Intern Report 7.9

Case Presentation by Dr. David Viau, MD

CC: Motor Vehicle Crash

HPI:
A 27 y.o. hispanic female is brought into Marquette, MI ED (a rural emergency department) by EMS as a trauma code on a backboard with a c-collar. The patient was driving on US41 (a small two lane highway) during a blizzard at 60mph when she all of a sudden she lost control of her car. The vehicle was found in the ditch with the front end smashed in by a large tree. Airbags were deployed. The patient was found by EMS standing next to the SUV, leaning on it for support, barely able to hold herself up. She does not remember what happened or if she was wearing a seat belt. She is currently complaining of feeling cold, neck pain and interscapular pain.

ROS:
Constitutional: Denies fevers
ENT: Denies epistaxis
Cardiovascular: Denies palpitation
Respiratory: Denies shortness of breath
Gastrointestional: Denies vomiting
Genitourinary: Denies hematuria
Musculoskeletal: Denies joint swelling
Integumentary: Denies rash
Neurological: Denies seizures
Psychiatric: Denies auditory or visual hallucinations

PMH: Histoplasmosis (from harvesting bat guano in Mexican caves), typhoid fever
PSH: 1 caesarian section for placenta previa
Social Hx: Patient denies smoking cigarettes and illicit drug use. She admits to EtOH consumption. Denies drink today. Last menstrual cycle 5 weeks ago.
Family HX: Hypertension, dyslipidemia, type 2 diabetes and obesity
Meds: prenatal vitamins
Allergies: Seasonal, Sulfa

Physical Exam:
Temperature: 34, HR 90s, BP 160/90, RR16, Sat 98% on RA
Constitutional: non-obese female immobilized on backboard w/c-collar.
Head and Neck: diffuse tenderness to palpation of the cervical spine.  There are no step-offs or deformities.  There are no raccoon eyes or battle signs present.
Eyes: Pupils are 3 mm round reactive to light bilaterally.  There is a good consensual reaction to light.  No sign of trauma to the eyes.
ENT: There is no hemotympanum present.  No rhinorrhea or bleeding from the naris.  The tongue is not swollen. Patient has a hoarse/raspy voice.
Cardiovascular: There is a normal S1 and S2 without murmur present.  The patient has 2+ pulses in the radial arteries bilaterally. There are 1+ pulses in the femoral arteries bilaterally.
Respiratory: Lung sounds are present bilaterally with appropriate air movement.  There is no wheezing appreciated.
Gastrointestional: Abdomen is soft, nondistended and nontender to palpation.  There is no guarding or rigidity.
Genitourinary: There is no signs of vaginal bleeding.
Musculoskeletal: No obvious deformity is noted in the extremities. Patient has 5/5 muscle strength to in arm flexion and extension, leg flexion and extenstion, dorsiflexion and plantar flexion bilaterally. She can touch thumb to each ringer and is able to resist separation of thumb from fingers appropriately .
Integument: Patient has a small haemostatic laceration on her left cheek. There is a seatbelt sign across the patient’s chest.
Neurological: GCS of 15, Patient is able to stick out tongue and move to both sides.  Uvula is not deviated. Smile and forehead wrinkling is symmetric.  Patient is able to shrug shoulders against resistance.  Patient has sensation in the V1, V2 and V3 distribution of the trigeminal nerve.  Extraocular eye movements are intact.  Patient has normal finger to nose test and normal heel-to-shin test.  There is a negative Babinski bilaterally.

Fast Exam: Did not reveal any intraperitoneal fluid or cardiac tamponade.

CXR: Did not show any acute cardiopulmonary process as per radiology intern.

Labs:
labs

QUESTIONS:

1.  What is the most sensitive diagnostic modality currently available given this patient’s scenario?
a) CT  Abdomen scan w/contrast
b) Chest x-ray
c) ED thoracotomy
d) Transesophageal echocardiogram
e) CT Chest w/contrast
f) CT head w/without contrast

2.  What is the best management for the patient with their suspected injury?
a) Nitroglycerin
b) Esmolol
c) Amlodipine
d) Dyazide

3. The patient complains of diffuse cervical spine tenderness to palpation. What is the most sensitive modality to detecting an injury?
a) Obtain a complete cervical spine x-ray series plus obliques.
b) CT c-spine
c) Able to use nexus criteria to clear c-spine without imaging.
d) Cervical spine sonography

Answers & Discussion:

1) e
2) b
3) b

1. The patient has an aortic tear secondary to a deceleration injury. Clues to this include the intrascapular pain, hoarse voice (compression of laryngeal nerve and slight compression of trachea, sometimes tracheal deviation will be observed) and decreased femoral pulses. Often the patients are hypertensive secondary to stretching the afferent sympathetic fibers at the isthmus of the aorta that may cause reflex hypertension(Rosen’s p. 452).

Initial diagnostic testing is as simple as a (b) chest x-ray. The big clue is widening of the superior mediastinum (50-90% sensitivity, 10% specificity). However mediastinum widening is not present in everyone with a blunt aortic injury, 7-44% of patients have no mediastinal widening. This implies mediastinal widening should increase our worry of a possible deceleration injury, but can neither confirm or rule out it’s existence. (a) CT scan w/contrast have nearly 100% sensitivity and specificity and are often thought of as better than historical gold standards of Aortogram. It is recommended that all patients with significant mechanism of injury under go a CT scan regardless of findings in the CXR. (d)Transesophageal echocardiogram (TEE) also provides great diagnostic power with a sensitivity of 87-100% (variability secondary to operator skill) and specificity of 98-100%.  Often surgical intervention will be started with TEE results alone.  (c) ED thoracotomy is not indicated here.

CORRECT ANSWER is (e), CT scanner is the most sensitive way to evaluate patients for aortic deceleration injuries..  

2. Management of the aortic rupture includes basic ABCs in the ED. Not all tears lead to immediate exsanguination. Other injuries such as intracranial injury or intra-abdominal hemorrhage may take priority. Strict blood pressure control should be maintained at all time with goal systolic blood pressures ranging from 100-120 mmHg. The goal with the decreased blood pressure is to decrease shearing forces exerted on the aorta. This is done by decreasing the number of pulsatile loads (heart rate) and managing the blood pressure.  (b) Beta blockers are the drugs of choice. Often a short acting titratable Esmolol is used, but lebatolol can be is used too.

Definitive management is surgical intervention either by open technique or utilizing endovascular technique. Patients should have prompt repair of the tear to decrease risk of rupture. However repair can often be delayed if more life threatening circumstances are present.

CORRECT ANSWER is (b) esmolol. (a,c,d) do not decrease heart rate, hence the shear force is not decreased. Rosen’s p.454

7.9

(google image)

flow across the vessel wall creates a Force perpendicular to the direction of flow. If the aorta intima has a tear it is liable to rupture through the adventitial layers and hemorrhage. Each pulsatile cycle increases risk.

3. (c)Complete cervical spine x-ray series plus oblique views are able to recognize spinal injuries with high accuracy as long as all seven cervical vertebrae are adequately visualized. They fail to recognize injury in 0.07% of patients with injuries and 0.008% of patients with unstable spinal injury. (Rosen’s p.403). That being said adequate visualization of all 7 cervical vertebrae is not obtainable on up to 25% of patients. Obesity is a risk factor for inadequate visualization of all 7 vertebrae.  The question needs rework.  I would get cross table lateral and transfer.

Often EM physicians lean on the (b) CT cervical scan too much to clear a c-spine, especially if the patients body habitus lends to easy x-ray visualization of all cervical vertebrae. That being said CT scans are superior to x-rays in the 25% of patients that we are unable to get adequate visualization of all cervical vertebrae. The sensitivity for CT to detect fractures varies according to studies, but generally has a sensitivity around 99.3-100%.

Other considerations are cost CT $4386 verses x-rays $513 and radiation exposure CT 26 mSv verses 4 mSv.

(c) Not accurate. The patient has cervical tenderness. Nexus criteria can be employed only if patient is non-tender. (d) this answer makes no sense, ultrasound is not used to detect injuries to the cervical spine.

Correct answer is (b). CT scan is the most sensitive way to detect c-spine injuries. That being said complete cervical spine X-ray series are appropriate and sufficient in many patients. X-rays have the advantage of being cheaper, less radiation and readily available. That being said there is 25% of the patient population who do not have adequate visualization of the cervical spine. These patients often being obese

References:
Rosen’s Emergency Medicine 8th edition.
Google image search for blood vessel image

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