A Different Kind of Stroke

By Christopher W. Root, MD, NRP; Emily Pearce, MD; Benjamin Rubin, NRP; and Kimberly Pruett, MD

Case: You are dispatched to an acute stroke call. Male, 55 years of age, with right lower extremity numbness.

En route, you and your partner review the Los Angeles Motor Scale (LAMS) assessment and discuss indications for transport to a primary vs. a comprehensive stroke center.

On Scene: You find the patient seated on the couch in his living room with the lights off. He is awake and alert, maintaining his airway, slightly tachypneic but without respiratory distress, he appears anxious and uncomfortable.

Vitals: BP 154/92, HR 107, RR 22, O2 saturation 98% on room air, and ETCO2 44.

History: The patient reports his right leg has become progressively numb and painful throughout the course of the day. The pain is constant, throbbing, 10/10 and it does not radiate anywhere. He took Tylenol and ibuprofen with no relief. The pain is worse when bearing weight. He has a history of hypertension but is not currently prescribed any medications; he also has a 25 pack-year smoking history. He reports that he was evaluated for a “mini-stroke” 2 weeks ago at the local university hospital, but he left before his workup was completed and was not started on any new medications. He has no known drug allergies, no prior surgeries.

Physical Exam: You note clear lung sounds, normal heart sounds, and palpable bilateral radial pulses. The patient’s face is symmetrical. There is no pronator drift. His speech is not slurred and his grip strength is equal. You assess his lower extremities and notice the right leg feels cooler than the left. He is able to move the left leg normally but he has pain with any attempts to move his right leg. His right leg is also significantly weaker than the left when he attempts to flex at the thigh or extend at the knee. You are able to palpate dorsalis pedis and posterior tibialis pulses in the left foot but cannot palpate either pulse in the right foot. With the light on in the room you note the right leg looks pale and slightly mottled compared to the left. Capillary refill in the right leg is greater than 10 seconds. The patient has pain with even light pressure applied through the right lower extremity from the thigh distally.

Arterial Thrombosis and Acute Limb Ischemia

A thrombus is a clot within a vessel in the body. Most commonly thrombi occur in the venous system in the lower extremities because the pressure and flows are lower, allowing blood more time to settle and form clots. This leads to the formation of deep vein thromboses (DVTs). When a thrombus breaks free and migrates elsewhere it becomes an embolus. Emboli in the venous system can lodge in the circulation of the lungs, causing pulmonary embolisms. Thrombi and emboli are more rare in the arterial system but they can occur.

Risk factors for arterial emboli include atrial fibrillation, atherosclerosis, traumatic injuries and arterial aneurysms.¹ Arterial emboli can travel to different parts of the body, causing different pathologies. Ischemic strokes are typically the result of an arterial embolus lodging in the circulation of the brain. Arterial emboli can also lodge in the circulation of the digestive system, resulting in mesenteric ischemia. Thrombi can also occur spontaneously anywhere in the arterial circulation—for example in the arteries of the lower extremities, as in this patient.

Often, the degree of symptoms can be correlated to the degree of occlusion of the vessel—i.e., how badly is the pipe clogged? If the vessel is only partly occluded, the patient may be asymptomatic. Partially occluded vessels may also only cause symptoms with exertion or increased blood flow, which increases the demand for oxygenated blood beyond what the partially occluded vessel can deliver. This is called intermittent claudication.²

If the embolus is completely occlusive, then the only blood flow into the limb will be what can be delivered by whatever small collateral circulation is present. This situation can lead to complete limb ischemia, which can result in compartment syndrome and potentially require amputation of the limb if normal blood flow is not restored promptly. Compartment syndrome can be recognized by the 6 Ps: Pain, Pallor, Pulselessness, Paraesthesia, Paralysis, and Poikilothermia.³ Both arterial emboli and compartment syndrome are surgical emergencies and require rapid intervention to minimize limb ischemia and tissue damage.

Case Resolution

You initiate IV access and administer 75 mcg of fentanyl IV. The patient reports a decrease in his pain and his heart rate decreases slightly. You initiate transport with lighs and sirens because you suspect the patient has a limb-threatening condition requiring time-sensitive intervention. In your radio report to the receiving hospital you specify the patient has a pulseless extremity and you are directed to proceed to the resuscitation room for an evaluation.

On arrival the emergency medicine physician takes your report and agrees with your physical exam findings. She places an ultrasound probe on the patient’s leg and identifies an arterial occlusion to the level of the common femoral artery. She pages vascular surgery emergently and the patient is taken directly to the OR after a CT scan confirms fully occlusive thrombus of the right lower extremity arterial system.

In the OR he has a thromboembolectomy to remove the arterial embolism. He also requires a fasciotomy while in the OR due to concern for compartment syndrome in the setting of his limb ischemia. He is discharged to an inpatient rehab on hospital day five.

Conclusion

Limb ischemia caused by an acute arterial embolism is a rare presentation; however, it can lead to significant morbidity and mortality if not recognized promptly. EMS clinicians should have a high index of suspicion for arterial embolism and limb ischemia in patients with risk factors for atherosclerotic disease and signs of decreased or absent blood flow to the extremities. Prehospital management of this condition consists of identifying the signs and symptoms, pain management and rapid transport for definitive surgical care.

References

1. Dag O, Kaygın MA, Erkut B. Analysis of Risk Factors for Amputation in 822 Cases with Acute Arterial Emboli. ScientificWorldJournal. 2012;2012:673483. doi:10.1100/2012/673483
2. Meru AV, Mittra S, Thyagarajan B, Chugh A. Intermittent claudication: An overview. Atherosclerosis. 2006;187(2):221-237. doi:10.1016/j.atherosclerosis.2005.11.027
3. Williams S, Chen S, Todd NW. Compartment Syndrome in the Foot and Leg. Clinics in Podiatric Medicine and Surgery, 2023; 40(1):1-21
4. Nazliel B, Starkman S, Liebeskind DS, Ovbiagele B, Kim D, Sanossian N, Ali L, Buck B, Villablanca P, Vinuela F, Duckwiler G, Jahan R, Saver JL. A brief prehospital stroke severity scale identifies ischemic stroke patients harboring persisting large arterial occlusions. Stroke. 2008 Aug;39(8):2264-7.

The 6 Ps of Compartment Syndrome

Los Angeles Motor Scale Assessment

Score ≥ 4 is 81% Sensitive and 89% Specific for Large Vessel Occlusive Stroke.⁴

ABOUT THE AUTHORS

Chris Root is an assistant professor in the Department of Emergency Medicine, University of New Mexico Health Sciences Center in Albuquerque, New Mexico.

Emily Pearce is an EMS Fellow at the University of Washington School of Medicine in Seattle, Washington.

Ben Rubin is a Paramedic Driver at Albuquerque Fire Rescue.

Kim Pruett is an assistant professor in the Department of Emergency Medicine, University of New Mexico Health Sciences Center in Albuquerque, New Mexico. She is also Medical Director of Albuquerque Fire Rescue and Medical Director of the EMS Bureau for the State of New Mexico.