Quality Corner – Head Trauma and Anticoagulation; Postdural Puncture Headache

Author: Cassandra Newburg, MD (EM Resident Physician, UT Southwestern Medical Center / Parkland Memorial Hospital) and Christine Kulstad, MD (EM Attending Physician, UT Southwestern Medical Center / Parkland Memorial Hospital) // Edited by: Alex Koyfman, MD (@EMHighAK) and Brit Long, MD (@long_brit)

Welcome to Quality Corner, an emDocs series evaluating tough cases and potential areas for improvement. The cases described below are based on ED bouncebacks, with all identifying details removed, and are limited to what was documented in the medical record.

Case 1 – Minor head trauma and anticoagulation

A 67-year-old female presents with a laceration after being punched in the side of the head. She did not lose consciousness and has no headache. She does have a history of atrial fibrillation for which she is taking Coumadin. Physical exam reveals a 3 cm laceration to the scalp and a normal neurologic exam. During the course of the ED visit the laceration was repaired, and her INR was found to be 3.8. The patient was instructed to hold 1 dose of Coumadin and follow-up for a re-check in 1 week.

The patient returned 2 hours later with headache, lightheadedness, and re-bleeding of the laceration. CT brain ordered at that time demonstrated a subarachnoid hemorrhage. She was given IV vitamin K, neurosurgery was consulted, and she was admitted to SICU. After monitoring in the SICU, no further intervention was required, and the patient was sent home after 3 days.

Case Discussion

This patient presented with a fairly minor head trauma and a normal neurologic exam, leading to the assumption that she was at low risk for a head bleed. However, some would argue that all patients with minor head trauma who are anti-coagulated should have a CT brain, despite a normal neurologic exam. After all the downside of getting a CT is lower in a patient who is 67 years old- less concern about developing a future malignancy when compared to a 7-year-old. What about a clinical decision rule? Well, a group of researchers attempted to develop a CDR for anti-coagulated patients to decrease the rate of imaging, but were unable to come up with criteria that accurately predicted who was safe to skip the scanner (Nishijima DK & Network., 2013).

How much higher is the risk of ICH in anti-coagulated patients? As is often the case, we don’t exactly know. Studies have shown a 6-25% ICH rate for those on warfarin (Nishijima DK & Network., 2013) (Brewer ES, 2011). Perhaps more alarming, studies show even higher rate with clopidogrel (usually + aspirin) of 12-38% (Nishijima DK & Network., 2013) (Levine M, 2014 ) (Brewer ES, 2011). Both providers and patients may not consider clopidogrel a significant risk factor since it’s technically not an anti-coagulant.

Let’s assume your CT is normal. Is your patient out of the woods? One of the theoretical dangers of minor head trauma in the anti-coagulated patient is that it triggers venous oozing, which can then slowly accumulate and cause problems due to the dreaded delayed bleed. This seems to occur relatively infrequently, a systematic review reported a range of 5.8 to 72 cases/1000 patients. Can you predict who is more at risk? One study said increasing age leads to increased rates of bleeding, while the value of INR did not lead to increased rates of bleeding (Miller J, 2015). Another retrospective study showed no relation between age or INR level and delayed bleed (Lim BL, 2016).

So if you can’t predict who will have a delayed bleed, should you play it safe and admit them all? One institution developed such a protocol and published their results. All patients were admitted for a 24 hour observation period with a recommended repeat CT. Of the 97 patients studied, 5 had new findings on the repeat CT, 1 of which required an intervention. Unfortunately, 2 other patients had bleeds even more delayed, neither of which required intervention (Menditto VG, 2012). Fairly low yield protocol, but something to consider if your patient would have difficulty returning if he or she becomes worse.

For more on disposition and delayed bleeding with anticoagulants/antiplatelet medications, see this emDocs Post

Take Home Points:

  • Patients on anti-coagulation or anti-platelet agents have a higher risk for ICH. Strongly consider CT for minor head trauma.
  • Delayed intracranial bleeding is a feared complication of minor head trauma in anti-coagulated patients, but it’s difficult to predict who is at risk. Discuss reasons to return with these patients and their family.


Case 2 – Headache following headache

A 46-year-old man presented to the ED with a sudden onset of head and neck pain, neck spasm, and nausea, starting 8 hours ago. He denied any preceding trauma, fevers, or recent illnesses. He had a normal neurologic exam and normal vital signs. His CT brain was normal, and due to a high suspicion of SAH with onset of symptom > 6 hours ago, a lumbar puncture was performed. CSF protein, glucose, and cell counts were normal. His pain resolved after being treated with prochlorperazine, diphenhydramine, and ketorolac. Sixteen hours later, he returned to the ED with a new headache. This headache was not bad when lying flat, but any prolonged sitting or standing triggered pain that so intense that he was unable to go to work.

Case Discussion

We have a difficult job in emergency medicine – in this case everything was done correctly. A life-threatening cause of headache was investigated and ruled out; the patient was treated and felt better. Unfortunately, he suffered a not uncommon complication, which was hopefully discussed during the informed consent process. Lumbar puncture is a common procedure in emergency medicine and a review of its complications, steps that may lessen their frequency, and ways to treat the most common are discussed below.

In general, serious complications from a lumbar puncture are quite rare. With a nod to worst first, cerebral herniation is possible following LP in patients with increased intracranial pressure. Although tempting to CT every patient prior to an LP to avoid this, it delays care and does not completely rule out elevated ICP. You can feel comfortable skipping a CT unless the patient has focal neurological deficits, AMS, seizures, or papilledema (Johnson & Sexton, 2016). Meningitis is rare with one reported incidence of 1 in 53,000 cases (Barnwell R, 2012). For more on head CT before LP, see this emDocs post. Patients’ most feared complication seems to be neurological complications such as paralysis. This complication is even more rare, except for those patients who are prone to bleeding. Patients with thrombocytopenia or who are anticoagulated are at risk for spinal hematomas, which can lead to neurological compromise (Johnson & Sexton, 2016). A general rule to follow is don’t do the LP if the platelet count is < 50,000, the INR is > 1.4, or the patient is taking NOACs. For more on this controversial area, see this emDocs post.

What do you actually have to worry about? Headache. Post-lumbar puncture headaches are fairly common, occurring in 10-30% of patients. The headache is characteristically very positional – pain is much worse when upright and improves when supine. Onset is typically hours to days after the procedure (Sun-Edelstein & Lay, 2018).

When you see your patient whose SAH you have ruled out back in the ED the next day for headache, what can you do for him or her? The first line treatment is oral medications for pain and bedrest for 24 hours (post-procedure) (Sun-Edelstein & Lay, 2018).  If the headache is persistent, or the patient cannot lie in bed for 24 hours you can try caffeine (Basurto Ona X, 2015). The evidence supporting its effectiveness is not robust, and it is not widely available on many hospital formularies.  Small studies have shown gabapentin, hydrocortisone, and theophylline to be somewhat effective in treating these headaches (Basurto Ona X, 2015). However, the most effective treatment appears to be an epidural blood patch, which can be repeated if ineffective the first time (Sun-Edelstein & Lay, 2018).

Wouldn’t it have been better to prevent that complication in the first place? Atraumatic needles, those shaped like a pencil point, instead of the more common cutting needle have been shown to decrease the rate of subsequent headaches (Arevalo-Rodriguez I M. L.-C., 2017). Since atraumatic needles are not as commonly stocked in EDs, the evidence suggests using a smaller gauge cutting needle (Zorrilla-Vaca A, 2016), orienting the bevel parallel to the dural fibers (Richman JM, 2006), and reinserting the stylet prior to removing the needle from the patient (Sun-Edelstein & Lay, 2018) will decrease rate of subsequent headaches. Neither lying flat after the procedure nor giving supplemental IVF has been shown to help the patient (Arevalo-Rodriguez I, 2016). The amount of fluid removed also does not seem to affect headache rate (Sun-Edelstein & Lay, 2018), so get as much as you need for all the relevant studies.

Take Home Points:

  • Order a CT before LP in patients with AMS, seizure, papilledema, or focal neurologic deficits. It is not necessary otherwise.
  • Avoid LP in patients with thrombocytopenia, elevated INR, or who are taking NOACs.
  • Post LP headache is relatively common. The most effective treatment is epidural blood patch.
  • Smaller needles, correct needle position, and reinsertion of the stylet prior to removal decrease the post LP headache rate.

References/Further Reading:

Arevalo-Rodriguez I, C. A. (2016, Mar). Posture and fluids for preventing post-dural puncture headache. Cochrane Database Syst Rev, 7(3).

Arevalo-Rodriguez I, M. L.-C. (2017, Apr). Needle gauge and tip designs for preventing post-dural puncture headache (PDPH). Cochrane Database Syst Rev, 7(4).

Barnwell R, B. V. (2012, Jul). Iatrogenic bacterial meningitis: an unmasked threat. CJEM, 14(4), 259-62.

Basurto Ona X, O. D. (2015, Jul). Drug therapy for treating post-dural puncture headache. Cochrane Database Syst Rev, 15(7).

Brewer ES, R. B. (2011, Jan). Incidence and predictors of intracranial hemorrhage after minor head trauma in patients taking anticoagulant and antiplatelet medication. J Trauma., 70(1), E1-5.

Johnson, K., & Sexton, D. (2016, Feb). Lumbar puncture: Technique, indications, contraindications, and complications in adults. Retrieved from UpToDate: www.uptodate.com/contents/lumbar-puncture-technique-indications-contraindications-and-complications-in-adults

Levine M, W. B. (2014 , Jan). Risk of intracranial injury after minor head trauma in patients with pre-injury use of clopidogrel. Am J Emerg Med, 32(1), 71-4.

Lim BL, M. C.-T. (2016, Jan). Outcomes of warfarinized patients with minor head injury and normal initial CT scan. Am J Emerg Med, 34(1), 75-8.

Menditto VG, L. M. (2012, Jun). Management of minor head injury in patients receiving oral anticoagulant therapy: a prospective study of a 24-hour observation protocol. Ann Emerg Med, 59(6), 451-5.

Miller J, L. L.-G. (2015, Aug). Delayed intracranial hemorrhage in the anticoagulated patient: A systematic review. J Trauma Acute Care Surg., 79(2), 310-3.

Nishijima DK, O. S., & Network, C. R. (2012, Jun). Immediate and delayed traumatic intracranial hemorrhage in patients with head trauma and preinjury warfarin or clopidogrel use. Ann Emerg Med, 59(6), 460-8.

Nishijima DK, O. S., & Network., C. R. (2013, Feb). Risk of traumatic intracranial hemorrhage in patients with head injury and preinjury warfarin or clopidogrel use. Acad Emerg Med, 20(2), 140-5.

Richman JM, J. E. (2006, Jul). Bevel direction and postdural puncture headache: a meta-analysis. Neurologist, 12(4), 224-8.

Sun-Edelstein, C., & Lay, C. (2018, Jan). Post-lumbar puncture headache. Retrieved from UpToDate: www.uptodate.com/contents/post-lumbar-puncture-headache

Zorrilla-Vaca A, H. R.-V. (2016). Finer gauge of cutting but not pencil-point needles correlate with lower incidence of post-dural puncture headache: a meta-regression analysis. J Anesth, 30(5), 855.


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