History

Fact Explanation
Pruritus Ani which occurs usually at night At night, the female of the Enterobius vermicularis species that lives in the colon migrates out of the anus and deposits her eggs on the perianal skin. Eggs become infective within hours. If a human ingests these eggs they hatch and become adult worms in weeks. [1],[2][3] This causes intense itching and irritation.
Disturbed sleep Nocturnal itch keeps the patients awake so they complain poor sleep. [1]
Irritability and agitation Pruritus ani is a psychologically irritating symptom so people some people become irritable. [1]
Secondary bacterial infections in the perianal region (painful pustules) Intense itching causes abrasions. Barrier effect of the skin is lost so secondary bacterial infections can occur.
Urinary complications( irritative voiding symptoms sush as Dysuria and Frequency) This can be a very rare incidence of bladder infestation by Enterobius vermicularis. Autoinoculation is the commonest mode of infestation.[3] In some patients prostate or ureters can become infestated.[5]
Genital complications causing pelvic pain In women, adult female pinworms can migrate to the genital tract, causing granulomas in the uterus, ovary, and the fallopian tubes, and pelvic peritoneum. [1],[2]
Genital complications: menorrhagia This occurs due to granuloma formation in the genital tract. [5]
Genital complications: vulval itch This is due to vulvovaginitis caused by Enterobius vermicularis. [2],[4]
Intestinal complications: chronic abdominal pain Chronic intermittent, abdominopelvic pain, commonly on the right side can be present. In a female patient: the pain is not associated with menstruation, can complain of right-sided pain with intercourse.[2] This is due to infestation of the appendix with Enterobius vermicularis. [2]
Intestinal complications: acute abdominal pain in the right iliac fossa Enterobius vermicularis is the most commonly encountered nematode that obstructs the lumen of the appendix and can cause acute appendicitis. [6]
Symptoms of anemia such as dyspnoea, fatigue and lethargy This is found in some patients. [7] This is due to chronic infestations.
Past history of pruritus ani Autoinfection by feco-oral transmission [4] is a possibility, because ingestion of eggs is the mode of transmission. [1]
Close contacts or family members with similar complaints. This nematode is transmitted directly from person to person. [1], [4]. The methods of infection are: via dust, food, hands[1],[5]. Overcrowding, sharing linen, beds, food handling can increase the rate of person -to- person transmission. It is common worldwide but is more commonly encountered in temperate regions. [1]
Drinking contaminated water Drinking water contaminated with eggs can also cause transmission. [1]
References
  1. KNOPP S, STEINMANN P, KEISER J, UTZINGER J. Nematode infections: soil-transmitted helminths and trichinella. Infect Dis Clin North Am [online] 2012 Jun, 26(2):341-58 [viewed 26 June 2014] Available from: doi:10.1016/j.idc.2012.02.006
  2. NACKLEY AC, NACKLEY JJ, YEKO TR, GUNASEKARAN S. Appendiceal Enterobius Vermicularis Infestation Associated With Right-Sided Chronic Pelvic Pain JSLS [online] 2004, 8(2):171-173 [viewed 26 June 2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3015526
  3. SAMMOUR ZEIN MOHAMED, GOMES CRISTIANO MENDES, TOME ANDRE LUIZ FARINHAS, BRUSCHINI HOMERO, SROUGI MIGUEL. Prolonged irritative voiding symptoms due to Enterobius vermicularis bladder infestation in an adult patient. Braz J Infect Dis [online] 2008 August, 12(4):352-352 [viewed 26 June 2014] Available from: doi:10.1590/S1413-86702008000400020
  4. KUCIK CJ, MARTIN GL, SORTOR BV. Common intestinal parasites. Am Fam Physician [online] 2004 Mar 1, 69(5):1161-8 [viewed 26 June 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/15023017
  5. PAMPIGLIONE S, RIVASI F. Enterobiasis in Ectopic Locations Mimicking Tumor-Like Lesions Int J Microbiol [online] 2009:642481 [viewed 26 June 2014] Available from: doi:10.1155/2009/642481
  6. CRUZ DB, FRIEDRISCH BK, FONTANIVE JUNIOR V, DA ROCHA VW. Eosinophilic acute appendicitis caused by Strongyloides stercoralis and Enterobius vermicularis in an HIV-positive patient. BMJ Case Rep [online] 2012 Mar 27 [viewed 26 June 2014] Available from: doi:10.1136/bcr.01.2012.5670
  7. CROSS JH, BARON S. Enteric Nematodes of Humans [online] 1996 [viewed 26 June 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/21413317

Examination

Fact Explanation
Visualization of the worm (perianal, perineal and very rarely in urine) Small males measure 2 to 5 mm, and the females measure 8 to 13 mm. They are whitish worms and can be rarely seen during clinical examination. [1]
Painful perianal pustules, abrasion marks and abscesses Intense itching causes abrasions. Barrier effect of the skin is lost so secondary bacterial infections can occur.
Pallor Pallor is present in some patients .[3] As chronic infestation can cause anemia.
Fever, tachycardia, hypotension and right iliac fossa tenderness, rebound tenderness These features are present in acute appendicitis due to Enterobius vermicularis. [2]
Abdominal tenderness This is due to inflammation of intra abdominal viscera such as appendix, ovaries etc. [2]
References
  1. KUCIK CJ, MARTIN GL, SORTOR BV. Common intestinal parasites. Am Fam Physician [online] 2004 Mar 1, 69(5):1161-8 [viewed 26 June 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/15023017
  2. CRUZ DB, FRIEDRISCH BK, FONTANIVE JUNIOR V, DA ROCHA VW. Eosinophilic acute appendicitis caused by Strongyloides stercoralis and Enterobius vermicularis in an HIV-positive patient. BMJ Case Rep [online] 2012 Mar 27 [viewed 26 June 2014] Available from: doi:10.1136/bcr.01.2012.5670
  3. CROSS JH, BARON S. Enteric Nematodes of Humans [online] 1996 [viewed 26 June 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/21413317

Differential Diagnoses

Fact Explanation
Anal fissure This is an extremely painful condition following constipation, anal intercourse.Blood can be seen streaking the stool. [1,2,3]
Haemorrhoids This is a painless condition with passing fresh blood and sensation of a descending mass while defecating. Infected lesions can cause pruritus and discharge. [1,2,3]
Crohn's disease This is associated with chronic diarrhea with or without blood and mucus. There may be extraintestinal manifestations such as arthritis,cutaneous manifestations and eye manifestations.[1,23]
Rectal malignancy Infiltration to sphincters can be present in addition bleeding, local or distant metastasis can be present. [1,3]
Drugs Drugs such as tetracycline, colchicine, quinidine, local anesthetics, neomycin [3] can cause pruritus ani.
Local Irritative factors Factors such as fecal incontinence, humidity, soap, excessive scrubbing can cause pruritus ani.[3]
Pelvic infection Pelvic infection [2] with pathogens such as chlamydia and gonorrhea can present with vaginal discharge,fever and abdominal tenderness.
Endometriosis Endometriosis[2] can present with symptoms such as subfertility, menorrhagia, and deep dyspareunia.
Colonic causes for abdominal pain Conditions such as colitis [4] can cause diarrhea, fever and vomiting in addition diverticulitis with pain,diarrhea with or without blood, Inflammatory Bowel Disease or Irritable Bowel Syndrome can present similar to appendicitis.
Gynecologic conditions Ectopic pregnancy [4] can present with acute abdominal pain, per-vaginal bleeding, and haemodynamic instability. Acute torsion of fibroids [4] or ovaries can give rise to sudden onset severe abdominal pain.
Renal conditions Conditions such as: nephrolithiasis (loin-to-groin pain,haematuria), pyelonephritis( fever with chills, loin tenderness) can present with a pain similar to an acute abdominal pain.
References
  1. MACLEAN J, RUSSELL D. Pruritus ani. Aust Fam Physician [online] 2010 Jun, 39(6):366-70 [viewed 26 June 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/20628673
  2. NACKLEY AC, NACKLEY JJ, YEKO TR, GUNASEKARAN S. Appendiceal Enterobius Vermicularis Infestation Associated With Right-Sided Chronic Pelvic Pain JSLS [online] 2004, 8(2):171-173 [viewed 26 June 2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3015526
  3. SONG SG, KIM SH. Pruritus Ani J Korean Soc Coloproctol [online] 2011 Apr, 27(2):54-57 [viewed 26 June 2014] Available from: doi:10.3393/jksc.2011.27.2.54
  4. CARTWRIGHT SL, KNUDSON MP. Evaluation of acute abdominal pain in adults. Am Fam Physician [online] 2008 Apr 1, 77(7):971-8 [viewed 26 June 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/18441863

Investigations - for Diagnosis

Fact Explanation
Adhesive-tape method and microscopy This is done for the detection of ova, segments or intact worms. [3] The eggs are stained with lactophenol cotton blue. The threadlike, white adult worms with a long, sharply pointed tail can be identified.
A complete blood count This is done in complicated cases, presenting as different disease entities (such as appendicitis.[1] Differential count can indicate eosinophilia in nematode infestation. [4],[6]
A urinalysis This is to exclude differential diagnosis for complicated cases for acute abdomen [2] such as urinary calculi where there can be haematuria and in pyelonephritis there can be pus cells and granular casts.
Urine beta hCG This is to exclude differential diagnosis for complicated cases for acute abdomen [2] because ruptured ectopic pregnancy is a differential diagnosis considered in acute abdomen.
Trans abdominal/ transvaginal ultrasonography This is to exclude differential diagnosis for complicated cases for acute abdomen. [2]
X-ray abdomen This is to exclude differential diagnosis for complicated cases for acute abdomen. [2] Important features such as gas under diaphragm in a ruptured viscus or urinary calculi can be identified.
Contrast enhanced CT scan This is to exclude differential diagnosis for complicated cases for acute abdomen. [2]
References
  1. CRUZ DB, FRIEDRISCH BK, FONTANIVE JUNIOR V, DA ROCHA VW. Eosinophilic acute appendicitis caused by Strongyloides stercoralis and Enterobius vermicularis in an HIV-positive patient. BMJ Case Rep [online] 2012 Mar 27 [viewed 26 June 2014] Available from: doi:10.1136/bcr.01.2012.5670
  2. CARTWRIGHT SL, KNUDSON MP. Evaluation of acute abdominal pain in adults. Am Fam Physician [online] 2008 Apr 1, 77(7):971-8 [viewed 26 June 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/18441863
  3. KNOPP S, STEINMANN P, KEISER J, UTZINGER J. Nematode infections: soil-transmitted helminths and trichinella. Infect Dis Clin North Am [online] 2012 Jun, 26(2):341-58 [viewed 26 June 2014] Available from: doi:10.1016/j.idc.2012.02.006 Link:http://saludesa.org.ec/biblioteca/MEDICINA%20TROPICAL/helmintos_y_trichinela.pdf
  4. TANDAN T, POLLARD A, MONEY D, SCHEIFELE D. Pelvic inflammatory disease associated with Enterobius vermicularis Arch Dis Child [online] 2002 Jun, 86(6):439-440 [viewed 26 June 2014] Available from: doi:10.1136/adc.86.6.439
  5. NACKLEY AC, NACKLEY JJ, YEKO TR, GUNASEKARAN S. Appendiceal Enterobius Vermicularis Infestation Associated With Right-Sided Chronic Pelvic Pain JSLS [online] 2004, 8(2):171-173 [viewed 26 June 2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3015526
  6. VILLARREAL O, VILLARREAL JJ, DOMINGO JA. Progressive eosinophilia and elevated IgE in enterobiasis. Allergy [online] 1999 June, 54(6):646-648 [viewed 26 June 2014] Available from: doi:10.1034/j.1398-9995.1999.00140.x

Management - General Measures

Fact Explanation
Improve Individual hygiene: by encouraging hand washing (with soap and warm water) after going to toilet, before handling food etc. Washing hands (with soap and warm water) [1],[2],[3] destroys and washes off infective eggs and prevents feco-oral transmission.
Improve Individual hygiene: cut fingernails short. Cutting finger nails short [2],[3] prevents feco-oral transmission
Improve Individual hygiene: avoid nail biting Avoiding nail biting [3] prevents feco-oral transmission.
Improve Individual hygiene: clean perianal area with soap and regular showers Cleaning perianal area with soap and showering regularly [3] washes the eggs away.
Improve household hygiene: regular cleaning of underwear, bed linen and towels Regular cleaning of underwear, bed linen and towels [1],[2],[3] prevents person to person transmission.
Improve household hygiene: advise not to share beds or bedlinen This prevents person to person transmission. [1]
References
  1. KNOPP S, STEINMANN P, KEISER J, UTZINGER J. Nematode infections: soil-transmitted helminths and trichinella. Infect Dis Clin North Am [online] 2012 Jun, 26(2):341-58 [viewed 26 June 2014] Available from: doi:10.1016/j.idc.2012.02.006 Link:http://saludesa.org.ec/biblioteca/MEDICINA%20TROPICAL/helmintos_y_trichinela.pdf
  2. CROSS JH, BARON S. Enteric Nematodes of Humans [online] 1996 [viewed 26 June 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/21413317
  3. Prevention & Control.Parasites - Enterobiasis .Centers for Disease Control and Prevention.[online] 2013. [viewed 26 June 2014] Available from: http://www.cdc.gov/parasites/pinworm/prevent.html

Management - Specific Treatments

Fact Explanation
Albendazole and Mebendazole These drugs prevent glucose uptake in nematodes and is effective in Enterobiasis. [2] This is given as a single oral doses and repeated after 1 week for the treatment of re-infection. [1] Family members are also treated because they are usually also infected with Enterobius vermicularis. [1] These drugs can be used to treat endometrial [4] and urinary [5] infections as well.
Pyrantel pamoate It depolarizes the neuromuscular junctions of the nematodes and expels them in feces. Pyrantel pamoate is given as a single dose and should be repeated in one week to prevent re-infection. [2], [3]
Management of acute complications Surgical management should be considered in acute appendicitis or any other surgical/gynecological complication. [6]
References
  1. KNOPP S, STEINMANN P, KEISER J, UTZINGER J. Nematode infections: soil-transmitted helminths and trichinella. Infect Dis Clin North Am [online] 2012 Jun, 26(2):341-58 [viewed 26 June 2014] Available from: doi:10.1016/j.idc.2012.02.006 Link:http://saludesa.org.ec/biblioteca/MEDICINA%20TROPICAL/helmintos_y_trichinela.pdf
  2. CROSS JH, BARON S. Enteric Nematodes of Humans [online] 1996 [viewed 26 June 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/21413317
  3. Prevention & Control.Parasites - Enterobiasis .Centers for Disease Control and Prevention.[online]2013.[viewed 26 June 2014] Available from: http://www.cdc.gov/parasites/pinworm/prevent.html
  4. SAMMOUR ZEIN MOHAMED, GOMES CRISTIANO MENDES, TOME ANDRE LUIZ FARINHAS, BRUSCHINI HOMERO, SROUGI MIGUEL. Prolonged irritative voiding symptoms due to Enterobius vermicularis bladder infestation in an adult patient. Braz J Infect Dis [online] 2008 August, 12(4):352-352 [viewed 26 June 2014] Available from: doi:10.1590/S1413-86702008000400020
  5. NG YW, NG SB, LOW JJ. Enterobius vermicularis infestation of the endometrium - a cause of menstrual irregularity and review of literature. Ann Acad Med Singapore [online] 2011 Nov, 40(11):514-5 [viewed 26 June 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/22206070
  6. CRUZ DB, FRIEDRISCH BK, FONTANIVE JUNIOR V, DA ROCHA VW. Eosinophilic acute appendicitis caused by Strongyloides stercoralis and Enterobius vermicularis in an HIV-positive patient BMJ Case Rep [online] :bcr0120125670 [viewed 26 June 2014] Available from: doi:10.1136/bcr.01.2012.5670