1. Home>
2. Specialties>
3. General Medicine>
4. Summary and Comment

Practice Guideline Comparisons for Strep Pharyngitis

Throat cultures are the most effective way to guide antibiotic therapy for patients with pharyngitis, but clinical scoring systems and rapid tests work pretty well and are more convenient.

Recommendations for the management of group A streptococcus (GAS) pharyngitis vary from throat cultures or in-office rapid-antigen tests (RATs) for all patients with sore throats to empirical treatment based on clinical scoring systems (such as the modified Centor score [see below]).

Researchers at a Canadian family practice clinic performed throat cultures and RATs on 787 children and adults who had modified Centor scores of 2 or higher. Six management strategies were evaluated:

• (1) Obtain cultures on all patients. Treat culture-positive patients.
  
• (2) Perform RAT in all patients. Treat RAT-positive children and obtain cultures in RAT-negative children; treat only RAT-positive adults (no cultures in adults).
  
• (3) Manage children as in strategy #2. Among adults with Centor scores of 2 or 3, perform RATs and treat RAT-positive patients; among adults with Centor scores of 4, treat empirically.
  
• (4) Manage children as in strategy #2. Empirically treat adults with Centor scores of 3 or higher.
  
• (5) Obtain cultures for all patients with Centor scores of 2 or 3, and treat culture-positive patients; empirically treat patients with Centor scores of 4 or higher.
  
• (6) Perform RATs on all patients. Treat only RAT-positive patients (no cultures in any group).
  

The prevalence of positive throat cultures was 29% (34% in children; 22% in adults). Overall, all strategies except #6 had sensitivities higher than 90% for identifying GAS pharyngitis, and specificities were higher than 93% in all strategies except #4. Unnecessary antibiotic use in children ranged from 0.7% in most strategies to 6.4% in strategy #5; unnecessary antibiotic use in adults ranged from 0.6% in most strategies to 44% in strategy #4.

Comment: Among adults, strategy #1 is most effective but also most cumbersome. Strategy #5 is probably the most practical and has the optimal combination of sensitivity, specificity, and low rate of unnecessary antibiotic use. Among children, all strategies have high sensitivity and specificity; #5 has the highest rate of unnecessary antibiotic use (but this was still only 6%). As an easily remembered and practical approach, many physicians might choose #5 for both children and adults, although #1, #2, or #3 would be effective for children as well.

— Thomas L. Schwenk, MD

Modified Centor Scoring System involves the following criteria: temperature, >38°C: 1 point; absence of cough: 1 point; swollen, tender anterior cervical nodes: 1 point; tonsillar swelling or exudates: 1 point; age 3-14 years: 1 point; age 15-44 years: 0 points; age 45 years: –1 point.

Published in Journal Watch General Medicine April 30, 2004

Citation(s):

McIsaac WJ et al. Empirical validation of guidelines for the management of pharyngitis in children and adults. JAMA 2004 Apr 7; 291:1587-95.

• Original article (Subscription may be required)
• Medline abstract (Free)