PANCE Blueprint EENT (7%)

Optic neuritis (ReelDx + Lecture)

VIDEO-CASE-PRESENTATION-REEL-DX

Optic Neuritis

50 y/o with pain and loss of vision in the left eye

Patient will present as → a 47-year-old school teacher with a cough, hemoptysis, fever, chills, and weight loss that has persisted since he returned from a summer trip to China. A chest radiograph is concerning for infection and a sputum culture is positive for acid-fast organisms. Treatment for this patient's condition is begun. Three weeks later the patient returns to the clinic with decreased visual acuity for one day in his right eye. He also reports pain in the eye with movement but no other symptoms. The patient has a family history of glaucoma, diabetes mellitus, factor V Leiden and stroke. On physical examination, when a penlight is shined into the affected eye there is no pupillary constriction in either eye. 

To watch this and all of Joe Gilboy PA-C's video lessons you must be a member. Members can log in here or join now.

Optic neuritis is associated with what TB medication?
Ethambutol (a common board question) 

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

  • Pt will present with acute monocular vision loss and pain in the affected eye
  • 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) 

Fundoscopy: Inflammation of the optic disc

  • MRI will confirm demyelination

Treatment is with methylprednisolone IV with a referral for neurology examination

Picmonic
Multiple Sclerosis

multiple-sclerosis-symptoms-and-diagnosis_5975_1492145264

Multiple sclerosis (MS) is a demyelinating disorder that demonstrates unclear pathogenesis but has significant evidence of autoimmune involvement. Clinical presentation is variable with subtypes delineated by symptom exacerbation, but it classically presents with Charcot’s neurologic triad, which consists of scanning speech, internuclear ophthalmoplegia, and nystagmus, with symptoms characteristically worsening after a hot shower. However, a wide range of clinical manifestations may be seen including optic neuritis, urinary, and fecal incontinence, motor abnormalities such as trembling and paresis, sensory changes ranging from pain to numbness and depression, all of which typically, though not exclusively, display a relapsing pattern. Diagnosis of MS includes the gold standard presence of simultaneous periventricular plaques on MRI, as well as elevated CSF immunoglobulins, most commonly IgG, and finally identification of oligoclonal IgG bands on immunoelectrophoresis.

MS Symptoms and Diagnosis
Play Video + Quiz
MS Features and Mechanisms
Play Video + Quiz

Question 1
A 24-year-old woman with HIV is diagnosed with Mycobacterium avium complex infection. She is started on a treatment regimen of clarithromycin with ethambutol. She needs to be educated that which of the following is a potential complication of this therapy?
A
anemia
Hint:
Anemia is associated with many of the drugs used to treat AIDS-related opportunistic infections, including trimethoprim-sulfamethoxazole, pentamidine, amphotericin B, ganciclovir, and valganciclovir.
B
azotemia
Hint:
Amphotericin B is associated with azotemia and trimethoprim with methemoglobinemia.
C
methemoglobinemia
Hint:
Amphotericin B is associated with azotemia and trimethoprim with methemoglobinemia.
D
mucositis
Hint:
Trimetrexate can cause mucositis.
E
optic neuritis
Question 1 Explanation: 
Optic neuritis is associated with the use of ethambutol. Anemia is associated with many of the drugs used to treat AIDS-related opportunistic infections, including trimethoprim-sulfamethoxazole, pentamidine, amphotericin B, ganciclovir, and valganciclovir. Amphotericin B is associated with azotemia and trimethoprim with methemoglobinemia. Trimetrexate can cause mucositis.
Question 2
A 30-year-old woman presents with acute vision loss in her right eye and pain on eye movement. She has no significant past medical history. This presentation is most commonly associated with which of the following conditions?
A
Diabetic retinopathy
Hint:
Typically presents with gradual vision loss and is not associated with pain on eye movement.
B
Glaucoma
Hint:
Causes gradual peripheral vision loss and is not typically painful.
C
Multiple sclerosis
D
Hypertensive retinopathy
Hint:
Associated with chronic hypertension and does not usually present with acute vision loss and pain on eye movement.
E
Retinal detachment
Hint:
Presents with flashes, floaters, and a "curtain" over the field of vision, without pain.
Question 2 Explanation: 
Optic neuritis, characterized by acute vision loss and pain with eye movement, is often associated with multiple sclerosis (MS), especially in young adults. It can be an initial presentation of MS or occur during the course of the disease.
Question 3
A 28-year-old male reports sudden loss of vision in his left eye over the past few days. He also experiences pain when moving his eye. On examination, there is a relative afferent pupillary defect in the left eye. What is the most appropriate diagnostic test to confirm the diagnosis?
A
Fundoscopic examination
Hint:
May be normal in optic neuritis or show optic disc swelling.
B
MRI of the brain and orbits with gadolinium
C
Visual field testing
Hint:
Useful but not definitive for diagnosing optic neuritis.
D
Intraocular pressure measurement
Hint:
More relevant in glaucoma.
E
Fluorescein angiography
Hint:
Used in retinal vascular disorders, not typically in optic neuritis.
Question 3 Explanation: 
MRI of the brain and orbits with gadolinium is the most appropriate diagnostic test for optic neuritis, especially to assess for demyelinating lesions indicative of multiple sclerosis. It helps in evaluating the optic nerve and detecting any associated central nervous system lesions.
Question 4
A 35-year-old woman is diagnosed with optic neuritis. She has no history of multiple sclerosis or other autoimmune disorders. What is the most appropriate initial treatment for her condition?
A
High-dose intravenous corticosteroids
B
Oral corticosteroids
Hint:
Not recommended as initial monotherapy for optic neuritis due to potential for recurrence.
C
Observation without treatment
Hint:
Not ideal for acute optic neuritis, as prompt treatment can aid faster recovery.
D
Intravitreal corticosteroid injection
Hint:
Not a standard treatment for optic neuritis.
E
Immunosuppressive therapy
Hint:
Considered in cases of recurrent optic neuritis or associated autoimmune disorders.
Question 4 Explanation: 
High-dose intravenous corticosteroids are the most appropriate initial treatment for acute optic neuritis. They can speed up visual recovery, although they do not affect the long-term outcome. This treatment is particularly important in the absence of a known underlying condition like multiple sclerosis.
There are 4 questions to complete.
List
Return
Shaded items are complete.
1234
Return

References: Merck Manual · UpToDate

Nystagmus (ReelDx) (Prev Lesson)
(Next Lesson) Papilledema (ReelDx)
Back to PANCE Blueprint EENT (7%)

NCCPA™ CONTENT BLUEPRINT

Memorial Day Sale Extended! Get 20% off your SMARTY PANCE purchase (One Day Only!)

X