IV Nerve Palsy A presentation
IV Nerve Palsy • Add description as an introduction?
Case History • Initial Orthoptist’s Observations:(aspects to look out for): • Head tilt/turn to opposite side of affected eye • Facial asymmetry (common in congenital fourth nerve palsy) • Affected eye-hypertropia
Case History • General Health: • Any illness/meds • Diabetes, Myasthenia Gravis, hypertension, • Intracranial tumour • Any injury/trauma-recent bump to the head • Family History • For suspected congenital fourth nerve palsy, there is evidence that it can be inherited in an autosomal dominant form (Botelho & Giangiacomo, 1996. Cited in: Ansons, A. M. and Davis, H. (2001) Diagnosis and Management of Ocular Motility Disorders pg. 374)
Case History • Previous Ocular History: • Treatment for diplopia or other eye related problems, glasses • With congenital fourth nerve palsy, patient may report always having had a head posture or may be unaware of it but on looking through old photographs notice that it was there in childhood
Case History • Questions to ask further as a basis for investigation: • Reason for visit-diplopia? • Vertical/horizontal? • How far apart images are? • Any torsion? • How long they have had it • When does it occur? Constant/ intermittent? • Worse when reading? • Neck pain?
Case History • 74 Year old male presented with a three day history of sudden onset vertical diplopia. This was worse when reading. He had had a mild left CVA one week previously resulting in hand weakness which later resolved (Fiona Rowe, Clinical Orthoptics, 2nd edition, page 344)
Case History • A 36-year-old woman has been bothered by a deviating right eye since early childhood. She has had diplopia for as long as she can remember but was able to tilt her head to relieve it. She has worn prism glasses for many years. Her friends and associates at work comment on the fact that she tilts her head constantly. (http://telemedicine.orbis.org)
Aetiology-Nerve pathway (Origin) • The trochlear nerve is the smallest (in diameter) of the 12 cranial nerves. It is the only nerve to originate in the brainstem (medulla).
Aetiology-Nerve pathway (Intracranial) • From its origin it decussates and exits the brainstem dorsally before passing temporally around the brainstem and projecting superiorly through the arachnoidal space. The trochlear pierces the arachnoid and enters the subdural space of the cavernous sinus. The trochlear then passes through the superior orbital fissure
Aetiology-Nerve pathway (Intraorbital) • The trochlear does not traverse through the Common Tendonous ring (annulus of Zinn). It projects anteriorly superiorly and medially to the Common Tendonous ring, traveling inferiorly and temporally to the superior oblique. The Trochlear finally pierces the belly of the superior oblique.
Aetiology-Children • Leading cause would be a congenital superior oblique palsy • Will usually develop an abnormal head posture
Aetiology-Adults • Leading cause of isolated 4th nerve palsy is trauma, specifically CHI • CHI :Closed head injury – blunt force damage that doesn’t cause a break in the scalp or mucous membranes • 4th nerve palsies are rarely due to aneurism and it is unlikely that a cavernous sinus fistula would cause an isolated 4th nerve palsy as it is much more likely that various palsies would occur, due to the proximity of the cranial nerves in the cavernous sinus.
References • http://www.google.co.uk/imgres?q=Trochlear+origin&num=10&hl=en&biw=1241&bih=606&tbm=isch&tbnid=OZD7_21RoHwOQM:&imgrefurl=http://www.sgul.ac.uk/depts/histopathology/ssm_archive/ssmpteresh/trochlear2.htm&docid=mpIaZKRmO2Qe9M&imgurl=http://www.sgul.ac.uk/depts/histopathology/ssm_archive/ssmpteresh/trochlear1.JPG&w=443&h=453&ei=nB1PULafJPS00QXXpIGwBQ&zoom=1&iact=rc&dur=3&sig=117787785741486807606&page=1&tbnh=128&tbnw=126&start=0&ndsp=23&ved=1t:429,r:2,s:0,i:79&tx=54&ty=50 http://www.google.co.uk/imgres?q=Cavernous+sinus&num=10&hl=en&biw=1241&bih=606&tbm=isch&tbnid=nu0IYzPJuAgcTM:&imgrefurl=http://persiapbba0611.blogspot.com/2010/07/infranuclear-opthalmoplegia.html&docid=A1oe2pLXU_3dqM&imgurl=http://3.bp.blogspot.com/_plbJ03T5zBk/TD8NawBKuzI/AAAAAAAAAAM/t_tRFOrFiy4/s1600/cavernoussinusthumb2.jpg&w=421&h=431&ei=KiBPUMezN8vK0AWYmYCwBg&zoom=1&iact=rc&dur=480&sig=117787785741486807606&page=1&tbnh=117&tbnw=112&start=0&ndsp=22&ved=1t:429,r:4,s:0,i:88&tx=53&ty=36 http://www.google.co.uk/imgres?q=cavernous+sinus&num=10&hl=en&biw=1241&bih=606&tbm=isch&tbnid=nu0IYzPJuAgcTM:&imgrefurl=http://persiapbba0611.blogspot.com/2010/07/infranuclear-opthalmoplegia.html&docid=A1oe2pLXU_3dqM&imgurl=http://3.bp.blogspot.com/_plbJ03T5zBk/TD8NawBKuzI/AAAAAAAAAAM/t_tRFOrFiy4/s1600/cavernoussinusthumb2.jpg&w=421&h=431&ei=ux9PUKa3HsfY0QX82oHQBA&zoom=1&iact=hc&vpx=749&vpy=138&dur=195&hovh=130&hovw=128&tx=108&ty=104&sig=117787785741486807606&page=1&tbnh=130&tbnw=126&start=0&ndsp=20&ved=1t:429,r:4,s:0,i:85 http://medical-dictionary.thefreedictionary.com/closed+head+injury
Clinical Characteristics • When first presenting to the clinic the following information should be gained by simple observation: • The type of deviation present • Any abnormal head posture
Clinical Characteristics cont. • Observed deviation http://www.pedseye.com/strabismus_hypertropia.htm LSO palsy RSO palsy
Clinical Characteristics cont. • Abnormal Head Posture • The patient may present with chin depression and a face turn or head tilt away from the affected side, to reduce their diplopia. (Ansons and Davis 2001) http://www.aao.org/publications/eyenet/200409/am_rounds.cfm Asymmetry of the face may be observed in cases of congenital IV nerve palsies. Typically a reduction in distance between the lateral canthus and the corner of the mouth on the side of the head tilt.
Clinical Characteristics cont. • Diplopia • Patients with a IV nerve palsy typically experience vertical diplopia and in some cases may be aware of cyclotorsion. http://galeri.uludagsozluk.com/r/vertical-diplopia-143415/ http://www.freakingnews.com/Double-Vision-Pictures--1762-0.asp
Expected Findings from Investigations • Visual Acuity • Cover Test for near and distance, with and without abnormal head posture • Investigating Cyclotorsion Using Synoptophore and Double Maddox Rod. Can be seen objectively on fundus examination if asymptomatic. • Bielschowsky Head Tilt Test • Past-pointing • Prism Fusion Range • Ocular Movements
Expected Findings from Investigations • Hess Chart Using Lees Screen: Right superior oblique palsy Ipsilateral inferior oblique overaction
References • Ansons, A. M. and Davis, H. (2001) Diagnosis and Management of Ocular Motility Disorders. Blackwell Publishing; Oxford.