3.1 Brown's Syndrome Flashcards
What are three causes of congenital Browns?
- Idiopathic
- Anatomical anomalies
- Congenital click syndrome
What are four causes of acquired Browns?
- Secondary changes in previously normal SO tendon or tendon-trochlear complex.
- Inflammatory
o Rheumatoid arthritis, causes swelling on the tendon. Stenosing tenovaginitis “trigger finger” analogy.
o Scleritis and lupus erythermatosus
o Pansinusisits - Trauma
o RTA, ENT surgery, orbital mass, direct tumour - Other
o Fibrous attachments between the SR and underlying SO tendon
o SO insertion abnormality
o Genetically determined predisposition to Brown syndrome.
What are some anatomical anomalies in Brown’s?
- Inelastic, stiff, or short superior oblique tendon
- Fibrotic strand
- Nodule or swelling of the tendon - SO muscle and tendon are unable to relax to allow the eye to elevate
- Bursa like structure
- Thickened trabeculae – SO tendon and trochlear connected during the embryological development by thickened trabeculae which persists rather than remodels and so inhibits passage of tendon through the trochlear.
- Thickened vascular sheath – Vascular sheath enveloping SO tendon may be thickened thus reducing smooth passage of tendon through the trochlear.
What causes Iatrogenic Browns?
- Following surgery to strengthen SO (tuck) or SO palsy.
List some features of mechanical disorders
- Positive forced duction test
- Normal saccadic velocity
- Normal forced generation test
- Retraction of the globe
- Equal limitation of ductions and versions
- Reversal of the deviation
- Limited muscle sequalae
- Rise in IOP on OM (in direction of the restriction)
List some features of Browns syndrome
- Limitation of elevation in adduction
- Down-drift of the affected eye on contralateral version, can be accompanied by widening of the palpebral fissure.
- Overaction of the contralateral SR (sometimes this is mistaken by parents as the eye with the disorder).
- V pattern more likely than A pattern on OMs
- Discomfort on elevation and elevation in adduction
- Improvement in elevation in adduction on repeat testing – can be accompanied by ‘click syndrome’
What is click syndrome?
- Audible click may be heard
- Best detected by placing a finger over the trochlear and ask the patient to look up and in
How is Browns syndrome graded?
Mild - elevation is only limited in adduction
Moderate - there is a minimal hypoT in PP and a downshoot is present
Severe - there is a slight to moderate hypoT in PP and occasional AHP in PP with a downshoot present.
What are some extended orthoptic assessments we would perform on a Browns patient?
Hess chart
Forced duction test
Browns Syndrome V IO palsy
Browns;
Vertical deviation - may not be present in PP (dependent on severity)
OM - ductions = versions
Alphabet Pattern - V pattern
FDT - +ve
Muscle sequelae - Often only contralateral synergist
Torsion - No fundus torsion in PP
BHTT - -ve
IO Palsy;
Vertical deviation - Hypo in PP
OM - ductions>versions
Alphabet pattern - A pattern
FDT - -ve
Muscle sequelae - Can display all stages of sequelae
Torsion - intorsion
BHTT - +ve
Name some differentials for Browns
IO palsy
Blow out fracture
Double elevator palsy
Congenital fibrosis of EOMs
Adherence syndrome
Glaucoma surgery
MG
TED
Why is monitoring favourable for Browns?
- Most patients are symptomless and can demonstrate BSV in PP and lower field.
- The limitation may improve over time, if not then upgaze is used less frequently as an adult than as a child.
- Spontaneous recovery can be found in literature.
Why do we need to monitor children?
- Ensure there is no disruption of BSV in PP
- RARELY amblyopia and refractive error are documented as associated
- Children must be monitored to ensure VA is developing in accordance with the age norms
How often do we review children with Browns?
- Policies differ depending on the trust.
- Ansons and Davis (2014) – Keep children under observation, monitor carefully for refractive error and amblyopia.
- Annual reviews for consideration in some circumstances:
a. Uniocular vision is stable and appropriate for age
b. Binocular vision is stable and appropriate for age
c. No parental concerns.
How can we communicate to parents the monitoring of Browns with no intention to treat?
- Children are monitored to ensure their vision is developing well
- We rarely surgically intervene
- The syndrome may improve with time BUT if it does not, up-gaze will be used less as the child grows in height meaning that the anomaly becomes less noticeable (Ansons and Davis, 2014).
