Boy presents with fever, painful swelling behind right ear
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A previously healthy and fully immunized 5-year-old male was seen in an urgent care clinic for an evaluation of a fever of 102.4°F and painful swelling behind his right ear.
His symptoms began 2 days earlier, with the subsequent development of drainage from the right ear canal. The fever was documented and a blood culture was obtained prior to the patient receiving a dose of ceftriaxone. A CT scan revealed pansinusitis and right mastoiditis, and the patient was transferred for hospitalization.
The patient has no other complaints, with an otherwise normal review of systems except for a past medical history of recurrent acute otitis media (AOM), treated with pressure equalization (PE) tubes placed at 18 months of age. The PE tubes eventually came out, with no episodes of AOM in the last 2 years.
Examination revealed a protruding right pinna (Figure 1), with diffuse postauricular painful swelling and erythema (Figure 2). The left tympanic membrane (TM) had an old scar from the previous PE tube, whereas the right canal was full of purulent debris. The on-call otolaryngologist cleaned out the canal, verified a perforation and sterilely obtained a culture of the drainage at the TM opening.
At 24 hours, the blood culture done at the referring facility has no growth, but the culture from the right ear drainage is growing gram-positive cocci (GPC) in chains (Figure 3).
In summary:
1. The patient is a fully immunized, 5-year-old male with a past history of recurrent AOM who had successful PE tube placement at 18 months of age, which subsequently came out.
2. The patient was well until 2 days prior to admission, presenting with fever and AOM with perforation and right mastoiditis.
3. A Gram stain from the right ear discharge is growing GPC in chains.
What’s your diagnosis (most likely cause)?
A. Haemophilus influenzae type b
B. Staphylococcus aureus
C. Streptococcus pneumoniae
D. Streptococcus pyogenes
Answer and discussion:
The culture of the material draining from this patient’s right tympanic membrane grew S. pyogenes (group A strep), which is the second most likely “true” pathogen causing acute mastoiditis. Pseudomonas aeruginosa has been occasionally implicated, but most often in this age group, the bacteria represent a sampling error due to surface contamination from the ear canal. S. pneumoniae by far leads the list of causes of acute mastoiditis when proper culture technique is used, with S. pyogenes being a distant second. However, in the era of enhanced, conjugated pneumococcal immunization, the chances that pneumococcus is causing acute mastoiditis are significantly lower than previous studies have suggested. In the case presented here, the clue is in the Gram stain.
Every now and then, we should go back to review some basic “medical school microbiology.” A properly performed Gram stain of S. pyogenes would reveal some chains of gram-positive (blue-stained) cocci, as shown in Figure 3, whereas that of S. pneumoniae would most likely be lancet-shaped, gram-positive diplococci (Figure 4). Regarding H. influenzae type b (Hib), the Gram stain would reveal gram-negative (red stained), pleomorphic rods, as shown in Figure 5. Pleomorphism means variable size and/or staining. In a fully immunized patient, Hib is very uncommon, which also rules against this choice. S. aureus falls in at the third or fourth spot in the order of commonality. Classically, S. aureus appears as clusters of gram-positive cocci, as shown in Figure 6. The pitfall in Gram stain interpretation can be in the staining technique or the “fake-out” of the size and shape of the organism. For example, gram-negative diplococci may actually be gram-negative rods with bipolar staining. I got sucker-punched with that one during my fellowship, much to the amusement of my program director James W. Bass, MD. So, what looked like Neisseria meningitidis to my naive eyes on the microscope turned out to be Hib. You may also notice that all these organisms are spelled in italics or underlined by universal convention, and that the word Gram is capitalized, except where it is in reference to the stain results, reflecting the name of the inventor of the stain, Hans Christian Gram, in 1884. End of microbiology refresher course.
The swelling of the soft tissue over the mastoid, or postauricular area, causes the pinna to be displaced forward, as seen in Figure 1. However, not all protruding pinnae are caused by acute mastoiditis. There are other causes for this swelling, such as an insect bite on the pinna, a cluster of herpetic lesions (more common than one might think) or other form of injury to the pinna or postauricular area.
Acute mastoiditis is virtually always a complication of AOM in a patient with a history of recurrent AOM. However, there are exceptions. The usual approach to management involves antimicrobial therapy directed at the usual causes, pending culture results and surgical placement of PE tubes, if not already there, with surgical drainage and debridement of the mastoid if needed. The commonly recommended antimicrobial agents include a broad-spectrum beta-lactam, such as a third-generation cephalosporin plus clindamycin, pending culture results. In the adolescent patient, an anti-pseudomonal beta-lactam might be used due to the increased chance of a true P. aeruginosa infection. Complications with proper management are uncommon. One such complication is facial nerve palsy, which is usually present at the point of presentation. Another potential complication is bacterial meningitis, which should be ruled out by testing or confident clinical criteria. The patient in this case, with the growth of S. pyogenes, finished his treatment with penicillin G and clindamycin (7 days in the hospital) with good clinical results, and transitioned to high-dose oral therapy with amoxicillin for an additional 3 to 4 weeks.
Columnist comments:
I would guess with confidence that we all had someone who had a strong influence on our choice of specialty (and subspecialty), usually as a 3 rd - or 4th -year student. My pediatric infectious disease mentor, who also happened to be a brilliant general pediatrician and hospitalist before there was such a designation, was Warren A. Todd, MD, who died on July 20 at 81 years of age after a private battle with a long illness. Warren was on the pediatric infectious diseases staff at Fitzsimons Army Medical Center in the 1970s, which is where we met in the summer of 1975 when I was there on a 3rd -year student rotation. He was a passionate and compassionate teacher, with a breadth of medical knowledge I have never known in any other colleague, and he inspired me to pursue a similar career; a worthy goal that I could never achieve. The bar was just too high but made me better for trying. Like many of you, I called my teachers early in my post-graduate years with difficult questions for reassurance. I would call Warren for help with any ID question I had before my fellowship. Later in my career, I called him to get his thoughts on leadership, policy or life in general, not just because of his common sense, but he also retired from the Army as a brigadier general, with the command experience that goes with that rank. He was like having a brilliant older brother who actually enjoyed hearing from you, problems and all. During residency, he introduced me to the “cowbell” on rounds, which he would ring when he sensed the presence of “bull feces” coming from the mouth of the presenting student or resident — an effective teaching practice that I took with me.
He did not bother people with his own problems. I spoke with him exactly 2 weeks before he died and still did not know he was sick. Such is the character of greatness. Farewell Woo Woo, from your favorite resident, Jim Bob.
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Brien is a member of the Infectious Diseases in Children and Infectious Disease News Editorial Boards, and an adjunct professor of pediatric infectious diseases at McLane Children's Hospital, Baylor Scott & White Health, in Temple, Texas. He can be reached at jhbrien@aol.com.