Thursday, February 19, 2015

Strep throat and rapid strep tests

People often get sore throats this time of year. Many sore throats are caused by viruses, but it is wise to determine if a sore throat is caused by bacteria. 

The most common bacteria that can cause a sore throat is Group A strep.  Strep throat can lead to inflamed kidneys, neurologic symptoms, scarlet fever, or rheumatic heart disease if left untreated (i.e. painful, inflamed joints, a rash, bloody urine, abnormal involuntary movements, and possible damage to the heart valves). 

Health care providers should consider the following clinical questions:
  1. Is there a fever (typically greater than 102)?
  2. Does the patient have tender anterior cervical adenopathy?
  3. Does the patient have no cough or a dry cough and/or mild upper respiratory symptoms?
  4. Does the patient have a red, painful throat, with enlarged tonsils with or without white exudates or red spots on the roof of the mouth?
  5. Has the patient been exposed to anyone known to be positive for strep throat?
Physical exam and history alone are not enough to determine if a sore throat is caused by a bacteria or a virus.  While a rapid strep test administered at the point of care can detect Group A strep in 5 minutes, rapid tests do not detect every case of Group A strep or other strains of strep throat. A negative rapid strep test does not guarantee strep throat is not present.  

A throat culture should be the next step, which will take approximately 48 hours for a result.  In the meantime, health care providers may choose to treat empirically with antibiotics for those who have more than 3 out of 5 risk factors or to monitor until the culture returns for those who have 2 or fewer risk factors. If the culture returns negative, then antibiotics can be stopped.

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