Opsoclonus myoclonus ataxia syndrome, ovarian teratoma and anti-NMDAR antibody: an 'unresolved' mystery.

Background: Opsoclonus-myoclonus-ataxia syndrome (OMAS) is characterised by the combination of opsoclonus and arrhythmic action myoclonus with axial ataxia and dysarthria. In adults, a majority are paraneoplastic secondary to solid organ tumours and could harbour antibodies against intracellular epitopes; however, certain proportions have detectable antibodies to various neuronal cell surface antigens. Anti-N-methyl-D-aspartate (NMDAR) antibodies and ovarian teratomas have been implicated in OMAS. Methods: Report of two cases and review of literature. Results: Two middle-aged women presented with subacute-onset, rapidly progressive OMAS and behavioural changes consistent with psychosis. The first patient had detectable antibodies to NMDAR in the cerebrospinal fluid (CSF) alone. Evaluation for ovarian teratoma was negative. The second patient had no detectable antibodies in serum or CSF; however, she had an underlying ovarian teratoma. Patient A was treated with pulse steroids, therapeutic plasma exchange (TPE) followed by bortezomib (BOR) and dexamethasone, while patient B was treated with steroids, TPE followed by surgical resection of ovarian teratoma. Both patients had favourable outcomes and were asymptomatic at the 6 monthly follow-up. Conclusions: With coexistent neuropsychiatric manifestations, OMAS can be considered a distinct entity of autoimmune encephalitis, pathogenesis being immune activation against known/unknown neuronal cell surface antigens. The observation of absence of anti-NMDAR antibody in patients with teratoma-associated OMAS and vice versa is intriguing. Further research on the potential role of ovarian teratoma in evoking neuronal autoimmunity and its targets is required. The management challenge in both cases including the potential use of BOR has been highlighted.

Sensitivity and specificity of phrenic nerve electrophysiology to predict mechanical ventilation in the Guillain-Barré syndrome.

INTRODUCTION/AIMS: In Guillain-Barré syndrome (GBS), the sensitivity and specificity of phrenic compound muscle action potential (CMAP) measurements to predict endotracheal mechanical ventilation are unknown. Hence, we sought to estimate sensitivity and specificity. METHODS: We performed a 10-year retrospective analysis of adult GBS patients from our single-center laboratory database (2009 to 2019). The phrenic nerve amplitudes and latencies before ventilation were recorded along with other clinical and demographic features. Receiver operating curve (ROC) analysis with area under the curve (AUC) was used to determine the sensitivity and specificity with 95% confidence interval (CI) for phrenic amplitudes and latencies in predicting the need for mechanical ventilation. RESULTS: Two hundred five phrenic nerves were analyzed in 105 patients. The mean age was 46.1 ± 16.2 years, with 60% of them being male. Fourteen patients (13.3%) required mechanical ventilation. The average phrenic amplitudes were lower in the ventilated group (P = .003), but average latencies did not differ (P = .133). ROC analysis confirmed that phrenic amplitudes could predict respiratory failure (AUC = 0.76; 95% CI, 0.61 to 0.91; P < .002), but phrenic latencies could not (AUC = 0.60; 95% CI, 0.46 to 0.73; P = .256). The best threshold for amplitude was ≥0.6 mV, with sensitivity, specificity, and positive and negative predictive values of 85.7%, 58.2%, 24.0%, and 96.4%, respectively. DISCUSSION: Our study suggests that phrenic CMAP amplitudes can predict the need for mechanical ventilation in GBS. In contrast, phrenic CMAP latencies are not reliable. The high negative predictive value of phrenic CMAP amplitudes ≥0.6 mV can preclude mechanical ventilation, making these a useful adjunct to clinical decision-making.

Chronic flaccid quadriparesis from tract specific myelopathy in neurosyphilis.

INTRODUCTION: Tract-specific myelopathies with distinctive imaging features are uncommon and typically occur with metabolic or paraneoplastic syndromes. We report a unique case of tract-specific myelopathy with neurosyphilis. CASE PRESENTATION: A 53-year-old male presented with a four-month history of flaccid quadriparesis, sensory loss, and bladder dysfunction. His MRIs revealed striking symmetric T2-weighted hyperintensities in the lateral corticospinal tracts and dorsal columns of the cervical spinal cord that extended rostrally into the pyramidal decussation and medial lemnisci of the medulla oblongata. Nerve conduction and needle electromyography studies excluded axonal or demyelinating lower motor neuron disorders. The patient reported previous untreated primary syphilis and was seropositive on the T.pallidum hemagglutination assay. Penicillin therapy resulted in substantial clinical improvement. DISCUSSION: Although syphilitic meningomyelitis is well-reported, our patient was unique because of the persistent flaccidity (possibly suggesting prolonged spinal shock) and striking tract-specific MRI patterns. These features are novel in syphilitic myelitis and suggest unknown mechanisms of tract-specific tropism and neuronal injury. CONCLUSIONS: "Tract-specific" complete transverse myelopathy with persistent flaccid weakness and areflexia is a novel presentation of neurosyphilis. Early recognition and crystalline penicillin therapy can alleviate morbidity. Our report describes this patient's findings and discusses the differential diagnoses of tract-specific myelopathies.

Infection-Associated Peripheral Nerve Hyperexcitability: An Under-Recognized Entity.

BACKGROUND: Peripheral nerve hyperexcitability (PNH) and neuromyotonia have been mainly attributed to antibodies against voltage-gated potassium channels (VGKC). Concurrent autoimmune disorders, malignancies, and heavy metal toxicity have also been implicated. There is scarce mention about infection as a triggering factor for PNH. There are no reports of methicillin-resistant Staphylococcus aureus (MRSA) infection being a possible precipitating factor for development of PNH. METHODS: Case series and literature review. RESULTS: Four subjects were diagnosed to have features of PNH based on clinical and electrophysiological assessment. All the subjects had concurrent evidence of cutaneous abscesses requiring surgical intervention and antibiotic therapy. The cultures in all of them revealed growth of Staphylococcus aureus with three of them being MRSA isolates. Two subjects tested positive for anti-VGKC antibodies. There was remarkable resolution in neuromyotonia after antibiotics in three subjects. One subject succumbed to fulminant MRSA septicemia. CONCLUSION: There appears to be a definitive link between staphylococcal infection (MRSA in particular) and development of PNH. The temporal evolution of PNH associated with the infection and resolution following treatment of the infection does support a causal association. The enterotoxins produced by staphylococci act as superantigens and could trigger an inflammatory cascade along with development of cross reacting antibodies against VGKC in peripheral nerves. Future studies with animal models could provide more directions in this regard.

Clinical Spectrum, Therapeutic Outcomes and Prognostic predictors in Paraneoplastic Neurological Syndromes - Experiences from a Tertiary Care Center in India.

BACKGROUND: Paraneoplastic Neurological Syndromes (PNSs) are a heterogeneous group of immune-mediated disorders that often precede tumor diagnosis. There are few systematic studies on the spectrum and follow-up of PNSs. OBJECTIVE: To analyze the clinical spectrum, associated tumors, antibody profile, outcomes, and prognostic predictors in a cohort of PNSs admitted in a tertiary care center. METHODS: This retrospective study included 97 patients (2008-2019). PNSs were further classified as "classical," "nonclassical," "definite," and "possible." Clinical profile, diagnostic strategies, therapeutic options, and predictors of outcomes were identified. RESULTS: The median age was 54 years (range 17-81). Thirty-nine (40.2%) had classical PNS, and 58 (59.8%) had nonclassical PNS, 74 (76.3%) had "Definite" PNS while 23 (23.7%) had "Possible" PNS. Cerebellar degeneration, peripheral neuropathy, and encephalopathy were the three most common neurological syndromes. Tumors were diagnosed in 66 (68%) patients; Lung cancer was the most common primary tumor. Antibodies were positive in 52 (53.6%). Anti-Yo antibody and anti-Ma2 antibody were the most common antibodies. The majority (57.7%) received immunotherapy in addition to definitive treatment for the tumor. A good outcome was seen in 53 (54.6%). Factors associated with good outcome were: early diagnosis, mRS <3 at presentation, absence of metastatic disease, and adjuvant immunotherapy. CONCLUSION: A high index of clinical suspicion is essential for early diagnosis and prompt management of PNS, especially the nonclassical syndromes. Multimodality diagnostic imaging techniques and antibody profiling play a crucial role in the diagnosis. A favorable prognosis can be expected with the judicious use of immunotherapy and definitive treatment of malignancy.

Utility of Serial Nerve Conduction Studies in the Electrodiagnosis of Guillain-Barre Syndrome.

BACKGROUND: Guillain-Barre syndrome can be electrophysiologically classified into demyelinating and axonal subtypes and nerve conduction studies remain the mainstay in electrodiagnosis. Accurate electrodiagnosis has both therapeutic and prognostic significance and different criteria sets have been proposed for classification. OBJECTIVES: To electrophysiologically classify GBS patients into AIDP and axonal subtypes according to various published criteria (Cornblath, 1990: Hadden, 1998, Rajabally, 2015), investigate if serial NCS changes the classification, and to identify additional parameters which may support the electrodiagnosis. MATERIALS AND METHODS: In a retrospective study, we included all patients aged 15 to 80 years, admitted with a diagnosis of GBS between August 2015 and July 2017, who had at least two serial NCS. The various published criteria were applied to the two serial NCS and subtype classification along with diagnostic shifts on serial NCS were ascertained. RESULTS: At the first test, the established criteria gave a yield of 45.2% to 71% for AIDP, while 29% to 54.8% of patients were classified as axonal GBS. In the second study, there was a change in electrodiagnosis, ranging from 9.6% to 16.1%. The resolution of reversible conduction failure and misclassification of subtypes were the major reason for diagnostic shifts. Sural sparing pattern, facial nerve dysfunction, abnormal blink reflex, and phrenic nerve dysfunction were more common in AIDP. CONCLUSIONS: Serial nerve conduction studies allow an accurate electrodiagnosis of GBS subtypes, which has both therapeutic and prognostic implications. Also, the use of additional parameters such as blink reflex facial and phrenic nerve conduction may supplement routine NCS.

Monoclonal Gammopathies of 'Neurological Significance': Paraproteinemic Neuropathies.

OBJECTIVES: To study the clinical profile and outcomes of patients with paraproteinemic neuropathy (PPN) and to explore the utility of nerve conduction studies (NCSs) to differentiate between the demyelinating subtypes. METHODS: We did a retrospective analysis of patients diagnosed with PPN between January 2010 and December 2019 in an inpatient setting. The study population consisted of patients above 16 years of age presenting with clinical features suggestive of chronic peripheral neuropathy and on evaluation was found to have PPN. RESULTS: A total of 74 patients were identified. The patients were predominantly in the 6th decade, and the majority were males. The subtypes of PPN were monoclonal gammopathy of undetermined significance (MGUS) (45.9%), POEMS syndrome (polyneuropathy, organomegaly, endocrinopathy, monoclonal plasma cell disorder, and skin changes) (24.3%), solitary plasmacytoma (17.6%), multiple myeloma (8.1%), and AL amyloidosis (4.1%). There are specific features on NCS which can help in identifying POEMS syndrome and IgM MGUS. The majority of patients with PPN tend to stabilize or improve with treatment; however, many have a severe residual disability. New terminology and classification of these entities as 'monoclonal gammopathies of neurological significance' can aid in early diagnosis and the development of effective treatment, to prevent residual disability. CONCLUSION: PPN has a heterogeneous spectrum of clinical, biochemical, and electrophysiological features. NCS can help distinguish POEMS syndrome and IgM MGUS from other demyelinating subtypes.

Neural Correlates of Hiccups in Patients with Lateral Medullary Infarction.

Background: Hiccups is a known presentation of lateral medullary infarction. However, the region in the medulla associated with this finding is not clearly known. In this study, we aimed to study the neural correlates of hiccups in patients with lateral medullary infarction (LMI). Methods: This retrospective study included all patients who presented with lateral medullary infarction between January 2008 and May 2018. Patients with hiccups following LMI were identified as cases and those with no hiccups but who had LMI were taken as controls. The magnetic resonance imaging of the brain was done viewed and individual lesions were mapped manually to the template brain. Voxel-based lesion-symptom mapping employing nonparametric permutation testing was performed using MRIcron. Results: There were a total of 31 patients with LMI who presented to the hospital during the study period. There were 11 (35.5%) patients with hiccups. Using the voxel-based lesion-symptom mapping analysis, the dorso-lateral region of the middle medulla showed significant association with hiccups. Conclusion: In patients with LMI, we postulate that damage to the dorsolateral aspect on the middle medulla could result in hiccups.

Clinical Spectrum and Outcome of Neurosarcoidosis: A Retrospective Cohort Study from a Teaching Hospital in India.

CONTEXT: Neurosarcoidosis (NS) is a chronic disease with a diverse clinical spectrum, therapeutic response, and outcome. There is scarce literature from our country regarding the same. AIMS: The aim of this study was to evaluate the clinical spectrum, therapeutic responses, and outcomes of NS in an Indian cohort. SETTINGS AND DESIGN: In a cross-sectional study, we included all patients with NS treated at a quaternary care teaching hospital in India from January 2007 to October 2019. SUBJECTS AND METHODS: Patients older than 18 years of age fulfilling the diagnostic criteria for NS from the Neurosarcoidosis Consortium Consensus Group were included in the study. The therapeutic response and the degree of disability at last follow-up were assessed. RESULTS: We identified 48 patients, among them 3 were categorized as having definite NS, 30 probable NS, and 15 possible NS. Cranial neuropathy was the most common presentation (47.9%), followed by myelopathy (25%). Systemic involvement was identified in 95.83% and mediastinal lymph nodes were the most common site. Clinical improvement was seen in 65.8% and disease stabilized in 28.9%, while 5.26% deteriorated. Fifty percent recovered without any residual disability, while 26.3% had minor and 23.7% had major residual sequelae. CONCLUSIONS: NS is a diverse illness, with a heterogeneous spectrum of clinical presentation, treatment response, and outcome. Cranial neuropathy is the most common presenting feature and has a good prognosis while myelopathy has an unfavorable prognosis. Meningeal and brain parenchymal disease is difficult to diagnose accurately unless systemic involvement is present. The diagnosis of NS should be clinically suspected in the appropriate clinical setting, the presence of systemic involvement should be investigated, and histologic confirmation should be attempted.

Network Localization of Central Hypoventilation Syndrome in Lateral Medullary Infarction.

BACKGROUND AND PURPOSE: The brainstem plays a key role in the control of respiration. Strokes involving the lateral medulla can rarely produce a central hypoventilation syndrome (CHS) characterized by loss of automatic respiration called Ondine's curse. In this study, we investigated the neuroanatomical correlates of CHS in patients with lateral medullary infarction (LMI). METHODS: Cases of CHS following LMI were identified from searching our medical records and literature. Voxel-based lesion-symptom mapping and lesion network-symptom-mapping (LNSM) analysis was performed to identify the regions connected to the lesion sites based on normative functional connectome data. RESULTS: Sixteen patients with CHS and 32 controls were included. The ventro-lateral region of the rostral medulla showed a significant association with CHS. LNSM analysis showed connections of this region to the rostral ventro-lateral medulla and caudal pons. CONCLUSIONS: In patients with LMI, disruption of the respiratory control network, at the level of ventro-lateral region of the rostral medulla, could result in CHS.

Acute Ischemic Stroke in Term Pregnancy Treated with Recombinant Tissue Plasminogen Activator.

Recombinant tissue plasminogen activator (rtPA) may be considered in acute ischemic strokes (AIS) occurring in pregnancy. This recommendation is based on case reports which had demonstrated the efficiency and safety of rtPA in early pregnancy. However, most of the pregnancy-related strokes occur in the peripartum period. There is a paucity of literature on the management of AIS in this clinically relevant period of pregnancy; with only 2 case reports describing the use of IV rt-PA in the last trimester. Here, we report a case of AIS in a full-term pregnancy treated successfully with intravenous rt-PA. The patient went on to have an uncomplicated vaginal delivery after 72 h post thrombolysis. To the best of our knowledge, this is only the third such case in the English literature.