Differential Diagnosis for a 9-Month-Old with Fever, Swollen Eye, and URI
Single Most Likely Diagnosis
- Viral Conjunctivitis: Given the context of a recent URI and the sudden onset of a swollen eye in a child who is otherwise happy, eating, and playing, viral conjunctivitis is a common and likely diagnosis. The fever could be part of the viral infection.
Other Likely Diagnoses
- Bacterial Conjunctivitis: This could also explain the swollen eye, especially if there's discharge. It's a common condition in children and can follow a viral URI.
- Periorbital Cellulitis: An infection of the skin and tissues around the eye, which can be a complication of sinusitis or an extension of conjunctivitis. The presence of fever and a swollen eye makes this a plausible diagnosis.
- Sinusitis: Given the 5-day history of URI, sinusitis could be a cause of the fever and potentially the swollen eye if there's an extension of the infection.
Do Not Miss Diagnoses
- Orbital Cellulitis: A serious infection of the tissues surrounding the eye, which can lead to severe complications if not promptly treated. It's crucial to distinguish this from periorbital cellulitis due to its potential for serious morbidity.
- Retinoblastoma or Other Orbital Tumors: Although rare, any sudden onset of a swollen eye in a child warrants consideration of these diagnoses due to their potential severity and the importance of early detection.
- Herpes Simplex Virus (HSV) Infection: HSV can cause severe ocular and systemic infections in infants. Given the fever and swollen eye, HSV should be considered, especially if there's any history of exposure.
Rare Diagnoses
- Juvenile Idiopathic Arthritis (JIA): This chronic autoimmune disease can present with ocular symptoms, including uveitis, which might cause eye swelling. However, it's less likely given the acute presentation and the context of a recent URI.
- Granulomatosis with Polyangiitis (formerly known as Wegener's Granulomatosis): A rare autoimmune disorder that can affect various parts of the body, including the eyes, but it's extremely uncommon in infants.
- Leukemia: Certain types of leukemia can present with ocular symptoms due to infiltration of leukemic cells into the orbit. This is a rare consideration but should be kept in mind due to the potential severity of the disease.