="pmid626573">{{cite journal |vauthors=Bradley EL, Isaacs J |title=Appendiceal abscess revisited |journal=Arch Surg |volume=113 |issue=2 |pages=130–2 |year=1978 |pmid=626573 |doi= |url=}}</ref> | ||
<ref> Wangensteen OH, Bowers WF. Significance of the obstructive factor in the genesis of acute appendicitis. Arch Surg 1937;34:496-526 </ref> | |||
==Causes== | |||
Microbiology responsible for [[appendicular]] [[abscess]] includes a mixture of [[aerobic]] and [[anaerobic]] [[organisms]] that are natural habitat of [[gut]]. The most commonly isolated [[aerobic]] organism is ''[[Escherichia coli]]'', and the most commonly observed [[anaerobic]] organism is ''[[Bacteroides fragilis]]''. The type and density of [[aerobic]] and [[anaerobic]] bacteria isolated from appendicular abscesses depends upon the organism that dominates the habitat and degree of obstruction.<ref name="pmid20034345">{{cite journal| author=Solomkin JS, Mazuski JE, Bradley JS, Rodvold KA, Goldstein EJ, Baron EJ et al.| title=Diagnosis and management of complicated intra-abdominal infection in adults and children: guidelines by the Surgical Infection Society and the Infectious Diseases Society of America. | journal=Clin Infect Dis | year= 2010 | volume= 50 | issue= 2 | pages= 133-64 | pmid=20034345 | doi=10.1086/649554 | pmc= | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=20034345 }} </ref> | |||
==Differential Diagnosis== | |||
Appendicular abscess should be diagnosed early and treat promptly not only to reduce [[morbidity]] and [[mortality]], but it is also important to differentiate from other abdominal diseases presenting with [[Right lower quadrant abdominal pain resident survival guide|RLQ pain]], [[fever]], [[nausea]], and [[vomiting]] such as [[psoas abscess]], [[cellulitis]], torsion of [[Testicular torsion|testis]] and [[Ovarian torsion|ovaries]], and [[ectopic pregnancy]] as the undrained abscess carries high risk of mortality. | |||
==Risk Factors== | |||
Identifying risk factors that predict the likelihood of complications of [[appendicitis]] is a crucial step in managing [[appendicular]] [[abscess]]. Appendicitis is most common risk factor of developing abscess; it is more common among people in the age group of 10 to 30 years old. Appendicitis is a medical emergency that requires proper attention, especially more than any other [[abdominal]] causes if symptoms are not conclusive. | |||
==Screening== | |||
According to the Guidelines by the Surgical Infection Society and the Infectious Diseases Society of America, there is insufficient evidence to recommend routine screening for appendicular abscess. | |||
==Natural History, Complications, and Prognosis== | |||
Without treatment, the patient will likely develop symptoms of diffuse [[abdominal]] [[pain]], which is different from typical [[appendicitis]] [[pain]], starting centrally (in the periumbilical region) before localizing to the [[right iliac fossa]] in the right lower quadrant of the [[abdomen]]. During the final stage of the untreated [[disease]] process, the [[appendix]] will rupture, and this may eventually lead to death if [[peritonitis]] develops. Complications that can develop as a result of the untreated [[appendicular]] [[abscess]] include:[[septicemia]], [[rupture]], [[peritonitis]], [[hemorrhage]] and death. Prognosis of the abscess is good with [[antibiotics]] and [[percutaneous]] drain and resolves without the need for [[Appendectomy|appendectomy,]] but it is recommended to follow and appendicular abscess by [[Appendectomy|interval appendectomy]] after 8-12 weeks to prevent recurrence. | |||
==Diagnosis== | |||
===History and Symptoms=== | |||
The key to an efficient and accurate diagnosis is a detailed and thorough history. The onset, location, radiation, and duration of [[pain]], aggravating or relieving factors, severity of pain (constant or intermittent), characteristics of the pain should be obtained in helping out the cause of [[abdominal pain]]. Symptoms of appendicular abscess are mostly atypical compared to [[appendicitis]] and include include [[Fever|high grade fever]], constant pain in the [[right iliac fossa]], [[Diarrhea|prolonged diarrhea]] associated with [[nausea and vomiting]] and increased [[micturition]] and [[tenesmus]]. | |||
===Physical Examination=== | |||
Physical examinations mostly focus on [[abdominal]] findings. The patient may appear toxic with [[diffuse]] [[abdominal]] [[pain]] and [[Fever|high grade fever]] and [[tachycardia]]. Even minimal pressure on the [[abdomen]] can elicit a marked response from the patient due to pain. Typical signs of [[appendicitis]] may not be elicited. | |||
===Laboratory Findings=== | |||
Hematologic parameters suggestive of [[infection]]-like [[leukocytosis]], [[anemia]], [[Thrombosis|abnormal platelet counts]], and [[Abnormal liver function test|abnormal liver function]] frequently are present in patients with appendicular abscess. Patients who are debilitated or elderly often fail to mount reactive [[leukocytosis]] or [[fever]]. [[Blood cultures]] indicating persistent polymicrobial [[bacteremia]] strongly implicate the presence of an abscess. Common [[electrolyte]] and [[Biomarker|bio-marker]] indicators of appendicitis include [[leukocytosis]] and a shift to the left in the segmented [[neutrophils]]. | |||
===Abdominal X-Ray=== | |||
[[Abdominal X-ray|Plain abdominal radiography]] is not the most useful tool in making a diagnosis of [[appendicular]] [[abscess]]. | |||
===Ultrasound=== | |||
In general, whenever available, CT scans are preferred over ultrasounds for diagnosing appendicular abscess. Ultrasound imaging presents the least amount of radiation and is therefore the investigation of choice for young patients. Findings include [[fluid]] collection (hypoechoic) in the appendicular region which may be well circumscribed with dilated [[Appendix Normal|appendicular wall]]. | |||
===Abdominal CT=== | |||
CT scans are the diagnostic test of choice for detecting appendicular abscess. They can provide critical information regarding the size of the [[abscess]]. CT scans are preferred over ultrasounds for the detection of abscess but is contraindicated in children due to risk of exposure. Findings include Appendiceal wall thickening (wall ≥ 3mm), appendiceal wall hyperenhancement, mural stratification of the appendiceal wall. | |||
===MRI=== | |||
Magnetic resonance imaging (MRI) has become the common technique for diagnosing abscess in children and pregnant patients. On an MRI, a periappendiceal stranding appears as an increased fluid signal on the T2 weighted sequence. | |||
===Ultrasound=== | |||
Findings of appendicular abscess on ultrasound include fluid collection in the appendicular region. | |||
==Treatment== | |||
===Medical Therapy=== | |||
No universal standard treatment exists for appendicitis complicated by abscess. The mainstay of treatment includes abscess drainage along with empiric [[antibiotics]]. [[Antibiotics]] should be started immediately once the diagnosis of [[abscess]] is made. The duration of treatment with intravenous [[antibiotics]] ranges from 5 to 10 days, until [[fever]] resolves. [[Monotherapy]] with a beta-lactam/beta-lactamase inhibitor is the preferred choice of drugs. Combination third generation [[cephalosporins]] plus [[metronidazole]] is also employed. [[Percutaneous|Percutaneous drainage]] can be performed under ultrasound or CT guidance, using either the [[Seldinger technique|Seldinger]] or trocar technique. When an abscess is deep in the [[pelvis]], depending on the specific location of the [[fluid]] collection, access may be obtained via transgluteal, transvaginal, or transrectal approaches. | |||
===Surgery=== | |||
Following drain and [[antibiotics]] an [[Appendectomy|interval appendectomy]] is recommended for patients after six to eight weeks, it is done to prevent recurrence of [[appendicitis]] and to exclude [[neoplasms]] as a cause (such as [[carcinoid]], [[adenocarcinoma]], [[mucinous cystadenoma]], and [[Cystadenocarcinoma|cystadenocarcinom<nowiki/>as]]). The surgical approach can be eithe[[Laparoscopic surgery|r laparoscopic]] or open ([[Laparotomy|laparotom]]<nowiki/>y) | |||
===Prevention=== | |||
There are no primary preventive measures available for appendicular abscess. Secondary prevention strategies following appendicular abscess include treatment of appendicitis in order to prevent significant morbidity. | |||
==References== | ==References== | ||
{{reflist|2}} | {{reflist|2}} | ||
[[Category:Disease]] | |||
[[Category:Up-To-Date]] | |||
[[Category:Gastroenterology]] | |||
[[Category:Surgery]] | |||
[[Category:Emergency medicine]] | |||
[[Category:Infectious disease]] | |||
Latest revision as of 20:28, 29 July 2020
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Aditya Ganti M.B.B.S. [2]
Overview
Appendicular abscess is defined as a collection of pus resulting from necrosis of the tissue superimposed with infection in an inflamed appendix. It is unusual and rare entity; appendicular abscess is a life-threatening complication of acute appendicitis (preoperatively) or appendectomy (postoperatively). It is observed in 2-7% of population presenting with appendicitis. Complications arise if appendicitis is not treated promptly. The abscess develops and is limited by the inflamed coils of intestine. The abscess can spread to pelvis leading to peritonitis if the abdominal wall is ruptured. In most of the patients, the intestinal coils and omentum in the abdominal cavity tend to cover the inflamed appendix forming an appendicular mass. [1]
Historical Perspective
Appendicitis was first described by Reginald J. Fitz of Harvard University in 1886. He also coined the term appendix. Since then, the appendectomy has become one of the most common surgical procedures. The laparoscopic appendectomy was invented in the 1980s, and has led to reduced length of hospital stay a decreased risk of infection, and a reduction in post-operative pain.[2] [3][3]
Classification
There is no classification system established for appendicular abscess.
Pathophysiology
An appendicular abscess is a complication of acute appendicitis. It is resulted due to the invasion of the appendix by bacteria following an obstruction. The appendix exists at the junction of the small and large intestine and is a natural habitat of wide variety of bacteria. It is, therefore, prone to develop complications when blocked. Coupled with an infection, acute appendicitis can be life threatening. Other serious complications which may develop as a result of neglected appendicitis or appendicular abscess include gangrene, appendicular masses, rupture, and general peritoneal infections. Obstruction of the tubular space inside the appendix is the main inciting event, this initial problem leads to the inflammation of the appendix, obstruction of the blood vessels supplying it, and finally infection. Inflammatory mediators along with various bacterial toxins and proteolytic enzymes from the neutrophils are released, resulting in the formation of an abscess in the appendix.[4] [5]
Causes
Microbiology responsible for appendicular abscess includes a mixture of aerobic and anaerobic organisms that are natural habitat of gut. The most commonly isolated aerobic organism is Escherichia coli, and the most commonly observed anaerobic organism is Bacteroides fragilis. The type and density of aerobic and anaerobic bacteria isolated from appendicular abscesses depends upon the organism that dominates the habitat and degree of obstruction.[6]
Differential Diagnosis
Appendicular abscess should be diagnosed early and treat promptly not only to reduce morbidity and mortality, but it is also important to differentiate from other abdominal diseases presenting with RLQ pain, fever, nausea, and vomiting such as psoas abscess, cellulitis, torsion of testis and ovaries, and ectopic pregnancy as the undrained abscess carries high risk of mortality.
Risk Factors
Identifying risk factors that predict the likelihood of complications of appendicitis is a crucial step in managing appendicular abscess. Appendicitis is most common risk factor of developing abscess; it is more common among people in the age group of 10 to 30 years old. Appendicitis is a medical emergency that requires proper attention, especially more than any other abdominal causes if symptoms are not conclusive.
Screening
According to the Guidelines by the Surgical Infection Society and the Infectious Diseases Society of America, there is insufficient evidence to recommend routine screening for appendicular abscess.
Natural History, Complications, and Prognosis
Without treatment, the patient will likely develop symptoms of diffuse abdominal pain, which is different from typical appendicitis pain, starting centrally (in the periumbilical region) before localizing to the right iliac fossa in the right lower quadrant of the abdomen. During the final stage of the untreated disease process, the appendix will rupture, and this may eventually lead to death if peritonitis develops. Complications that can develop as a result of the untreated appendicular abscess include:septicemia, rupture, peritonitis, hemorrhage and death. Prognosis of the abscess is good with antibiotics and percutaneous drain and resolves without the need for appendectomy, but it is recommended to follow and appendicular abscess by interval appendectomy after 8-12 weeks to prevent recurrence.
Diagnosis
History and Symptoms
The key to an efficient and accurate diagnosis is a detailed and thorough history. The onset, location, radiation, and duration of pain, aggravating or relieving factors, severity of pain (constant or intermittent), characteristics of the pain should be obtained in helping out the cause of abdominal pain. Symptoms of appendicular abscess are mostly atypical compared to appendicitis and include include high grade fever, constant pain in the right iliac fossa, prolonged diarrhea associated with nausea and vomiting and increased micturition and tenesmus.
Physical Examination
Physical examinations mostly focus on abdominal findings. The patient may appear toxic with diffuse abdominal pain and high grade fever and tachycardia. Even minimal pressure on the abdomen can elicit a marked response from the patient due to pain. Typical signs of appendicitis may not be elicited.
Laboratory Findings
Hematologic parameters suggestive of infection-like leukocytosis, anemia, abnormal platelet counts, and abnormal liver function frequently are present in patients with appendicular abscess. Patients who are debilitated or elderly often fail to mount reactive leukocytosis or fever. Blood cultures indicating persistent polymicrobial bacteremia strongly implicate the presence of an abscess. Common electrolyte and bio-marker indicators of appendicitis include leukocytosis and a shift to the left in the segmented neutrophils.
Abdominal X-Ray
Plain abdominal radiography is not the most useful tool in making a diagnosis of appendicular abscess.
Ultrasound
In general, whenever available, CT scans are preferred over ultrasounds for diagnosing appendicular abscess. Ultrasound imaging presents the least amount of radiation and is therefore the investigation of choice for young patients. Findings include fluid collection (hypoechoic) in the appendicular region which may be well circumscribed with dilated appendicular wall.
Abdominal CT
CT scans are the diagnostic test of choice for detecting appendicular abscess. They can provide critical information regarding the size of the abscess. CT scans are preferred over ultrasounds for the detection of abscess but is contraindicated in children due to risk of exposure. Findings include Appendiceal wall thickening (wall ≥ 3mm), appendiceal wall hyperenhancement, mural stratification of the appendiceal wall.
MRI
Magnetic resonance imaging (MRI) has become the common technique for diagnosing abscess in children and pregnant patients. On an MRI, a periappendiceal stranding appears as an increased fluid signal on the T2 weighted sequence.
Ultrasound
Findings of appendicular abscess on ultrasound include fluid collection in the appendicular region.
Treatment
Medical Therapy
No universal standard treatment exists for appendicitis complicated by abscess. The mainstay of treatment includes abscess drainage along with empiric antibiotics. Antibiotics should be started immediately once the diagnosis of abscess is made. The duration of treatment with intravenous antibiotics ranges from 5 to 10 days, until fever resolves. Monotherapy with a beta-lactam/beta-lactamase inhibitor is the preferred choice of drugs. Combination third generation cephalosporins plus metronidazole is also employed. Percutaneous drainage can be performed under ultrasound or CT guidance, using either the Seldinger or trocar technique. When an abscess is deep in the pelvis, depending on the specific location of the fluid collection, access may be obtained via transgluteal, transvaginal, or transrectal approaches.
Surgery
Following drain and antibiotics an interval appendectomy is recommended for patients after six to eight weeks, it is done to prevent recurrence of appendicitis and to exclude neoplasms as a cause (such as carcinoid, adenocarcinoma, mucinous cystadenoma, and cystadenocarcinomas). The surgical approach can be either laparoscopic or open (laparotomy)
Prevention
There are no primary preventive measures available for appendicular abscess. Secondary prevention strategies following appendicular abscess include treatment of appendicitis in order to prevent significant morbidity.
References
- ↑ Williams, Norman (2013). Bailey & Love's short practice of surgery. Boca Raton, FLa: CRC Press. ISBN 978-1444121285.
- ↑ Williams GR. "Presidential Address: a history of appendicitis. With anecdotes illustrating its importance". Annals of Surgery. 197 (5): 495–506. PMC 1353017. PMID 6342553. Retrieved 2012-08-09.
- ↑ 3.0 3.1 McCarty, Arthur C. "History of Appendicitis Vermiformis Its diseases and treatment." The Innominate Society http://www.innominatesociety.com/Articles/History%20of%20Appendicitis.htm (1927). APA
- ↑ Bradley EL, Isaacs J (1978). "Appendiceal abscess revisited". Arch Surg. 113 (2): 130–2. PMID 626573.
- ↑ Wangensteen OH, Bowers WF. Significance of the obstructive factor in the genesis of acute appendicitis. Arch Surg 1937;34:496-526
- ↑ Solomkin JS, Mazuski JE, Bradley JS, Rodvold KA, Goldstein EJ, Baron EJ; et al. (2010). "Diagnosis and management of complicated intra-abdominal infection in adults and children: guidelines by the Surgical Infection Society and the Infectious Diseases Society of America". Clin Infect Dis. 50 (2): 133–64. doi:10.1086/649554. PMID 20034345.