Patient Presents With Sore Throat
Common complaint, mostly self-limited, occasionally bacterial.
- ~12M: Annual US visits (primary care encounters/yr)
- 85–90%: Viral cause share (of all sore throat cases)
- 5–15%: Group A strep share (bacterial cases, adults)
- 5–15 yrs: Peak strep age (school-age incidence peak)
Why differentiate viral from bacterial
Guides testing, antibiotic use, and complication risk.
Typical presentation
Sore throat, odynophagia, variable fever and malaise.
Symptom Checklist — Six Clinical Signs
Toggle signs on or off to update the model live.
- 4: Centor criteria items (classic prediction rule)
- ~50–60%: Exudate sensitivity (for GAS pharyngitis)
- 3: Viral coryza signs tracked (cough, rhinorrhea, conjunctivitis)
- +1 pt: Node tenderness weight (bacterial-favoring feature)
Viral-favoring signs
Cough, rhinorrhea, conjunctivitis suggest a viral cause.
Bacterial-favoring signs
Exudate, tender nodes, fever without cough suggest strep.
Weighted Differential Score Computed Live
Each active sign adds one weighted point to its side.
- 0–6: Score range (total weighted points)
- +1: Weight per sign (each feature, either category)
- Instant: Recalculation (on every toggle change)
- Visual only: Severity influence (does not change the score)
Weighted scoring model
Each toggled sign adds one point to its category.
Live recalculation
Score updates instantly as signs are toggled.
Likely Etiology — Viral, Bacterial, or Indeterminate
Lean percentage sorts the case into three bands.
- ≥65%: Viral-leaning cutoff (lean toward viral)
- ≤35%: Bacterial-leaning cutoff (lean toward bacterial)
- 35–65%: Indeterminate band (needs further testing)
- ~85–90%: RADT sensitivity (rapid antigen detection test)
Classification bands
Viral-leaning, bacterial-leaning, or indeterminate by lean percent.
Clinical correlation
Etiology estimate still needs confirmatory testing.
Management Implication — Supportive Care vs Antibiotics
Viral gets rest and fluids; bacterial gets testing.
- 10 days: Antibiotic course (penicillin/amoxicillin standard)
- ~4000: NNT for rheumatic fever (number needed to treat)
- 5–7 days: Supportive care duration (typical viral course)
- ~60%: Overtreatment estimate (sore throats given antibiotics needlessly)
Viral management
Supportive care only — fluids, rest, analgesia.
Bacterial management
Consider rapid strep testing, then targeted antibiotics.