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Objective: Acute tonsillitis is primarily caused by viral infection. Group A Streptococcus (GAS), however, is the only causative agent of acute tonsillitis for which there is a specific diagnosis and treatment. Nevertheless, antibiotics are commonly prescribed without a confirmed diagnosis. McIsaac criteria can be used to confirm GAS-associated acute tonsillitis. Herein, we aimed to study McIsaac criteria with throat cultures, procalcitonin (PCT) and C-reactive protein (CRP) levels, white blood cell counts (WBC), neutrophil counts and erythrocyte sedimentation values and to investigate utility of McIsaac criteria in the definitive diagnosis and treatment of acute tonsillitis.
Methods: We assessed 97 patients diagnosed with acute tonsillitis. Medical files were scanned retrospectively, and WBC counts, neutrophil counts, erythrocyte sedimentation values, CRP and PCT measurements and patient throat cultures were compared with the McIsaac scores.
Results: Patients were separated into two groups according to McIsaac criteria. Group one had McIsaac scores ≤2, and group two had McIsaac scores ≥3. There were 29 patients in group one, and 68 patients in group two. Normal bacterial flora (NBF) were present in all group one patients, while NFB and GAS were respectively found in 52 and 16 group two patients. There was a statistically significant difference between McIsaac scores ≥3 and GAS presence in throat cultures (p < 0.05). CRP, WBC and total neutrophil counts were significantly higher in patients with throat cultures positive for GAS than in patients with GAS-negative throat cultures (p < 0.05).
Conclusions: The McIsaac scoring system is useful and informative for clinicians and will reduce unnecessary antibiotic use to treat acute tonsillitis.