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Show PHOTO ESSAY Bilateral crocodile tears in a patient with Guillain- Barre syndrome Yvonne M. Delaney, FRCOphth, and John S Elston, FRCS Fig. 1. A: Face in repose. B, C: Attempt at puffing cheeks ( B) and showing teeth ( C) shows bilateral mild weakness consistent with lower motor neuron 7th nerve palsy. Reproduced with permission. We describe the first reported case of the development of bilateral crocodile tears in Guillain- Barre Syndrome. This finding is an expression of axonal degeneration in the acute phase and misdirection- in- regeneration in the chronic phase. ( JNeuro- Ophthalmol 2002: 22: 113- 115) Case Report A 52- year- old male presented in May 2001 with a 2- month history of lacrimation while eating, leading to social embarrassment. On examination there was moderate bilateral facial weakness ( Fig. 1). Synkinetic movements- twitching of the corner of the mouth on blinking- were observed. The height of the tear meniscus was less than 1mm Department of Ophthalmology, John Radcliffe Hospitals NHS Trust, Oxford, UK. Address correspondence to John S. Elston, Oxford Eye Hospital, Radcliffe Infirmary, Woodstock Road, Oxford OX2 6HE, UK. E- mail: y. delaney@ virgin. net and there was no evidence of tear film instability. Bilateral lacrimation was observed only while the patient was eating ( Fig. 2), confirming a diagnosis of crocodile tears. The patient declined treatment with botulinum A toxin ( 2). Seven months previously, the patient had developed Guillain- Barre Syndrome, with severe generalized paralysis and respiratory muscle involvement that necessitated ventilation for a period of 4 weeks. Cranial nerve involvement with facial diplegia and oculomotor weakness was severe. Nerve conduction studies showed only one recordable compound muscle action potential from the right median nerve and abductor pollicis brevis muscle, which had a prolonged distal latency of 13 ms and a severely reduced amplitude of 400 LIV. Needle EMG of the right tibialis anterior and first dorsal interosseus demonstrated fibrillations and positive sharp waves indicating acute denervation, representing either primary or secondary axonal damage. The patient was treated with plasmapheresis and corticosteroids with recovery of function, but still suffers persistent disability from residual weakness of both the quadriceps and facial muscles. _ JNewo- Opfghqlwol,. Vol. 22,% Na, 2, 2002 „ . . DOI: 10.1097/, 01. WNO, 0Q00019686.44209.75 , JJ3 , Copyright © Lip pincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited. JNeuro- Ophthalmol, Vol. 22, No. 2, 2002 PHOTO ESSAY Fig. 2. When patient eats, tears flow ( arrows). Reproduced with permission. Discussion This report presents a case of crocodile tears, evidence of aberrant regeneration, documented for the first time in Guillain- Barre Syndrome. Histologically, Guillain- Barre Syndrome is thought to be an inflammatory peripheral neuropathy, with both arms of the immune system participating in macrophage- induced demyelination ( 3), resulting in conduction slowing ( demonstrated in this patient) and/ or acute conduction block ( 1). In general, axons are spared except in the most severe forms, in which Wallerian degeneration may occur. This axonal involvement may be secondary to severe inflammatory infiltration, as in the most common variant of Guillain- Barre Syndrome called " acute inflammatory demyelinating polyneuropathy" ( AIDP) ( 4); alternatively, a direct attack on axons may occur in the absence of both inflammation and/ or demyelination, as in the rarer " acute motor axonal neuropathy" or " acute motor- sensory axonal neuropathy" ( 1). Distinguishing this form in its advanced stages from AIDP ( with secondary axonal degeneration) by clinical or electrodiagnos-tic criteria remains difficult. In our patient, there was elec-trodiagnostic evidence of axonal damage as evidenced by active denervation in the limb muscles. This occurred in the presence of a compound muscle action potential from the right median nerve, which had a markedly prolonged distal latency of 13 ms ( normal value < 4.3 ms) ( 5), evidence of severe demyelination indicating that in this case the axonal injury was most likely secondary to a severe inflammatory form of AIDP. The facial nerve is the most commonly involved cranial nerve in Guillain- Barre syndrome, with facial diplegia occurring in more than 50% of patients ( 1). Axonal compression or disruption at any point along the course of the facial nerve may lead to neural misdirection caused by aberrant regeneration. Aberrant regeneration refers to the re-sprouting of axons down incorrect myelin sheaths after disruption of the nerve. The facial nerve contains fibers that are secretomotor for the submandibular and sublingual salivary glands, as well as secretory fibers to the lacrimal gland. Following severe proximal seventh nerve injury, the regenerating salivary secretomotor fibers may become misdirected and divert, via the greater superficial petrosal nerve, to innervate the lacrimal gland ( 6). The result is lacrimation in response to gustatory stimuli (" gustatory lacrimation"), which would normally excite a flow of saliva rather than tears ( 7). The term " crocodile tears" arises out of an ancient Greek myth that crocodiles tear to lure their prey and then continue to tear as they devour them ( 8). Unilateral cases of crocodile tears have been reported following Bell's palsy and less often following surgery for acoustic neuroma ( 9) or basilar skull fracture ( 7); however, bilateral cases are rare ( 10). The bilateral nature of crocodile tears in this case is not entirely unexpected, given the essentially symmetrical involvement of the facial nerve in Guillain- Barre Syndrome. It is surprising that this phenomenon has not been reported before. Permanent disabling weakness occurs in 5% to 10% of patients with Guillain- Barre Syndrome ( 3), and one would therefore have expected previous reports of incomplete recovery following facial axonopathy to be complicated by the effects of aberrant regeneration. A partial explanation may be that aberrant regeneration in polyneuropathies is less well documented than regeneration in focal nerve lesions. In most polyneuropathies, in contradistinction to focal nerve lesions in which the nerve is partially or completely transected, the architecture of the nerve is maintained and misrouting of axons is therefore thought less likely to occur ( 7). Regrowing axons are constrained to run inside the old basal lamina sheaths and are thus led automatically back to the appropriate place. However, Brown et al. ( 11) have shown that regrowing axons can cross endo-neurial walls even though the longitudinal continuity of these sheaths has not been broken. The effect of such exchanges may be minimal, as in lesions of peripheral nerve trunks in the limbs, where neighboring fibers tend to be destined for the same muscle. However, in the case of the facial nerve, where axons destined for the salivary glands closely intermingle with axons en route to the lacrimal gland, exchanging of even a small number of endoneurial sheaths will inevitably lead to far more overt errors, manifesting in this case as crocodile tears. Botulinum toxin type A is the present treatment of choice to manage the motor complications of aberrant regeneration of the facial nerve. Recently, various authors have also shown it to be highly effective in managing the autonomic complications, such as crocodile tears ( 2). Treatment with botulinum A toxin was declined by our patient. „ 114 . , „ . , „ . . © 2002 Lippincott Williams & Wilkins , Copyright © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited. PHOTO ESSAY JNeuro- Ophthalmol, Vol. 22, No. 2, 2002 We believe this to be the first report of neural misdirection following severe axonal degeneration of the facial nerve in a patient with the acute inflammatory demyelinat-ing polyneuropathy variant of Guillain- Barre Syndrome. This case is unusual in that the condition is bilateral and follows a polyneuropathy known to be primarily demyelin-ating in nature. REFERENCES 1. Lange DJ, Latov N, Trojaborg W. Acquired neuropathies. In Rowland LP, ed. Merritt'sNeurology, 10fh ed. Philadelphia: Lippincott Williams & Wilkins, 2000: 613- 5. 2. Boroojerdi B, Ferbert A, Schwarz M, et al. Botulinum toxin treatment of synkinesia and hyperlacrimation after facial palsy. J Neurol Neurosurg Psychiatry 1998; 65: 111- 4. 3. Ropper AH. The Guillain- Barre syndrome. NEngUMed 1992; 326: 1130- 6. 4. Vedanarayanan VV, Chaudhry V. Guillain- Barre Syndrome- Recent Advances. Indian JPediatr 2000; 67: 635^ 16. 5. Alam TA, Chaudhry V, Cornblath DR. Electrophysiological studies in the Guillain- Barre syndrome: distinguishing subtypes by published criteria. Muscle & Nerve 1998; 21: 1275- 9. 6. Hedges TR, Friedman DI, Horton JC, et al. Neuro- ophfhalmology. In Section 5, Basic and Clinical Science Course. San Francisco: American Academy of Ophthalmology, 1997: 158- 61. 7. Thomas PK. Clinical aspects of PNS regeneration. In Waxman SG, ed. Functional Recovery in Neurologic Disease. New York: Raven Press, 1988: 9- 18. 8. Guggisberg CA. Crocodiles ( eds). Their Natural History, Folklore and Conservation. Newton Abbot: David & Charles, 1972: 164- 5. 9. Irving RM, Viani L, Hardy DG, et al. Nervus intermedius function after vestibular schwannoma removal: clinical features and pathophysiological mechanisms. Laryngoscope 1995; 105( 8 Pt 1): 809- 13. 10. Spiers AS. Syndrome of " crocodile tears." Pharmacological study of a bilateral case. Br J Ophthalmol, 1970; 54: 330- 4. 11. Brown MC, Hardman VJ. A reassessment of the accuracy of rein-nervation by motoneurons following crushing or freezing of the sciatic or lumbar spinal nerves of rats. Brain 1987; 110: 695- 705. Copyright © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited. |
