Differential Diagnosis - SO/SR - Unilateral/Bilateral Palsy Flashcards
Why are RSO and LSR palsy difficult to differentially diagnose from one another?
In pp of a RSO palsy we expect:
- Right Hypertropia (if LE fixing in a RSO palsy)
- Left Hypotropia (if RE fixing in a RSO palsy)
In pp of a LSR palsy we expect:
- Right Hypertropia (if fixing with left eye)
- Left Hypotropia (if fixing with right eye)
and the muscle sequelae pattern
What is the muscle sequelae of a RSO palsy and a LSR palsy?
u/a RSO, o/a LIR, o/a RIO, u/a LSR
u/a LSR, o/a RIO, LIR o/a, u/a RSO
See Hess pictures slides 12-14, 26 and 27 on the powerpoint
Which of these causes are we expecting to result in a RSO palsy?
- CNIII palsy
- CNIV palsy
- Congenital
- Traumatic
- TED
- MG
- CNIII palsy - No
- CNIV palsy - Yes
- Congenital - Possible
- Traumatic - Possible
- TED - Unlikely
- MG - Possible
Which of these causes are we expecting to result in a LSR palsy?
- CNIII palsy
- CNIV palsy
- Congenital
- Traumatic
- TED
- MG
- CNIII palsy - Superior Division CNIII
- CNIV palsy - No
- Congenital - No
- Traumatic - Unlikely
- TED - Possible
- MG - Possible
What symptoms are we expecting in an RSO palsy from this list?
- Ptosis
- AHP
- History
- Deviation
- Diplopia & Vertical Deviation
- Near/Distance Diplopia
- Parks-Bielchowsky Head Tilt Test (BHTT)
Ptosis - Absent
AHP - Head down, turn and tilt left
History - Trauma
Deviation - Eso
Diplopia & Vertical Deviation - Max laevo depression
Near/Distance Diplopia - Greater for near
Parks-Bielchowsky Head Tilt Test (BHTT) - +ve
What symptoms are we expecting in an LSR palsy from this list?
- Ptosis
- AHP
- History
- Deviation
- Diplopia & Vertical Deviation
- Near/Distance Diplopia
- Parks-Bielchowsky Head Tilt Test (BHTT)
Ptosis - L Ptosis
AHP - Head up, turn and tilt left
History - None specific
Deviation - Exo
Diplopia & Vertical Deviation - Max laevo elevation
Near/Distance Diplopia - Greater for distance
Parks-Bielchowsky Head Tilt Test (BHTT) - -ve
How do we differentiate between a RSO and LSR?
Bielschowsky Head Tilt Test (BHTT)
How do we do the bielschowsky head tilt test (BHTT) to differentiate between RSO and LSR?
- Patient fixes target at 3m (because SO works best Nr and SR works best at Dist so need to not favour either)
- Tilt head to the right
- Observe right eye for elevation
- Alt CT to check if increase in R hyper deviation
- PCT tilt right, primary position & tilt left (tilt prism the same amount as head)
- Increase in R hyper deviation of ≥ 5PD noted
If a RSO palsy, the right eye elevates and RHT increases on PCT giving a positive result
If a LSR palsy, no change in the position of the right eye on right head tilt, no increase in RHT gives a negative result
A positive result confirms a superior oblique palsy BUT a negative result doesn’t eliminate it
On head tilt right what happens to the eyes?
Head tilt RIGHT
RIGHT eye INTORTS
Intorsion occurs due to: SO and SR
Depression = SO and elevation = SR which balances out the eye to remain level
In SO palsy elevating action if SR in unopposed and hyperdevation increases When tilting head right, right eye goes up, left eye goes down in this action too.
What are the characteristics of a bilateral CNIV palsy in relation to:
- AHP
- CT
- OM
- Hess
- Field of BSV
- Torsion
AHP - Head Down
CT - No/small vertical
OM - Reversal of HT, V eso (>25PD)
Hess - See slides 26 and 27
Field of BSV - BSV upper field
Torsion - >10degrees excyclo
What are the characteristics of a unilateral CNIV palsy in relation to:
- AHP
- CT
- OM
- Hess
- Field of BSV
- Torsion
AHP - Head down, head turn to affected side, head tilt to unaffected side
CT - HT affected eye
OM - HT max on contralateral depression
Hess - see slides 26/27
Field of BSV - BSV upper ipsilateral field
Torsion - <10 degrees excyclo
What did Kushner (1988) find about Bilateral CNIV palsy?
- Reversal of HT in any oblique fields of gaze
- Subjective extorsion >10° in primary position
- Chin down posture - no tilt
- Bilateral fundus extorsion
- Small HT in primary with large HT on tilt to both sides
- V pattern of >20Δ
What should we think about with torsion in bilateral cases
- Think of possibility
of bilateral case in all SO palsies unless proven otherwise - Look for subtle clinical signs
- Warn patients with SOP pre-op of possible reversal
How much torsion is considered bilateral or unilateral CNIV palsy?
Georgievski (1995) -
Unilateral excyclo = 5.6 degrees
Bilateral excyclo = 9.6 degrees
Roper-Hall & Chung (1997) -
Bilateral if cyclotorsion >15 degrees
