PANCE Blueprint EENT (6%)

ReelDx Virtual Rounds (Nystagmus)

Involuntary, jerking movements of the eyes

• Downbeat nystagmus/upbeat nystagmus: CNS dysfunction
• Vestibular (horizontal): labyrinth or vestibular nerve dysfunction
• Gaze-evoked: most common and often benign

DX: Caloric reflex test in which one ear canal is irrigated with warm or cold water or air. The temperature gradient provokes the stimulation of the horizontal semicircular canal and the consequent nystagmus.

• The resulting movement of the eyes may be recorded and quantified by electronystagmography (ENG) or a videonystagmograph (VNG)
• Special swinging chairs with electrical controls can be used to induce rotatory nystagmus
• Orthoptists may also use an optokinetic drum or electrooculography to assess a patient's eye movements

TX: medications baclofen and gabapentin

• Several therapeutic approaches, such as contact lenses, surgery, and low-vision rehabilitation, have also been proposed
• Surgery: tenotomy
• Physical therapy

ReelDx Virtual Rounds (Optic neuritis )

Acute inflammation and demyelination of the optic nerve leading to acute monocular vision loss/blurriness and pain on extraocular movements

• Typically occurs over hours or days
• Multiple sclerosis is the most common cause, and optic neuritis is often the initial presenting symptom
• Optic neuritis is associated with the use of ethambutol (a common board question) 

DX: Fundoscopy ⇒ inflammation of the optic disc

• MRI will confirm demyelination

TX: IV corticosteroids

• Refer to neurology for evaluation of Multiple Sclerosis

ReelDx Virtual Rounds (Papilledema)

Papilledema is optic disc swelling that is caused by increased intracranial pressure. The swelling is usually bilateral and can occur over a period of hours to weeks

• Causes include malignant hypertension, brain tumor/abscess, meningitis, cerebral hemorrhage, encephalitis, pseudotumor cerebri

DX: Diagnosis is by ophthalmoscopy with further tests, usually brain imaging and sometimes subsequent lumbar puncture, to determine the cause

• MRI or CT scan of the head looking for a cause. Focus on finding intracranial pathology = tumor or bleed, cerebral edema, CSF outflow obstruction, or overproduction
• Increased opening pressure with lumbar puncture confirms increased intracranial pressure

TX: Treat underlying cause