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The Q-Wave: Empiric Therapy in Infectious Disease

John Bielinski, MS PA-C By March 27, 2019No Comments
The Q-Wave: Empiric Therapy in Infectious Disease

Welcome to part three of our Q-Wave series on infectious disease. When it comes to teaching infectious disease, there are so many germs and so many antibiotics that it can be almost overwhelming. That’s why we have to break down this information and make it part of the fundamentals. In my experience, anybody who teaches a different way leaves gaps in the learning and understanding of their students.

  • Part 1: You have to know the germs.
  • Part 2: You have to know the antibiotics.
  • Part 3: Part 3 is empiric therapy.

If you are just joining us now, visit our podcast, Talk EM, or our YouTube channel for Part 1 and Part 2. Today, I want to cover Part 3, empiric therapy for the primary infections we see in primary care, emergency medicine and urgent care medicine.

Otitis Media in Kids

I’m a huge fan of Sanford’s Guide; it’s the gold standard and it’s updated every year. If you’ve bought the book before (it’s typically on the counter where you buy your medical books), you know the book is hard to read and interpret. If you get the app or online access, it’s very helpful.

This literature on otitis media is from Sanford’s Guide. So, how do we diagnose otitis media in children? There are three primary ways:

  1. The tympanic membrane is bulging, moderate to severe, with a new onset of ear pain (less than 48 hours). Nonverbal kids will be holding or tugging at their ear.
  2. There’s otorrhea, or discharge from the ear.
  3. There’s really bad erythema of the tympanic membrane.

Remember, when a kid is crying the tympanic membrane will look red, so you have to keep that in mind.

Here’s the deal with empiric therapy. If it’s severe acute otitis media, with moderate to severe ear pain, especially greater than 48 hours or a temperature over 102.2, you should pull the trigger and start antibiotics. What determines severe otitis media? Moderate to severe pain with a fever greater than 102.2. It’s recommended in the pediatric literature that you start antibiotics.

What if you have a patient under two years old? If they’re less than two years old you have to be more aggressive, even in mild cases. With children greater than two, it’s reasonable to observe for 48 hours with acetaminophen or ibuprofen. Under two, you need to pull the trigger earlier.

What should we treat them with? As long as the patient hasn’t had antibiotics in the last 30 days, doesn’t have conjunctivitis at the same time, and doesn’t have a history of recurrent otitis media, I would use high-dose amoxicillin or Augmentin. High-dose Augmentin is 90 mg/kg per day either BID or TID. Compared to when I used to write a lot of pediatric prescriptions, that’s a massive dose. But I’ll say it again; it’s 90 mg/kg either divided BID or TID. Or, you could use Augmentin, amoxicillin or clavulanic acid at 90/6.4 mg/kg with a BID dosing structure.

When should Augmentin be your go-to for otitis media? It’s preferred if a kid failed antibiotics in the last month or failed amoxicillin in the past. It’s also preferred in cases of purulent conjunctivitis or a history of acute otitis media. The literature shows that Augmentin is better for resolving effusions than amoxicillin.

Conjunctivitis Otitis Syndrome

For me, 99% of the time conjunctivitis is a benign, viral, self-limiting thing that we put on antibiotics to lubricate the eye. But this next piece of information is a game changer. If a kid comes in with conjunctivitis, you have to look at the tympanic membrane. If the tympanic membrane has bulged, it’s what’s called conjunctivitis otitis syndrome.

If you have someone with a gooky eye, look at the ear. The literature shows that if the tympanic membrane is bulged, even without ear pain, you need to treat them. About 25% of patients with conjunctivitis have concurrent otitis media even in the absence of severe pain. Every kid with conjunctivitis needs to have a really good ear exam; that’s in the pediatric infectious disease literature.

Conjunctivitis otitis syndrome happens because there is communication between the middle ear and the eye. It’s the Eustachian tubes and the lacrimal glands. When you see conjunctivitis otitis syndrome, it’s a different beast and you need to treat with Augmentin. This is important because Haemophilus influenzae is colonized there. H. flu is the most common pathogen. They need oral antibiotics.

Otitis Media in Adults

If the patient hasn’t had any antibiotics in the prior month, opt for high-dose amoxicillin (1,000 mg TID) or Augmentin (ER 2000/125 mg BID). If they’ve had antibiotics in the last month, we’re going to jump to Augmentin or a fluoroquinolone like levofloxacin or moxifloxacin. Interestingly, the levofloxacin is a five-day course of 750 once a day. Remember from Parts 1 and 2, you need to be careful with fluoroquinolones.

While we’re talking about the middle ear, I want to bring up vertigo. It’s clearly not an infectious disease, but I think it’s very tricky. You have all of these peripheral causes of vertigo, like BPPV, vestibular neuritis or Meniere’s disease. No big deal, just a nuisance and self-limiting. Then, you have vertigo that’s brain stem ischemia or cerebellar infarct. In my experience, you need to know what you’re doing with vertigo because it can be super risky.

I spent nine years working in one critical access emergency room and I saw a lot of vertigo, but it was always benign. I never got worked up about it. Then, when I worked at a regional stroke center, I’d see vertigo and my mindset was, “Ah, it’s a benign self-limiting problem,” just to do an MRI and see a cerebellar infarct. That, obviously, makes me very concerned.

I’m not going to go in depth here, but I do in my emergency medicine curriculum. Just know that vertigo is not just dizziness. You can’t rush the history with vertigo. When you have someone with vertigo you have to sit down and have them say “I feel like the room is spinning.” You have to keep asking questions.

When someone comes in with hearing loss, the Rinne and Weber tests are important. When you have someone with acute onset of neurosensory hearing loss, you better get ENT on the phone. Remember: Weber goes toward wax. If you use the tuning fork on the patient’s forehead and it sounds loudest in the ear they can’t hear out of, it’s a conductive hearing problem. Rinne is trickier, but you need to know the difference.


The million-dollar question with cellulitis is, “Are they a diabetic?” If you don’t ask this question, it tells me you don’t know the significance of diabetic cellulitis. It’s a big deal. I also want to know if there is lymphangitis or lymphadenopathy. That’s the verbiage you should use. It shows people you’re in the know.

If someone has focal cellulitis, they have no lymphangitis, no lymphadenopathy, and no malaise. They don’t feel like they’re getting sick. When you have someone with lower extremity cellulitis, make sure you really look between their toes, because tinea pedis is often a point of entry for the cellulitis.

What are some oral agents versus MRSA? We have clindamycin, trimethoprim/sulfamethoxazole and doxycycline. The efficacy of clindamycin and Bactrim (or trimethoprim/sulfamethoxazole) is comparable. That was documented in the New England Journal of Medicine.

UTI in Females

If there are no signs of pyelo (no fever or back pain), you did a urine culture, and considered an STD, if it really is a UTI, Bactrim is a reasonable choice. This is based on Sanford’s Guide. The dose is one tab BID of the double strength for three days, Pyridium plus or minus. If they’re sulfa allergic or you have greater than 20% resistance to E. coli, opt for nitrofurantoin at 100 mg PO BID for five, plus or minus Pyridium. Don’t use nitrofurantoin in the last trimester of pregnancy, because you can get hemolytic anemia of newborns. Nitrofurantoin (Macrodantin or Macrobid) is the drug of choice for pregnant women with UTIs, but not in the third trimester.

Fluoroquinolones are not recommended as a primary regime. There are a lot of side effects, as well as resistance patterns that are starting to parallel Bactrim. Avoid fluoroquinolones for uncomplicated UTIs.

Strep Throat

Remeber the strep throat diagnosis criteria, CENTOR:

  • Cough: Do they have a cough? Strep should not cough. If the patient is coughing, the problem is vocal cord south. It’s a pertinent negative.
  • Exudates: Do they have purulent-looking tonsils?
  • Nodes: Do they have cervical adenopathy?
  • Temp: Do they have a fever?
  • Or could they have mono?

You’re looking for three out of the four. The treatment for strep is penicillin; it’s the drug of choice. A lot of the time, we use amoxicillin, which is fine. But what’s recommended in Sanford’s Guide is penicillin V, 250 mg PO BID or TID for ten days in pediatrics. It could just be the benzine penicillin, 250,000 units per kg as an IM shot to a maximum of 1.2 million units. It could be amoxicillin suspension, which tastes like bubble gum. Or, it could be Augmentin; 45 mg/kg per day BID.

In adults, it’s Pen V, 500 mg PO BID or 250 mg PO QID. You can also do Augmentin, and that’s 875 PO BID. If you get an adult with really, really bad strep throat, do not hesitate to give them 125 of Solu-Medrol and some IV ceftriaxone. The next day, they feel like a million dollars and they’re really thankful. It’s not the antibiotic that kicked them that fast. It’s a regime that I’ve used. This is not something that’s recommended in Sanford’s Guide; it’s a John-ism. Use it if you’d like.

Community-Acquired Pneumonia

When it comes to primary regimes for cases of community-acquired pneumonia you’re sending home, Sanford’s Guide recommends azithromycin, with 500 mg on day one and 250 the next few days. I do not like azithromycin. I’d rather have something stronger like clarithromycin.

If the patient has had antibiotics in the last three months, you want combination therapy. Use the macrolide, azithromycin and/or clarithromycin with Augmentin 1000 mg BID, amoxicillin 1 gram PO TID or levofloxacin. I’m going to say it again. If they’ve had antibiotics in the last three months, you want to go with a really strong regime. If they’ve had comorbidities, Sanford’s Guide recommends Levaquin, 750 mg daily for five days.


They’ve got a temperature of greater than 102 with costovertebral tenderness. You always want to culture their urine. If you have a guy with a pyelo, you need to look for a problem and have a urological consult.

Ciprofloxacin is a reasonable treatment for outpatient therapy because this isn’t a simple UTI. It’s a complicated one, so the treatment is 500 mg BID or the Cipro ER once a day, or levofloxacin 750 or Ofloxacin, which I’ve never written, for 400 mg BID for five to seven. If you know the E. coli resistance of fluoroquinolone is greater than 10% where you work, you may want to consider ceftriaxone and/or a one-time dose of gentamicin. Remember, gentamicin is 5-7 mg/kg and as a one-time dose, it knocks the crap out of E. coli.


Sinusitis isn’t really about the antibiotics – it’s about getting the crap out of their sinuses. You want to thin out the mucous membranes with lots of fluid and open up the ostia with decongestants, such as Afrin nasal spray or pseudoephedrine.

Be very, very careful. You can get sinusitis that’s induced by allergies. When that happens, some clinicians put them on antihistamines. The problem with that is that if they have gook in their sinuses, antihistamines or anticholinergics dry them up and make their sinusitis way worse. Avoid antihistamines with sinusitis.

So, antibiotics are rarely needed. Oral fluids and perhaps nasal saline irrigation are reasonable treatments. Sinusitis is a common cause of antibiotic overuse. What are the guidelines for using antibiotics? There are three situations where you should pull the trigger on antibiotics.

  1. Fever greater than 102.2 in children
  2. Intense facial pain
  3. Purulent nasal discharge

If you withheld antibiotics and they still have symptoms 10 days out, then you have to think either allergies or sinusitis. In Lancet in 2008, they did nine double-blind trials and found no real clinical significance between signs and symptoms that justified treatment, even after seven to 10 days. In randomized placebo-controlled trials in adults, a 10-day course of amoxicillin compared to placebo did not reduce symptoms at day three of therapy.

We’ve covered the big ones here. If you have any questions, concerns or want me to go into depth on something, please let me know. At CME4Life, we want to maximize your mind. I’m a battle-tested clinician. I don’t want to waste your time, because I know it’s valuable. I want to give you real tools that can make a difference in your clinical practice.

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