RESEARCH MANUSCRIPT FINAL

8/7/2019 RESEARCH MANUSCRIPT FINAL

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INDICATIONS FOR COMPUTED TOMOGRAPHY IN

EVALUATING MINOR HEAD TRAUMA PATIENTS

OF QUIRINO MEMORIAL MEDICAL CENTER:

A PROSPECTIVE STUDY

Submitted by

MARIA THERESA M. NAVARRO, MD.Quirino Memorial Medical Center

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INDICATIONS FOR COMPUTED TOMOGRAPHY IN EVALUATING MINOR HEADTRAUMA PATIENTS OF QUIRINO MEMORIAL MEDICAL CENTER:

A PROSPECTIVE STUDY

ABSTRACT

Purpose: This study aims to identify the clinical criteria that can be used as indicationsin performing cranial CT scans in minor head trauma patients.

Materials and Methodology: A purposive sampling technique was utilized in obtainingthe population, with the following inclusion criteria: 1) male and female minor headtrauma patients, ages 1 to >60 years old, brought to the emergency room, 2) time framebetween injury to consult at ER is within 24 hours; and 3) these minor head trauma

patients who underwent cranial CT scans. Patients with Glasgow coma scale of 13-15,with normal findings on a brief neurologic examination were classified to have minorhead trauma. Positive and negative CT scans were determined. Positive scansidentified as those having one or more of the following abnormal findings: subduralhematoma, epidural hematoma, parenchymal hematoma, subarachnoid hemorrhage,cerebral contusion, and skull fracture. Other abnormal findings such as scalp hematoma/ soft tissue swelling, and probable intrasinus hemorrhage, but with normal brain wereclassified under negative CT scans. Clinical findings were also enumerated. Data wasgathered using checklist forms and official CT scan results.

Results: For a period of 10 months (January 2008 to October 2008), a total of ninety six(96 ) patients, ages 1 to 83 years old, who were seen at the emergency surgery unit of

Quirino Memorial Medical Center were included in the study. Of the 96 patients, 38(39.6%) had positive cranial CT scans and 58 (60.4%) had negative cranial CT scans.The sensitivity and specificity of having at least one of the criteria set by NOC predictingthe presence of a clinically significant abnormal cranial CT scans were 94.7% and32.7%, respectively.

Conclusion: The clinical findings set by NOC can be used as indications for doingcranial CT scan in minor head trauma patients, and CT scan may not be done if all ofthese clinical findings are absent.

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INTRODUCTION

CT scanning of the head is the criterion standard for patients with acute

closed head injuries, and it is warranted, except for patients with only minor head trauma

who are neurologically intact and not intoxicated with drugs or alcohol.1 It has several

advantages such as: 1) it is noninvasive and rapid ; 2) very sensitive for acute

hemorrhage; 3) defines the nature of intracerebral hemorrhage ; 4) defines anatomical

location; and 5) identify the presence of fractures.

Osterwell says that doing a CT or not is the main concern of clinicians

when a patient with minor head injury comes in the emergency room 2. If we dont scan

there might be a risk of missing an intracranial bleed. If we scan all of these patients,

one will spent too much time and money chasing after too few serious cases. Hence,

inefficient use of the CT scan adds significantly to healthcare costs and burden to the

patients. Since Quirino Memorial Medical Center is a government hospital, most of its

patients are indigents or belong to the low income earners. CT scanning will be costly

for this group of people, who are most likely unable to pay the full amount of the

procedure, or at least the discounted price. Because of these, efficient use of CT in

evaluating minor head trauma patients should be done. It will also save time and effort

for the clinicians in the immediate management of their patients.

To help the clinicians in identifying patients who are at risk of developing

intracranial damage following minor head injuries, many researchers tried to develop

clinical decision rules, and the two most well studied and validated decision rules are: 1)

the New Orleans Criteria (NOC)3,4,5, wherein minor head injury is defined as loss of

consciousness after head trauma with normal neurologic examination and Glasgow

Coma Scale (GCS) score of 15, and 2) Canadian CT Head Rule (CCHR)6, with minor

head injury defined as GCS score of 13 to 15, loss of consciousness, definite amnesia,

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or witnessed disorientation from trauma. These two clinical decision rules have been

compared and results showed that NOC and CCHR appear equally sensitive in

predicting the need for neurosurgical intervention following minor head injury 7. For

patients with minor head injury and GCS score of 13 to 15, the CCHR has a lower

sensitivity than NOC for neurocranial traumatic CT findings, but it would identify all cases

requiring neurological intervention. CCHR can significantly reduce CT use, however,

studies have shown that some clinical findings which the rule consider unimportant

underwent neurosurgical intervention or had poor neurologic outcomes2.

This study then aims to identify the clinical criteria that can be used as

indications in performing cranial CT scans in minor head trauma patients of Quirino

Memorial Medical Center. Specifically, it aims to:

1. to determine the sensitivity and specificity of the clinical criteria set by the NOC in

predicting clinically significant cranial CT scans of minor head trauma patients;

2. to describe the profile of minor head trauma patients who fulfilled the set criteria;

3. to identify the cranial CT findings of minor head trauma patients encountered in

Quirino Memorial Medical.

MATERIALS AND METHODOLOGY

The research design is a prospective study using the descriptive survey

method conducted from January 2008 to October 2008 at the emergency room of

Quirino Memorial Medical Center.

A purposive sampling technique was utilized in obtaining the population, with

the following inclusion criteria: 1) male and female minor head trauma patients, ages 1

to >60 years old, brought to the emergency room, 2) time frame between injury to

consult at ER is within 24 hours; and 3) these minor head trauma patients who

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underwent cranial CT scans. Patients with Glasgow coma scale of 13-15, with normal

findings on a brief neurologic examination were classified to have minor head trauma.

Patients with onset of injury more than 24 hours before seen at the emergency room,

patients with co morbidity ( i.e. stroke, diabetes mellitus, etc), and with GCS score of


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RESULTS

For a period of 10 months (January 2008 to October 2008), ninety six

(96 ) patients, ages 1 to 83 years old, who were seen at the emergency surgery unit of

Quirino Memorial Medical, were included in the study. Among the 96 minor head trauma

patients, 66.7% are male, and 33.3% are female ( see Table 1). The overall most

common cause of head injury is vehicular accident (51%) and for each group of patients,

vehicular accident is the most common cause in adults (67.4%), while fall (62.8%) is the

most common cause for pediatric patients, especially in the lower age group.

Table 1. Characteristics of Minor Head Trauma Patients Seen At The ER of QMMC

AGE inyears

SEX NATURE OF TRAUMA

M F TotalVehicularaccident

Mauling Fall

1 1821

(21.8%)

22

(22.9%)

43

(44.8%)

14

(32.5%)

2

(4.6 %)

27

(62.8%)

19-5940

(41.8%)

6

(6.3%)

46

(47.9%)

31

(67.4%)

7

( 15.2% )

8

(17.4%)

>603

(3.1 %)

4

(4.2 %)

7

(7.2%)

4

(57.1%)

0

(0%)

3

(42.8)

Overall64

(66.7%)

32

(33.3%)N = 96

49

(51%)

9

( 9.4%)

38

(39.6%)

Table 2 shows the following pertinent clinical findings and risk factors which are as

follows: alcohol intake, headache, vomiting, posttraumatic seizure, visible trauma above

clavicles, short-term memory loss, and age above 60 years old. The top three clinical

findings which resulted to a positive CT scan result were headache (15.8 %), vomiting

(31.6%), and presence of visible trauma above the clavicles (55.3%).

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Table 2 Clinical Findings and CT Results of Minor Head TraumaPatients at the ER of QMMC

FindingsTotal (n=96);

no (%)

Positive CTScan (n=38); no

(%)

Negative CTScan (n=58); no

(%)Likelihood Ratio

Alcohol

Intake2 (2) 0 2 (3.4) 0

Headache 14 (14.6) 6 (15.8) 8 (13.8) 1.1

Vomiting 31 (32.3) 12 (31.6) 19 (32.7) 0.96

Seizure 1 (1) 0 1 (1.7) 0

VisibleTraumaAbove

Clavicles

43 (44.8) 21 (55.3) 22 (37.9) 1.4

Short-termMemory

Loss3 (3) 1 (2.6) 2 (3.4) 0.76

Age > 60

years7 (7.3) 2 (5.3) 5 (8.6) 0.61

Figure 1 describes the positive CT findings of the patients and results

show that skull fracture (21.9%) is the most common. Other positive findings are :

intrasinus hemorrhage(20.3%), scalp hematoma/ subgaleal hematoma(17.2%), subdural

hemorrhage(6.2%), subarachnoid hemorrhage(2.3%), hemorrhagic contusion or

parenchymal contusion(3.9%), non-hemorrhagic contusion (3.1%), epidural

hemorrhage(0.7%),and pneumocephalus (0.7%). For findings considered as negative,

30 (23.4%) patients were found to have normal examination, i.e. brain is normal with no

evidence of soft tissue swelling, 26 (20.3%) had haziness of the sinuses, which were

signed out as either secondary to sinusitis and/or hemorrhage but with normal brain, and

22 (17.2%) had soft tissue swelling of the scalp, but with normal brain, signed out as

scalp hematoma, or subgaleal hematoma.

Figure 1. Cranial CT Findings of Minor Head Trauma Patients SeenAt The ER of QMMC *

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0

5

10

15

20

25

30

CT Findings

Normal

Intrasinus hemorrhage

vs. SinusitisScalp hematoma /

subgaleal hematomaSkull Fracture

Subarachnoid

hemorrhageHemorrhagic contusion

/ Parechymal contusionSubdural hemorrhage

Epidural hematoma

Pneumocephalus

Nonhemorrhagic

Contusion

* Some of the patients had at least one of the above cranial CT findings

Seventy-five patients (75) had pertinent clinical findings/risk factors, 36

had positive CT scan results, and 39 had negative CT scan results. Twenty one (21)

patients did not have any of the clinical findings/risk factors, but 2 presented with a

positive CT scan, and 19 presented with negative CT scans ( Table 3). The values for

sensitivity, and specificity of the criteria for patients with GCS 13-15, were 94.7% (95%

CI 81% - 99% and 32.7% (95% CI 21% - 46%), respectively, with the probability that the

absence of any of the clinical findings will result to a negative CT scan (negative

predictive value) of 90.4%.

Table 3. Association Between The Nine Clinical Findings and CT Results In 96Patients With Minor Head Injury

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Positive Cranial CTScans

Negative Cranial CTScans

Total

With Clinical Findings 36 39 75

Without ClinicalFindings

2 19 21

Total 38 58 96

DISCUSSION

In an attempt to minimize the unnecessary use of cranial CT scans in

minor head trauma patients, several sets of criteria were developed and two of the most

studied head rules are the Canadian CT Head Rule (CCHR) and New Orleans Criteria

(NOC). NOC uses the following criteria4: short-term memory loss, drug or alcohol

intoxication, physical evidence of trauma above the clavicles, age more than 60 years

old, seizure, headache, and vomiting while CCHR uses the following criteria6: basal skull

fracture, two or more episodes of vomiting, age 65 years or older, more than 30 minutes

of amnesia of events prior to the injury, GCS score less than 15 at two hours or more

after injury, suspected open or depressed skull fracture, and dangerous mechanism.

These studies were compared, and results showed that both have 100% sensitivity, with

CCHR having a higher specificity than NOC (50.6% vs. 12.7%; p < .001) 7,8. Also, since

CCHR has a tendency to disregard some clinical findings which can be significantly

important and miss intracranial injuries, the researcher decided to apply NOC instead to

its set of population but with the inclusion of patients with GCS 13-15.

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Table 2 showed that head trauma is more common in males than in

females especially in the adult group (19-59 years old) and vehicular accident is the

most common cause of head trauma. For the pediatric age group, fall is the most

common cause of trauma. These findings were likewise shown by Bordignon and

Arruda when they described the CT findings of 2,000 cases of mild head trauma patients

in Southern Brazil 9. Vehicular accident is also the leading cause of head trauma in youth

and middle age people according to a research done in Taiwan 10. Moreover, although it

is not well documented, motorcycle accidents were mostly the type of vehicular accident

that QMMC encountered at the ER.

Compared with the study done by Haydel et al, wherein short-term

memory loss, drug or alcohol intoxication, and physical evidence of trauma above

clavicles were significantly associated with positive CT scan results, the present study

showed that headache, vomiting, and visible trauma above the clavicles were noted to

be significantly associated, with likelihood ratios of 1.1, 0.96, and 1.4 respectively.

Difference in findings maybe attributed to the difference in the type and nature of trauma

experienced by the patients or the difference in size of samples. However, vomiting was

also one of the major clinical findings / risk factor in another study11.

For the lesion types, findings of skull fracture as the most common

clinically significant abnormal finding, requiring neurosurgical follow-up or referral are

comparable to the other series of studies that described CT findings in mild head

trauma.9, 12 Nine out of 19 patients who had intracranial hematomas (47.3%) were noted

to have associated skull fractures. In Stein and Ross study, 7 out of 11 (63.6%) cases

of intracranial hematoma have skull fractures13. In the study of Bordignon and Arruda 9

only one case of intracranial hematoma was associated with skull fracture.

The sensitivity and specificity of the clinical findings set be NOC and

CCHR in determining positive cranial CT were 94.7% and 32.7%, respectively, close to

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the values of CCHR and NOC 5. Results should have shown that those patients who did

not have any of the clinical criteria should also have a negative CT scan. However, in

our study, 2 of the patients who did not have any of the clinical findings and with

Glasgow coma scale of 15 had significant positive CT findings (fracture, and non-

hemorrhagic contusion). For this case, the clinician might have missed or failed to report

pertinent data and thus created a discrepancy in our results. However, despite of this

the author may confidently conclude that the criteria set by NOC can be used as

indications for doing cranial CT scan in minor head trauma patients, and CT scan may

not be done if all of these criteria are absent. Other studies made by Khan14, and

Saboori15 also derived at the same conclusion.

As observed, two major limitations were identified: 1) the population or

sample under observation is relatively low such that determining the sensitivity and

specificity of NOC and CCHR separately cannot be done; and 2) as mentioned, since

there was a discrepancy in the clinical findings and CT scan result, there is a great

possibility of inaccurate data reporting. Hence, the following recommendations were

derived: 1) research regarding the external validation of other CT rules, such as the

recently developed CT in Head Injury Patients (CHIP)16, maybe done in the future, but

the author suggests a longer time frame, or participation of other hospitals could be done

to gather enough sample size; 2) strict compliance in the proper filling-up of forms by

the clinicians and the researcher must make sure that proper physical examination has

been done to maintain accuracy of findings. 3) and lastly, although it is not included in

the scope of this study, detailed account of the type of trauma maybe done in order to

correlate it with the clinical and CT findings.

REFERENCES

1 Rangel-Castillo, Leonardo. Closed head trauma: Differential Diagnoses and Work-up.

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eMedicine. Feb. 2008.

2 Osterwell, Neil. Criteria for head injury CTs go head to head. Medpage Today. September28, 2005

3 Haydel MJ. Clinical decision instruments for CT scanning in minor head injury. JAMA2005; 294: 1551-3.

4 Haydel MJ, Hoff JR, Herbert M, et al. Indications for computed tomography in patients withminor head injury. N Engl J Med. 2000; 343: 100-5

5 Kirchner JT. Use of CT scan in assessing minor head trauma. American FamilyPhysician. 2001; 63(1).

6 Steill IG, Wells GA, Vandemheen K, et al. The Canadian CT Head Rule for patients withminor head injury. Lancet2001; 357:1391-96.

7 Steill IG, Clement CM, Rowe BH, et al. Comparison of the Canadian CT Head Rule andNew Orleans Criteria in patients with minor head injury. JAMA 2005; 394: 1511-8.

8 Ebell MH. Computed tomography after minor head injury. American Family Physician.June 15, 2006.

9 Bordignon KC, Arruda WO. CT scan findings in mild head trauma. Arq Neuro-Psiquiatr.2002; 60(20

10 Lee ST, Lui TN, Chang CN, et al. Features of head injury in a developing country Taiwan(1977-1987). J Trauma. 1990; 30:194-199.

11 Latip A, Alias A., and Ariff AR, et al. CT scan in minor head injury: a guide for ruraldoctors. Journal of Clinical Neuroscience. 2004; 11(8):835-839.

12 Schackford SR, Wald SL, Ross SE, et al. The clinical utility of computed tomographic

scanning and neurologic examination in the management of patients with minor headinjuries. J Trauma. 1992; 33:385-394.

13 Stein SC, Ross SE. Mild head injury: plea for routine early CT scanning. J Trauma. 1992;33: 11-13.

14 Khan SF, Nazir R. Indications for computed tomography in patients with minor head injury.Pak J Radiol. 2001; 12(4): 2-9.

15 Saboori M, Ahmadi J, et al. Indications for brain CT scan in patients with minor headinjury. Clin Neurol Neurosurgery. 2007; 109(%): 399-405

16 Smits M, Dippel DWJ, Steyerberg EW, et al. Predicting intracranial findings on computed

tomography in patients with minor head injury: The CHIP Prediction Rule. Ann Intern Med.2007; 146:397-405

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