Response: Re: Clinical Diagnosis of Bordetella Pertussis Infection: A Systematic Review
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* Mark H. Ebell

*To the Editor:* We thank Dr. Poddighi for his thoughtful commentary on our article regarding the clinical diagnosis of pertussis.1 We fully agree that the overall clinical impression, sometimes called “clinical gestalt,” is a vital diagnostic tool for many conditions. In fact, we are in the process of performing a systematic review of clinical gestalt for the diagnosis of a range of respiratory infections; we hope that study will shed more light on its accuracy.

Well-validated clinical decision rules (CDRs) can be very useful to support a physician's clinical gestalt. Of course, it is important to remember that CDRs are clinical decision *support* tools, not decision *replacement* tools. They must always be applied in the full context of what is known about a patient. For example, a Centor Score in the range of low or moderate probability will be interpreted differently if the clinician knows that a household member had been diagnosed with streptococcal pharyngitis the previous week. CDRs can also help physicians, especially those in training, learn what is important in a history and physical examination and what is not, even if they only integrate these signs and symptoms implicitly (ie, clinical gestalt) rather than explicitly using a CDR.

Finally, we fully agree with Dr. Poddighi's advice to always consider pertussis in the differential diagnosis of a patient with prolonged cough or typical signs and symptoms, such as the characteristic whoop, paroxysmal cough, or posttussive retching or vomiting. A previous systematic review by our research group showed that nearly 1 in 5 children with prolonged cough have pertussis.2

## Notes

*   The above letter was referred to the author of the article in question, who offers the following reply.

## References

1.  1.Ebell MH, Marchello C, Callahan M. Clinical diagnosis of bordetella pertussis infection: a systematic review. J Am Board Fam Med 2017;30:308–19.
    
    [Abstract/FREE Full Text](http://www.jabfm.org/lookup/ijlink/YTozOntzOjQ6InBhdGgiO3M6MTQ6Ii9sb29rdXAvaWpsaW5rIjtzOjU6InF1ZXJ5IjthOjQ6e3M6ODoibGlua1R5cGUiO3M6NDoiQUJTVCI7czoxMToiam91cm5hbENvZGUiO3M6NToiamFiZnAiO3M6NToicmVzaWQiO3M6ODoiMzAvMy8zMDgiO3M6NDoiYXRvbSI7czoyMDoiL2phYmZwLzMwLzUvNjgyLmF0b20iO31zOjg6ImZyYWdtZW50IjtzOjA6IiI7fQ==) 

2.  2.Marchello C, Perry A, Thai T, Han DS, Ebell MH. Prevalence of atypical pathogens in patients with cough and community-acquired pneumonia: a meta-analysis. Ann Fam Med 2016;14:552–66.
    
    [Abstract/FREE Full Text](http://www.jabfm.org/lookup/ijlink/YTozOntzOjQ6InBhdGgiO3M6MTQ6Ii9sb29rdXAvaWpsaW5rIjtzOjU6InF1ZXJ5IjthOjQ6e3M6ODoibGlua1R5cGUiO3M6NDoiQUJTVCI7czoxMToiam91cm5hbENvZGUiO3M6ODoiYW5uYWxzZm0iO3M6NToicmVzaWQiO3M6ODoiMTQvNi81NTIiO3M6NDoiYXRvbSI7czoyMDoiL2phYmZwLzMwLzUvNjgyLmF0b20iO31zOjg6ImZyYWdtZW50IjtzOjA6IiI7fQ==)