Page 24 - Journal of Special Operations Medicine - Fall 2017

and performed an abbreviated physical examination, which Table 2 Differential Diagnosis in Suspected Acute Ischemic Stroke
revealed truncal ataxia. The flight paramedic then enlisted the Migraine/cluster headache
help of another Soldier to call the unit’s flight surgeon. Via Intracranial hemorrhage, subarachnoid hemorrhage, subdural
telephone, the patient reported similar symptoms, but addi- hematoma
tionally reported left-sided facial numbness, lacrimation, and Bell’s palsy
left arm sensory deficits. The flight surgeon recommended the Transient ischemic attack
patient go to the aid station, which was in the basement of the Meningitis
patient’s barracks. The flight paramedic assisted the patient to
the aid station. Carotid artery dissection
Vertebral artery dissection
Once in the aid station, the flight paramedic again obtained
the patient’s vital signs, which revealed marked tachycardia Therefore, several sources focus on early detection, expedi-
and acute hypertension (Table 1). Although a handheld rapid tious ambulance dispatching, and supportive care, rather than
blood analyzer was available, its software was out of date; medical management. In most sources, antiplatelet therapy
4,5
therefore, essential initial measurements like glucose were un- is not recommended until the patient has reached the hospi-
attainable. Physical examination revealed ptosis, miosis, and tal and been evaluated by a physician. Other sources actively
numbness along the left side of the face in the distribution discourage ASA administration by paramedics. Ward et al.
6
of the CN VII (facial nerve). The electrocardiogram revealed gave two reasons for discouraging paramedic administration
sinus tachycardia. of ASA for suspected AIS: first, the difficulty of ruling out
intracerebral hemorrhage (ICH) on clinical grounds makes
The differential diagnosis (Table 2) at this point was ICH, potential harm to the patient a possibility; second, dyspha-
SAH, carotid artery dissection, vertebral artery dissection, gia secondary to stroke is also a potential risk (though rectal
AIS, transient ischemic attack, and cluster headache with neu- administration is a possibility). Ward et al. concluded that
6
rologic symptoms. Considering a recent case at the local hos- a short delay in therapy will likely not result in harm to the
pital in which specialists would not see urgent or emergent patient; however, this conclusion assumes that the patient
patients on weekends and holidays (this was now early Satur- reaches a hospital within 1 hour.
day morning), the flight surgeon administered aspirin (ASA)
325mg orally. The Soldier’s neurologic symptoms abated Because of the time-sensitive nature of AIS, American Heart
within 30 minutes of ASA administration. An ambulance ar- Association/American Stroke Association (AHA/ASA) guide-
rived and took the patient to the closest hospital. A CT scan lines for therapy are understandably temporally correlated.
7
showed no hemorrhage. The patient was then transferred to a Definitive medical treatment of AIS is centered on antifibri-
hospital with higher level of care. nolytic therapy (specifically, recombinant tissue-plasminogen
activator [rt-PA]). The AHA/ASA currently recommends rt-
He received routine screening laboratory tests, a lumbar punc- PA therapy within 4.5 hours of onset of AIS. This intervention
ture, and plain film radiograph of the cervical spine. The lum- improves outcomes measured at 3 months after stroke occur-
bar puncture revealed a slight increase in lymphocytes and rence. Endovascular therapy with stent retrievers is recom-
normal glucose and protein levels. The Soldier underwent mended it the patient meets the following criteria: prestroke
intravenous acyclovir therapy until the culture eventually re- modified Rankin scale score, 0 to 1; receipt of IV rt-PA within
turned negative for infectious pathogens. No neurologist or 4.5 hours of AIS onset; occlusion of the internal carotid or
internal medicine staff rounded on the patient on Saturday or proximal middle cerebral artery; age greater than 18 years;
Sunday. The patient underwent MRI early Monday morning National Institutes of Health Stroke Scale score of greater
after the staff neurologist made his rounds. The MRI revealed than or equal to 6; Alberta stroke program early CT score
a large, right-side, posterior-inferior cerebellar artery stroke. greater than or equal to 6; and treatment can begin within
The flight surgeon insisted that the patient be transferred to 6 hours of stroke onset. Signs, symptoms, and treatment
Landstuhl Regional Medical Center (LRMC). On Tuesday, for reperfusion injury were not mentioned in the AHA/ASA
the patient arrived at LRMC and was evaluated by cardiol- guidelines. 7
ogy and neurology. The patient eventually was prescribed a
statin, ASA, and an angiotensin-converting enzyme inhibitor. The 2013 AHA guidelines recommend ASA therapy in the
The Soldier is currently without sequelae or symptoms and first 24 to 48 hours of suspected stroke, because of a small
will hopefully return to aviation duties. but statistically significant decrease in mortality and recurrent
stroke. A large study that combined the findings of the In-
4
ternational Stroke Trial and Chinese Acute Stroke Trial con-
Discussion
cluded that significant benefits of early ASA administration
Prehospital management of suspected AIS is often initiated by (within the first 24 to 48 hours of stroke symptoms) include
emergency medical services personnel or nonmedical citizens. decreased morbidity and mortality without harm to patients. 8
Table 1 Patient’s Prehospital Vital Signs
Blood Pressure, Respiratory Rate
Location Heart Rate, bpm mmHg Temperature, °F per Minute Oxygen Saturation, %
Patient’s room 80 Palpable pulse — — —
Aid station 124 168/112 99.3 20 97
Before entering
ambulance 108 156/98 98.9 22 98
—, no data; bpm, beats per minute.

22 | JSOM Volume 17, Edition 3/Fall 2017