to CT or not CT?: Canadian CT Head Rule & New Orleans Criteria

CT or NOT?

--Papa et al. study looked at both decision rules (link below)

--314 patients (73%) had a GCS of 15

--22 of the 314 (7%) had evidence of a traumatic intracranial lesion on CT

--3 of 314 (1.0%) required neurosurgical intervention

NEW ORLEANS CRITERIA (if ANY of these are true, then do a CT ):

• headache
• vomiting
• age > 60 years
• drug or alcohol intoxication
• deficits in short-term memory
• evidence of trauma above the clavicles
• seizure

CANADIAN CT HEAD RULES (if ANY of these are true, then do a CT):

• GCS < 13
• failure to reach GCS of 15 within 2 h
• suspected open skull fracture
• any sign of basal skull fracture
• vomiting >2 episodes
• age >65 years
• amnesia before impact >30 min 
• dangerous mechanism of injury (pedestrian struck by car, ejection from MVC, fall > 3 feet or > 5 stairs)

--NOC and CCHR both had 100% sensitivity (95% confidence interval [CI] = 82% to 100%)

--CCHR was more specific (36.3% specificity) for detecting any traumatic intracranial lesion on CT vs. NOC (10.2% specificity)

Reference(s): study; mdcalc: canadian; mdcalc: new orleans; picture

decision rule for subarachnoid hemorrhage?

THOSE CANADIANS ARE AT IT AGAIN:
--study by Ottawa docs, Perry et al. reviewed nicely in an AAEM/Common Sense article (see reference)
--tried to identify a set of clinical characteristics to make a decision rule for those who need SAH workup


BASIC STRUCTURE:
--1,999 patients, 130 diagnosed with SAH
--SAH diagnosis defined by +CT, xanthrochromia, or >5 x 10^6/L RBCs + aneurysm/AVM on cerebral angiography

--included:

• adults (>16 yo)
• chief complaint = headache
• GCS 15
• non-traumatic
• peak intensity of HA within 1 hr

--excluded:

• >2 wks after symptom onset
• prior SAH
• previous CT and/or LP workup
• 3 similar HA's within past six months
• papilledema/focal neuro symptom
• prior hydrocephalus or cerebral neoplasm

RULES THEY CAME UP WITH:
--all have sensitivity 100%, but specificity sucked (28-39%)

--the rules (each set works to help rule-out SAH):

• age >40, neck pain/stiffness, witnessed LOC, DBP > 100mmHg
• arrival by EMS, age>45, vomiting, DBP > 100
• arrival by EMS, age 45-55, neck pain/stiffness, SBP > 160

BOTTOM LINE:
--nice study, helps think about why we do what we do, but isolated population
--the extra H&P details (age, BP, vomiting, neck pain/stiffness, etc.) are not very specific for SAH, but together might be sensitive (reminds me of appendicitis)
--not ready for primetime just yet, but food for thought


Submitted by S. Lee.


Reference(s): AAEM/RSA review, picture

cervical radiculopathy

LIKELY CULPRITS:

--Disc herniation accounts for 20-25% of young pt’s cervical radiculopathy

--foraminal narrowing is the most common cause of elderly pt’s symptoms. 

--Risk factors are manual labor, smoking, and driving/operating vibrating equipment.

MRI IN ED? 

--As in lumbar radiculopathy, MRI is the appropriate test but should be limited to those symptomatic after 4-6 weeks of nonsurgical treatment given high frequency of abnormalities detected in asymptomatic adults.


Submitted by T. Boyd.

Reference(s): Carette et al. Cervical Radiculopathy. NEJM. 2005; 353:392-399. Malanga et al. Cervical Radiulopathy. Emedicine. picture

spinal epidural abscess: how good is our H&P?

Spinal epidural abscesses have variable presentations with:

• 70-90% having back pain
• (only) 60-70% having fever
• 33% having point tenderness to palpation
• 71% have an abnormal neuro exam
• 94% of these patients have an elevated ESR

IMAGING:
--MRI spine
--CT myelogram


BOTTOM LINE:
--symptoms for epidural abscess include fever, spine tenderness, back pain
--unfortunately, less patients show up with these than you'd think (or like to think)
--MRI or CT myelogram if suspicious
--good luck


Submitted by T. Boyd.

Reference(s): Tompkins et al. Spinal Epidural Abscess. J Emerg Med. 39:3; 2010.; picture

How to tell a traumatic tap vs. SAH

QUICK REVIEW:

--There is no criteria for how many RBCs in the CSF are needed to diagnose SAH

--One of the best methods to distinguish traumatic tap vs SAH is by looking for xanthochromia

--Can measure xanthochromia by visual inspection (subjective, human error) OR spectrophotometry (very sensitive but not very specific, not widely available at most hospitals)

--Occurs via breakdown of Hgb -> oxyhemoglobin (pink-orange, can happen in vitro) -> bilirubin (yellow, only happens in vivo)

PEARLS:

--False positive xanthochromia can occur from jaundice (usually total serum bili of at least 10-15 mg/dL), rifampin, high CSF protein concentration (>150 mg/dL), or excess carotenoid intake

--Oxyhemoglobin can be present in traumatic tap and appear faintly yellow

--Formation of bilirubin takes time, but after 12 hrs from onset of aneurysm rupture (i.e. “worst HA of my life”), CSF should show xanthochromia in patients with SAH

--Elevated opening pressure (> 20 cm H2O) + bloody CSF strongly suggests SAH

--When all else fails, you may repeat the LP at a higher interspace

Submitted by F. DiFranco.

Reference(s): Shah, K.H., & Edlow, J.A. Distinguishing traumatic lumbar puncture from true subarachnoid hemorrhage. The Journal of Emergency Medicine. 23(1), 67-74, 2002. picture

blood pressure control guidelines (head bleed, dissection, AAA)

RAGING HYPOTHETICAL:

--you have a patient with a vessel somewhere that has either ruptured or is about to

--you call the appropriate surgeon, who is on the way, but in the meantime, what can you do?

MINIMIZE THE DAMAGE:

ICH:

--lowering to SBP 140-160 probably safe

--theory: less/slower hematoma growth

--options: nicardipine (less cerebral vasospasm)

AORTIC DISSECTION:

--SBP 100-120, HR <60

--theory: reduce shear forces

--options: beta blocker (labetolol push, esmolol drip), nitroprusside

RUPTURED AAA:

--goal SBP 80-100

--theory: permissive hypotension; bleed slower, less likely to blow out the few clots they're making

Reference(s): uptodate.com: Ruptured abdominal aortic aneurysm, management of aortic dissection, Spontaneous intracerebral hemorrhage: Prognosis and treatment, Kodama K, et al. Tight heart rate control reduces secondary adverse events in patients with type B acute aortic dissection, picture