J Neurol (1990) 237 : 489-490 Journal of

Neurology © Springer-Verlag 1990

Miller-Fisher syndrome and pontine abnormalities on MRI: a case report

M. Giroud 1, C. Mousson 2, J. M. Chalopin 2, G. Riße 2, and R. Dumas 1

1 Service de Neurologie, Hôpital Général, 3 rue du Faubourg Raines, F-21033 Dijon Cedex, France 2Service de Néphrologie, Hôpital du Bocage, F-21000 Dijon, France

Received January 15, 1990 / Accepted July 2, 1990

Summary. The au thors r epo r t a pa t ien t with Mi l le r -F i sher s y n d r o m e in w h o m M R I of the b ra in s t em showed in- c r ea sed signal dens i ty on T2 sequence an te r io r to the fou r th ven t r ic le , on the r ight and the left. The au thors discuss the r e l a t ion b e t w e e n these M R I abno rma l i t i e s and some cl inical f ea tu res of the s y n d r o m e . The au thors be l i eve tha t the ca rd ina l f ea tu res of Mi l l e r -F i she r syn- d r o m e are due to pe r i phe ra l ne rvous sys tem dysfunct ion , bu t tha t this does not p r e c l u d e a poss ib le cen t ra l ne rvous sys tem invo lvemen t .

Key words: Mil l e r -F i she r s y n d r o m e - Pon t ine les ions - Magne t i c r e s o n a n c e imaging

On examination, there was severe gait and truncal ataxia, with inability to walk or sit without aid. Slight finger-to-nose dysmetria was present, No limb weakness or sensory dysfunction was detect- ed except for a slight distal diminution of vibration sense of the lower limbs.

Introduction

The s y n d r o m e o f o p h t h a l m o p l e g i a , a tax ia and a re f lex ia was first de sc r ibed by F i she r in 1956 [2]. A l t h o u g h mos t cl inical and e lec t rophys io log ica l f indings in this s y n d r o m e suggest an unusua l va r ian t of the acu te id iopa th ic po ly- neur i t i s of G u i l l a i n - B a r r é [3], even F i she r t hough t tha t not all o f the signs cou ld be i n t e r p r e t e d as man i fe s t a t ions of a d i s tu rbance solely of p e r i p h e r a l neurons . Some find- ings suggest an add i t i ona l i n v o l v e m e n t of the cen t ra l ne rvous sys tem (CNS) such as a ce r ebe l l a r t ype of a tax ia and s u p r a n u c l e a r eye m o v e m e n t s d i so rde r s [4, 10]. The fo l lowing case r e p o r t desc r ibes M R I f indings which dem- o n s t r a t e d a d i s tu rbance of the CNS.

Case report

A 47-year-old woman who had had renal transplants 2 years previ- ously for polycystic renal disease had received treatment with cor- ticoid 20 mg/day. Two weeks after an upper respiratory tract infec- tion, she complained in March 1988 of increasingly impaired bal- ance which, within 2 days, made it impossible for her to stand and walk. Four days later, diplopia and dysarthria developed.

Offprint requests to: M. Giroud Fig. 1, MRI shows in the pons an increased signal on T2 sequence on the right and left, anterior to the fourth ventricle

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There was areflexia in all limbs and a marked restriction of eye movements in all directions, including a paralysis of upward gaze, and lateral gaze nystagmus. Pupillary diameter and reflexes were normal. Mild bilateral facial weakness was observed, with palatal palsy and a nasal quality to the speeeh. [nvestigations, including haematok)gical, bioehemical, virological and renäl function, were normal. Three abnormalities were noted: a slight increase of CSF protein content (0.61 g/l) 3 days after the onset of the first symp- toms; a marked decrease of sensory and motor nerve conduction velocity (ulnar, median, tibial and peroneal nerves) distally and bilaterally, prolonged distal latencies of tibial and peroneal nerves bilaterally, prolonged soleus H-reflex latencies, prolonged R1 and R2 blink-reflex ]atencies, and block of conduction in median and tibial nerves bilaterally, 10 days after the onset of symptoms. Be- eause cranial CT showed no pontine lesion, magnetie resonance imaging (MRI) was performed 1 month after discharge and showed two pontine lesions, anterior to the fourth ventricle: an increased signal density on T2 sequence on each side (Fig. 1). Two months later, all elinical signs and symptoms had resolved spontaneously and electrophysiological findings had become normal ó months later.

Discussion

The clinical and electrophysiological features of this pa- tient belong to the classical Miller-Fisher syndrome. The patient had no renal failure at the time of her neurologi- cal illness, and renal failure does not cause these abnor- malities. Corticoid therapy more often causes a myopath- ic than a neurogenic disorder.

The Miller-Fisher syndrome usually reflects an im- munological disorder involving the peripheral nervous system; the three classical symptoms ataxia, areflexia and ophthalmoplegia are due to peripheral nervous sys- tem lesions [3, 10]. That the CNS is affected in a few cases is shown by the following signs: symmetrical clini- cal features; no abnormalities of pupil function; some- times, ataxia appears to be of cerebellar origin and there may be supranuclear or internuclear eye movement dis- orders [7]. However, CNS lesions have not be seen either at autopsy examination [9], or on CT and MRI [5, 6, 8, 11]. Some authors [1] consider that the brain stem may

be affected by direct vital injury or by an immuno-aller- gic mechanism similar to that affecting the peripheral nervous system.

We think that our case shows by M R I for the first time a pontine lesion in a classical Miller-Fisher syn- drome. We believe that the cardinal features of Miller- Fisher syndrome are due to peripheral nervous system dysfunction, hut that this does not preclude a possible CNS involvement.

References

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