A 7-year-old boy is brought to the office by his parents due to 2 days of sore throat, poor appetite, and malaise. Several classmates have missed school due to similar symptoms. The patient has no cough, rhinorrhea, or nasal congestion. He takes no daily medications and has no known allergies. Immunizations are up to date. Temperature is 38.9 C (102 F), blood pressure is 110/70 mm Hg, pulse is 130/min, and respirations are 16/min. On examination, the tonsils are swollen and covered with thin, white exudates. Small, tender anterior cervical lymph nodes are palpated. Rapid streptococcal antigen detection testing is negative. Which of the following is the most appropriate next step in management of this patient?
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This patient has acute pharyngitis, which can be caused by viruses (more common) or bacteria (group A Streptococcus [GAS]). Although the Centor criteria are often used in the evaluation of adults with acute pharyngitis, these clinical rules are less predictive in children. In children, tonsillar erythema and exudates, tender anterior cervical nodes, and palatal petechiae are features that can be seen with both GAS and viral pharyngitis; however, viruses often cause additional symptoms, such as cough, rhinorrhea, congestion, and/or oral ulcers. Therefore, testing for GAS is recommended in children with pharyngitis who do not have symptoms of viral illness, as is the case in this patient.
Initial evaluation is typically with rapid antigen detection testing (RADT), which is quick and highly specific but has limited sensitivity. Because the risk of acute rheumatic fever is much higher in children with untreated streptococcal pharyngitis than in adults, a negative RADT in a child should be confirmed with a throat culture, which has greater sensitivity (Choice D). In contrast, confirmatory culture is not typically required in adults. The preferred treatment in a patient with a positive RADT or throat culture is penicillin or amoxicillin.
(Choice A) Antistreptolysin O antibodies peak approximately a month after streptococcal infection and are not helpful in diagnosing acute pharyngitis.
(Choice B) Heterophile antibody testing is used to diagnose infectious mononucleosis (IM) caused by Epstein-Barr virus. Although IM can cause fever and exudative tonsillitis, it is most common in adolescents and is usually accompanied by posterior cervical lymphadenopathy and, sometimes, splenomegaly. This patient's age and anterior cervical lymphadenopathy make IM less likely.
(Choice C) Rapid influenza testing, which has high specificity and low to moderate sensitivity, can be performed to guide antiviral treatment decisions. However, influenza typically presents with fever, pharyngitis, and other viral symptoms (eg, cough, rhinorrhea), which this patient lacks.
Educational objective:
Children with pharyngitis and no viral symptoms (eg, rhinorrhea, cough) should undergo group A Streptococcus (GAS) rapid antigen detection testing. Due to the risk of acute rheumatic fever with untreated GAS, a throat culture is performed to confirm a negative result.