Ascariasis overview: Difference between revisions
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==Overview== | ==Overview== | ||
Ascariasis is a globally occurring helminthic infection of humans.<ref name="Nelson Textbook of Pediatrics">Kliegman, Robert; Stanton, Bonita; St. Geme, Joseph; Schor, Nina (2016). "Chapter 291:Ascariasis (Ascaris lumbricoides)". Nelson Textbook of Pediatrics Twentieth Edition. Elsevier. pp. 1733–1734. ISBN 978-1-4557-7566-8.</ref> It is the most common human [[helminth]] infection.<ref name="Murray and Nadel's Textbook of Respiratory Medicine">Kim, Kami; Weiss, Louis; Tanowitz, Herbert (2016). "Chapter 39:Parasitic Infections". Murray and Nadel's Textbook of Respiratory Medicine Sixth Edition. Elsevier. pp. 682–698. ISBN 978-1-4557-3383-5.</ref> The transmission of infection is usually from hand to mouth, and humans are the only known host.<ref name="Murray and Nadel's Textbook of Respiratory Medicine">Kim, Kami; Weiss, Louis; Tanowitz, Herbert (2016). "Chapter 39:Parasitic Infections". Murray and Nadel's Textbook of Respiratory Medicine Sixth Edition. Elsevier. pp. 682–698. ISBN 978-1-4557-3383-5.</ref> Ascariasis is more common in tropical areas of the world and predominantly affects the pediatric age group.<ref name="Ferri's Clinical Advisor">Ferri, Fred (2017). "Chapter:Ascariasis". Ferri's Clinical Advisor 2017. Elsevier. pp. 117–117. ISBN 978-0-3232-8048-8.</ref> | |||
==Historical Perspective== | ==Historical Perspective== | ||
== | Ascariasis has been around for several years and the scientific study of [[Ascaris lumbricoides]] was promoted by Edward Tyson.<ref name="pmid15463076">{{cite journal| author=Crompton DW| title=The prevalence of Ascariasis. | journal=Parasitol Today | year= 1988 | volume= 4 | issue= 6 | pages= 162-9 | pmid=15463076 | doi= | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=15463076 }} </ref> | ||
==Pathophysiology== | ==Pathophysiology<ref name="Murray and Nadel's Textbook of Respiratory Medicine" /><ref name="Ferri's Clinical Advisor">Ferri, Fred (2017). "Chapter:Ascariasis". Ferri's Clinical Advisor 2017. Elsevier. pp. 117–117. ISBN 978-0-3232-8048-8.</ref><ref name="Nelson Textbook of Pediatrics">Kliegman, Robert; Stanton, Bonita; St. Geme, Joseph; Schor, Nina (2016). "Chapter 291:Ascariasis (Ascaris lumbricoides)". Nelson Textbook of Pediatrics Twentieth Edition. Elsevier. pp. 1733–1734. ISBN 978-1-4557-7566-8.</ref>== | ||
The transmission of infection is usually from hand to mouth, and humans are the only known host. Following ingestion of infective eggs, larvae hatch and invade the [[intestinal mucosa]]. The larvae are carried via the portal, then [[systemic circulation]] to the [[lungs]]. The larvae mature further in the [[lungs]], penetrate the [[Alveolus|alveolar walls]], and ascend the [[bronchial tree]] to the [[throat]]. The larvae are then swallowed. Upon reaching the [[small intestine]], they develop into adult worms. The adult worms can live for 1 to 2 years. | |||
==Causes== | ==Causes== | ||
Ascariasis is a soil [[helminth]] infection caused by the [[nematode]] [[Ascaris lumbricoides]].<ref name="Murray and Nadel's Textbook of Respiratory Medicine">Kim, Kami; Weiss, Louis; Tanowitz, Herbert (2016). "Chapter 39:Parasitic Infections". Murray and Nadel's Textbook of Respiratory Medicine Sixth Edition. Elsevier. pp. 682–698. ISBN 978-1-4557-3383-5.</ref> | |||
==Differentiating Ascariasis from other Diseases== | ==Differentiating Ascariasis from other Diseases== | ||
Ascariasis can mimic other worm infections, and also gastrointestinal pathologies like [[peptic ulcer disease]], [[intussusception]] in children, [[bile duct]] stone, etc.<ref name="pmid2260195">{{cite journal| author=Hamed AD, Akinola O| title=Intestinal ascariasis in the differential diagnosis of peptic ulcer disease. | journal=Trop Geogr Med | year= 1990 | volume= 42 | issue= 1 | pages= 37-40 | pmid=2260195 | doi= | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=2260195 }} </ref><ref name="pmid23078449">{{cite journal| author=Goel A, Lakshmi CP, Pottakkat B| title=Biliary ascariasis: mimicker of retained bile duct stone. | journal=Dig Endosc | year= 2012 | volume= 24 | issue= 6 | pages= 480 | pmid=23078449 | doi=10.1111/j.1443-1661.2012.01338.x | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=23078449 }} </ref> | |||
==Epidemiology and Demographics== | ==Epidemiology and Demographics== | ||
Ascariasis affects at least 1 billion people worldwide and about 4 million people in the United States.<ref name="Ferri's Clinical Advisor">Ferri, Fred (2017). "Chapter:Ascariasis". Ferri's Clinical Advisor 2017. Elsevier. pp. 117–117. ISBN 978-0-3232-8048-8.</ref> It is more common in the pediatric age group (ages 2-10 years).<ref name="Ferri's Clinical Advisor">Ferri, Fred (2017). "Chapter:Ascariasis". Ferri's Clinical Advisor 2017. Elsevier. pp. 117–117. ISBN 978-0-3232-8048-8.</ref> Ascariasis is three times more common in African-Americans compared to Caucasians.<ref name="Ferri's Clinical Advisor">Ferri, Fred (2017). "Chapter:Ascariasis". Ferri's Clinical Advisor 2017. Elsevier. pp. 117–117. ISBN 978-0-3232-8048-8.</ref> | |||
==Risk factors== | ==Risk factors== | ||
The risk factors for ascariasis are often associated with poor sanitary conditions and environmental fecal contamination.<ref name="Nelson Textbook of Pediatrics">Kliegman, Robert; Stanton, Bonita; St. Geme, Joseph; Schor, Nina (2016). "Chapter 291:Ascariasis (Ascaris lumbricoides)". Nelson Textbook of Pediatrics Twentieth Edition. Elsevier. pp. 1733–1734. ISBN 978-1-4557-7566-8.</ref> | |||
==Natural History, Complications and Prognosis== | ==Natural History, Complications and Prognosis== | ||
Ascariasis is often asymptomatic and more than 80% of infected individuals experience minimal or no symptoms of the disease.<ref name="Principles and Practice">Durand, Marlene (2015). "Chapter 288:Intestinal Nematodes (Roundworms)". Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases Updated Edition, Eighth Edition. Elsevier. pp. 3199–3207. ISBN 978-1-4557-4801-3.</ref> Complications may arise when adult worms move to certain organs such as the [[bile duct]], [[pancreas]], or [[appendix]].<ref name="Principles and Practice">Durand, Marlene (2015). "Chapter 288:Intestinal Nematodes (Roundworms)". Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases Updated Edition, Eighth Edition. Elsevier. pp. 3199–3207. ISBN 978-1-4557-4801-3.</ref> A high worm burden can also result in complications such as [[intestinal obstruction]].<ref name="Nelson Textbook of Pediatrics">Kliegman, Robert; Stanton, Bonita; St. Geme, Joseph; Schor, Nina (2016). "Chapter 291:Ascariasis (Ascaris lumbricoides)". Nelson Textbook of Pediatrics Twentieth Edition. Elsevier. pp. 1733–1734. ISBN 978-1-4557-7566-8.</ref> The prognosis is good as most cases of ascariasis are asymptomatic, but mortality can sometimes be as high as 60,000 per year.<ref name="Principles and Practice">Durand, Marlene (2015). "Chapter 288:Intestinal Nematodes (Roundworms)". Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases Updated Edition, Eighth Edition. Elsevier. pp. 3199–3207. ISBN 978-1-4557-4801-3.</ref> Mortality from ascariasis is usually as a result of complications from the infection, approximately 4.6% of patients hospitalized with complications of ascariasis die from the infection.<ref name="pmid9236818">{{cite journal| author=de Silva NR, Chan MS, Bundy DA| title=Morbidity and mortality due to ascariasis: re-estimation and sensitivity analysis of global numbers at risk. | journal=Trop Med Int Health | year= 1997 | volume= 2 | issue= 6 | pages= 519-28 | pmid=9236818 | doi= | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=9236818 }} </ref> | |||
==History and Symptoms== | ==History and Symptoms== | ||
Ascariasis is often asymptomatic. It can sometimes present with mild [[pulmonary]] and [[abdominal]] symptoms such as [[cough]], [[dyspepsia]], and [[Nausea and vomiting|nausea]]. However, severe cases of ascariasis occasionally occur especially following mechanical obstruction of a [[viscus]].<ref name="Principles and Practice">Durand, Marlene (2015). "Chapter 288:Intestinal Nematodes (Roundworms)". Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases Updated Edition, Eighth Edition. Elsevier. pp. 3199–3207. ISBN 978-1-4557-4801-3.</ref> | |||
==Physical Examination== | ==Physical Examination== | ||
The physical examination findings in ascariasis vary and it is usually dependent on the worm burden and the involved organ.<ref name="Nelson Textbook of Pediatrics">Kliegman, Robert; Stanton, Bonita; St. Geme, Joseph; Schor, Nina (2016). "Chapter 291:Ascariasis (Ascaris lumbricoides)". Nelson Textbook of Pediatrics Twentieth Edition. Elsevier. pp. 1733–1734. ISBN 978-1-4557-7566-8.</ref> Abdominal tenderness can occur secondary to [[intestinal obstruction]], [[appendicitis]], [[biliary colic]], [[Cholangitis|acute cholangitis]], [[acute cholecystitis]], [[hepatic abscess]], etc.<ref name="pmid24926166">{{cite journal| author=Das AK| title=Hepatic and biliary ascariasis. | journal=J Glob Infect Dis | year= 2014 | volume= 6 | issue= 2 | pages= 65-72 | pmid=24926166 | doi=10.4103/0974-777X.132042 | pmc=4049042 | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=24926166 }} </ref> | |||
==Laboratory Findings== | ==Laboratory Findings== | ||
==X ray== | Ascariasis is frequently diagnosed in the laboratory via microscopic identification of eggs in the feces.<ref name="Principles and Practice">Durand, Marlene (2015). "Chapter 288:Intestinal Nematodes (Roundworms)". Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases Updated Edition, Eighth Edition. Elsevier. pp. 3199–3207. ISBN 978-1-4557-4801-3.</ref> | ||
==Chest and Abdominal X-ray== | |||
A chest x-ray can reveal varying sizes of oval or round infiltrates ([[Loffler's syndrome]]). These infiltrates usually resolve spontaneously.<ref name="Ferri's Clinical Advisor">Ferri, Fred (2017). "Chapter:Ascariasis". Ferri's Clinical Advisor 2017. Elsevier. pp. 117–117. ISBN 978-0-3232-8048-8.</ref> Plain abdominal radiographs and contrast studies can reveal worm masses in bowel loops.<ref name="Ferri's Clinical Advisor">Ferri, Fred (2017). "Chapter:Ascariasis". Ferri's Clinical Advisor 2017. Elsevier. pp. 117–117. ISBN 978-0-3232-8048-8.</ref><ref name="Principles and Practice">Durand, Marlene (2015). "Chapter 288:Intestinal Nematodes (Roundworms)". Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases Updated Edition, Eighth Edition. Elsevier. pp. 3199–3207. ISBN 978-1-4557-4801-3.</ref> | |||
==CT== | ==CT== | ||
CT scan with contrast can reveal foreign bodies such as worms in the [[gastrointestinal tract]].<ref name="Ferri's Clinical Advisor">Ferri, Fred (2017). "Chapter:Ascariasis". Ferri's Clinical Advisor 2017. Elsevier. pp. 117–117. ISBN 978-0-3232-8048-8.</ref><ref name="Principles and Practice">Durand, Marlene (2015). "Chapter 288:Intestinal Nematodes (Roundworms)". Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases Updated Edition, Eighth Edition. Elsevier. pp. 3199–3207. ISBN 978-1-4557-4801-3.</ref> | |||
==Ultrasound== | ==Ultrasound== | ||
Ultrasonography can reveal worms in the [[biliary tree]], [[pancreatic duct]] and bowel loops.<ref name="Ferri's Clinical Advisor">Ferri, Fred (2017). "Chapter:Ascariasis". Ferri's Clinical Advisor 2017. Elsevier. pp. 117–117. ISBN 978-0-3232-8048-8.</ref><ref name="Principles and Practice">Durand, Marlene (2015). "Chapter 288:Intestinal Nematodes (Roundworms)". Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases Updated Edition, Eighth Edition. Elsevier. pp. 3199–3207. ISBN 978-1-4557-4801-3.</ref> | |||
==Other Diagnostic Studies== | ==Other Diagnostic Studies== | ||
Imaging studies such as [[endoscopic retrograde cholangiopancreatography]] ([[ERCP]]) can identify worms in the pancreaticobiliary tract.<ref name="Ferri's Clinical Advisor">Ferri, Fred (2017). "Chapter:Ascariasis". Ferri's Clinical Advisor 2017. Elsevier. pp. 117–117. ISBN 978-0-3232-8048-8.</ref> | |||
==Medical Therapy== | ==Medical Therapy== | ||
All ascariasis infection (symptomatic and asymptomatic) should be treated with antimicrobial therapy.<ref name="Principles and Practice">{{cite book |last=Durand |first1=Marlene |title=Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases Updated Edition, Eighth Edition |publisher=Elsevier |date=2015 |pages=3199-3207 |chapter=Chapter 288:Intestinal Nematodes (Roundworms) |isbn=978-1-4557-4801-3}}</ref> Due to the high rate of reinfection, it is sometimes necessary to repeat antimicrobial therapy.<ref name="Nelson Textbook of Pediatrics">Kliegman, Robert; Stanton, Bonita; St. Geme, Joseph; Schor, Nina (2016). "Chapter 291:Ascariasis (Ascaris lumbricoides)". Nelson Textbook of Pediatrics Twentieth Edition. Elsevier. pp. 1733–1734. ISBN 978-1-4557-7566-8.</ref> Antimicrobial therapy with [[albendazole]] is usually the treatment of choice for ascariasis, although other [[antihelminthic]] medications can effectively eradicate the [[Parasites|parasite]].<ref name="Murray and Nadel's Textbook of Respiratory Medicine">Kim, Kami; Weiss, Louis; Tanowitz, Herbert (2016). "Chapter 39:Parasitic Infections". Murray and Nadel's Textbook of Respiratory Medicine Sixth Edition. Elsevier. pp. 682–698. ISBN 978-1-4557-3383-5.</ref> | |||
==Surgery== | ==Surgery== | ||
Ascariasis is usually managed conservatively with medical therapy but surgery may be indicated when medical management fails or complications arise.<ref name="Principles and Practice">Durand, Marlene (2015). "Chapter 288:Intestinal Nematodes (Roundworms)". Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases Updated Edition, Eighth Edition. Elsevier. pp. 3199–3207. ISBN 978-1-4557-4801-3.</ref> Some of the indications for the surgical management of ascariasis include complete [[intestinal obstruction]] with inadequate decompression, complications such as [[volvulus]], [[intussusception]] or [[intestinal perforation]], [[acute appendicitis]], worms trapped in ducts, etc.<ref name="Principles and Practice">Durand, Marlene (2015). "Chapter 288:Intestinal Nematodes (Roundworms)". Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases Updated Edition, Eighth Edition. Elsevier. pp. 3199–3207. ISBN 978-1-4557-4801-3.</ref> | |||
==Prevention== | |||
The prevention of ascariasis is best achieved through improvements in personal hygiene and environmental sanitation.<ref name="cdc1">Centers for Disease Control and Prevention.https://www.cdc.gov/parasites/ascariasis/prevent.html Accessed on the 3rd of March, 2017.</ref> | |||
==References== | ==References== | ||
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Latest revision as of 20:28, 29 July 2020
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Ascariasis overview On the Web |
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American Roentgen Ray Society Images of Ascariasis overview |
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]Associate Editor(s)-in-Chief: Fatimo Biobaku M.B.B.S [2]
Overview
Ascariasis is a globally occurring helminthic infection of humans.[1] It is the most common human helminth infection.[2] The transmission of infection is usually from hand to mouth, and humans are the only known host.[2] Ascariasis is more common in tropical areas of the world and predominantly affects the pediatric age group.[3]
Historical Perspective
Ascariasis has been around for several years and the scientific study of Ascaris lumbricoides was promoted by Edward Tyson.[4]
Pathophysiology[2][3][1]
The transmission of infection is usually from hand to mouth, and humans are the only known host. Following ingestion of infective eggs, larvae hatch and invade the intestinal mucosa. The larvae are carried via the portal, then systemic circulation to the lungs. The larvae mature further in the lungs, penetrate the alveolar walls, and ascend the bronchial tree to the throat. The larvae are then swallowed. Upon reaching the small intestine, they develop into adult worms. The adult worms can live for 1 to 2 years.
Causes
Ascariasis is a soil helminth infection caused by the nematode Ascaris lumbricoides.[2]
Differentiating Ascariasis from other Diseases
Ascariasis can mimic other worm infections, and also gastrointestinal pathologies like peptic ulcer disease, intussusception in children, bile duct stone, etc.[5][6]
Epidemiology and Demographics
Ascariasis affects at least 1 billion people worldwide and about 4 million people in the United States.[3] It is more common in the pediatric age group (ages 2-10 years).[3] Ascariasis is three times more common in African-Americans compared to Caucasians.[3]
Risk factors
The risk factors for ascariasis are often associated with poor sanitary conditions and environmental fecal contamination.[1]
Natural History, Complications and Prognosis
Ascariasis is often asymptomatic and more than 80% of infected individuals experience minimal or no symptoms of the disease.[7] Complications may arise when adult worms move to certain organs such as the bile duct, pancreas, or appendix.[7] A high worm burden can also result in complications such as intestinal obstruction.[1] The prognosis is good as most cases of ascariasis are asymptomatic, but mortality can sometimes be as high as 60,000 per year.[7] Mortality from ascariasis is usually as a result of complications from the infection, approximately 4.6% of patients hospitalized with complications of ascariasis die from the infection.[8]
History and Symptoms
Ascariasis is often asymptomatic. It can sometimes present with mild pulmonary and abdominal symptoms such as cough, dyspepsia, and nausea. However, severe cases of ascariasis occasionally occur especially following mechanical obstruction of a viscus.[7]
Physical Examination
The physical examination findings in ascariasis vary and it is usually dependent on the worm burden and the involved organ.[1] Abdominal tenderness can occur secondary to intestinal obstruction, appendicitis, biliary colic, acute cholangitis, acute cholecystitis, hepatic abscess, etc.[9]
Laboratory Findings
Ascariasis is frequently diagnosed in the laboratory via microscopic identification of eggs in the feces.[7]
Chest and Abdominal X-ray
A chest x-ray can reveal varying sizes of oval or round infiltrates (Loffler's syndrome). These infiltrates usually resolve spontaneously.[3] Plain abdominal radiographs and contrast studies can reveal worm masses in bowel loops.[3][7]
CT
CT scan with contrast can reveal foreign bodies such as worms in the gastrointestinal tract.[3][7]
Ultrasound
Ultrasonography can reveal worms in the biliary tree, pancreatic duct and bowel loops.[3][7]
Other Diagnostic Studies
Imaging studies such as endoscopic retrograde cholangiopancreatography (ERCP) can identify worms in the pancreaticobiliary tract.[3]
Medical Therapy
All ascariasis infection (symptomatic and asymptomatic) should be treated with antimicrobial therapy.[7] Due to the high rate of reinfection, it is sometimes necessary to repeat antimicrobial therapy.[1] Antimicrobial therapy with albendazole is usually the treatment of choice for ascariasis, although other antihelminthic medications can effectively eradicate the parasite.[2]
Surgery
Ascariasis is usually managed conservatively with medical therapy but surgery may be indicated when medical management fails or complications arise.[7] Some of the indications for the surgical management of ascariasis include complete intestinal obstruction with inadequate decompression, complications such as volvulus, intussusception or intestinal perforation, acute appendicitis, worms trapped in ducts, etc.[7]
Prevention
The prevention of ascariasis is best achieved through improvements in personal hygiene and environmental sanitation.[10]
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 Kliegman, Robert; Stanton, Bonita; St. Geme, Joseph; Schor, Nina (2016). "Chapter 291:Ascariasis (Ascaris lumbricoides)". Nelson Textbook of Pediatrics Twentieth Edition. Elsevier. pp. 1733–1734. ISBN 978-1-4557-7566-8.
- ↑ 2.0 2.1 2.2 2.3 2.4 Kim, Kami; Weiss, Louis; Tanowitz, Herbert (2016). "Chapter 39:Parasitic Infections". Murray and Nadel's Textbook of Respiratory Medicine Sixth Edition. Elsevier. pp. 682–698. ISBN 978-1-4557-3383-5.
- ↑ 3.0 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 Ferri, Fred (2017). "Chapter:Ascariasis". Ferri's Clinical Advisor 2017. Elsevier. pp. 117–117. ISBN 978-0-3232-8048-8.
- ↑ Crompton DW (1988). "The prevalence of Ascariasis". Parasitol Today. 4 (6): 162–9. PMID 15463076.
- ↑ Hamed AD, Akinola O (1990). "Intestinal ascariasis in the differential diagnosis of peptic ulcer disease". Trop Geogr Med. 42 (1): 37–40. PMID 2260195.
- ↑ Goel A, Lakshmi CP, Pottakkat B (2012). "Biliary ascariasis: mimicker of retained bile duct stone". Dig Endosc. 24 (6): 480. doi:10.1111/j.1443-1661.2012.01338.x. PMID 23078449.
- ↑ 7.00 7.01 7.02 7.03 7.04 7.05 7.06 7.07 7.08 7.09 7.10 Durand, Marlene (2015). "Chapter 288:Intestinal Nematodes (Roundworms)". Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases Updated Edition, Eighth Edition. Elsevier. pp. 3199–3207. ISBN 978-1-4557-4801-3.
- ↑ de Silva NR, Chan MS, Bundy DA (1997). "Morbidity and mortality due to ascariasis: re-estimation and sensitivity analysis of global numbers at risk". Trop Med Int Health. 2 (6): 519–28. PMID 9236818.
- ↑ Das AK (2014). "Hepatic and biliary ascariasis". J Glob Infect Dis. 6 (2): 65–72. doi:10.4103/0974-777X.132042. PMC 4049042. PMID 24926166.
- ↑ Centers for Disease Control and Prevention.https://www.cdc.gov/parasites/ascariasis/prevent.html Accessed on the 3rd of March, 2017.