Risk of Internal Bleeding Heightened with Anticoagulant Therapy

Man with unremarkable injuries is confused after a fall

 

 
 
 

Bryan Bledsoe, DO, FACEP, FAAEM, EMT-P | From the September 2013 Issue | Wednesday, August 14, 2013


A 74-year-old man is playing an early-morning round of golf on a plush course in western Las Vegas near the retirement community where he lives. As he walks to the seventh hole, he looks up and somehow trips over the tee box marker. He stumbles, falls and hits his head on the granite marker that displays a map of the course.

The patient is somewhat confused and gets up slowly. He subsequently becomes coherent and attempts to complete his shot. However, his regular golfing colleagues sense that things aren’t quite right. They sit him down and give him a bottle of water. He keeps saying he’s OK and that they should continue their round of golf. Still, when he gets up he appears a little unsteady on his feet.

After a brief wait, one of his friends dials 9-1-1. An American Medical Response ambulance and the Clark County Fire Department are summoned. The responders are met by golf course personnel, are quickly taken to the patient in golf carts and promptly begin their initial assessment.

Prehospital Care

The patient appears fit with no acute distress. He’s somewhat embarrassed and insists he's OK. However, he still seems somewhat confused, so the paramedics question him further. He’s not entirely sure what happened and looks to his friends for answers. After some prompting from his colleagues, he gives paramedics permission to assess him.

They complete the primary assessment and find no immediate life threats. They then place a 12-lead EKG monitor, record a tracing and obtain a set of vital signs. The patient’s blood pressure is 140/93, his pulse is 88 bpm, his respirations are 16 and his SpO2 is 98% on room air. His Glasgow Coma Score is 14 (eye-opening response=4, verbal response=4, motor response=6). The ECG reveals atrial fibrillation with a ventricular rate of 74. No acute changes are noted. A point-of-care glucose is 124 mg/dL.

The patient states that he has high blood pressure, type II diabetes, atrial fibrillation and an enlarged prostate. His only surgery had been an appendectomy when he was a soldier in the Vietnam War. He’s taking lisinopril (Zestril), metformin (Glucophage), finasteride (Proscar), dabigatran (Pradaxa) and a multivitamin. He’s allergic to penicillin.

The paramedics complete the secondary assessment. They find a scalp contusion and a superficial laceration on the right temporal region. They feel no bony step off or other evidence of fracture. The patient doesn’t have any blood draining from his ears. His neck is non-tender. The remainder of the physical exam is unremarkable. However, the patient does have some repetitive questioning and still seems minimally confused. Paramedics advise him to go to the hospital to be “checked out.” He initially refuses, but they caution him about the possibility of bleeding within the brain due to the dabigatran (an oral anticoagulant) he is taking for his atrial fibrillation. The patient recalls his doctor warning him about an increased risk of bleeding within his brain when he started the medication and agrees to go to the hospital.

Hospital Course

The patient is transported to the University Medical Center trauma unit, as it’s the closest hospital to the golf course. There the emergency physician, whose examination is similar to the paramedics’, promptly evaluates him. The patient, still minimally confused, asks some repetitive questions. He’s neurologically intact. Following the initial evaluation, a CT scan of the brain without contrast is obtained. In addition, the cervical spine is also imaged, and baseline laboratory studies and an EKG are also obtained.

The CT scan reveals two small areas of hemorrhage within the parenchyma of the right temporal lobe. The two bleeds are small but definitely present. The CT scan of the spine is negative for fracture, dislocation or other abnormality. The patient is admitted to the ICU and evaluated by neurosurgery. He’s carefully monitored for 24 hours and the CT scan of the brain is repeated 24 hours later. This scan shows improvement in the two areas of hemorrhage and the patient is allowed to return home. He ultimately does well, and by his 72-hour follow-up all symptoms have resolved. No additional complications are reported.

Teaching Points

Patients who have atrial fibrillation are at an increased risk of a clot forming in the heart that can subsequently travel to other parts of the body, such as the brain. Atrial fibrillation is the rapid, irregular beating of the atria of the heart. These rapid contractions are weak and inefficient, and can result in slowing of blood flow in the atrium. In fact, atrial fibrillation can reduce overall cardiac output by up to 25% due to loss of the “atrial kick.” With atrial fibrillation, the blood pools and becomes sluggish and can result in the formation of blood clots (thrombi). If a clot leaves the heart (thromboembolism) and travels to the brain, it can cause a stroke by blocking the flow of blood through cerebral arteries.

The risk of stroke associated with atrial fibrillation increases with age. Because of this, patients who develop atrial fibrillation are commonly started on anticoagulants to prevent a clot from forming.1 In people over 80 years of age, atrial fibrillation is the direct cause of 1 in 4 strokes. For many years, the drug of choice for the prevention of thromboembolic events associated with atrial fibrillation was warfarin (Coumadin). This medication antagonizes Vitamin K (a vitamin essential to coagulation) and is highly effective in reducing the incidence of stroke associated with atrial fibrillation and similar conditions. However, warfarin therapy must be carefully and routinely monitored with repeated blood tests that measure the effect of the warfarin on blood clotting. The results are normally expressed as an International Normalized Ratio (INR) that is based on the prothrombin time. A normal prothrombin time is usually 12–13 seconds. Thus, a normal INR, which is a ratio of the normal and measured prothrombin time, is 0.8-1.2 seconds. With warfarin therapy, the goal is to keep the INR between 2 and 4, based on the patient's condition. If the INR is too low, the patient is at risk of forming a clot. If the INR is too high, the patient is at increased risk of hemorrhage. Thus, it’s essential that warfarin therapy be carefully monitored. The effectiveness of warfarin is also related to the amount of vitamin K in the diet and can vary on a meal-by-meal basis. However, routine testing of the INR means multiple trips to the clinic and can interrupt the lifestyle of busy patients.

With the widespread use of warfarin for disorders of coagulation, various pharmaceutical companies began to research and develop alternative drugs for treatment of these conditions as an alternative to warfarin. These drugs, called direct prothrombin inhibitors, have become extremely popular. Unlike warfarin, they don’t require routine INR monitoring. The first drug in this new class of oral anticoagulants released in the United States was dabigatran (Pradaxa).2 It was heavily marketed on television and in other media outlets. Additional direct prothrombin inhibitors are now available in the U.S. and Canada. These include rivaroxaban (Xarelto), apixaban (Elquis) and others. More and more patients are being prescribed these newer medications.

As use of the direct prothrombin inhibitors increased, it was noted that there appeared to be an increasing incidence of intracranial hemorrhage and other bleeding events in patients taking anticoagulants. In addition, patients who sustained injuries (e.g., hip fractures and traumatic brain injuries) while taking anticoagulants had an increased incidence of bleeding complications because of the medication.3,4 Anticoagulation with warfarin can be reversed with the administration of vitamin K (Aqua-Mephyton) which is helpful in minimizing oral anticoagulant-induced bleeding. However, there is presently no reversal agent for the new class of direct prothrombin inhibitors. This has complicated care in many situations.5

In the case presented here, the paramedics sensed that the patient had suffered more than a simple slip and fall. His confusion and repetitive questioning were worrisome for a concussion or a more sinister intracranial event. Once the paramedics determined that the patient was taking an oral anticoagulant, they knew his risk for an intracranial hemorrhage was increased. Eventually, there was not one, but two, small intracerebral hemorrhages found. Fortunately for the patient, these were nonsurgical. The small bleeds were resorbed over time and the patient ultimately did well.

It’s important to remember that patients who take oral anticoagulants are at an increased risk for hemorrhage. This risk is not limited to just warfarin or the new class of direct prothrombin inhibitors, and is increased for patients who take platelet aggregation inhibitor agents such as clopidogrel (Plavix) and similar drugs. The risk is less pronounced in patients who simply take a daily aspirin.

It’s important for EMS personnel to obtain an accurate history in regard to home medications as well as current medical conditions. These findings can help you assess risk for serious conditions, as noted in this case. There are myriad prescription and over-the-counter medications on the market but it’s impossible to remember and understand all of these. Thus, it’s prudent to have constant access to an accurate database for home medications. Smartphone-based programs such as Epocrates, Lexi-Drug and other reference sources are available and readily accessible. It’s important to look up any unfamiliar medication in order to help determine whether they place your patient at an increased risk of complications related to the medication.

Summary

The case detailed here is not uncommon. A day rarely passes at UMC where we don’t evaluate and subsequently admit a patient from the Las Vegas valley and surrounding regions that has sustained an intracranial hemorrhage secondary to oral anticoagulants. Because of this, EMS and emergency department personnel should have an increased incidence of suspicion for the possibility of a bleeding complication in patients taking oral anticoagulants. You should always question patients who have atrial fibrillation in regard to oral anticoagulant usage.

In the case discussed here, probing questions by paramedics were able to elucidate a history of atrial fibrillation and the use of an oral anticoagulant. This allowed the paramedics to stratify the patient’s risk for hemorrhage and need for further medical care. Ultimately, the patient was assessed and transported to a hospital that could care for any possible complications related to

the injury. 

 

References

1. Wolf PA, Abbott RD, Kannel WB. Atrial fibrillation as an independent risk factor for stroke: the Framingham Study. Stroke. 1991;22(8):983–988.

2. Connolly SJ, Ezekowitz MD, Yusuf S, et al. Dabigatran versus warfarin in patients with atrial fibrillation. N Engl J Med. 2009; 361(12):1139–1151.

3. Silva IR, Provencio JJ. Intracerebral hemorrhage in patients receiving oral anticoagulation therapy. J Intensive Care Med. May 20, 2013 [epub ahead of print].

4. U.S. Food and Drug Administration (FDA). (May 5, 2013). FDA drug safety communication: Safety review of post-market reports of serious bleeding events with the anticoagulant Pradaxa (dabigatran etexilate mesylate). Retrieved July 23, 2014, from www.fda.gov/drugs/drugsafety/ucm282724.htm.

5. Obeng-Gyasi SM, Loor MM, Samotowka MA, et al. Management of dabigatran-induced anticoagulation in trauma and acute care surgery patients. J Trauma Acute Care Surg. 2012;73(5):1064–1069.

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Related Topics: Patient Care, Special Patients, Pradaxa, internal bleeding, falls, dabigatran, brain hemorrhage, atrial fibrillation, anticoagulants, Jems Features

 
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Bryan Bledsoe, DO, FACEP, FAAEM, EMT-PDr. Bledsoe is an emergency physician and Professor of Emergency Medicine and Director of the EMS fellowship at the University of Nevada School of Medicine in Las Vegas. He is the author of numerous EMS textbooks and articles.

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