Conditions Affecting the Internal Eye for the Physician Assistant Exam
Some eye conditions can become medical emergencies if not treated. For the Physician Assistant Exam, you will need to know about papilledema, glaucoma, and hyphema, as well as optic neuritis.
Papilledema: Intracranial pressure
Papilledema is swelling of the optic disc due to increased intracranial pressure. Rich has seen this condition in people who present to the hospital with hypertensive emergencies.
The diagnosis is made with an ophthalmoscope. Papilledema has many causes, including a brain malignancy (primary or metastasis, usually with elevated intracranial pressure and midline shifting when severe), bleeding in the brain, benign intracranial hypertension, and malignant hypertension. On ophthalmic examination, the optic disc looks blurred because you’re no longer able to see the margins.
The treatment is to lower the intracranial pressure in the brain. For a hypertensive emergency, this means a gradual lowering of the blood pressure. For a brain tumor, it may mean high-dose steroids, mannitol, and/or neurosurgery.
Glaucoma: Intraocular pressure
Glaucoma is defined as damage to the optic nerve secondary to a very elevated intraocular pressure. If left untreated, this condition can result in permanent blindness. Be aware of two big types of glaucoma:
Open-angle glaucoma: This type, which is the most common, is often hereditary and painless. The affected person can describe a gradual loss of vision. On examination, the ophthalmologist often sees damage to the optic nerve.
Angle-closure glaucoma: Angle-closure glaucoma, which is a medical emergency, is characterized by the triad of a fixed and dilated pupil, severe eye pain, and loss of vision. The intraocular pressure is very high. This form of glaucoma is treated surgically.
A variety of eye drops are used to treat glaucoma by lowering the intraocular pressure. Although marijuana (cannabis) may lower intraocular pressure, this effect lasts for only a few hours and isn’t as effective as other medications.
A hyphema is blood in the anterior chamber of the eye. The most common cause is trauma. Another significant risk factor is any type of coagulopathy. This condition usually affects one eye, not both. Clinical symptoms can include eye pain and photosensitivity.
Many hyphemas resolve on their own, but the medical professional often recommends avoiding strenuous physical activity, avoiding further trauma, and avoiding rubbing or touching the eyes. Correcting any coagulopathies is a good idea, too.
Optic neuritis is the inflammation of the optic nerve. It causes acute vision loss and pain in the eye. It can be the initial symptom of multiple sclerosis. On examination, you see an abnormality in the optic nerve. Immediate treatment is either intravenous hydrocortisone or the more commonly used methylprednisolone sodium succinate. Finding the underlying cause is key, because this condition can be associated with other autoimmune and rheumatologic disorders.