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Concordance of Clinical Findings and Clinical Judgment in the Diagnosis of Streptococcal Pharyngitis
Author(s) -
Nawaz Haq,
Smith David S.,
Mazhari Ramesh,
Katz David L.
Publication year - 2000
Publication title -
academic emergency medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.221
H-Index - 124
eISSN - 1553-2712
pISSN - 1069-6563
DOI - 10.1111/j.1553-2712.2000.tb01259.x
Subject(s) - medicine , pharyngitis , sore throat , throat , throat culture , visual analogue scale , erythema , concordance , dermatology , pharynx , prospective cohort study , surgery , streptococcus , biology , bacteria , genetics
.Objective: It is uncertain how reliably clinicians apply clinical predictors of group A beta hemolytic streptococcal pharyngitis (GABHSP) to form a clinical impression, and how reliably this impression predicts culture results. The objective was to study clinician accuracy in diagnosing GABHSP. Methods: This was a prospective cohort study, conducted at an urgent care center of a major university. A convenience sample of 218 patients, aged 9‐83 years, presenting with sore throat, was enrolled. Symptoms and signs of pharyngitis were documented on a standardized form; the likelihood of GABHSP was plotted on a visual analog scale; and throat culture was obtained. A comparison was then made between the clinical impression on presentation and the throat culture result. Results: Throat cultures were positive for GABHSP in 41 patients (19%). The probability of GABHSP was related to node size and tenderness, tonsillar exudate and hypertrophy, and pharyngeal erythema (p < 0.05); but not throat soreness, degree of fever, or cough. A strong clinical impression of GABHSP (>50% on the visual analog scale) was associated with tonsillar exudate and hypertrophy, tender nodes, and pharyngeal erythema. Together, these four predictors had a sensitivity of 71%, a specificity of 77%, and a positive predictive value of 46%. Conclusions: Clinicians in this study based their impression of GABHSP on the most reliable symptoms and signs. While a strong clinical suspicion of GABHSP predicted a greater probability of positive culture, the clinicians consistently overestimated the probability of GABHSP. Symptoms and signs predict GABHSP unreliably when used alone; they are helpful in modifying estimates of disease probability to facilitate optimal use of laboratory tests and antibiotics.