Immediate Head CT Without Contrast is Indicated
This patient requires an immediate non-contrast head CT scan based on validated clinical decision rules for mild traumatic brain injury. 1, 2
Clinical Assessment Framework
This Patient Meets High-Risk Criteria for Imaging
The patient presents with mild traumatic brain injury (GCS 15) after blunt head trauma from a 5-kg object. According to the Canadian CT Head Rule (CCHR), she meets medium-risk criteria requiring CT imaging 1:
- Vomiting (nausea with potential for vomiting)
- Mechanism of injury (5-kg object to head constitutes significant force)
- Persistent headache with associated symptoms
The New Orleans Criteria (NOC) would also support imaging given the mechanism and symptoms 1.
Why CT is Mandatory Here
Head CT without contrast is the only appropriate initial imaging modality for acute head trauma 2. The sensitivity approaches 100% for detecting neurosurgically significant injuries, and multiplanar reformatted images should be included 2.
- MRI, skull radiographs, and other modalities have no role in initial acute head trauma evaluation 2
- CT identifies hemorrhage, herniation, hydrocephalus, and skull fractures that require intervention
- Only 10% of mild TBI cases show positive CT findings, but 1% require neurosurgical intervention 2
Management Algorithm
1. Immediate Actions
- Order non-contrast head CT with multiplanar reformats 2
- Maintain NPO status until imaging complete
- Serial neurologic examinations every 1-2 hours
- Monitor for deterioration: altered mental status, focal deficits, worsening headache, repeated vomiting
2. If CT is Negative
- Safe for discharge if neurologic examination remains normal (negative predictive value 100% for deterioration requiring surgery) 2
- No observation period or repeat imaging needed in this non-anticoagulated patient 1
- Provide head injury discharge instructions
- Return precautions: worsening headache, vomiting, confusion, weakness, seizures
3. If CT Shows Traumatic Findings
- Neurosurgical consultation
- Hospital admission for observation
- Reclassify as "complicated" mild TBI with worse functional prognosis 2
Critical Pitfalls to Avoid
The Hypothyroidism is Irrelevant to Acute Management
Do not delay imaging or alter acute trauma management based on her hypothyroidism. 3 While hypothyroidism can cause headaches (30-34% prevalence) 4, 5, these are:
- Nonpulsatile, bilateral, continuous, mild headaches 4
- Not associated with trauma, nausea, or phonophobia
- Responsive to thyroid hormone therapy over weeks 5
This patient's presentation is entirely explained by acute head trauma, not her well-controlled hypothyroidism on levothyroxine 50 mcg.
Do Not Confuse This with Anticoagulation Cases
This patient is NOT on anticoagulants or antiplatelet agents (other than potentially aspirin, which wasn't mentioned). The extensive discussion in guidelines about repeat imaging and observation periods applies only to anticoagulated patients 1.
- Anticoagulated patients have 3.9% risk of intracranial hemorrhage vs 1.5% in non-anticoagulated patients 1
- They require consideration of repeat imaging at 4-6 hours
- This patient requires only single CT if negative with normal exam
Vital Signs Are Reassuring But Don't Exclude Injury
- SpO2 98%, pulse 82, BP 130/90, temp 37.5°C are all stable
- Stable vitals do NOT exclude intracranial injury in mild TBI
- The mechanism (5-kg object) and symptoms mandate imaging regardless
Disposition Planning
If CT negative and exam normal: Discharge home with reliable adult supervision for 24 hours, written head injury instructions, and primary care follow-up in 3-5 days.
Continue levothyroxine 50 mcg daily without interruption 3. No adjustment needed for this acute event.