Use of Occipital Nerve Block in the Emergency Department

Case Presentation

• Patient: 36-year-old man to ED with episodic headaches

• Pain originates in the back of his head from a point overlying his occipital skull. The pain usually starts on the left; from there it spreads up his scalp and down his neck. The pain is sharp, up to 7/10 in intensity, and lasts for about an hour.

• Episodes occur a couple times per week, with no clear triggers. Mild relief with Tylenol.

• He does not have primary care, but has been to other Emergency Departments before and has been treated with “migraine cocktails” and muscle relaxants, both of which have been mildly successful acutely, but nothing has been able to prevent his headaches from recurring.

• PE: well-developed man lying in bed, afebrile, VSS. Neuro, cardiac and respiratory exams all unremarkable. On HEENT exam, there are no signs of trauma. There is point tenderness on his occipital scalp at the site where his headaches originate.

Clinical Question

What are the indications for administration of an occipital nerve block in the Emergency Department?

Background

An occipital nerve block is a procedure in which anesthetic agents, with or without steroids, are injected around the greater occipital nerve (GON) along its course overlying the occipital skull. The goal of the procedure is to provide relief from headaches, both as an abortive measure and also for prevention of recurrence. The procedure has traditionally been performed by neurologists. However it is technically simple, relatively safe, and potentially effective in the acute treatment of headache, and has thus begun to be performed in ED setting as well (1).

Summary of Evidence:

• Systematic review (2):

• Grade B evidence for occipital nerve blocks for the treatment of occipital neuralgia and cluster headaches, and grade C evidence for migraine headache

• Strengths of evidence: Randomized controlled trials have demonstrated statistically significant decrease in pain sensation and frequency in patients in the days-weeks following injection in all of these headache types. In fact, there are reports of patients having resolution of headache symptoms entirely for even months following injection.

• Weakness of evidence is small sample size in studies (almost all had n < 100). Further, blinding is difficult as injection of anesthetic such as lidocaine is associated with a burning sensation by the patient that is noticed immediately compared to injection of normal saline.

• TTP over the site of GON is used as a selection criteria for patients who should receive the nerve block -> this is NOT supported by evidence -> patients with occipital neuralgia will have TTP by definition, whereas TTP does not seem to be a good predictor of success for the procedure in other headache types (3).

• Evidence supports a central pain modulatory effect of the nerve block. For example, one study demonstrated that, in patients given occipital nerve blocks, there was a decrease in brush allodynia in the trigeminal nerve distribution as well as photophobia within five minutes of the procedure – regions that are not innervated by the greater occipital nerve (4). This give theoretical backing to using the nerve block for indications outside of occipital neuralgia.

Procedure:

Technique (5):

• Patient positioned seated, provider standing behind patient

• Injection site: along superior nuchal line, medial to the occipital artery (feel for pulsation)

• can use US to localize nerve – but no studies exist showing improved outcomes with US

• Medication: 3-5mL on each side of a 1:1 mixture of 2% lidocaine:bupivacaine, mixed with a steroid such as betamethasone 2-4mg.

Contraindications (6):

• Local anesthetic allergy – do NOT use lidocaine/bupivacaine, but can inject with just steroids which has demonstrated efficacy

• Pregnancy – do NOT perform occipital nerve block – bupivacaine is FDA category C for teratogenicity; steroids accelerate fetal lung maturation

Special Considerations:

• Elderly – At higher risk of hypertension as an adverse effect, but this increased risk is only seen with high concentration lidocaine and bilateral blocks. Use 1-2% lidocaine, perform unilateral block, and observe for 30 minutes for hypertension before discharge (7).

• Alopecia – There are case reports of patients developing alopecia at injection sites following occipital nerve block with steroids. Risk is likely low given scarcity of reports, but this is a risk that should be discussed with patients. There are no reports of alopecia with injections of just local anesthetic, and these may be similarly efficacious; offer as an alternative (8).

Recommendations:

• Good evidence to use for both abortive therapy and prevention of recurrence for patients presenting with occipital neuralgia and cluster headache with little risk.

• Less evidence for its efficacy in migraine headache, but appropriate to attempt for patients who fail “migraine cocktail” or for patients with frequent presentations to the Emergency Department For migraine given its potential to alleviate symptoms for weeks.

• Screen for above contraindications and special populations to prevent adverse outcomes.

References

1. Headache Classification Committee of the International Headache Society (IHS). The international classification of headache disorders. Cephalalgia. 2013 Jul;33(9):629-808

2. Voigt CL, Murphy MO. Occipital nerve blocks in the treatment of headaches: safety and efficacy. The Journal of emergency medicine. 2015 Jan 1;48(1):115-29.

3. Tobin J, Flitman S. Occipital nerve blocks: when and what to inject?. Headache: The Journal of Head and Face Pain. 2009 Nov;49(10):1521-33.

4. Young W, Cook B, Malik S, Shaw J, Oshinsky M. The first 5 minutes after greater occipital nerve block. Headache: The Journal of Head and Face Pain. 2008 Jul;48(7):1126-8.

5. Ward JB. Greater occipital nerve block. InSeminars in neurology 2003 (Vol. 23, No. 01, pp. 059-062). Thieme Medical Publishers, Inc., 333 Seventh Avenue, New York, NY 10001.

6. Blumenfeld A, Ashkenazi A, Napchan U, Bender SD, Klein BC, Berliner R, Ailani J, Schim J, Friedman DI, Charleston IV L, Young WB. Expert consensus recommendations for the performance of peripheral nerve blocks for headaches–a narrative review. Headache: The Journal of Head and Face Pain. 2013 Mar;53(3):437-46.

7. Sahai-Srivastava S, Subhani D. Adverse effect profile of lidocaine injections for occipital nerve block in occipital neuralgia. The journal of headache and pain. 2010 Dec 1;11(6):519-23.

8. Shields KG, Levy MJ, Goadsby PJ. Alopecia and cutaneous atrophy after greater occipital nerve infiltration with corticosteroid. Neurology. 2004 Dec 14;63(11):2193-4.