Strep Pharyngitis 2010 A Pediatric Perspective for Primary Care

1. Strep Pharyngitis 2010(A Pediatric Perspective for Primary Care) Mark Gabay DO Assistant Professor of Pediatrics Nova Southeastern University – College of Medicine Osteopathic Pediatric Residency Program Director Pediatric Residency Associate Program Director Miami Children’s Hospital

2. Case A 10 year old male with no history of GAS pharyngitis presents to your office for a sore throat for the past 2 days, fever to 102F, and mild URI symptoms for the past week. Physical exam is remarkable for tender cervical adenopathy, no hepatosplenomegaly and a pharynx that looks as follows:

3. Case

4. Case What is the diagnosis? Is it bacterial or viral? Would you perform testing, and if so what test(s)? How would you treat and counsel the patient (and family) during this encounter?

5. Objectives To gain a basic understanding in the background, epidemiology and presentation of Strep pharyngitis To become familiar with methods used in diagnosing Strep throat in the pediatric population To become familiar with various treatment options for Strep throat To become aware of various complications due to Strep pharyngitis

6. What is Pharyngitis? Irritation or infection of the pharynx Occurs in adults but is more commonly seen in the pediatric population Most commonly due to infectious causes

7. Causes of Pharyngitis Infectious (viral) Infectious (bacterial) Infectious (other) Allergy Neoplasm Toxins Trauma The most common cause of pharyngitis is viral!

8. Strep Pharyngitis This is the most common and significant bacterial cause of pharyngitis in children and adults Also known as: Strep throat GAS pharyngitis Streptococcus pyogenes Group A Beta-Hemolytic Strep

9. Streptococcus pyogenes Gram positive Nonmotile Oxidase negative Catalase negative Cocci in pairs or chains There are multiple strains with varying virulence more than 120 serotypes

10. Strep Throat Up to 30% of pediatric cases of pharyngitis can be attributed to Group A Strep Commonly seen between the ages of 5-15 with the highest incidence in children aged 5-11 Not common under the age of 3 but can be seen

11. Strep Throat More prevalent in late autumn to spring (cooler months) Spread by human-human secretions (saliva or nasal secretions) Infection due to local, direct invasion of pharyngeal mucosa Incubation period: 2-5 days

12. Other infectious (bacterial) agents causing pharyngitis Arcanobacterium haemolyticum Pharyngitis and rash Corynebacterium diphtheriaete Lack of immunizations, adherent greyish membrane in throat Group C Strep Group G Strep

13. Bacterial Causes Continued… Mycoplasma pneumoniae Teens and adults, cough, URI symptoms Chlamydia pneumoniae Similar to Mycoplasma Neisseria gonorrhea Orogenital sexual activity Fusobacterium necrophorum Lemierre’s Syndrome: pharyngitis, septic thrombophlebitis

14. Other infectious (viral) agents causing pharyngitis Epstein-Barr virus May mimic Strep, constitutional symptoms HIV Mono-like syndrome, lymphopenia HSV Ulcers and/or vesicular lesions Adenovirus Conjunctivitis, pharyngitis, fever, URI symptoms

15. Viral Causes Continued Rhinovirus Cold symptoms Coronavirus Cold symptoms Coxsackie (enterovirus) Vesicles in posterior pharynx +/- hand or foot lesions Parainfluenza Stridor, URI symptoms Influenza A and B Fever, cough, myalgia, headache

16. History & Symptoms Suggestive of Strep Throat Sudden onset of symptoms Fever above 101F Sore throat Loss of appetite Painful, swollen lymph nodes of the neck Pain or difficulty swallowing Stomach pain Headache Nausea / vomiting Rash (scarlatiniform)

17. History & Symptoms Suggestive of Strep Throat Continued Lack of cough History of prior, recent Strep throat Recent contact with persons diagnosed with GABHS History of rheumatic fever Rhinorrhea, cough, coryza, conjunctivitis and/or diarrhea are more suggestive of a viral etiology

18. Signs & Exam Suggestive of GAS Pharyngitis Tender or enlarged anterior cervical nodes Pharyngeal or tonsillar exudates Palatine petichiae One of the more specific exam findings May also be seen in EBV (Mono) Scarlatiniform (sandpaper) rash

19. Physical Exam

20. Diagnosis of Strep Pharyngitis Determination of the infectious cause of pharyngitis is difficult when only relying on history and physical exam. Differentiation of bacterial vs. viral infection is accurate approximately 50% of the time Strep throat tends to be over-diagnosed and pharyngitis overtreated with antibiotics.

21. Clinical Tools Aid in Diagnosis Due to the difficulty in accurately diagnosing Strep throat and who to test, clinical decision tools were devised and validated to help determine the likelihood of GABS pharyngitis Centor score McIsaac score

22. McIsaac Score The presence of each sign/symptom is assigned 1 point Fever above 38C Absence of cough Tonsillar exudates or swelling Anterior cervical LAD Age below 15 If above 45 years old, subtract 1 point

23. McIsaac Score Continued

24. When to perform testing History and exam clinically suggestive Symptoms with exposure to GABS Symptoms with family member with rheumatic fever or poststreptococcal glomerulonephritis Lab confirmation of GABS pharyngitis is recommended for the pediatric population Vigorous sampling of both tonsils and posterior pharynx

25. Rapid Antigen Testing Rapid antigen detection test Provides a quick method for aiding in the diagnosis of Strep throat Most are designed to detect a carbohydrate antigen from a throat swab specimen RADT are compared to throat culture

26. Rapid Antigen Testing Specificity is high for these tests Sensitivities are variable but improved compared to older generation rapid detection testing Dependent on quality of swab, experience of test performer, and initial likelihood of infection Newer tests such as optical immunoassay and DNA probes may be as sensitive as throat cultures

27. RADT and Sensitivity Study Study published in Pediatrics by Edmonson and Farwell in 2005 Evaluated cost effectiveness and sensitivities of second generation RADT on pediatric patients in an outpatient setting Results: As clinical likelihood increased (increased McIsaac score), sensitivity of the RADT increased

28. RADT and Sensitivity Study Continued With McIsaac scores 2 or less, sensitivities drop to 0.62 Cost effectiveness impaired In pediatric patients with high clinical likelihood of Strep throat (less than 15 years old, lack of cough, exudate) sensitivities were high (0.94)

29. Throat Culture The gold standard to which RADTs are compared to Culture on sheep blood agar A positive culture cannot distinguish between carrier state and active infection Prevalence of Strep pyogenes up to 15% in asymptomatic children Sensitivity up to 95%

30. Throat Culture Properly obtained cultures have less than 10% false-negatives in patients that are symptomatic If a RADT is positive, a throat culture is not needed If a RADT is performed and negative, a throat culture should be obtained and incubated for 2 days

31. Throat Culture A study published in Pediatrics in 2004 examined RADT obtained in private pediatric practice against backup throat cultures When compared to 24hr culture, RADT sensitivity was 92% When compared to 48hr culture, RADT dropped to 86%

33. Treatment GABS pharyngitis will resolve without treatment in most cases Antibiotic therapy Shorten the course of illness Decrease transmission of disease Prevention of suppurative (abscess) and nonsuppurative complications (acute rheumatic fever) If started up to 9 days after illness onset, there still is effective prevention of rheumatic fever

34. Antibiotic Treatment Adequate antibiotic treatment is recommended by the AAP, AHA, IDSA Antibiotic treatment indicated for Strep throat confirmed by lab testing (RADT, culture) If RADT and throat culture are negative, it is recommended to withhold antibiotics for uncomplicated pharyngitis

35. Antibiotic Treatment All GAS are susceptible to Beta-lactams Penicillins Cephalosporins No single regimen eliminates GAS in all treated patients

36. Antibiotic Treatment Multiple factors involved in deciding antibiotic selection Allergies Cost Route and administration Palatability Efficacy Side effects

37. Antibiotic Treatment Penicillin V and benzathine penicillin G are the antibiotics of choice for GAS Except in those with penicillin allergy

38. Antibiotic Treatment If penicillin allergic:

39. Antibiotic Treatment Not acceptable for treatment: Tetracyclines Fluoroquinolones Sulfonamides Trimethoprim-sulfamethoxazole Patient is not considered contagious after 24 hrs after start of treatment

40. Treatment Failure May be chronic carriers Seen more in patients taking oral penicillin versus IM penicillin May be related to: Compliance issues Antibiotic formulation Copathogens Age of patient

41. Treatment Failure If asymptomatic, treatment generally is not indicated but may be indicated if Patient has history of rheumatic fever or family members with rheumatic fever Outbreak of rheumatic fever or PSGN Outbreak of GAS pharyngitis in community Multiple episodes of GAS pharyngitis within a household

42. Treatment Failure If symptomatic, retreat with: Same therapy Alternate oral drug IM injection Clindamycin Amoxicillin-clavulanic acid Narrow spectrum cephalosporin Penicillin with rifampin

43. Non Antibiotic Treatment Supportive care Warm or cold fluids Salt water mouth rinses Lozenges Oral antiseptic sprays Pain medication: acetaminophen Steroids

44. Complications of Strep Infection Can occur despite treatment but are mostly preventable and reduced if adequately treated Complications can be divided into 2 categories Suppurative Nonsuppurative

45. Suppurative Complications Peritonsillar abscess Retropharyngeal abscess Lymphadenitis Otitis media Mastoiditis Endocarditis Streptococcal toxic shock syndrome

46. Nonsuppurative Complications Poststreptococcal glomerulonephritis Not prevented by antibiotic treatment Occurs after an asymptomatic latent period Acute rheumatic fever Affects 20 million persons More prevalent in developing countries ARF and rheumatic heart disease is the most common cause of death due to cardiovascular disease before the age of 50

47. Acute Rheumatic Fever Low incidence in the United States with few outbreaks Antibiotics can be started up to 9 days after onset of Strep phayrngitis and still be effective in the prevention of rheumatic fever Thought to occur due to molecular mimicry 2-4 weeks after initial Strep throat

48. Jones Criteria for Rheumatic Fever Diagnosis requires one major and two minor criteria or two major criteria along with evidence of recent GAS infection

49. In Conclusion GABHS pharyngitis is a common in the pediatric population but not easily distinguished from other infectious causes based on history and physical exam alone If clinically suspected, lab confirmation with RADT and/or backup throat culture is recommended Completion of an appropriate antibiotic regimen is recommended for Strep positive patients with active pharyngitis

50. References

51. References

52. References