Thymoma-associated progressive encephalomyelitis with rigidity and myoclonus successfully treated with thymectomy and intravenous immunoglobulin

An update on malignant tumor-related stiff person syndrome spectrum disorders: clinical mechanism, treatment, and outcomes

Stiff person syndrome (SPS) is a rare central nervous system disorder associated with malignancies. In this review, we retrieved information from PubMed, up until August 2023, using various search terms and their combinations, including SPS, stiff person syndrome spectrum disorders (SPSSDs), paraneoplastic, cancer, and malignant tumor. Data from peer-reviewed journals printed in English were organized to explain the possible relationships between different carcinomas and SPSSD subtypes, as well as related autoantigens. From literature searching, it was revealed that breast cancer was the most prevalent carcinoma linked to SPSSDs, followed by lung cancer and lymphoma. Furthermore, classic SPS was the most common SPSSD subtype, followed by stiff limb syndrome and progressive encephalomyelitis with rigidity and myoclonus. GAD65 was the most common autoantigen in patients with cancer and SPSSDs, followed by amphiphysin and GlyR. Patients with cancer subtypes might have multiple SPSSD subtypes, and conversely, patients with SPSSD subtypes might have multiple carcinoma subtypes. The first aim of this review was to highlight the complex nature of the relationships among cancers, autoantigens, and SPSSDs as new information in this field continues to be generated globally. The adoption of an open-minded approach to updating information on new cancer subtypes, autoantigens, and SPSSDs is recommended to renew our database. The second aim of this review was to discuss SPS animal models, which will help us to understand the mechanisms underlying the pathogenesis of SPS. In future, elucidating the relationship among cancers, autoantigens, and SPSSDs is critical for the early prediction of cancer and discovery of new therapeutic modalities.

Progressive encephalomyelitis with rigidity: A Taiwanese case and review of literature

INTRODUCTION

Progressive encephalomyelitis with rigidity and myoclonus (PERM) is a rare disorder. However, the outcome is still variable with different serological and tumor associations, and the elements to good response with less relapse is yet to be elucidated.

METHOD

We present a case and obtain a literature review of patients with PERM and make comparisons based on different serological groups. We also analyze patients with idiopathic PERM that had detailed medical records.

RESULTS

81 patients were collected and analyzed. The largest group were glycine receptor-antibody (GlyR-Ab)-positive (70%), and the seropositive-GlyR-Ab-negative group had better response to immunotherapy. Malignancy can occur up to 2 years from the presentation of PERM. Among the 18 cases with detailed records, the patients who had good outcome initiate immunotherapy within 2 months from presentation. 9 of the 12 patients who experienced no relapse had non-steroid immunotherapy. The maximal interval time of relapse was 24 months.

CONCLUSION

We recommend tumor surveillance up to 2 years in patients with PERM and early administration of immunotherapies and maintain with non-steroid immunotherapy with or without oral corticosteroid for a minimum of 2 years to reduce the risk of relapse in GlyR-Ab-positive patients.

Progressive Encephalomyelitis With Rigidity and Myoclonus With Thymoma: A Case Report and Literature Review

Progressive encephalomyelitis with rigidity and myoclonus (PERM) is part of the variant type of the Stiff Person Syndrome (SPS) and is a rare neurological disease. We report here a patient with PERM who had thymoma and was positive for anti-glutamic acid decarboxylase (anti-GAD) antibodies. Her symptoms improved after treatment with hormones and gamma globulin. We also summarized the literature review of patients with PERM accompanied by tumors reported.

A systematic review of paraneoplastic syndromes associated with thymoma: Treatment modalities, recurrence, and outcomes in resected cases

OBJECTIVE

Paraneoplastic syndromes associated with thymomas remain incompletely understood. The objective was to examine the association between surgically resected thymomas and paraneoplastic syndromes over the past half century.

METHODS

A primary PubMed/MEDLINE search was used to identify published articles describing paraneoplastic syndromes associated with thymomas from 1960 to 2019. A secondary search identified additional articles referenced in the articles found in the primary search. Kaplan-Meier and log-rank test were used for time-to-event data analyses.

RESULTS

From 407 articles describing 507 patients, 123 different paraneoplastic syndromes were associated with thymoma. The 5 most common paraneoplastic syndromes were myasthenia gravis, pure red cell aplasia, lichen planus, Good syndrome, and limbic encephalitis. Complete or partial resolution of paraneoplastic syndrome symptoms after surgery was noted in 76% of patients, of whom 21% had a relapse or new paraneoplastic syndrome onset after surgery. The most common adjunctive therapy associated with resolution of paraneoplastic syndrome was corticosteroids (30%). For all patients after surgery, thymoma recurrence was observed in 17% of cases, whereas recurrence of paraneoplastic syndrome was observed in 34% of cases, and both were observed in approximately 11% of cases. The 5- and 10-year overall survivals were 78% and 66%, respectively. Improved overall survival was associated with patients who had total resolution from paraneoplastic syndrome.

CONCLUSIONS

A comprehensive assessment of publications over the past half century suggests that a multimodal treatment approach that includes surgical resection of thymomas is able to achieve paraneoplastic syndrome resolution in a majority of patients. Onset of new paraneoplastic syndromes after surgery is associated with the recurrence of the first paraneoplastic syndrome, and resolution of paraneoplastic syndrome is associated with improved overall survival.

Antiglycine receptor antibody related disease: a case series and literature review

BACKGROUND AND PURPOSE

Antibodies to glycine receptors (GlyR-Abs) were first defined in progressive encephalopathy with rigidity and myoclonus (PERM) but were subsequently identified in other clinical presentations. Our aim was to assess the clinical associations of all patients identified with GlyR-Abs in Queensland, Australia, between April 2014 and May 2017 and to compare these to cases reported in the literature.

METHODS

A literature review identified the clinical features of all published GlyR-Ab-positive cases through online databases. A case series was undertaken via collection of clinical information from all patients diagnosed or known to immunology, pathology or neurological services in Queensland during the study period of 3 years.

RESULTS

In all, 187 GlyR-Ab-positive cases were identified in the literature. The majority (47.6%) had PERM, 22.4% had epilepsy, but the remaining 30% included mixed phenotypes consisting of cerebellar ataxia, movement disorders, demyelination and encephalitis/cognitive dysfunction. By contrast, in our series of 14 cases, eight had clinical presentations consistent with seizures and epilepsy and only three cases had classical features of PERM. There was one case each of global fatiguable weakness with sustained clonus, laryngeal dystonia and movement disorder with hemiballismus and tics. The rate of response to immune therapy was similar in all groups.

CONCLUSION

Antibodies to glycine receptors are linked to a spectrum of neurological disease. The results of the literature review and our case series suggest a greater relationship between GlyR-Abs and epilepsy than previously reported.

Pragmatic Treatment of Stiff Person Spectrum Disorders

Background

Stiff person spectrum disorders (SPSD) are a group of rare conditions clinically characterized by stiffness, spasms, and heightened stimulus sensitivity. They also share a spectrum of antibodies.

Methods

We reviewed the literature and our own experience with the aim of providing a practical approach to the treatment of SPSD.

Results

Because of the rarity of SPSD, there is little evidence to guide treatment decisions. The treatment of SPSD is based on the triad of symptomatic treatment, immunotherapy, and tumor treatment where appropriate. Moreover, the management involves continuous and appropriate monitoring of the symptoms of the disease, its autoimmune associations, and potential treatment side effects.

Conclusions

Here we delineated a pragmatic treatment approach to SPSD, based on our experience and existing literature. We also highlighted how our understanding of neuronal antibodies and their implications reflects on management considerations.

Thymoma-associated Progressive Encephalomyelitis with Rigidity and Myoclonus (PERM) with Myasthenia Gravis

We report a case of a 72-year-old woman who initially presented with symptoms of bulbar myasthenia and was positive for anti-acetylcholine receptor antibodies. She subsequently developed painful muscle spasms, myoclonus, and stiffness. Thymoma was detected, and both anti-glycine receptor and anti-glutamic acid decarboxylase antibodies were found. She was diagnosed with thymoma-associated progressive encephalomyelitis with rigidity and myoclonus (PERM). She experienced marked improvement after thymectomy followed by plasma exchange and intravenous immunoglobulin and prednisolone. This case suggests that thymectomy followed by sufficient immunosuppression may be useful in the treatment of thymoma-associated PERM. Myasthenia gravis may develop in thymoma-associated PERM patients.

Myoclonus in the critically ill: Diagnosis, management, and clinical impact

Myoclonus is the second most common involuntary non-epileptic movement in intensive care units following tremor-like gestures. Although there are several types of myoclonus, they remain underappreciated, and their diagnostic and prognostic associations are largely ignored. This review discusses clinical, electrophysiological, neuroanatomical, and neuroimaging characteristics of different types of myoclonus in critically ill adults along with their prognostic impact and treatment options. Myoclonus is characterized by a sudden, brief, and sometimes repetitive muscle contraction of body parts, or a brief and sudden cessation of tonic muscle innervation followed by a rapid recovery of tonus. Myoclonus can resemble physiologic and other pathologic involuntary movements. Neurologic injuries, anesthetics, and muscle relaxants interfere with the typical appearance of myoclonus. Identifying "real myoclonus" and determining the neuroanatomical origin are important, as treatment responses depend on the involved neuroanatomical structures. The identification of the type of myoclonus, the involved neuroanatomical structures, and the associated illnesses is essential to direct treatment. In conclusion, the combined clinical, electrophysiological, and neuroradiological examination reliably uncovers the neuroanatomical sources and the pathophysiology of myoclonus. Recognizing cortical myoclonus is critical, as it is treatable and may progress to generalized convulsive seizures or status epilepticus.

Paraneoplastic disorders in thymoma patients

Thymic malignancy is often associated with paraneoplastic neurological diseases (PNDs) and recognition of these disorders is important for physicians who treat these patients. The most common thymoma-associated PNDs are myasthenia gravis (MG), acquired neuromyotonia (Isaacs' syndrome), encephalitis, Morvan's syndrome, and myositis. Diagnosis of these disorders is complex but often aided by testing for specific autoantibodies, including those to the acetylcholine receptor for MG and to contactin-associated protein-like 2, protein of the voltage-gated potassium channel complex, in patients with acquired neuromyotonia, Morvan's syndrome, or encephalitis. Patients who manifest these disorders should be screened for thymoma at diagnosis, and worsening of these PNDs may be associated with recurrent thymoma. These disorders can cause profound disability but usually respond to immunotherapy, and often improve with thymoma treatment. Close cooperation among a team of specialists is required to take proper care of these patients.

[A case of progressive encephalomyelitis with rigidity and myoclonus associated with anti-GAD, anti-glycine receptor and anti-GM1 antibodies]

A 62-year-old woman with one-year history of type 1 diabetes mellitus was admitted to our hospital with progressive weakness in the lower extremities and urinary dysfunction following high fever. On admission, she had rigidity and myoclonus in the upper extremities with sensory ataxia. Cerebrospinal fluid examination revealed mild pleocytosis and oligoclonal band. Glutamic acid decarboxylase (GAD) antibodies were detected at high titer in serum, but antibodies to glycine receptor (GlyR), thyroid peroxidase, mitochondrial M2, and GM1 were also detected. She was diagnosed with progressive encephalomyelitis with rigidity and myoclonus (PERM), which probably developed on the basis of polyglandular autoimmune syndromes. The clinical symptoms began to improve after initiation of intravenous high-dose methylprednisolone. Muscle weakness might be related to GM1 antibodies. This is the first report of PERM, in which GM1 antibodies were detected with GAD and GlyR antibodies.

Anti-glycine receptor antibody mediated progressive encephalomyelitis with rigidity and myoclonus associated with breast cancer

We describe a 66-year-old woman who presented with a dramatic course of PERM. Anti-glycine receptor antibodies were found. She stabilized after plasma-exchange and partly recovered. Eighteen months later, a diagnosis of smouldering breast cancer with bone marrow metastasis was made. There are indications that this tumor was already present at first presentation. An overview of PERM and anti-glycine receptor antibodies is given.

Glycine receptor antibody mediated Progressive Encephalomyelitis with Rigidity and Myoclonus (PERM): a rare but treatable neurological syndrome

A 40-year-old man presented with respiratory compromise and was intubated. After tracheostomy, he was found to have ophthalmoplegia, severe limb rigidity, stimulus-sensitive myoclonus and autonomic dysfunction. For 1 week before admission, there had been a prodromal illness with low mood, hallucinations and limb myoclonus. Serum glycine receptor antibodies were strongly positive: we diagnosed progressive encephalomyelitis with rigidity and myoclonus. Despite a relapse, he has done well following immunotherapies. The clinical syndrome of encephalomyelitis with rigidity, described in 1976, often has a severe progressive course. A minority of patients have glutamic acid decarboxylase antibodies. The association with glycine receptor antibody was first reported in 2008, and we briefly review subsequent case reports to illustrate the range of clinical features. The antibody is likely to be disease mediating, although this remains unproven. The spectrum of diagnosable and treatable antibody mediated neurological syndromes is expanding. It is vital to recognise these conditions early to reduce morbidity and mortality.