Trochlear Palsey

Question 1

What is it

Answer 1

Dysfunction of the trochlear nerve (cranial nerve IV), which controls the superior oblique muscle, leading to vertical diplopia and head tilt.

Question 2

Clinical features

Answer 2

Vertical diplopia (double vision, especially when looking down) 👀📖
Head tilt to the opposite side (compensatory) 🏾↖️
Eye misalignment (hypertropia – affected eye higher)
Difficulty with downward gaze (e.g., reading, stairs) 📚

Question 3

Epidemiology

Answer 3

CN IV is the most commonly injured cranial nerve in trauma 🚑
Can be congenital or acquired
Rare compared to other cranial nerve palsies

Question 4

Age Groups Affected

Answer 4

Congenital cases: Seen in childhood but may not be noticed until later
Acquired cases: Common in older adults with vascular risk factors or trauma patients

Question 5

Risk Factors

Answer 5

✅ Modifiable:
Head trauma (most common cause) 🏍️🚗
Diabetes & hypertension (microvascular ischemia)
Brain tumors & aneurysms
Infections (e.g., meningitis)

🚫 Non-Modifiable:
Congenital CN IV palsy (may cause strabismus from birth)
Stroke or demyelinating diseases (e.g., multiple sclerosis)

Question 6

Clinical Presentation

Answer 6

🔹 Congenital CN IV Palsy:

Long-standing head tilt (compensatory)
Mild symptoms, often diagnosed later in life

🔹 Acquired CN IV Palsy (Common Causes: Trauma, Stroke, Tumor):
Sudden onset vertical diplopia
Difficulty looking down (trouble with stairs & reading) 📖📉
Head tilt to the opposite side to compensate 🏾↖️

Question 7

Prognosis

Answer 7

🔹 Depends on the cause:

Trauma-related: May recover in months but can be permanent

Microvascular (diabetes, hypertension): Usually resolves in 3-6 months

Tumor or aneurysm: Requires treatment of underlying cause
🔹 Congenital cases can be treated with prism glasses or surgery if severe

Question 8

Test

Answer 8

H - Test

Outcomes - vertical diplopia