Bouncebacks: Back Pain

Finished the segment and was immediately dispatched to a man with recent lumbar decompression surgery with complaints of urine and bowel retention. Nice to have the complications fresh in my mind!

There is suggestion that ESR & CRP would be helpful in the back pain patient. I suppose that in THIS post surgical patient with impending/ongoing badness it would probably throw a big red flag that would have kept the patient from going home.

However, is this counterproductive in the rest of the of back pain patients with some recent surgery, but no fever, essentially normal exam, and who do end up having a "benign" cause of their pain?

I would think ESR and CRP would be elevated in most people recently post-op, due to resultant inflammation. If the post-op ESR / CRP are elevated, you are left chasing a nonspecific abnormal lab value.

My question, would there be a better role for lactate in this type of patient? Does anyone have an ER perspective on appropriate lab or other tests for the post-op back pain that looks well overall and you think can go home? Assume that MRI is not an option... also assume normal white count is useless...

I have not heard the Bounce Back this month yet but I can guess the scenario--it is an uncommonly seen but commonly missed diagnosis--patients presenting to the ED with back/neck pain following a spine procedure and there is a "failure to diagnose" spine infection, resulting in the patient's paralysis or death. Review of the literature will not provide a reliable approach to these patients. We presented an abstract at ACEP in 2010 and recently submitted a study to Annals that I believe helps address this difficult conundrum. We studied 179 patients who presented to the ED with severe back pain, 44 had spine infections (SEA, vertebral osteo, discitis, paravertebral abscess, paraspinous abscess, psoas or ileospsoas abscess or infected psuedomeningocele). 56 out of 179 had a spine procedure before presenting and 14 of these 56 patients were infected. Only 6/14 had a fever of 101 (or greater) at triage (only 11/63 non-iatrogenic spine infections had fever at triage in D Davis’ study JEM 2004). The neuro exam is generally nonspecific in these patients until it is too late, leukocytosis is also a late finding and ESR is elevated after most neurosurgeries for months with/our without infection and lastly many patients with infection have benign looking wounds—all leading to the difficulty in these cases. And lastly, even the MRI is not 100% sensitive nor specific at detecting spine infection following recent spine surgery. Any "expert witness” who says it is, is disingenuous. So, how do you diagnose this condition? A CRP > 50 mg/L detected 13/14 in our series. The mean CRP was 126 mg/L and mean WBC was 10.9 K for these 13. The CRP is generally < 50 mg/L after post-op-day 5 or 6 in patients without infection and prolonged ESR elevation precludes it as a viable test for infection in these patients. Bets are off for the CRP before post-op-day 5 because that patient’s CRP is often elevated from the surgery itself with no infection present. The cryptic knowledge of spine infection prevalence following spine procedures would be helpful if it was known, well here it is: epidural anesthesia (0.05%), minidiscectomy (~0.13%), standard discectomy (1%-3%), multilevel vertebral fusion (1-10%). Epidural steroid injection and lumbar puncture I could not find—case reports only, no series. If you knew the infection rate was 1:10 following multilevel lumbar fusion—even if the patient had no overt symptoms—you’d be concerned about infection. My personal feeling is: surgeons, like pilots have a great deal of denial that they have done any wrong until it is too late—the surgeon may tell you on the phone to “have the patient followup in the office” (especially if the neurosurgeon you're talking to is on-call for the original surgeon)—you send them home, allowing their infection to advance can result in disaster for you and the patient. So calling the surgenon may not be an easy solution either. Studies giving EPs the confidence in diagnosing this condition are severely lacking and the holes in the Swiss cheese can really line-up in these patients. Based on our series, my personal guidelines are: in pts presenting to the ED with positional back/neck pain following a spine procedure (ESI, obstetric epidural anesthesia, MITR discectomy, minidiscectomy etc...), consider obtaining a CRP. If it is > 50 mg/L then consider imaging (primarily MRI with Gadolinium contrast). A caveat to the CRP: the one patient in our small study with infection whose CRP was less than 50, was on antibiotics from their neurosurgeon for ~4 days before presentation to the ED. Steroids may act similarly? The lactate question is a good one and probably the subject of another study that I am sure has not been done yet. If I have guessed wrong and this is not the correct bounce back scenario please forgive my bloviation. Steven Shroyer MD FACEP, Long time EMRAP listener.

Very helpful Steven, thanks for the insight!

Kevin Mickelson MD

Thanks Steven... Answers my question

Great comments Steven!

Mel, this comment is good enough and important enough, you might want to get Dr Shroyer on an upcoming EMRAP to discuss the topic!
Way helpful.