Autoimmune Encephalitis: Pathophysiology and Imaging Review of an Overlooked Diagnosis

Altered cerebral glucose metabolism normalized in a patient with a pediatric autoimmune neuropsychiatric disorder after streptococcal infection (PANDAS)-like condition following treatment with plasmapheresis: a case report

Background

Pediatric autoimmune neuropsychiatric disorder after streptococcal infection (PANDAS) is a specific autoimmune response to group-A streptococcal infections in children and adolescents with a sudden onset of obsessive-compulsive disorders or tic-like symptoms. Cerebral metabolic changes of patients have not yet been observed.

Case presentation

We present a case of an 18-year old male with a PANDAS-like condition after developing tic-like symptoms and involuntary movements three weeks after cardiac surgery. The patient had suffered from pharyngotonsillitis before the symptoms started. The anti-streptolysin O (ASO) titer was elevated (805 kU/l). Antibiotic therapy did not improve his condition. Intravenous immunoglobulins and high-dose cortisone therapy had minor beneficial effects on his involuntary movements. 18F-Fluorodeoxyglucose positron emission tomography/ computer tomography (18F-FDG PET/CT) demonstrated pronounced hypermetabolism of the basal ganglia and cortical hypometabolism. The patient was treated with five cycles of plasmapheresis. A marked clinical improvement was observed after four months. Cerebral metabolic alterations had completely normalized.

Conclusions

This is the first report of cerebral metabolic changes observed on FDG-PET/CT in a patient with a PANDAS-like condition with a normalization following immunomodulatory treatment. Cerebral FDG-PET/CT might be a promising tool in the diagnosis of PANDAS.

Paraneoplastic limbic encephalitis associated with lung cancer

Paraneoplastic limbic encephalitis (PLE) is a rare autoimmune neurological syndrome observed in lung cancer patients. We retrospectively investigated the clinical characteristics, treatment responses, and prognoses in 16 PLE patients who were subsequently diagnosed with lung cancer. Fifteen patients initially presented with disturbance of consciousness, 13 with disorientation, and 12 with seizures. Thirteen patients had autoantibodies, including eight with gamma aminobutyric acid B receptor (GABABR) antibodies and eight with Hu antibodies. PET-CT revealed lung neoplasms in 13 patients, nine of whom exhibited abnormal metabolic activity in the temporal lobe and hippocampus. Fifteen cases were confirmed as limited-stage small cell lung cancer and one as stage IV large cell neuroendocrine carcinoma. Eleven patients received immunomodulatory therapy, and four showed neurological improvement, who all had antibodies against GABABR. Fifteen patients received chemotherapy, of which 14 maintained or improved their PLE status. The overall cancer response rate was 75%, and two-year overall survival was 74.7%. Our results suggest patients with GABAB encephalitis might respond better to immunotherapy than the classical PLE patients with anti-Hu antibodies. Anti-cancer treatment could further improve neurological symptoms. Lung cancer patients with PLE, especially those in limited stage, might have better outcome due to earlier diagnosis and prompt anti-cancer treatment.

A clinical approach to new-onset psychosis associated with immune dysregulation: the concept of autoimmune psychosis

Growing data point to the overlap between psychosis and pathological processes associated with immunological dysregulation as well as inflammation. Notably, the recent discovery of antibodies against synaptic and neuronal cell membrane proteins such as anti-N-methyl-d-aspartate receptor provides more direct evidence of the etiological connection between autoimmunity and subsequent hazard of psychosis. Here, we advocate the use of term “autoimmune psychosis,” as this term suggests that autoimmune disorders can masquerade as drug-resistant primary psychosis, and this subtype of psychosis has anatomical and immunological footprints in the brain, despite the frequent absence of structural abnormalities on conventional brain MRI. Furthermore, this term might serve as a reminder not to overlook appropriate neurological workup such as neuroimaging and EEG testing, as well as CSF analysis, for cases with acute or subacute atypical onset of neuropsychiatric presentations including those dominated by acute psychotic symptoms. We propose etiologically and serologically oriented subclassification as well as multi-modal diagnostic approach to address some of the challenges inherent to early diagnosis of patients presenting with atypical and refractory new-onset psychotic symptoms of autoimmune origin. This is particularly relevant to the diagnosis of seronegative but probable autoimmune psychosis (SPAP) that might masquerade as antipsychotic drug-resistant primary psychotic disorder. This distinction is therapeutically important as autoimmune-related psychotic symptomatology can frequently respond well to timely treatment with proper immune modulatory therapies.

Acute Leukoencephalopathy with Restricted Diffusion

Treatment and outcome of children with acute encephalopathy depend on the cause, prompt treatment of the underlying cause, and use of adequate supportive measures. Many novel causes of acute encephalopathy are emerging where lumbar puncture, computed tomography of the head, and routine biochemical testing can be normal such as acute disseminated encephalomyelitis and febrile infection-related refractory epilepsy syndrome. Magnetic resonance imaging (MRI) plays an important role in the workup of children with acute leukoencephalopathy. Despite this in few cases, a correct diagnosis is not possible and novel conditions have been described in the last decade. One such condition is acute encephalopathy with biphasic seizures and restricted diffusion also called as acute leukoencephalopathy with restricted diffusion. Here, the routine MRI sequences such as T1, T2, and fluid-attenuated inversion recovery sequences can be normal. Here, we have reviewed the etiology, types, clinicoradiological features, and treatment of this condition.

Clinical Characteristics and Predictors of Outcome for Onconeural Antibody-Associated Disorders: A Retrospective Analysis

Objective

To describe and analyze the clinical characteristics, laboratory data, management, and outcome of patients with onconeural antibody-associated disorders (OAAD) and identify predictors for poor outcome.

Methods

This was a retrospective review of all patients with potential OAAD, who were hospitalized in Jinan General Hospital between September 2009 and July 2017. We clarified the diagnosis, collected comprehensive information and categorized patients into three groups: paraneoplastic neurological disorders (PNDs), autoimmune encephalitis (AE), and possible OAAD. Within the three groups, we analyzed a range of clinical and laboratory parameters and used univariate and multivariate regression analysis to identify predictors for poor outcome [modified Rankin Scale (mRS) = 3–6].

Results

From 158 patients, we identified 70 who fulfilled the criteria for OAAD, including 44 men (62.9%) and 26 women (37.1%). There were 38 patients (54.3%) in the PNDs group, 14 patients (20%) in the AE group, and 18 patients (25.7%) in the possible OAAD group. After the last follow-up, 14 (36.8%), 9 (64.2%), and 12 (66.7%) had a good outcome (mRS = 0–2). However, 6 (15.8%), 2 (14.3%), and 3 (16.7%) died, respectively. Univariate analysis showed that duration prior to the hospital (p = 0.0224) and urinary incontinence/retention (p = 0.0043) were associated with poor outcome (mRS = 3–6). After multivariate regression analysis, urinary incontinence/retention (p = 0.0388) and an immunocompromised state (p = 0.0247) remained as significant factors for poor outcome.

Conclusion

Urinary incontinence/retention and an immunocompromised state represent significant predictors of a worse prognosis for patients with OAAD. By contrast, cerebrospinal fluid analysis showed that serum autoantibodies and tumor markers, the function of crucial organs, electrophysiology, and radiological findings were not associated with a poor outcome.