Title: Chiari 1 Malformation presenting as
1 Chiari 1 Malformation presenting as
Strabismus of obscure cause
- Kowal, L Yahalom, C
- OMC CERARVEEH, Melbourne
2Chiari 1 malformation (C1M)
- Tonsillar herniation 3 - 5 mm below foramen
magnum - Unlike many congenital CNS malformations, C1M
patients usually asymptomatic until late
childhood or early adulthood
3Symptoms Signs of C1M
- Symptoms nonspecific - headache, dizziness,
neck pain, extremity weakness, numbness . - Neurologic signs ataxia, dysarthria, nystagmus,
cranial nerve deficit .
4THIS SERIES 12 CASES
- 12 cases of acquired strabismus mostly
convergent esotropia as the presenting sign of
C1M. - No other credible explanation for the strabismus
- Isolated acquired esotropia has been previously
described as a rare presenting sign of C1M in
several case reports - this will be the largest
series so far.
5NON- STRABISMIC FEATURES
- 10/12 minor neurological symptoms esp.
headache - 2/12 CHIARI PLUS - more serious neurological
signs/symptoms (10 11)
610 /12 patients with esotropia
- 4/10 DgtN divergence insuff
- Some may be bilateral 6ths
- 2/10 NgtD convergence Xs
- 1/10 ND
- 1/10 6th nerve palsy
- 2/10 ET vertical deviation
74 patients ET DgtN
Follow up y Treatment ET ? Presenting signs/ symptoms. Duration. Age at presentation
3 Glasses N6-22 D14-26 i/mitt diplopia 1y 7 1
0.1 Glasses N9 D16 i/mitt diplopia 8y 20 4
0.2 Glasses N35 D40 diplopia 1y 18 7
1 NSD (age 6 ½) N14 - 30 D25 - 35 i/mitt ET 1mo 6 9
- All Headache, no other neurological
symptoms/signs. - All Refraction -1.50 to 1 DS
- 9 ET N30, D35 at age 7 yrs. Strab surgery
planned - NSD Neurosurgical decompression
- Range of measurements at different examinations
82 patients ET NgtD
Follow up yrs Treatment ET ? Presenting signs symptoms Age at presentation yrs
1.2 Glasses N6-12 D1-4 i/mitt near diplopia 11y 19 6
4 BMR in 10/04. Early orthotropia Increasing to constant ET N42, D36 Infrequent ET 0.5 10
10 Chiari plus. She has developmental
delay, and early closure of fontanelles. MRI
7 mm C1M, stable mild ventriculomegaly.
9Other presentations
F/up yrs Other Refrn Manifest deviation ? Presenting symptoms Age at presentation
1.2 L IO L SO- Mild L/R R1.25 L1.50 ET 40 ND Recent onset diplopia 14 12
1 R LR- RL -9 ET PP 0-14. R gaze 12-22 Diplopia on R gaze 15 mo 16 5
0.5 Convergence insufficiency R-1.50 L-0.50 XT 18N OD Near Diplopia 18y. Pixilated vision 28 2
- Patient 12 NSD 6 mo s/p dx of CM1. Little
improvement in ET ? Bimedial recession 2/04.
Ortho 8 mo later - The other patients manage with glasses.
- Patients 12 and 2 presented with headache as
well as diplopia
10Other presentations
F/u (yrs) Other Signs and findings Pres. symptoms Age presentation
1.3 Myasthenia and thyroid r/u poor motor fusion H -2 to 1 V/-0.5 Esophoria / hyperphoria I/mitt H V diplopia 45 3
1.6 Upper limb paresthesia poor motor fusion RIO , LSO-. Tilt R AHP diplopia 9 8
0.2 Nystagmus ET 16 DN Constant H diplopia 10 y Oscillopsia 60 11
- 11 is the second Chiari plus. His symptoms
began with diplopia and balance problems.
Diplopia persisted s/p 2 neurosurgical
procedures. - 3 and 8 manage well with glasses.
11Our patients who had surgery
- 10 Squint sx with good early results (f/u 4w)
- 9 NSD. Strab persists. BMR planned.
- 11 NSD. Strab persists. Prism working.
- 12 NSD. Strab persists. Successful squint sx
(f/u 8 mo).
NSD neurosurgical decompression
12Age at presentation
Most of the patients presented outside normal age
range for strabismus
13ET as only manifestation of C1MSummary of
published literature
Neurosurgery Squint Sx Age y Nunber of cases
Yes with resolution of ET Before C1M Dx Recurrence 6 mo later 13 1 Bixenman J Ped Ophthal Strab 1987
Yes. ET no better PT in borderline C1M. Recurrence 6 mo later. Second sx successful s/p neuro-sx. 13 1 Pokharel JAAPOS 2004
PT2 with resolution of ET. F/u 2-3 y PT in 2. One successful. 2nd recurrence s/p 2 sx. 5 to 37 4 Biousse AJO 2000
Yes with resolution of ET Recurrence 12 mo after surgery 24 1 Passo J Clin N-Ophthal 1984
Yes with resolution of ET Recurrence after surgery 2 Weeks Hamed Ophthalmology1999
Yes. PT4 patients with resolution of ET. gt 4y f/u No 17 to 37 5 Lewis J N-ophthal 1996
PT with resolution of ET No 9 1 Defoort-Dhellemmes Amer Jnl Ophthal 2002
PT - ET no better Botox to LMR (successful after 6 mo f/u) 14 1 Imes -Ophthalmology 2001
One patient from Lewiss series did not get any
sx treatment / PT Primary treatment
14Summary of published literature ET as the ONLY
manifestation in C1M
- 16 patients ages 5 - 37
- 7/16 strabismus sx as primary treatment
- 6/7 recurrence of strabismus
- 4/5 subsequent NSD with resolution of strab
- 8 patients NSD as primary treatment
- 7/8 had resolution all signs/symptoms
- Conclusion Strab Sx alone usually ineffective.
NSD usually necessary effective.
15Summary
- We describe 12 cases of acquired strabismus of
obscure cause probably caused by C1M - 5/12 aged 10-20 _at_ presentation
- 10/12 had headache
- Esotropia was the usual squint (10/12)
- 4/12 divergence insufficiency ET, D gt N
- 1/12 apparent sixth nerve palsy
- 1/12 unexplained head tilt.
- 2/12 i/mitt diplopia with poor motor fusion
16Summary
- Most patients were referred for neurosurgical
evaluation. 3/12 had NSD. It is generally felt
by neurosurgeons that strabismus alone is an
inadequate reason for NSD. - Strabismus did not resolve in these 3 cases,
with subsequent successful squint surgery in
1case. - Other patients Most manage well with prism
glasses.
17Conclusions
- Isolated acquired strabismus is not a rare
presenting sign of C1M, and there might be a good
number of patients being mis / under- diagnosed. - Appropriate primary management of C1M with
strabismus alone whether strabismus surgery or
NSD is unclear.