west nile virus ( wnv ) is an arthropod borne neurotropic single stranded rna flavivirus .
the virus is introduced into the host by the vector ( culex mosquito ) during its blood meal .
wnv originated in the middle east and africa but in recent years has reached the united states . from 1999 to 2011 , a total of 31,414 cases of wnv were reported in the united states .
the 2012 incidence of wnv neuroinvasive disease was 0.3 per 100,000 in the united states .
approximately 45% of wnv cases were reported in texas , usa . seasonal outbreaks occur annually but are often quite focal and unpredictable in size and location .
the majority of those infected with wnv are asymptomatic and only 20 - 30% will present with flu like symptoms . less than 1% of individuals will eventually develop neurological deficits .
immunocompromised and elderly patients are more prone to developing wnv meningitis or encephalitis compared to the general population .
wnv and other arboviral infections should be considered in the differential diagnosis of aseptic meningitis or encephalitis , especially if the geographical area is prone to wnv infection .
the definitive diagnosis of wnv meningoencephalitis is a combination of clinical suspicion and csf serology .
we are presenting a very rare case of a immunocompromised patient that developed opsoclonus myoclonus syndrome following wnv encephalitis .
forty - eight year old caucasian female presented with a sudden onset of altered mental status after being found unresponsive .
she was confused with intermittent bouts of alertness / lethargy and unintelligible responses to questioning .
her medical problems included endometrial cancer that was treated with a total abdominal hysterectomy with bilateral salpingectomy and postoperative chemotherapy .
the endometrial adenocarcinoma was a stage 2 according to the international federation of gynecology and obstetrics ( figo ) staging : 8 cm tumor , grade 2 , no lymph node involvement , and < 50% invasion of the myometrium and cervical stroma .
the patient was currently in remission after receiving chemotherapy ( paclitaxel and carboplatin ) and dexamethasone .
initial vital signs on admission included a rectal temperature was 41.1 degrees celsius , tachycardia ( heart rate of 108 ) , stage 1 hypertension ( blood pressure of 140/61 ) and tachypnea ( respiratory rate of 34 ) .
pertinent physical examination findings revealed a morbidly obese female that was alert but not oriented to person , place or time and only able to answer yes or no to questioning .
her pupils were 3 mm bilaterally , equal round and reactive to light with intact extraocular movements and no nystagmus noted .
no motor or sensory deficits to light , touch , pain , position sense or vibration noted .
initial laboratory work - up ( table 1 ) was unremarkable except hyponatremia and thrombocytopenia .
brain computed tomography ( ct ) on admission was negative for any acute pathological abnormalities .
the patient was started on ceftriaxone 2 g iv daily , vancomycin 2 g iv twice daily , and acyclovir 1.5 g iv every 8 hours due to our high suspicion of encephalitis .
a lumbar puncture with cerebrospinal fluid ( csf ) analysis and csf serology ( table 2 ) was consistent with aseptic meningitis .
magnetic resonance imaging ( mri ) of the brain was unremarkable for any acute intracranial abnormalities .
vancomycin and acyclovir were discontinued and fluconazole 400 mg po daily was added to the management on the sixth hospital and ceftriaxone was continued until the tenth hospital day . by the seventh hospital day , we noted involuntary random movements of her eyes ( see video 1 ) and generalized jerking movements ( myoclonus ) , mostly in lower extremities .
an electroencephalography ( eeg ) showed a severe and diffuse slowness , consistent with encephalopathy .
she was placed on fosphenytoin 100 mg iv every 8 hours without any improvement . on the eighth hospital day , her gcs decreased to 3 and was subsequently intubated .
the platelet count continued to decrease during the hospitalization and eventually reached its lowest count of 2110/ul by the tenth hospital day . the west nile virus ( wnv ) antibody igm and igg
were noted to be positive on the twelfth hospital day . after determining that the encephalitis was due to the wnv we continued supportive care and discontinued the fluconazole .
they diagnosed her to have opsoclonus myoclonus syndrome ( oms ) induced by the wnv meningoencephalitis .
paraneoplastic antibodies anti - yo , anti - hu , anti - ri and anti - nmdar were negative .
a percutaneous endoscopic gastrostomy tube ( peg ) and tracheostomy were performed on hospital day 26 .
the patient continued to have improvement in her neurological status and was subsequently discharge to a long term acute care ( ltac ) facility for further rehabilitation .
she underwent rehabilitation for six months and eventually had complete resolution of her neurological deficits on follow visit .
opsoclonus - myoclonus syndrome ( oms ) is a rare neurological disorder associated with chaotic multidirectional eye movements , myoclonus and less frequently cerebellar ataxia .
the eye movements are characterized by multidirectional , high amplitude , arrhythmic and conjugate ocular saccadic intrusions without intersaccadic latency causing oscillopsia .
it should not be confused with nystagmus which is usually unidirectional and has a slow component .
myoclonus may affect any part of the body and may be evoked by action , intention , auditory and visual stimuli .
the pathogenesis of opsoclonus is unknown but , one hypothesis suggests that opsoclonus is due to damage of the omnipause cells in the nucleus raphe interpositus of the pons .
this prevents unwanted saccades by inhibiting burst neurons in the paramedian pontine reticular formation and rostral interstitial nucleus of cajal .
another explanation suggests that opsoclonus may be generated by disinhibition of the oculomotor region of the fastigial nucleus by a process that interferes with the inhibitory projections of the purkinje cells of the deep cerebellar nuclei to the fastigial nuclei .
the pathogenesis is not fully understood , however , an autoimmune pathophysiology has been proposed .
autoimmune dysfunction of purkinje cells in the dorsal vermis and subsequent disinhibition of oculomotor fastigial region seems to be the most probable mechanism .
however , other common causes of opsoclonus include paraneoplastic , viral brainstem encephalitis and drugs .
the onconeuronal antibodies associated with oms are anti - ri antibodies ( gynecologic cancers ) and , less frequently , anti - hu , anti - yo , and anti - ma-2 antibodies .
paraneoplastic diseases associated with oms include small - cell lung , ovarian and breast cancer .
most infectious disease causes involve the central nervous system or a post infection immune mediated process .
the post infectious mechanism has been described as a dysfunction of the cell mediated and humoral immune response .
this immune mediated process was postulated because the presence of autoantibodies and the response of oms to immunosuppressive therapy .
the specific microorganism is rarely identified however oms has been reported to occur after infection with enterovirus , borrelia burgdorferi , streptococcus , coxsackie virus , epstein - barr virus , mumps or west nile virus .
opsoclonus myoclonus syndrome can result in significant long term neurological sequelae if either untreated or undertreated .
therapy options have been directed towards the suppression of antibody formation and the removal of the autoantibodies .
several therapeutic attempts can be utilized to remove the autoantibodies in patients with oms , such as ivig , plasmapheresis , and immunoadsorption .
however there is no available data from clinical trials that suggest a definitive treatment strategy .
because the opsoclonus - myoclonus syndrome is so rare , there are no randomized controlled trials to provide guidelines for either symptomatic or disease modifying treatments . according to current medical literature
, only two other case reports have reported opsoclonus myoclonus syndrome induced by west nile virus encephalitis .
 west nile virus ( wnv ) is an arthropod borne neurotropic single stranded rna flavivirus with < 1% developing presenting with neurological disease . 
 immunocompromised and elderly patients are more prone to developing wnv meningitis or encephalitis . 
 definitive diagnosis of wnv meningoencephalitis is a combination of clinical suspicion and cerebrospinal fluid ( csf ) serology . 
 forty - eight year old caucasian female presented with a sudden onset of altered mental status after being found unresponsive . 
 she was confused with intermittent bouts of alertness / lethargy and unintelligible responses to questioning . 
 her medical problems included endometrial cancer that was in remission after undergoing a total abdominal hysterectomy with bilateral salpingectomy and postoperative chemotherapy with paclitaxel and carboplatin . 
 pertinent physical examination revealed muscle strength that was significantly decreased , nuchal rigidity and + 2 pitting edema of both lower extremities . computed tomography and magnetic resonance imaging of the brain were negative for any intracranial pathology . 
 csf analysis was consistent with aseptic meningitis with all csf serology being negative except for positive wnv antibody . a few days after being admitted she developed involuntary random movements of her eyes and generalized jerking movements ( myoclonus ) . 
 this was determined to be opsoclonus myoclonus syndrome ( oms ) induced by the wnv meningoencephalitis . 
 she then received five consecutive days of plasmapheresis with a significant improvement in her neurological status . 
 opsoclonus - myoclonus syndrome ( oms ) is a rare neurological disorder associated with chaotic multidirectional eye movements , myoclonus and less frequently cerebellar ataxia . 
 oms affects as few as 1 in 10,000,000 people per year . 
 the pathogenesis is not fully understood with the majority of cases of opsoclonus - myoclonus syndrome being idiopathic . according to current medical literature 
 there have only been two previous case reports of opsoclonus myoclonus syndrome associated with wnv encephalitis . 
Introduction
Case Report
Discussion and Conclusions