Anti-leucine-rich glioma-inactivated 1 encephalitis with manic symptoms as the initial manifestation

To the Editor

Autoimmune encephalitis has characteristic neuropsychiatric presentations. Memory disturbance, subacute confusion and faciobrachial dystonic seizures (FBDS) are specific symptoms of anti-leucine-rich glioma-inactivated 1 (anti-LGI1) encephalitis (Rosenfeld and Dalmau, 2012). A patient with atypical presentations is presented.

A 43-year-old woman, admitted to the psychiatric ward in August 2016, exhibited irritability, decrease need of sleep, talkativeness, hyperactivity, racing thoughts and psychosis with auditory hallucinations for 1 month. Despite receiving valproic acid and olanzapine for 1 month, she showed poor response. Moreover, she also experienced transient disorientation, memory disturbance, stutter and facial jerk. Upon admission, generalized tonic-clonic seizure (GTCS) attacked twice.

Lab data revealed acute onset syndrome of inappropriate antidiuretic hormone secretion–induced hyponatremia. Electroencephalography (EEG) suggested an intermittent disturbance of cerebral activity over left anterior-mid temporal area. Magnetic resonance imaging (MRI) of the brain revealed high signal changes in bilateral basal ganglia to midbrain, suggesting the possibility of autoimmune encephalitis (Figure 1(a) and (b)). Cerebral spinal fluid study for the limbic encephalitis eventually showed positive anti-LGI1 antibody, with anti-LGI1 encephalitis confirmed.

Figure 1.

(a) Areas of high signal changes were noted in bilateral basal ganglia to midbrain on T2WI-FLAIR and (b) DWI in August 2016, especially on the right side. (c) Improvements in high signal changes over basal ganglia to midbrain on T2WI-FLAIR and (d) DWI could be seen in January 2017.

The patient received 1000 mg of methylprednisolone intravenous bolus for 5 days, followed by oral prednisolone 1 mg/kg/day. Her cognitive functions and psychiatric symptoms improved soon. She was discharged under partial improvement of manic symptoms. After 3 months of oral corticosteroid (25 mg/day), ziprasidone (40 mg/day) and antiepileptic drugs, her manic symptoms remitted, the frequency of FBDS decreased to once a week and her short-term memory deficits recovered. Improvements could be observed from brain MRI in January 2017 (Figure 1(c) and (d)). Moreover, she could resume her daily life functions.

The diagnosis of autoimmune limbic encephalitis is challenging. It is until our patient developed GTCS twice with EEG and MRI abnormalities that the organic cause of her psychiatric symptoms was suspected.

First-line treatment of anti-LGI1 encephalitis was immunotherapy. Most patients were treated with intravenous or oral corticosteroids, intravenous immunoglobulin (Van Sonderen et al., 2016). Hippocampal atrophy and poor memory recovery are common, suggesting permanent functional damage. More intense immunotherapies could improve outcomes (Malter et al., 2014).

Our patient had atypical psychiatric symptoms among anti-LGI1 encephalitis. Reviewing the literature, this is the first case with manic symptoms as the early presentation of anti-LGI1 encephalitis. Also, the patient’s cognitive functions preserved well according to psychological test, which was different from known results of the literature. The satisfactory clinical outcome might be explained by early diagnosis of the disease, with prompt interventions within 2-months after symptoms onset, while hippocampus atrophy had not yet developed.