Differential Diagnosis for Red Eye with Fixed Pupil
Single Most Likely Diagnosis
- Acute Angle-Closure Glaucoma: This condition is characterized by a sudden increase in intraocular pressure, leading to a red, painful eye with a fixed, mid-dilated pupil. It is a medical emergency requiring prompt treatment to prevent vision loss.
Other Likely Diagnoses
- Uveitis: Inflammation of the uvea can cause a red eye with a constricted or fixed pupil due to irritation and spasm of the iris sphincter.
- Endophthalmitis: A severe infection within the eye, usually following surgery or trauma, can present with a red eye and a fixed pupil due to inflammation and damage to the iris and other ocular structures.
- Retinal Detachment: Although not always associated with a fixed pupil, a retinal detachment can cause a red eye and vision changes, with the pupil sometimes becoming fixed due to associated conditions like uveitis.
Do Not Miss Diagnoses
- Central Retinal Artery Occlusion: This condition, which blocks the blood supply to the retina, can present with sudden vision loss and a red eye, sometimes with a fixed pupil. Prompt diagnosis and treatment are crucial to restore vision.
- Ocular Malignancy (e.g., Melanoma): Although less common, ocular tumors can cause a red eye and changes in pupil reactivity. Missing this diagnosis could have severe consequences, including loss of the eye or life.
- Intraocular Foreign Body: Especially if the foreign body is metallic, it can lead to severe inflammation and potentially a fixed pupil. Prompt removal is necessary to prevent further damage.
Rare Diagnoses
- Tadpole Retinal Detachment: A specific type of retinal detachment that can cause a red eye and sometimes a fixed pupil due to its unique presentation and associated inflammation.
- Sympathetic Ophthalmia: A rare, bilateral inflammation of the eyes following trauma or surgery to one eye, which can result in a red eye and changes in pupil reactivity in the unaffected eye.
- Phacolytic Glaucoma: Associated with a mature or hypermature cataract, this condition can cause a red eye and a fixed pupil due to the leakage of lens proteins into the anterior chamber, leading to inflammation and increased intraocular pressure.