🧠 NEXUS-II Criteria for Head CT in Blunt Head Trauma

Purpose: To identify patients with blunt head trauma (GCS ≥13) who are at low risk for clinically significant intracranial injury (ICI) and may not require head CT.

A Head CT is recommended if ANY of the following are present: - Evidence of significant skull fracture (e.g., basilar signs, palpable step-off) - Scalp hematoma - Neurological deficit - Altered level of alertness - Abnormal behavior - Coagulopathy - Persistent vomiting - Age ≥ 65 years

Inclusion Criteria:

Blunt head trauma
GCS ≥ 13
Age ≥ 1 year
Stable vital signs

Performance:

Sensitivity: ~98–99% (excellent for ruling out significant injury)
Specificity: Low (many unnecessary scans avoided only if used judiciously)

📊 Comparison with Other Head CT Rules

Rule	GCS Range	Focus	Sensitivity	Specificity
NEXUS-II	≥13	Safety net, easy to apply	Very high	Low
CCHR	13–15	High-risk neurosurgical signs	High	Moderate
NOC	15	Symptom-based	Very high	Low

Clinical Tip: NEXUS-II is a broad and highly sensitive rule that helps rule out the need for CT in patients with no red flags. Especially valuable in busy EDs or resource-limited settings.