Correlation of trismus with the progression of peritonsillar abscesses

Background: Trismus is a common clinical finding in peritonsillar abscess, but its value as a predictor of extension into deep neck spaces remains uncertain. Objective: To evaluate the usefulness of trismus as a clinical predictor of peritonsillar abscess extension. Material and methods: A retrospective study was conducted at Hospital Español de México. Medical records of patients diagnosed with peritonsillar abscess between 2020 and 2026 were reviewed. Trismus at initial presentation and deep neck space extension confirmed by contrast-enhanced computed tomography were recorded. Odds ratios (OR), sensitivity, specificity, predictive values, likelihood ratios, and χ² testing were calculated. Results: Forty-four patients with a mean age of 33 years were included. Trismus was present in 20 patients (45.4%), and deep neck space extension occurred in 12 (27.3%), involving the parapharyngeal space in all cases. Trismus showed a nonsignificant association with extension (OR: 2.05; 95% CI: 0.53-7.86; p = 0.39). Sensitivity was 58.3%, specificity 59.4%, positive predictive value 35% and negative predictive value 79.2%, with LR+ 1.44 y LR− 0.70. Conclusions: Trismus was not a reliable predictor of peritonsillar abscess extension into deep neck spaces. Contrast-enhanced computed tomography remains the reference standard for determining disease extent and guiding appropriate therapeutic management.