An 18-month-old boy is brought to the office for right ear pain. About 4 weeks ago, he had fever and right ear pain and was prescribed a 10-day course of high-dose amoxicillin for acute otitis media; he completed the course and had a normal follow-up visit 2 weeks ago. While on the medication, he experienced improvement in his symptoms. For the past 3 days, he has been tugging on his right ear and crying; he developed fever today. He has no nasal congestion, neck stiffness, cough, emesis, or other symptoms. He is otherwise healthy and takes no medications. His immunizations are up to date. Temperature is 38.5 C (101.3 F), blood pressure is 108/66 mm Hg, pulse is 96/min, and respirations are 21/min. Physical examination demonstrates an alert, uncomfortable child. Pupils are equal and reactive; the conjunctivae are injected bilaterally and have purulent discharge. There is no rhinorrhea or sinus tenderness. The external ears appear normal and are not painful to manipulation; there is no drainage in the external canal. The right tympanic membrane is erythematous, bulging, and immobile on pneumatic air insufflation. The left tympanic membrane appears normal. Both mastoids are nontender and nonerythematous. The neck is nontender and has full range of motion. Cardiopulmonary examination is normal.
Which of the following is the most likely cause of this patient's current symptoms?

Question

An 18-month-old boy is brought to the office for right ear pain.  About 4 weeks ago, he had fever and right ear pain and was prescribed a 10-day course of high-dose amoxicillin for acute otitis media; he completed the course and had a normal follow-up visit 2 weeks ago.  While on the medication, he experienced improvement in his symptoms.  For the past 3 days, he has been tugging on his right ear and crying; he developed fever today.  He has no nasal congestion, neck stiffness, cough, emesis, or other symptoms.  He is otherwise healthy and takes no medications.  His immunizations are up to date.  Temperature is 38.5 C (101.3 F), blood pressure is 108/66 mm Hg, pulse is 96/min, and respirations are 21/min.  Physical examination demonstrates an alert, uncomfortable child.  Pupils are equal and reactive; the conjunctivae are injected bilaterally and have purulent discharge.  There is no rhinorrhea or sinus tenderness.  The external ears appear normal and are not painful to manipulation; there is no drainage in the external canal.  The right tympanic membrane is erythematous, bulging, and immobile on pneumatic air insufflation.  The left tympanic membrane appears normal.  Both mastoids are nontender and nonerythematous.  The neck is nontender and has full range of motion.  Cardiopulmonary examination is normal. 
Which of the following is the most likely cause of this patient's current symptoms?

Quizplus · Accepted Answer

Explanation: 11ec2b69_bfb3_ba02_8f63_cde874612c87_MD0005_00 This child with fever, ear pain, and a bulging, erythematous, immobile tympanic membrane has the classic presentation of acute otitis media (AOM). The diagnosis is clinical and requires: Fluid (effusion) in the middle ear: Manifesting as limited tympanic membrane motility on insufflation Tympanic membrane inflammation: Manifesting as bulging of the tympanic membrane (sensitive and specific) Other nonspecific signs of eardrum inflammation include otalgia, tympanic membrane erythema, and fever. The most common bacterial pathogens are Streptococcus pneumoniae, nontypeable Haemophilus influenzae, and Moraxella catarrhalis. Recurrent infection within 2 weeks of treatment is sometimes caused by the same pathogen as the initial infection due to resistant strains (as a result of AOM overdiagnosis and excessive antibiotic prescription). Infection that develops >2 weeks later is usually due to different pathogens. Concurrent otitis media and purulent conjunctivitis (otitis-conjunctivitis syndrome) is typically caused by nontypeable H influenzae. (Choice A) Viral and bacterial causes of AOM are indistinguishable on otoscopy. However, adenovirus infection is a less common causative organism than nontypeable H influenzae. In addition, adenovirus usually causes concurrent symptoms such as nonpurulent (rather than purulent) conjunctivitis, pharyngitis, upper respiratory infection, and gastroenteritis, which are not present in this patient. (Choice B) In the past, H influenzae type b infections were a more common cause of AOM; however, due to widespread vaccination, their incidence has decreased and most cases of H influenzae AOM are caused by nontypeable strains. (Choice C) M catarrhalis is a common cause of AOM; however, its incidence is significantly lower than that of S pneumoniae and H influenzae. In addition, M catarrhalis does not cause otitis-conjunctivitis syndrome. (Choice E) Although Staphylococcus aureus is a common skin flora, it is an uncommon cause of AOM or otitis externa except in patients with tympanostomy tubes. Educational objective: The most common pathogens responsible for acute otitis media include Streptococcus pneumoniae, nontypeable Haemophilus influenzae, and Moraxella catarrhalis. H influenzae may cause otitis-conjunctivitis syndrome, in which purulent conjunctivitis occurs at the same time as acute otitis media. References: Otitis media: diagnosis and treatment. (http://www.ncbi.nlm.nih.gov/pubmed/24134083) The diagnosis and management of acute otitis media. (http://www.ncbi.nlm.nih.gov/pubmed/23439909)

An 18-Month-Old Boy Is Brought to the Office for Right