快樂小藥師 Im pharmacist nichts glücklich

University of Michigan Health System. Pharyngitis. Ann Arbor (MI): University of Michigan Health System; 2013 May. 10 p.
[Free full-text University of Michigan Quality Management Program guideline PDF | National Guideline Clearinghouse version online]

[EXCERPTS]

Major Recommendations

Key Points

General Principles

• Viral pathogens cause most cases of pharyngitis: around 90% in adults and 70% in children [C].
• The primary reason to identify and treat group A streptococcal (GAS) pharyngitis is to decrease the risk of acute rheumatic fever (ARF) [IB]. The endemic incidence of ARF is around 0.23-1.88/100,000.
• Early treatment of GAS can decrease the time a patient is symptomatic by 1-2 days from a typical 3-7 days [IB] and can decrease the period of contagiousness [IB].

Diagnosis

• Signs/symptoms of severe sore throat, fever, tender anterior cervical lymphadenopathy, red pharynx with tonsillar swelling +/- exudate, and no cough indicate a higher probability of GAS pharyngitis for both adults and children. Algorithms of epidemiologic and clinical factors improve diagnosis by identifying patients with an exceedingly low risk of GAS infection [C].
• Laboratory confirmation:
  • Neither culture nor rapid antigen screen differentiate individuals with GAS pharyngitis from GAS carriers with an intercurrent viral pharyngitis.
  • Consider clinical and epidemiological findings (see Table 2 in the original guideline document) when deciding to perform a microbiological test [IB].
  • Patients with manifestations highly suggestive of a viral infection such as coryza, scleral conjunctival inflammation, hoarseness, cough, discrete ulcerative lesions, or diarrhea, are unlikely to have GAS infection and generally should NOT be tested for GAS infection [IIB].
• Throat culture is the presumed "gold standard" for diagnosis. Rapid streptococcal antigen tests identify GAS more rapidly, but have variable sensitivity [B].
  • Reserve rapid strep tests for patients with a reasonable probability of having GAS.
  • Confirm negative screen results by culture in patients <16 years old (and consider in parents/siblings of school age children) due to their higher risk of acute rheumatic fever [IIC].
  • If screening for GAS in very low risk patients is desired, culture alone is cost-effective [IIC].

Treatment

• Penicillin V is the drug of choice in patients who can swallow pills.
• If using suspension, amoxicillin is better tolerated than penicillin V due to the salty/bitter taste.
• Amoxicillin as a single daily dose (1 gram/day) for 10 days is as effective as penicillin V or amoxicillin given multiple times per day for 10 days.
• A single dose of intramuscular penicillin G benzathine avoids the problem of adherence, but is painful.
• If allergic to penicillin, a 10-day course of a first generation cephalosporin is indicated if no history of a type I hypersensitivity to penicillin. Oral clindamycin is an acceptable alternative, if one is unable to use a first generation cephalosporin.
• A macrolide is also acceptable for patients allergic to penicillins (resistant rates range 5-8%).
• Children with a recurrence of GAS pharyngitis shortly after completing a course of an oral antimicrobial agent can be retreated with the same agent, given an alternative oral drug, or given an intramuscular injection of penicillin G benzathine (expert opinions differ).
• Antibiotics must be started within 9 days after onset of acute illness and continued for 10 days (5 days for azithromycin) to eradicate GAS from the upper respiratory tract and prevent ARF [D].

Controversial Areas

• Diagnosis over the telephone based on symptoms alone without lab testing is unreliable [IIID].
• Based on a phone description, a nurse triage algorithm may guide screening for GAS [IID].
• When an appropriately symptomatic patient is ≥3 years old and has a family member recently diagnosed with laboratory confirmed GAS pharyngitis, one may treat without screening [IID].