guillain - barre syndrome ( gbs ) is one of the acute flaccid paralysis syndromes . different subtypes producing the clinical picture of gbs have been described including acute inflammatory demyelinating polyradiculoneuropathy ( aidp ) , acute motor axonal neuropathy ( aman ) , acute motor and sensory axonal neuropathy ( amsan ) , acute sensory neuropathy , acute pandysautonomia and the fisher syndrome . presentations with central features such as depressed level of consciousness , and hyper - reflexia were reported in bickerstaff brainstem encephalitis ( bbe ) . in bickerstaff ophthalmoplegia and ataxia were common among patients diagnosed with bickerstaff encephalitis and fisher syndrome ( fs ) . it was always thought that both bbe and fs were distinct disorders from gbs , but considered as a spectrum disorder with an autoimmune mechanism targeting primarily the central nervous system . the discovery of anti - gq1b antibody was a turning point in explaining the fact that certain patients share similar clinical features suggestive of gbs , bbe or fs . the gq1b antigen is highly expressed in the paranodes and the neuromuscular junctions of the oculomotor , trochlear and abducens nerves , muscle spindles in the limbs , and probably reticular formation in the brainstem . the neurological effects of anti - gq1b antibodies are induced by complement - mediated destruction of both perisynaptic schwann cells ( by inhibiting ca influx ) and axonal terminals resulting in neuromuscular junction blockade and ultimately muscle weakness . herein , we report a case of atypical anti - gq1b syndrome in a patient presented with both central and peripheral nervous system involvements . a fifteen years - old right - handed boy presented to the emergency department with progressive weakness of upper and lower extremities for 3 days . he was unable to walk and was having difficulty elevating his arms above the shoulder . although he did not describe any bulbar symptoms , he was complaining of significant binocular diplopia . in addition , he described abdominal pain associated with urinary retention , and a foley s catheter was inserted draining over 500 ml of urine . there was no associated history of headache , fever , recent immunization or travel , or any changes in level of consciousness . on initial exam , he was hemodynamically stable with temperature 36.7c and o2 saturation of 98% on room air . cranial nerve examination revealed normal pupillary reaction , upward and gaze - evoked horizontal nystagmus . motor exam assessment according to medical research council ( mrc ) scale revealed flaccid tone with significant symmetrical proximal more than distal weakness as follows : deltoid 3/5 , biceps 2/5 , triceps 3/5 , wrist and finger extensors 3/5 , wrist and fingers flexors 2/5 , hip flexors 1/5 , knee flexors 2/5 , knee extensors 3/5 , dorsiflexors 4/5 , planterflexors 4-/5 . deep tendon reflexes were reduced ( 1 + ) in triceps and biceps and absent in brachioradialis , knees , and ankles . cerebellar and gait exam were deferred due to his significant weakness . his basic laboratory investigation including hematological , liver and renal function testes were within normal limits . erythrocyte sedimentation rate was elevated at 32 . magnetic resonance imaging ( mri ) of brain / spine with gadolinium was unremarkable . cerebral spine fluid ( csf ) examination revealed 20 white cells ( 100% lymphocytic ) while protein and glucose were within normal limits . the gramstain was unremarkable . given that he had a prodromal illness along with the presentation of symmetrical proximal more than distal weakness with areflexia , gbs was suspected . however , given the presence of brainstem features ( nystagmus ) , pyramidal signs ( extensor plantars ) along with acute urinary retention , other diagnoses such as bickerstaff encephalitis and acute disseminated encephalomyelitis ( adem)-like syndrome were considered despite the preservation of consciousness and normal mri . forced vital capacity was 2.2 l on second day of admission and remained between 2.0 - 2.6 l in the first week . an improvement in the power of upper limbs and neck flexor weakness were evident on day 3 ( deltoid 4/5 , biceps 3/5 , triceps 4/5 , wrist and finger extensors 4/5 , wrist and finger flexors 3/5 ) . his lower limb power was essentially the same apart from improvement of knee extensors 4+/5 , knee flexors 3/5 . nerve conduction study was performed on day 4 of admission , and revealed normal sensory nerve action potentials ( snaps ) but absent compound muscle action potentials ( cpams ) in the lower limbs and reduced cmaps in the upper extremities without conduction block . on day 4 , he developed bilateral lateral abduction paresis and mild facial weakness indicative of the involvement of both cn vi and vii . the decision was made to start iv immunoglobulin 2 g / kg course over 3 days given his clinical progression . he continued to have supportive measures by means of physical therapy , dvt prophylaxis along with urological follow - up in order to train his bladder muscles . a follow - up mri brain and spine , which was performed on day 10 , was unremarkable . on day 14 , he started to regain the function of upper extremities and was able to lift his arms above his shoulders with good support of neck muscles . on day 30 , the power of hip flexors was 3/5 and he was able to stand with 2-person assist . on day 42 , he started to walk unassisted but needed support in rising from a chair . on day 50 , the urinary catheter was removed after bladder training and he was able to urinate without any difficulty . on day 62 , his neurological examination revealed mild limitation of both lateral recti with no evidence of nystagmus . in terms of power testing , his mrc grade for muscles were as follows : deltoid 4 + , biceps 5 , triceps 5 , intrinsic hand muscles 4 + , hip flexor 4- , knee flexors 4 + , knee extensor 4 + , dorsiflexors 5 , planterflexors 5 . he was referred to an outpatient rehabilitation center . at one - year follow - up , our case illustrated atypical presentations and findings , which pointed toward a central involvement since gaze - evoked horizontal nystagmus is usually localized to the cerebellum while upbeat nystagmus is commonly associated with lesions in the rostral pons . in addition , the presence of extensor plantars was indicative of corticospinal tract involvement , which in association with acute urinary retention , was pointing towards spinal cord localization . on the other hand , certain clues in the examination ( distribution of weakness being proximal more than distal , neck flexor weakness and areflexia ) were indicative of polyradiculitis , raising the suspicion of a gbs - variant . although few cases were reported in the literature with central features in gbs patients , it was proposed that corticospinal tract might be functionally involved in patients with anti - ganglioside antibody associated syndromes . kariyama et al . described a patient who had asymmetrical weakness , which was confused for a stroke initially but later was diagnosed with gbs . the central weakness was confirmed by mean of abnormal central motor conduction time ( cmct ) on a motor evoked potential study . the autonomic dysfunction manifested by the acute urinary retention in our patient added to the dilemma of the co - existence of both upper and lower motor signs . in gbs , bladder or bowl disturbance at presentation watson et al . studied 26 children with gbs , of whom 7 had bladder or bowl disturbance at presentation . one patient presented with , and three subsequently developed urinary retention necessitating catheterization for a median of 7.5 days . dysautonomia is usually associated with aidp and it is rare in other types such as aman , and the nerve conduction study in our patient revealed features supportive of the latter . on the other hand , it is not unusual to have urinary retention with areflexia in a spinal shock stage resulting from an acute myelitis . in our case , the persistent urinary retention makes it different from gbs where urinary retention is a transient occurrence . the presence of anti - gq1b antibody in our patient reflects a unique clinical spectrum , which represents an existing continuum between several conditions ( fisher , bickerstaff and guillain - barre syndromes ) presenting with variable central and peripheral nervous system involvements . fisher syndrome presents when the binding of anti - gq1b antibodies to gq1b antigens expressed on the relevant cranial nerves and muscle spindles whereas bickerstaff brainstem encephalitis is induced when the anti - gq1b antibodies enter the brainstem and bind to gq1b antigens . a more inclusive nomenclature such as anti - gq1b antibody syndrome could be used to include the common serological profile when referring to the clinical syndromes described by both bickerstaff and fisher . however , nystagmus ( observed in our patient ) was never reported in the literature to be associated with anti - gb1b antibody syndrome despite the occasional presence of ophthalmoplegia and other brainstem features odaka et al . evaluated 194 anti - gq1b seropositive patients , among whom 110 had fs , 31 had an overlap of fs with gbs , 12 had bbe , and 11 had an overlap of bbe with gbs . in another study of 62 patients with bbe , the authors described positive anti - gq1b antibody in 66% of patients and approximately 60% of the overall cohort associated flaccid symmetrical tetraparesis . maier et al . studied 13 autopsy cases of gbs patients and they revealed evidence of pathological mononuclear cell infiltrates composed of macrophages and t - lymphocytes within the spinal cord in 8 out of 13 cases , within the medulla oblongata in 8 out of 12 cases , within the pons in 5 out of nine cases , and in one out of four midbrains . the authors did not find any evidence of primary demyelination in the cns but rather axonal with secondary myelin impairment , microglial activation and inflammatory infiltration . given the challenging diagnostic nature of our case , and the predominant central features , we elected to treat the patient with a combination of iv methylprednisone ( ivmp ) and iv immunoglobulin ( ivig ) . the rationale was based on the faster effect of ivmp in view of myelitis - like picture , which tends to respond to high dose parental steroids . on the hand , given that the pathogenesis of anti - gq1b antibody syndrome is similar to gbs , ivig was subsequently added as it has been shown to be efficacious in improving outcomes in gbs . although there have been reports of clinical improvement with steroid administration , its role in the anti - gq1b antibody syndrome is less clear . the presence of nystagmus along with other central features may pose diagnostic dilemma in patients suspected to have gbs variants . our case highlights the importance of broad - based approach in dealing with atypical presentations involving both peripheral and central nervous system where the clinical spectrum of anti - gq1b syndrome might be considered .
variants of guillain - barre syndrome such as bickerstaff encephalitis and miller - fisher syndrome have been reported . 
 we report a 15-year - old boy who presented , after a prodromal illness , with 3-day progressive limb weakness , diplopia , and acute urinary retention . 
 clinically , he had horizontal gaze - evoked and upbeat nystagmus , bilateral extensor plantars in addition to quadriparesis and areflexia . 
 magnetic resonance imaging of the brain and spine was unremarkable and cerebral spinal fluid analysis showed lymphocytic pleocytosis . 
 nerve conduction study revealed symmetrical axonal neuropathy . 
 anti - gq1b antibody was positive . 
 a combination of iv methylprednisone followed by ivig was instituted which led to remarkable clinical recovery . this case underpins the importance of recognizing atypical presentations of acute autonomic dysfunction and central nervous system features such as nystagmus , which may be associated with anti - gq1b antibody syndrome 
 . features mimicking myelitis and brainstem encephalitis may pose diagnostic and therapeutic dilemma among the treating physicians .