Bob's Bits

So I received a request from a partner whose identity will remain anonymous. Let's just call this person "Rob Rarrali"... Well "Rob" requested some info on a couple of topics and since I aim to please, let's try to enlighten the group. In this discussion we'll discuss peritonsillar abscesses (PTA)'s:

• To drain or not to drain?
• To CT or not to CT?
• To Admit or 'vaya con dios'?
• What Abx?
• When to involve ENT?

To begin with let's review some background information on the subject. Fun useless fact of the day: The other name for PTA is "Quinsy". The diagnosis of PTA is not always easy. Obviously your landmarks can be distorted, trismus may limit visualization and most importantly the hallitosis may prevent close inspection. One case series showed that the clinical diagnosis of PTA is only 78% sensitive (not great). The most common actual diagnosis (if it's not a PTA) is peritonsillar cellulitis. This can as well give you tonsillar erythema and edema.

Why do we care so much about PTA's. Won't they just eventually burst, drain and resolve? Well silly, of course if you want to wait for that to happen, you'll need to hope they avoid airway obstruction. Also, PTA's untreated can resolve in caudad spread with mediastinitis, sepsis and pericardial tamponade. Other than that, they're not such a big deal. All of the literature I reviewed felt that needle aspiration or I&D were required. Not one mentioned observation and IV Abx as being adequate treatment for a true PTA.

Also if you do perform a needle aspiration, the false negative rate for experienced physicians is still 10-12% (likely higher in the inexperienced or those using the patented "Mattison Blind Repeated Stabbing Technique")... Ergo, we want to make sure that there's actually an abscess to drain if we're going to go through this much trouble.

With regards to CT, yes, it's an excellent test in the diagnosis of PTA (nearly 100% sensitive). However, in the acute patient who doesn't want to stay supine or has impending airway issues, I don't feel comfortable waiting for the BMP to be drawn so they can get their CT w/ IV contrast to evaluate and confirm what I already suspect is there (thus delaying definitive treatment by at least 2 hours usually).

So why don't we just stick a needle in suspected PTA's? Well of course, the concern is about tapping into "big red" (aka carotid artery).

An interesting study done by Blaivas et al (Am J Emerg Med 2003;21:155-158) evaluated the ue of bed-side U/S by ED docs to confirm the presence and assist in aspiration of PTA's. Prior studies evaluated intraoral (IO) placement of an U/S probe (which to me is the most difficult part of this study to stomach. I gag brushing my teeth, much less tolerating an U/S probe in my mouth while I already have a PTA - and let's keep the jokes about gagging and probes in mouth to a minimum people)...

Earlier studies showed sensitivities of detecting PTA's with IO probes to be 89-92% while specificity was 80-100%. This particular study evaluated the use of IO probes by ED physicians in 6 probable PTA cases. Three of the cases ended up being confirmed as peritonsillar cellulitis on U/S, while the other three were confirmed PTA and they utilized real-time guidance to perform the aspiration (two of the three originally had multiple blind attempts resulting in failure aspiration was successful w/ an IO probe). Now obviously this is a small N, however it's the only study looking at ED docs using these probes.

Now seeing that we still need a portable U/S probe and the fact that our ENT coverage is improving, I think realistically we won't be doing IO-guided aspirations in the next year. However, if we have the portable SonoSite with an IO probe, it'd be an excellent way to quickly confirm the diagnosis. Plus, if ENT is not readily available, we could perform real-time IO-guided aspiration. Also, the odds of tapping into "big red" are significantly reduced by the IO technique. Finally, there are IO probes that have guide needles already attached so it's point and shoot (no hand-eye coordination required for those video-game challenged).

What about antibiotics? Well obviously in peritonsillar cellulitis IV abx are required (and no I&D). Preferred Abx are PCN + Flagyl. Other choices are cefoxitin, augmentin, and clindamycin. You'll need the same spectrum of Abx for abscesses.

As for ENT consultation, once I have a PTA diagnosed, I try to get a hold of them. It sounds like we'll have some difficulty at MGMC for awhile. The question is whether IV Abx and close observation is adequate. From my experience and point of view, all PTA's need to be seen by ENT that day. If that means having to transfer to another ED and then having them be d/c'd home fine. If that means IV Abx in the ED and the patient being seen in less than six hours, that's acceptable.

Hope this has been helpful. More questions to be answered soon.