Patient Safety Tip of the Week

July 8, 2014

Update: Minor Head Trauma in the Anticoagulated Patient



Recently we’ve had a lot of hits on our prior columns on minor head trauma in the anticoagulated patient. In our July 17, 2007 Patient Safety Tip of the Week “Falls in Patients on Coumadin or Heparin or Other Anticoagulants” we highlighted the problem of delayed hemorrhage after falls in patients on anticoagulants. Specifically we discussed the patient who falls and has minor head trauma, has a negative CT scan of the head, and then later develops a subdural hematoma (or other intracranial hemorrhage). The example we gave was an elderly patient with a cardiac condition on full-dose heparinization while an inpatient who had an unwitnessed fall in the hospital one evening. He did not lose consciousness and was alert and fully oriented when the medical resident examined him after the fall. He had a mild ecchymosis on his right forehead but no focal neurological signs and no evidence of trauma elsewhere on the body. Because the patient was fully anticoagulated, the resident ordered an emergency head CT scan, which was normal. No changes were made in his heparin regimen. The following morning the patient was more somnolent than usual and a repeat CT scan showed a sizeable subdural hematoma that required surgical evacuation.


Our June 5, 2012 Patient Safety Tip of the Week “Minor Head Trauma in the Anticoagulated Patient” discussed some new studies on the issue. We again noted that the several good clinical decision rules on head scanning after minor head trauma, such as the Canadian CT Head Rule (Stiell 2001), and the New Orleans criteria (Haydel 2000) do not apply to patients on anticoagulants. The new studies we reviewed showed that collectively the incidence of delayed intracranial hemorrhage in anticoagulated patients with a normal initial CT scan is actually quite low. The biggest predictor of delayed intracranial hemorrhage in one study (Menditto 2012) was an INR >3.


Now a recent article in the Journal of Emergency Medicine (Cohn 2014) again asked the question “What is the risk of delayed ICH (intracranial hemorrhage) in anticoagulated patients with minor head injury and a normal initial CT scan?”. The authors did a comprehensive search of the literature to determine the evidence base for answers to this question. Though their search strategy identified 279 articles, they found that only four articles really focused on the question at hand, three of which (Menditto 2012, Nishijima 2012, Kaen 2010) we’ve already discussed in our June 5, 2012 Patient Safety Tip of the Week “Minor Head Trauma in the Anticoagulated Patient.


The authors noted that these studies showed the incidence of delayed intracranial hemorrhage after an initially normal head CT scan ranged from 0.6% to 6%. However, they go on to appropriately note that we are not really interested in those patient having asymptomatic delayed ICH in whom no intervention is necessary. What we are really interested in is those patients in whom death or neurosurgical intervention (i.e clinically significant outcomes) occurred. The incidence of these ranged from 0 to 1.1%.


They also go on to note that not all patients are the same. Many of the studies included consisted of predominantly geriatric patients. Others were on concomitant antiplatelet therapy. And, as we noted in our June 5, 2012 Patient Safety Tip of the Week “Minor Head Trauma in the Anticoagulated Patient” the degree of anticoagulation is important.


The authors conclude that routine hospital observation for 24 hours or repeat head CT scan for all anticoagulated patients with minor head trauma and a normal CT scan is not warranted but that we need to identify subgroups at higher risk in whom those recommendations might apply. They note that patients with supratherapeutic INR’s and those on concomitant antiplatelet therapy might be such high risk patients meriting further observation or repeat CT scans.


A commentary at the end of the Cohn paper by one of the co-authors (AB Sanders) adds the issue of cost into the picture. He notes the editorial by Li (Li 2012) that estimated 24-hour observation and a repeat CT scan would add approximately $1 million per patient undergoing neurological intervention. Sanders also notes that it is not clear whether such strategy would actually impact mortality.


A second almost identical recent review of the literature (Rendell 2014) found 7 papers relevant to the question and also came to the conclusion that observation is unnecessary following a normal brain CT in warfarinized patients with head injury. Rendell notes that, though anecdotal reports have led to the practice of 24-hour observation and repeat CT in anticoagulated patients with head trauma, the experience in the larger studies would support discharge home for such patients with normal CT scan and INR <3.


Unfortunately, there is a new factor not discussed in either the Cohn or Rendell paper (or the literature they reviewed) that confounds the issue: more and more patients are now on the newer oral anticoagulants (eg. dabigatran, rivaroxaban, apixaban) in whom we can’t easily measure their degree of anticoagulation. All those TV commercials you see touting “you don’t need to go for monthly lab work anymore” with these agents may come back to bite us when trying to identify which anticoagulated patients are really at higher risk of delayed ICH.


So, as before, we emphasize the need for good instructions for the patient and, more importantly, for the caregivers when such patients are to be discharged. The major initial symptoms and signs of subdural hematomas are usually related to changes in the level of consciousness or cognition rather than “focal” neurological signs. These signs can be subtle. That’s why we previously warned in our July 17, 2007 Patient Safety Tip of the Week “Falls in Patients on Coumadin or Heparin or Other Anticoagulants” that the “neuro checks” must be carried out as ordered (whether the patient is under hospital observation or being observed by family or others at home). We’ve often seen in that past that there is a tendency for “neuro checks” to be overlooked when the patient is asleep – which is exactly when neuro checks are most important! The article by Rendell also notes that telephone follow-up the next day may be an effective strategy.


The patient with the supratherapeutic INR or concomitant antiplatelet therapy or no reliable caregiver who can observe them at home would be one you might consider for 24 hour hospital observation and repeat CT scan in 24 hours. However, as in our June 5, 2012 Patient Safety Tip of the Week “Minor Head Trauma in the Anticoagulated Patient” the optimal timing of subsequent CT scans remains unkown.


Note that our comments all pertain to anticoagulated patients in whom the initial CT scan is normal. Another recent study in head trauma patients with intracranial hemorrhage on initial CT scan (Joseph 2014) found that patients previously treated with warfarin, aspirin or clopidogrel had a threefold increase in the rate of worsening on repeat CT scan (26% vs. 9%).



Some of our other columns on head trauma in the anticoagulated patient:


April 16, 2007 “Falls With Injury

July 17, 2007  Falls in Patients on Coumadin or Heparin or Other Anticoagulants

June 5, 2012    Minor Head Trauma in the Anticoagulated Patient”.

July 8, 2014    Update: Minor Head Trauma in the Anticoagulated Patient

August 21, 2018 “Delayed CT Scan in the Anticoagulated Patient







Stiell IG, Wells GA, Vandemheen K, et al. for the CCC Study Group. The Canadian CT Head Rule for patients with minor head injury. Lancet 2001; 357: 1391–96



Haydel MJ, Preston CA, Mills TJ, et al. Indications for computed tomography in patients with minor head injury. N Eng J Med 2000; 343(2): 100-105



Menditto VG, Lucci M, Polonara S, Pomponio G, et al. Management of Minor Head Injury in Patients Receiving Oral Anticoagulant Therapy: A Prospective Study of a 24-Hour Observation Protocol. Ann Emerg Med 2012; 59(6): 451-455



Cohn B, Keim SM, Sanders AB. Can Anticoagulated Patients Be Discharged Home Safely From the Emergency Department After Minor Head Injury? J Emerg Med 2014; 46(3): 410-417



Nishijima DK, Offerman SR, Ballard DW, Vinson DR, et al. Immediate and Delayed Traumatic Intracranial Hemorrhage in Patients With Head Trauma and Preinjury Warfarin or Clopidogrel Use. Ann Emerg Med 2012; 59(6): 460-468



Kaen A, Jimenez-Roldan L, Arrese I, et al. The Value of Sequential Computed Tomography Scanning in Anticoagulated Patients Suffering From Minor Head Injury.

Journal of Trauma-Injury Infection & Critical Care 2012; 68(4): 895-898



Li J. Admit All Anticoagulated Head-Injured Patients? A Million Dollars Versus Your Dime. You Make the Call. Ann Emerg Med 2012; 59(6): 457-459



Rendell S. Observation is unnecessary following a normal CT brain in warfarinised head injuries: an update. BestBets (Best Evidence Topics) 2014. 30th April 2014



Joseph B, Sadoun M, Aziz H, et al. Repeat head computed tomography in anticoagulated traumatic brain injury patients: still warranted. Am Surg 2014; 80(1): 43-47






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