Headache and the LP: To Tap or Not to Tap?

Roughly 1 in 20 subarachnoid hemorrhages are missed during initial presentation in the emergency department – substantially increasing the risk of complications and mortality. That’s scary. But is it a reason to do a lumbar puncture every time a patient’s head hurts? EMRA*Cast host Will Smith (@WTSmithMD IG/Twitter) shares some expert insight from Lt. Col. Roderick Fontenette (@RodFontenette1).

Overview: Depending on the symptoms, the workup for a headache can vary greatly. Sometimes a simple combination of medications and IV hydration will provide complete resolution of symptoms and the patient is discharged home. Other times imaging may be indicated and when there is high suspicion for a subarachnoid bleed, a lumbar puncture is performed. But how do we know what symptoms constitute which work up? A lumbar puncture may seem aggressive, but an SAH could be fatal. What if suspicion is high for a bleed, but imaging and LP are negative? This episode will take a deep dive into the literature and discuss the best guidelines for working up a patient with a headache when your gestalt is telling you there is a little more going on.

TAKE-HOME POINTS

• Not every patient who comes in with a headache needs an LP; typically these are reserved for patients in whom a subarachnoid hemorrhage is suspected.
• 1-2% of the patients who come in with a headache will have an SAH, but the overall mortality rate of those bleeds can be as high as 70-80%.
• The Perry Study showed that when a modern third-generation CT machine is used, a CT Head without contrast is almost 100% sensitive in identifying a SAH when performed within the first 6 hours of symptom onset.
• Xanthochromia may not show up for 12 hours, so a negative LP does not mean no SAH.
• CTA head and neck may also be an option, but it's best to loop neurosurgery into the decision-making process.

Resources

1. Perry JJ, Stiell IG, Sivilotti ML, et al. Sensitivity of computed tomography performed within six hours of onset of headache for diagnosis of subarachnoid haemorrhage: prospective cohort study. BMJ. 2011;343:d4277. 
2. Perry JJ, Stiell IG, Sivilotti ML, et al. Clinical decision rules to rule out subarachnoid hemorrhage for acute headache. JAMA. 2013;310(12):1248-1255. 
3. Chu KH, Keijzers G, Furyk JS, et al. Applying the Ottawa subarachnoid haemorrhage rule on a cohort of emergency department patients with headache. Eur J Emerg Med. 2018;25(6):e29-e32.
4. Perry JJ, Stiell IG, Sivilotti ML, et al. High risk clinical characteristics for subarachnoid haemorrhage in patients with acute headache: prospective cohort study. BMJ. 2010;341:c5204. Published 2010 Oct 28. 
5. Nath S, Koziarz A, Badhiwala JH, et al. Atraumatic versus conventional lumbar puncture needles: a systematic review and meta-analysis. Lancet. 2018;391(10126):1197-1204.