Chiari 1 Malformation presenting as

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Chiari 1 Malformation presenting as
Strabismus of obscure cause

•  Kowal, L Yahalom, C
• OMC CERARVEEH, Melbourne

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Chiari 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

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Symptoms Signs of C1M

• Symptoms nonspecific - headache, dizziness,
  neck pain, extremity weakness, numbness .
• Neurologic signs ataxia, dysarthria, nystagmus,
  cranial nerve deficit .

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THIS 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.

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NON- STRABISMIC FEATURES

• 10/12 minor neurological symptoms esp.
  headache
• 2/12 CHIARI PLUS - more serious neurological
  signs/symptoms (10 11)

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10 /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

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4 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
  

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2 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.
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Other 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

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Other 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.

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Our 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
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Age at presentation
Most of the patients presented outside normal age
range for strabismus
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ET 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
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Summary 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.

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Summary

• 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

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Summary

• 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.

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Conclusions

• 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.