Recently, movie star Bill Paxton tragically passed away due to complications following heart surgery. It was reported he was having a valve replacement surgery due to rheumatic heart disease from a bout of rheumatic fever he had when he was 13. What is the most common cause of rheumatic fever? Untreated Strep Throat.
Parents generally worry about strep throat because they assume that it won’t go away unless treated with antibiotics. This is actually not true. Strep throat will typically resolve in 3-7 days with or without antibiotics. The true peril with strep throat and the reason you want to make sure it is treated with antibiotics is due to the risk of developing rheumatic fever if untreated. Rheumatic fever is caused by an immune response to bacteria that can develop and cause joint inflammation/pain 2-3 weeks after the initial infection occurs. This immune response can also cause rheumatic heart disease and permanent damage to valves in the heart. Other complications of untreated sore throat include abscess formation in the throat or temporary kidney injury.
Generally, throat culture is considered the most cost efficient and accurate way to diagnose strep throat. Unfortunately, culture results are typically not available for 2-3 days. As such, clinicians often use rapid strep tests along with clinical assessment to direct care.
Although many rapid strep tests claim to be 90% accurate, these claims are not backed up by independent studies. For example, a study from the Journal of Clinical Microbiology showed a wide range of accuracy with these tests based on the personnel performing them. Lab technicians showed a 90% accuracy rate with the rapid strep test while other trained medical personnel get less accurate results around 75%. Without training or retraining, non-lab personnel were found to have accuracy rates as low as 56% with the rapid strep test.* At home testing kits performed by parents would fall into this lower accuracy category, meaning these tests have about as good of a chance of being correct as a coin flip.
Due to the inadequacy of rapid testing alone, clinicians generally combine test results with clinical exam findings to improve accuracy. Certain exam findings such as the Centor criteria: enlarged or exudative tonsils, swollen anterior cervical lymph nodes, fever, and lack of cough, combined with age can be strong predictors of strep throat. Throat cultures can also be sent off on negative rapid tests to ensure the diagnosis is not missed.
Rheumatic fever is not common but can have a devastating outcome. As such, relying on an unreliable rapid home test may not be the best choice. Combining rapid test results with clinical exam findings by an experienced medical provider and following up negative results with throat culture is a much safer way to evaluate the sore throat.