Benign Abducens Nerve Palsy of Childhood H e r m a n A. Cohen , MD,

M o s h e Nuss inov i tch , MD,

Arieh Ashkenaz i , M D ,

Rache l S traussberg , MD, and Arieh Kaushansky , M D

Benign acquired isolated abducens nerve palsy in in- fants and children is a rare condition and recurrence is even less common. The diagnosis is essentially one of exclusion. Six children (1 male, 5 females) are re- ported with benign isolated abducens nerve palsy, ranging in age from 8 months to 12 years (median: 5.5 years). The left side was affected in all patients. Re- covery occurred within 18-55 days, but 3 patients developed recurrence with complete resolution of symptoms within 10-21 days.

Cohen HA, Nussinovitch M, Ashkenazi A, Straussberg R, Kaushansky A. Benign abducens nerve palsy of child- hood. Pediatr Neurol 1993;9:394-5.

Introduction

The development of isolated acquired abducens nerve palsy in children has been associated with meningitis, Gradenigo syndrome, posterior fossa tumor, trauma, hy- drocephalus, and increased intracranial pressure [ 1 ]; how- ever, a distinct entity of benign painless abducens nerve palsy, usually affecting the left side has been associated with viral infections, vaccinations, Lyme borreliosis, and Q fever [1-9]. During a period of 6 years (1986 to 1991), 6 patients with benign abducens nerve palsy were diag- nosed and followed up at the Pediatric Ambulatory Out- Patient Clinic.

Case Reports

Patient 1. This 3V2-year-old girl had a 5-day history of a febrile ill- ness followed by acquired torticollis. Physical and neurologic examina- tions were normal except for left abducens palsy. The leukocyte count w a s 12,000 mm 3 with 70% lymphocytes of which 22% w e r e atypical. IgM serology for Epstein-Barr virus (EBV) was positive. Initial IgG

titers measured 1:40 and rose to 1: t20. No evidence ~q rc~en, inleclum by cytomegalovirus (CMV), herpes, influenzae, enlerm:iruses. ~i lox~ plasma was documented by serologic examination. The palsy lasted for 20 days and resolved spontaneously. During a 3+year I\,llow-up period. no recurrence was observed.

Patient 2. This 8-month-old female had a 3-day history ol uppm respiratory tract infection followed by torticollis. Physical and neuro- logic examinations were normal except lot left abducens palsy. The leukocyte count was 18,500 mm 3 with 80cA lymphocytes, of which 20% were atypical. IgM serology for EBV was positive. IgG titers rose from 1/40 to 1/320. No evidence of recent infection by CMV. herpes, influen- zae, enteroviruses, or toxoplasma was documented by serologic exam- ination. The palsy lasted for 40 days and resolved spontaneously.

During a follow-up period of 3 years, left abducens nerve palsy recurred after an upper respiratory tract illness. It resolved slxmtaneous- ly within 10 days.

Patient 3. This 4-year, 8-month-old female with a history ol left otitis media was treated with amoxycillin for 7 days. Three days later, left abducens nerve palsy was documented upon physical examination. The rest of the physical and neurologic examinations were normal. Routine laboratory examination, including blood count, biochemistry, and uri- nalysis, was normal.

There was no serologic evidence of recent infection by EBV. CMV. herpes, influenzae, enteroviruses, or toxoplasmae.

Computed tomography (CT) of the brain and orbits was normal. Ab- ducens nerve palsy lasted for 22 days and resolved spontaneously. No recurrence was observed in a 2-year follow-up period.

Patient 4. This 5-year-old male had a 4-day history of upper res- piratory tract infection followed by torticollis and diplopia for 2 days. Physical and neurologic examinations were normal except for left ab+ ducens nerve paresis. Routine laboratory examinations and CT of the brain and orbits were normal. Spontaneous recovery from abducens nerve paresis was observed within 55 days. Four months later, a second episode of left abducens nerve paresis, lasting 20 days was documented. No evidence of recent infection by EBV, CMV, herpes, enteroviruses, or toxoplasmae was documented by serologic examination.

Patient 5. This 7-year-old female presented with a 7-day history of diplopia. No history of recent infection was obtained. The physical and neurologic examinations were normal except for left abducens nerve paresis. Spontaneous recovery was documented in 25 days. Eight months later, a second episode of left abducens nerve palsy was docu- mented, lasting 21 days. No evidence of recent infection by EBV. CMV, herpes, enteroviruses, or toxoplasmae was documented by serologic ex- amination. CT of the brain and orbits was normal.

Patient O. This 12-year-old girl had a 4-day history of diplopia and torticollis. A complaint of mild left side periorbital pain was presented 2 days before admission, followed by a history of upper respiratory tract infection. Physical and neurologic examinations were normal, except lor left abducens nerve palsy. Laboratory findings were normal.

No evidence of recent infection by EBV, CMV, herpesvirus, entero- virus, or toxoplasma was documented by serologic examination. CT of brain and orbits was normal. The abducens nerve paresis resolved slmn- taneously within 18 days. No recurrence was documented m a 1-year follow-up.

Discussion

The majority of acquired abducens nerve palsies in childhood are the result of intracranial neoplasia (39%), trauma (20%), and inflammatory disease (17%). The re- maining group comprises a miscellaneous number of dis-

From the Department of Pediatrics; Golda Medical Center; Hasharon Hospital; Suckler School of Medicine; Tel Aviv University; Petach Tikvah, Israel.

Communications should be addressed to: Dr. Cohen; Department of Pediatrics; Hasharon Hospital; Petach Tikvah, Israel. Received March 8, 1993; April 27, 1993.

394 PEDIATRIC NEUROLOGY Vol. 9 No. 5

Table 1. Data on 7 children with benign abducens nerve palsy

Patient No./ Abducens Duration of No. of Re- Recent Age/Sex Paresis Paresis (days) currences Infections

1/3V2 yrs/F Left 20 - EBV

2/8 mos/F Left 40 1 EBV

3/4 yrs, Left 22 - ND 8 mos/F

4/5 yrs/M Left 55 1 ND

5/7 yrs/F Left 25 1 ND

6/12 yrs/F Left 18 - ND

Abbreviations: EBV = Epstein-Barr virus ND = Not defined

orders of which hydrocephalus is the most common [6]. Robertson et al. proposed that if trauma were excluded, the etiology of abducens nerve palsy in children due to brain tumor is high [10]. Because most tumors causing lateral rectus palsy arise in the posterior fossa, magnetic resonance imaging would be the preferred imaging tech- nique [ 11 ].

Benign acquired isolated abducens nerve palsy of childhood is rare and recurrence is even rarer. Viral etiol- ogy from EBV [12] and CMV [8] infection has been documented. In our series, Patients 1 and 2 had a recent EBV infection as documented by the serologic test.

Association of abducens nerve palsy with immuniza- tion (MMR and DTP) [1-5], Lyme disease [7], and Q fever [9] has also been reported. Short febrile illness pre- ceding the palsy was reported by Sternberg et al. [3] and Boger et al. [4].

Five of our 6 patients were females and ages ranged from 8 months to 12 years (Table 1). The left side was affected in all patients. Abducens nerve palsy recurred in 3 patients on the same side with recovery within 18-40 days. During the second episode, resolution occurred in 10-21 days. In all patients, complete recovery was docu- mented. Afifi et al. concluded that all reported patients with benign abducens nerve paresis share the following features [11]:

(1) Childhood occurrence; (2) Spontaneous recovery within 6 months in the majo-

rity of patients; (3) Ipsilateral recurrence; (4) Painless palsy; and (5) Female and left-sided preponderance.

The paresis is believed to be a consequence of a neuro- tropic effect of an infectious agent [ 1 ], but parainfectious etiology is equally likely. The prognosis for benign iso- lated abducens nerve palsy is excellent.

References

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[2] Knox DL, Clark DB, Schuster FF. Benign VI nerve palsies in children. Pediatrics 1967;40:560-4.

[3l Sternberg I, Ronen S, Arnon N. Recurrent isolated post fe- brile abducens nerve palsy. J Pediatr Ophthalmol Strabismus 1980;17: 323-4.

[4] Boger WP III, Puliafito CA, Magoon EH, Sydnor CE Knupp JA, Buckley EG. Recurrent isolated sixth nerve palsy in children. Ann Oph- thalmol 1984; 16:237-8,240-4.

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[6] Sullivan SC. Benign recurrent isolated VI nerve palsy of child- hood. Clin Pediatr 1985;24:160-1.

[7] Huber A, Baumann W. Clinical manifestation of Lyme bor- reliosis in childhood. Klin Padiatr 1989;201:133-5.

[8] George JL, Abellan P, Gehin E Regressive abducens palsy in a child. A cytomegalovirus infection presumed. Rev Otonearoophtalmol 1984;56:67-70.

[9] Shaked Y, Samra Y. Q fever meningoencephalitis associated with bilateral abducens nerve paralysis, bilateral optic neuritis and abnormal cerebrospinal fluid findings. Infection 1989; 17:394-5.

[10] Robertson DM, Himes JD, Rucker CW. Acquired sixth-nerve paresis in children. Arch Ophthalmol 1970;83:574-9.

[11] Afifl AK, Bell WE, Memezes AH. Etiology of lateral rectus palsy in infancy and childhood. J Child Neurol 1992;7:295-9.

[12] Chris ten JH, Aksu F, Petersen CE. Isolated abducens nerve paralysis in infectious mononucleosis. Monatsschr Kinderheilkd 1983; 131:532-4.

Cohen et al: Benign Abducens Nerve Palsy 395