Differential Diagnosis for a 2-Month-Old Infant
Single Most Likely Diagnosis
- Acute Otitis Media (AOM): The infant's symptoms of irritability, fussiness, pulling at the right ear, and the physical assessment findings of a erythematous and bulging right tympanic membrane with discharge are classic for AOM. The absence of fever does not rule out this diagnosis, as young infants may not always present with fever.
Other Likely Diagnoses
- Otitis Media with Effusion (OME): Although the infant has symptoms suggestive of an acute infection, OME could be a consideration if the discharge is serous or if the tympanic membrane is not as inflamed. However, the presence of a bulging tympanic membrane and discharge leans more towards AOM.
- External Otitis (EO): Also known as swimmer's ear, EO could be a possibility if the infant has been exposed to water or has had a history of ear trauma. However, the physical exam findings of a bulging tympanic membrane are more suggestive of AOM.
Do Not Miss Diagnoses
- Mastoiditis: Although less likely, mastoiditis is a serious complication of AOM that requires prompt recognition and treatment. The absence of fever and more severe symptoms such as headache or neck stiffness makes this less likely, but it should still be considered.
- Petrous Apicitis: A rare but serious complication of AOM, petrous apicitis can present with similar symptoms to AOM but may also have additional symptoms such as headache, neck stiffness, or cranial nerve palsies.
- Bacterial Meningitis: Although the infant does not have fever or other symptoms suggestive of meningitis, this diagnosis should always be considered in a young infant with signs of infection, especially if they are not responding to treatment or have a severe presentation.
Rare Diagnoses
- Cholesteatoma: A rare condition where a skin cyst forms in the middle ear, cholesteatoma can cause similar symptoms to AOM but is less likely in a 2-month-old infant.
- Middle Ear Tumor: Extremely rare in infants, a middle ear tumor could cause similar symptoms to AOM but would be an unusual diagnosis in this age group.
- Eustachian Tube Dysfunction: Although not typically considered a diagnosis, Eustachian tube dysfunction can contribute to the development of AOM or OME, especially in infants with a history of respiratory infections or allergies.