6.8 Brown Syndrome

Definition

  • Hallmark: Syndrome of deficient elevation in adduction due to restriction of the superior oblique (SO) tendon or trochlea-tendon complex
  • The limitation in elevation improves to normal or near normal elevation in abduction
  • Also known as Superior Oblique Tendon Sheath syndrome

Aetiology

Congenital (no Diplopia Suppression)

Idiopathic

  1. Mild (limited elevation in adduction)
  2. Moderate (+ downshoot in adduction)
  3. Severe (+ hypotropia in primary)

Acquired (May Get Diplopia)

  • Trauma to the trochlea or SO tendon (e.g. “canine tooth syndrome”)
  • Inflammation of the trochlea or SO tendon (rheumatoid arthritis, sinusitis, scleritis)

Severity Grading

Downshoot in Adduction

Hypotropia in Primary

Surgery

Mild

Downshoot in Adduction

No

Hypotropia in Primary

No

Surgery

No

Moderate

Downshoot in Adduction

Yes

Hypotropia in Primary

No

Surgery

No

Severe

Downshoot in Adduction

Yes

Hypotropia in Primary

Yes

Surgery

No

Examination Structure

1. Visual Acuity (Best Corrected)

  • Amblyopia is rare

2. Spectacles

3. Inspection

  1. Abnormal head position- chin up, head turn to the opposite side
  2. Hirschberg (Pupil margin = 15°, Iris margin = 30°)
  3. (Lids normal)
  4. (Pupils normal)
  5. Inspect for trauma around the trochlea
Figure 6.8.1 Left Brown Syndrome

Figure 6.8.1
Left Brown Syndrome

Limited elevated in adduction of the left eye (the patient is attempting to look up to their right)

4. Cover-Testing

  • Often straight or small hypotropia in primary (congenital)
  • Acquired usually have larger hypotropia

5. Ocular Rotations

  • ~90% Unilateral
  • Hallmark: Limited elevation in adduction, which improves to normal or near normal elevation in abduction. Most easily demonstrated by bringing the eye from abduction to adduction in upgaze and seeing it fall (the “falling eye sign”)
  • No improvement with ductions
  • No “superior oblique overaction” (SOOA)
  • V pattern

6. Palpate Trochlea

  • Feel for trauma, inflammation (in acquired Brown syndrome)

7. Forced Duction Testing

  • Positive
  • Tested by feeling for a click on elevation in adduction.
  • Accentuated in this position by retropulsion

Differential Diagnosis

1. IO Palsy

Browns

IO Palsy (rare)
Damage to inferior division of CNIII

Monocular Elevation Deficit

Laterality

Browns

90% Unilateral

IO Palsy (rare)
Damage to inferior division of CNIII

Unilateral

Monocular Elevation Deficit

Unilateral

Primary

Browns

Straight or hypotropic (usually <10Δ)

IO Palsy (rare)
Damage to inferior division of CNIII

More hypotropia (usually >10Δ)

Monocular Elevation Deficit

Hypotropia

Adduction

Browns

± Downshoot
Limitation of elevation in adduction
No improvement with ductions

IO Palsy (rare)
Damage to inferior division of CNIII

± Downshoot
Limitation of elevation in adduction
Improvement with ductions

Monocular Elevation Deficit

Limited elevation in both adduction and abduction

“SOOA”

Browns

No

IO Palsy (rare)
Damage to inferior division of CNIII

Yes

Monocular Elevation Deficit

No

Alphabet pattern

Browns

V pattern

IO Palsy (rare)
Damage to inferior division of CNIII

A pattern

Monocular Elevation Deficit

No alphabet pattern

Forced duction

Browns

Positive

IO Palsy (rare)
Damage to inferior division of CNIII

Negative

Monocular Elevation Deficit

Normal or positive
FGT may show weak SR

Trochlear

Browns

May feel click

IO Palsy (rare)
Damage to inferior division of CNIII

Normal

Monocular Elevation Deficit

Normal

2. Monocular Elevation Deficit (“Double Elevator Palsy”)

  • Limitation of elevation in adduction and abduction

3. Restriction (TED, Orbital Wall Fracture, Myositis)

Investigations

  • In non-traumatic acquired cases consider work up for connective tissue disease (e.g. rheumatoid factor / ANA / ESR)
  • Consider MRI especially if features of pain, inflammation

Hess Chart

Figure 6.8.2 Hess Chart of Right Brown Syndrome

Figure 6.8.2
Hess Chart of Right Brown Syndrome

There is underaction of elevation in adduction of the right eye. As a sequelae there is overaction of the left (contralateral) superior rectus.

Management

A. Treat Amblyopia / Refractive Error

  • Amblyopia is present in up to 15% of patients and is usually secondary to anisometropia / refractive error rather than the strabismus

B. Surgical

A. Indications

Most don’t need surgery. Becomes less noticeable as child grows taller.

  1. Abnormal head posture, torticollis
  2. Cosmetically unacceptable - hypotropia in primary, Downshoot in adduction
B. Operation

1. Congenital

  • Ipsilateral SO tenotomy ±IO myectomy to balance
  • Tendon spacer to lengthen the tendon

2. Acquired

  • Can observe – 2 / 3 resolve spontaneously
  • Non-steroidal anti-inflammatory drugs (NSAIDS)
  • Steroids (systemic or trochlea injection)
  • Surgery after 12 months

          

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