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limbic encephalitis ( le ) is an uncommon neurological disorder characterized by a subacute and progressive altered consciousness , memory disturbance , and recurrent seizures .
antibodies including anti - hu , anti - yo , anti - cv2/crmp5 , anti - ri , anti - ma2 , and anti - amphiphysin are associated with paraneoplastic le .
recently , new antibodies were identified that target neuronal cell surface antigens , ion channels ( i.e. , voltage - gated potassium channels [ vgkc ] ) , and ligand - gated ion channels ( i.e. , nmda , ampa , and gabab receptor channels ) , which are not commonly related to tumors [ 3 - 5 ] .
le associated with antibodies against leucine - rich glioma inactivated-1 ( lgi1 ) , one of the specific targets of vgkc - complex antibodies , is characterized by faciobrachial dystonic seizures ( fbds ) and memory loss with a subacute clinical course [ 5 - 7 ] . usually , fbds precedes other symptoms and prompts the diagnosis of anti - lgi1 le .
however , here we report a case of anti - lgi1 le that presented with atypical chest pain and spontaneous relapsing - remitting course that complicated the diagnosis .
she developed confusion with disorientation to the time and place and had no memory of a recent family trip before 2 days of admission . upon admission ,
eeg failed to indicate any abnormality , and no focal deficit was found on neurological examinations .
after correction of hyponatremia , she was discharged without significant problems , except for memory disturbance . her korean mini - mental state examination ( k - mmse )
score was 25 at the time of discharge ( 8/10 on time and place orientation and 0/3 on memory recall ) .
the patient was readmitted to our hospital 12 months after her initial admission . since two months before readmission , she was experiencing recurrent chest discomfort that she described as squeezing and dull in nature , typically lasting 10~30 seconds .
the frequency of these episodes was initially once a day , but progressed to more than 20 times a day after 2 months .
she reported that her memory disturbance was aggravated and she had developed intermittent confusion with disorientation .
she repeatedly asked , " where am i ? " and , " why am i here ? " and sometimes lost her sense of direction . on the day before her readmission , she experienced chest discomfort and subsequently lost consciousness and collapsed with facial grimacing and abnormal arm - twisting movements .
she regained consciousness a few minutes later , but was disoriented to the time and place .
definite convulsive movements were not observed . at admission , she was alert , oriented and showed no focal deficits on neurological examination .
her k - mmse score was 24 ( 8/10 on time and place orientation , 4/5 on attention and calculation and 0/3 on memory recall ) , and she showed no difficulties with daily activity during her admission .
routine blood tests and a brain mri were normal ; a routine eeg failed to show definite abnormalities . for her chest discomfort , transthoracic echocardiography , ct coronary angiography , and 24-h electrocardiography
supine blood pressure was 130/60 mmhg , and orthostatic blood pressure at 0 , 1 , 3 , and 5 min was 120/60 , 125/60 , 130/60 , and 125/65 mmhg , respectively .
initially , we diagnosed the patient with anxiety disorder and administered a selective serotonin reuptake inhibitor and an anxiolytic . however , her chest discomfort persisted . on video - eeg monitoring , ictal discharges were observed in the right temporal area during her chest discomfort ( fig .
the frequency and duration of her chest discomfort reduced to a few times a day and lasted only a few seconds , whereas her memory disturbance persisted .
thus , we suspected autoimmune causes for the limbic encephalitis , and anti - lgi1 antibody was detected in both serum and csf ( fig .
immunogloblin ( 0.4 g / day for 5 days ) and antiepileptic drugs ( oxcarbazepine and levetiracetam ) , the chest discomfort and memory disturbance markedly improved .
her follow - up k - mmse score was 27 ( 8/10 on time and place orientation and 4/5 on attention and calculation ) .
anti - lgi1 le usually involves the medial temporal area , which causes memory dysfunction and seizures .
this disorder was recently identified as an autoimmune encephalitis , which has distinctive clinical features , such as limbic dysfunction , seizures , and occasional hyponatremia [ 7 - 9 ] .
the cause of chest discomfort was identified as partial seizure in video - eeg , and thus it was related to the autoimmune activities .
our patient showed spontaneous remission for 10 months after the initial manifestation of hyponatremia and memory disturbance .
this spontaneous remission and relapse is very unusual in this autoimmune encephalitis , and delayed the diagnosis of the patient . in anti - lgi1 le ,
mri may show signal changes in medial temporal lobes and basal ganglia [ 5 - 9 ] , but pet is a more sensitive tool because it can detect abnormal glucose metabolism in these areas [ 7 , 9 , 10 ] .
however , a number of patients do not show abnormalities on mri or pet , and evidence of inflammation , including pleocytosis or protein elevation , can be absent from csf [ 7 - 9 ] .
chest tightness is usually documented in patients with cardiogenic or vasovagal syncope related to esophageal disorders such as esophageal spasm or gastroesophageal reflux .
syncope is the first differential diagnosis in a patient with loss of consciousness without convulsive movements . in this patient , however , the possibility of cardiac or chest disease was excluded by thorough cardiac , chest and upper gastrointestinal work - ups , or with an orthostatic blood pressure examination . instead
, the symptom was related to parital seizures originating from right temporal lobe . because her chest discomfort partially responded to an antiepileptic
however , until video - eeg monitoring , the cause of chest pain had been obscured . because of the atypical manifestations , only the previous history of hyponatremia and memory disturbance , in addition to a recent history of fbds , could make us to suspect anti - lgi1 le .
hyponatremia is commonly detected in patients with anti - lgi1 le [ 5 - 9 ] .
however , hyponatremia is a non - specific sign , because it is also caused by other medical conditions , such as decreased salt intake , salt loss by vomiting or diarrhea , or medical disorders including hypothyroidism or syndrome of inappropriate antidiuretic hormone secretion . cognitive impairment and confusion , which are cardinal manifestations of le , are also found in patients with hyponatremia . in our patient ,
memory disturbance , which is very common in the elderly , persisted after her plasma sodium level had normalized , whereas her other symptoms disappeared .
because these symptoms were similar to those of other medical disorders , we encountered difficulty with correctly diagnosing the patient on her first admission .
because the patient presented with the atypical manifestation of a spontaneous relapsing - remitting disease course with a 10-month interval , rather than a subacute progressive course , we encountered further difficulty with the diagnosis our patient showed normal neuroimaging and csf findings , along with an atypical clinical presentation that mimicked other disorders with symptoms including anxiety , vasovagal , cardiogenic syncope , metabolic encephalopathy , psychiatric disorders , and geriatric cognitive impairment .
a history of hyponatremia , pharmacoresistant partial seizures and early documentation of seizures by video - eeg monitoring could prompt the diagnosis .
nevertheless , it is notable that the atypical chest pain as well as the chronic remitting - relapsing condition were another manifestations of anti - lgi1 le in our patient , and that early and optimal treatments are crucial for full recovery .
anti - leucine - rich glioma inactivated-1 ( lgi1 ) limbic encephalitis ( le ) is a rare neurological disorder that has a subacute course of progressive encephalopathy and fasciobrachial dystonic seizures . 
 we report a patient with anti - lgi1 le that presented with atypical manifestations that complicated the diagnosis . a 62-year - old woman presented with a chronic course of memory disturbance and a subsequent relapse with an altered mental status after 10 months . 
 the patient reported frequent chest pain of squeezing and dull nature , typically lasting 10 - 30 seconds . 
 the chest pain was related to partial seizures , which were confirmed by video - eeg monitoring . 
 anti - lgi1 antibody was identified in serum and csf . 
 the patient 's symptoms improved by immune modulation treatment . patients with anti - lgi1 le can experience atypical partial seizures , and a chronic relapsing course . 
 clinical suspicions and video - eeg monitoring are helpful for the early diagnosis and effective immune modulation .