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===Laboratory testing===
===Laboratory testing===
A [[rapid strep test]] (also called rapid antigen detection testing or RADT) or a throat culture may be undertaken to clarify diagnosis. The rapid strep test is quicker but less sensitive and specific than a throat culture developed on a blood [[agar plate]].<ref name=IDSAGuideline2002>{{cite journal |author=Bisno AL, Gerber MA, Gwaltney JM, Kaplan EL, Schwartz RH |title=Practice guidelines for the diagnosis and management of group A streptococcal pharyngitis. [[Infectious Diseases Society of America]] |journal=Clin. Infect. Dis. |volume=35 |issue=2 |pages=113–25 |year=2002 |month=July |pmid=12087516 |doi=10.1086/340949 |url=http://www.journals.uchicago.edu/doi/abs/10.1086/340949}}</ref> Positive tests in association with symptoms establish a positive diagnosis, which can be treated with antibiotics.<ref name=IDSAGuideline2002/> Asymptomatic patients should not be routinely tested with a throat culture because a certain percentage of the population persistently "carries" strep throat.<ref name=IDSAGuideline2002/>
A [[rapid strep test]] (also called rapid antigen detection testing or RADT) or a throat culture may be undertaken to clarify diagnosis. While the rapid strep test is quicker, it has a lower [[sensitivity (tests)|sensitivity]] (70%) and statistically equal [[specificity (tests)|specificity]] (98%) as throat culture developed on a blood [[agar plate]] (sensitivity 81%, specificity 97%) in a [[cross sectional study]]. <ref name="pmid19171607">{{cite journal| author=|title=Performance of a rapid antigen-detection test and throat culture in community pediatric offices: implications for management of pharyngitis.|url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=clinical.uthscsa.edu/cite&retmode=ref&cmd=prlinks&id=19171607|year=2009|journal=Pediatrics |pmid=19171607|pmc=|doi=10.1542/peds.2008-0488}} [http://pubmed.gov/19949185 Evid Based Med Review] </ref> Combining the RADT with throat culture increased the sensitivity to 85% in this study. <ref name="pmid19171607"/> The sensitivities of both RADT and throat culture increased when used to diagnose patients who were exhibiting multiple symptoms of Streptococcal pharyngitis. When used to diagnose patients exhibiting multiple symptoms, RADT alone had a sensitivity of 78%, throat culture alone had a sensitivity of 87%, while RADT combined with throat culture had a sensitivity of 91%. <ref name="pmid19171607">{{cite journal| author=|title=Performance of a rapid antigen-detection test and throat culture in community pediatric offices: implications for management of pharyngitis.|url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=clinical.uthscsa.edu/cite&retmode=ref&cmd=prlinks&id=19171607|year=2009|journal=Pediatrics |pmid=19171607|pmc=|doi=10.1542/peds.2008-0488}} [http://pubmed.gov/19949185 Evid Based Med Review] </ref> A positive RADT or throat culture in association with symptoms establishes a positive diagnosis, which can be treated with antibiotics.<ref name=IDSAGuideline2002/> Asymptomatic patients should not be routinely tested with a throat culture because a certain percentage of the population persistently "carries" strep throat.<ref name=IDSAGuideline2002/>


==Transmission==
==Transmission==

Revision as of 21:04, 24 March 2010

Streptococcal pharyngitis
SpecialtyOtorhinolaryngology, infectious diseases Edit this on Wikidata

Streptococcal pharyngitis or streptococcal sore throat (known colloquially as strep throat in American English) is a form of group A streptococcal infection[1] that affects the pharynx and possibly the larynx and tonsils. It is a very contagious infection, spread by close contact with an infected individual, which can lead to various other complications if not swiftly treated. Antibiotics can help reduce contagiousness.

Signs and symptoms

Streptococcal pharyngitis usually appears suddenly with severe sore throat pain that may make talking or swallowing painful.

Signs and symptoms may include

Additional symptoms such as sinusitis, vaginitis, or impetigo may be present if the strep bacteria infects both the throat and a secondary location. For additional information on non-pharynx symptoms, see Group A Streptococcal (GAS) Infection.

Diagnosis

History and physical examination

There are several causes for pharyngitis, not just streptococcus bacteria. Productive coughing, nasal discharge, and red, irritated eyes in addition to fever and sore throat are more indicative of a viral sore throat than of strep throat, though a co-infection with a virus is possible and may explain the presence of these additional symptoms. The presence of marked lymph node enlargement along with sore throat, fever and tonsillar enlargement may also occur in infectious mononucleosis (glandular fever).[5]

A study of 729 patients with pharyngitis, in which 17% had a positive throat culture for group A streptococcus, identified the following four best predictors of streptococcus, also called the Centor criteria:[6]

Number of symptoms Probability of Strep
0 2.5%
1 6.0 - 6.9%
2 14.1 – 16.6%
3 30.1 – 34.1%
4 55.7%

Another study on 621 patients, assigned one point for each of the following symptoms:[8]

  • Temperature greater than 38°C (100.4°F)
  • Absence of cough
  • Tender anterior cervical adenopathy
  • Tonsillar swelling or exudate
  • Age younger than 15
  • Subtracting a point for age older than 45.
Points Probability of Strep Management
1 or less 0% Negative: No antibiotic
2 17% Indeterminate: antibiotic based on throat culture
3 35%
4 or 5 51% Positive: for throat culture and antibiotics

Finally, patients usually experience swelling of the tonsils and lymph nodes in the neck, but swelling can also be located in the soft palate in the top of the mouth. The absence of tender anterior cervical lymph nodes, tonsillar enlargement, and tonsillar or pharyngeal exudates has been suggested as being the most useful finding in ruling out strep throat, with a negative likelihood of 0.74.[9]

Laboratory testing

A rapid strep test (also called rapid antigen detection testing or RADT) or a throat culture may be undertaken to clarify diagnosis. While the rapid strep test is quicker, it has a lower sensitivity (70%) and statistically equal specificity (98%) as throat culture developed on a blood agar plate (sensitivity 81%, specificity 97%) in a cross sectional study. [10] Combining the RADT with throat culture increased the sensitivity to 85% in this study. [10] The sensitivities of both RADT and throat culture increased when used to diagnose patients who were exhibiting multiple symptoms of Streptococcal pharyngitis. When used to diagnose patients exhibiting multiple symptoms, RADT alone had a sensitivity of 78%, throat culture alone had a sensitivity of 87%, while RADT combined with throat culture had a sensitivity of 91%. [10] A positive RADT or throat culture in association with symptoms establishes a positive diagnosis, which can be treated with antibiotics.[11] Asymptomatic patients should not be routinely tested with a throat culture because a certain percentage of the population persistently "carries" strep throat.[11]

Transmission

Strep throat is caused by Group A streptococcal infection (GAS),[12] specifically the bacterium Streptococcus pyogenes.[13] It is spread by direct, close contact with an infected person.[14] It has been found that dried bacteria in dust are not infectious. Although moist bacteria on toothbrushes or similar items, which can persist for up to fifteen days,[15] might theoretically spread it, a decreased rate of recurrence in families following hygienic measures has not been shown rigorously.[12] Rarely, contaminated food, especially milk and milk products, can result in outbreaks.[16]

The incubation period for strep throat is thought to be between two to five days, but has been reported as long as eight days.[17][18]

Treatment

Symptomatic therapies

Nonprescription over the counter drugs of ibuprofen and paracetamol (acetaminophen) both help relieve throat pain and reduce fever by an average of 2.2˚C or 2.3˚C in children.[19] Aspirin is not recommended for children due to the risk of Reye's syndrome. In adults aspirin, paracetamol, or ibuprofen help reduce back pain by 48% and sore throat by 31%.[20]

Antibiotics

Antibiotics decrease the duration of symptoms (which last about 3–5 days[11]) by 1 or 2 days and reduce contagiousness. They are also prescribed out of a motivation to reduce rare complications such as acute rheumatic fever, acute glomerulonephritis (incidence of glumerulonephritis is not reduced by antibiotic therapy), and suppurative complications such as peritonsillar abscess.[21] The use of antibiotics should be balanced by the consideration of side-effects,[15] and it is reasonable to suggest no antimicrobial treatment in healthy adults who are averse to medication.[21] Antibiotics are prescribed for strep throat at a higher rate than would be expected from its prevalence.[22]

In one clinical trial, the greatest reduction in symptoms after antibiotic treatment occurred after 3 days. Out of all symptoms, reduction scores for muscle or joint pain was the most at 86%, and the lowest for sore throat at 67%.[23] Another clinical trial found that only (17%) of 42 children had positive throat cultures a day after antibiotic treatment.[24] Sometimes penicillin fails to completely treat the infection.[25]

Cephalosporins (such as cefazoline, cefuroxime, and ceftriaxone) are recommended for penicillin-allergic patients. In another study, 41 patients with confirmed penicillin allergy were evaluated with cefazoline, cefuroxime, and ceftriaxone—all cephalosporins—to see the allergic reaction. Skin tests with cephalosporins were clearly negative in 39 patients and all 41 patients tolerated the three cephalosporins administered.[26][27] Second-line antibiotics included amoxicillin,[28] clindamycin,[29] and oral cephalosporins which have a significantly better cure rate than penicillin.[30]

Studies have also shown that the broader-spectrum of antibiotics offer more effective short treatment courses than the traditional 10 days of Penicillin V,[31] but noted that "widespread use of broad-spectrum agents for a common infection is a significant concern in an age of increasing bacterial antibiotic resistance".[32] It is important to complete the full course of antibiotics to prevent rheumatic fever or an abscess on the tonsils. In one report of 500 patients, 30% had group A beta-hemolytic streptococcal pharyngitis, 0.2% had rheumatic fever and 0.2% had peritonsillar abscess (an abscess on the tonsils).[5]

Azithromycin and other macrolides have been used to treat strep throat in penicillin-allergic patients, however macrolide resistant strains of GAS are occasionally encountered. Approximately 5% of GAS isolates are macrolide resistant in the U.S., however local resistance rates may vary. In these strains, cross-resistance to macrolides, lincosamides, and streptogramins is possible. Some of the initial motivation for using antibiotics to treat all strep throat with antibiotics came from early studies showing that it reduced acute rheumatic fever at a military base, but it's difficult to generalize these findings to the current population.[33]

Complications

The symptoms of strep throat usually improve even without treatment in three to five days,[11] but without treatment the patient remains contagious for several weeks. Lack of treatment or incomplete treatment of strep throat can lead to various complications. Some of them may pose serious health risks. Therefore, streptococcal tonsillitis is important to recognize and treat early. There are also home remedies such as gargling salt water, lemon juice, in some cases mouthwash. The patient is considered to be contagious up to three days after being treated with antibiotics.[34]

List of complications arising from disseminated streptococcal infection (originating in the throat)[35]

See also

References

  1. ^ "streptococcal pharyngitis" at Dorland's Medical Dictionary
  2. ^ Xu J, Schwartz K, Monsur J, Northrup J, Neale AV (2004). "Patient-clinician agreement on signs and symptoms of 'strep throat': a MetroNet study". Fam Pract. 21 (6): 599–604. doi:10.1093/fampra/cmh604. PMID 15528291. {{cite journal}}: Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)
  3. ^ Know the Tell-Tale Signs of Strep, http://www.myfamilywellness.org/MainMenuCategories/FamilyHealthCenter/ChildrensHealth/Strep.aspx
  4. ^ Kids Health
  5. ^ a b Ebell MH (2004). "Epstein-Barr virus infectious mononucleosis". Am Fam Physician. 70 (7): 1279–87. PMID 15508538.
  6. ^ Centor RM, Dalton HP, Campbell MS, Lynch MR, Watlington AT, Garner BK (1986). "Rapid diagnosis of streptococcal pharyngitis in adult emergency room patients". J Gen Intern Med. 1 (4): 248–51. doi:10.1007/BF02596194. PMID 3534175.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  7. ^ Komaroff AL, Pass TM, Aronson MD; et al. (1986). "The prediction of streptococcal pharyngitis in adults". J Gen Intern Med. 1 (1): 1–7. doi:10.1007/BF02596317. PMID 3534166. {{cite journal}}: Explicit use of et al. in: |author= (help)CS1 maint: multiple names: authors list (link)
  8. ^ McIsaac WJ, Goel V, To T, Low DE (2000). "The validity of a sore throat score in family practice". CMAJ. 163 (7): 811–5. PMC 80502. PMID 11033707.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  9. ^ Eaton CA (2001). "What clinical features are useful in diagnosing strep throat?". J Fam Pract. 50 (3): 201. PMID 11252201.
  10. ^ a b c "Performance of a rapid antigen-detection test and throat culture in community pediatric offices: implications for management of pharyngitis". Pediatrics. 2009. doi:10.1542/peds.2008-0488. PMID 19171607. Evid Based Med Review
  11. ^ a b c d Bisno AL, Gerber MA, Gwaltney JM, Kaplan EL, Schwartz RH (2002). "Practice guidelines for the diagnosis and management of group A streptococcal pharyngitis. [[Infectious Diseases Society of America]]". Clin. Infect. Dis. 35 (2): 113–25. doi:10.1086/340949. PMID 12087516. {{cite journal}}: URL–wikilink conflict (help); Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)
  12. ^ a b Falck G, Kjellander J, Schwan A (1998). "Recurrence rate of streptococcal pharyngitis related to hygienic measures". Scand J Prim Health Care. 16 (1): 8–12. doi:10.1080/028134398750003331. PMID 9612872.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  13. ^ Gieseker KE, Roe MH, MacKenzie T, Todd JK (2003). "Evaluating the American Academy of Pediatrics diagnostic standard for Streptococcus pyogenes pharyngitis: backup culture versus repeat rapid antigen testing". Pediatrics. 111 (6 Pt 1): e666–70. doi:10.1542/peds.111.6.e666. PMID 12777583.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  14. ^ Lindbaek M, Høiby EA, Lermark G, Steinsholt IM, Hjortdahl P (2004). "Predictors for spread of clinical group A streptococcal tonsillitis within the household". Scand J Prim Health Care. 22 (4): 239–43. doi:10.1080/02813430410006729. PMID 15765640.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  15. ^ a b Hayes CS, Williamson H (2001). "Management of Group A beta-hemolytic streptococcal pharyngitis". Am Fam Physician. 63 (8): 1557–64. PMID 11327431. {{cite journal}}: Unknown parameter |month= ignored (help)
  16. ^ Asteberg I, Andersson Y, Dotevall L; et al. (2006). "A food-borne streptococcal sore throat outbreak in a small community". Scand. J. Infect. Dis. 38 (11–12): 988–94. doi:10.1080/00365540600868370. PMID 17148066. {{cite journal}}: Explicit use of et al. in: |author= (help)CS1 maint: multiple names: authors list (link)
  17. ^ Sarvghad MR, Naderi HR, Naderi-Nassab M; et al. (2005). "An outbreak of food-borne group A Streptococcus (GAS) tonsillopharyngitis among residents of a dormitory". Scand. J. Infect. Dis. 37 (9): 647–50. doi:10.1080/00365540510044085. PMID 16126564. {{cite journal}}: Explicit use of et al. in: |author= (help)CS1 maint: multiple names: authors list (link)
  18. ^ Coburn, A.F.; Pauli, R.H. (1941). "The interaction of host and bacterium in the development of communicability by Streptococcus haemolyticus". The Journal of Experimental Medicine. 73 (4): 551–570. doi:10.1084/jem.73.4.551. PMC 2135145. PMID 19871096. {{cite journal}}: More than one of |author2= and |last2= specified (help)CS1 maint: PMC format (link)
  19. ^ Figueras Nadal C, García de Miguel MJ, Gómez Campderá A, Pou Fernández J, Alvarez Calatayud G, Sánchez Bayle M (2002). "Effectiveness and tolerability of ibuprofen-arginine versus paracetamol in children with fever of likely infectious origin". Acta Paediatr. 91 (4): 383–90. doi:10.1080/080352502317371607. PMID 12061352.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  20. ^ Farhan, M., Leparc, J.M., Moore, N., Pelen, F., Vanganse, E., Verriere, F., & Wall, R. (1999). "The PAIN Study: Paracetamol, Aspirin and Ibuprofen New Tolerability Study: A Large-Scale, Randomised Clinical Trial Comparing the Tolerability of Aspirin, Ibuprofen and Paracetamol for Short-Term Analgesia". Clinical Drug Investigation. 18 (2): 89–98. doi:10.2165/00044011-199918020-00001. Retrieved 2008-12-08. {{cite journal}}: Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)
  21. ^ a b Snow V, Mottur-Pilson C, Cooper RJ, Hoffman JR (2001). "Principles of appropriate antibiotic use for acute pharyngitis in adults" (PDF). Ann. Intern. Med. 134 (6): 506–8. PMID 11255529. {{cite journal}}: Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)
  22. ^ Linder JA, Bates DW, Lee GM, Finkelstein JA (2005). "Antibiotic treatment of children with sore throat". JAMA. 294 (18): 2315–22. doi:10.1001/jama.294.18.2315. PMID 16278359. {{cite journal}}: Unknown parameter |doi_brokendate= ignored (|doi-broken-date= suggested) (help); Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)
  23. ^ Melbye H, Bjørkheim MK, Leinan T (2002). "Daily reduction in C-reactive protein values, symptoms, signs and temperature in group-A streptococcal pharyngitis treated with antibiotics". Scand. J. Clin. Lab. Invest. 62 (7): 521–5. doi:10.1080/003655102321004530. PMID 12512742.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  24. ^ Snellman LW, Stang HJ, Stang JM, Johnson DR, Kaplan EL (1993). "Duration of positive throat cultures for group A streptococci after initiation of antibiotic therapy". Pediatrics. 91 (6): 1166–70. PMID 8502522.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  25. ^ Brandt CM, Allerberger F, Spellerberg B, Holland R, Lütticken R, Haase G (2001). "Characterization of consecutive Streptococcus pyogenes isolates from patients with pharyngitis and bacteriological treatment failure: special reference to prtF1 and sic / drs". J. Infect. Dis. 183 (4): 670–4. doi:10.1086/318542. PMID 11170997.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  26. ^ Novalbos A, Sastre J, Cuesta J; et al. (2001). "Lack of allergic cross-reactivity to cephalosporins among patients allergic to penicillins". Clin. Exp. Allergy. 31 (3): 438–43. doi:10.1046/j.1365-2222.2001.00992.x. PMID 11260156. {{cite journal}}: Explicit use of et al. in: |author= (help)CS1 maint: multiple names: authors list (link)
  27. ^ Pichichero ME (2005). "A review of evidence supporting the American Academy of Pediatrics recommendation for prescribing cephalosporin antibiotics for penicillin-allergic patients". Pediatrics. 115 (4): 1048–57. doi:10.1542/peds.2004-1276. PMID 15805383.
  28. ^ Feder HM, Gerber MA, Randolph MF, Stelmach PS, Kaplan EL (1999). "Once-daily therapy for streptococcal pharyngitis with amoxicillin". Pediatrics. 103 (1): 47–51. doi:10.1542/peds.103.1.47. PMID 9917438.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  29. ^ Martin JM, Green M, Barbadora KA, Wald ER (2004). "Group A streptococci among school-aged children: clinical characteristics and the carrier state". Pediatrics. 114 (5): 1212–9. doi:10.1542/peds.2004-0133. PMID 15520098.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  30. ^ Casey JR, Pichichero ME (2004). "Meta-analysis of cephalosporin versus penicillin treatment of group A streptococcal tonsillopharyngitis in children". Pediatrics. 113 (4): 866–82. doi:10.1542/peds.113.4.866. PMID 15060239.
  31. ^ Adam D, Scholz H, Helmerking M (2000). "Short-course antibiotic treatment of 4782 culture-proven cases of group A streptococcal tonsillopharyngitis and incidence of poststreptococcal sequelae". J. Infect. Dis. 182 (2): 509–16. doi:10.1086/315709. PMID 10915082.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  32. ^ Lord RW (2000). "Is a 5-day course of antibiotics as effective as a 10-day course for the treatment of streptococcal pharyngitis and the prevention of poststreptococcal sequelae?". J Fam Pract. 49 (12): 1147. PMID 11132064.
  33. ^ David H. Newman (2008). Hippocrates' Shadow. Scribner (2008). p. 110–16. ISBN 1-4165-5153-0.
  34. ^ Mitchell, Richard Sheppard; Kumar, Vinay; Abbas, Abul K.; Fausto, Nelson (2007). Robbins Basic Pathology: With STUDENT CONSULT Online Access. Philadelphia: Saunders. p. 537. ISBN 1-4160-2973-7. {{cite book}}: Unknown parameter |edith= ignored (help)CS1 maint: multiple names: authors list (link)
  35. ^ UpToDate Inc


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