Stiff-persons' syndrome associated with thymoma and subsequent myasthenia gravis

Machine learning characterization of a rare neurologic disease via electronic health records: a proof-of-principle study on stiff person syndrome

BACKGROUND

Despite the frequent diagnostic delays of rare neurologic diseases (RND), it remains difficult to study RNDs and their comorbidities due to their rarity and hence the statistical underpowering. Affecting one to two in a million annually, stiff person syndrome (SPS) is an RND characterized by painful muscle spasms and rigidity. Leveraging underutilized electronic health records (EHR), this study showcased a machine-learning-based framework to identify clinical features that optimally characterize the diagnosis of SPS.

METHODS

A machine-learning-based feature selection approach was employed on 319 items from the past medical histories of 48 individuals (23 with a diagnosis of SPS and 25 controls) with elevated serum autoantibodies against glutamic-acid-decarboxylase-65 (anti-GAD65) in Dartmouth Health's EHR to determine features with the highest discriminatory power. Each iteration of the algorithm implemented a Support Vector Machine (SVM) model, generating importance scores-SHapley Additive exPlanation (SHAP) values-for each feature and removing one with the least salient. Evaluation metrics were calculated through repeated stratified cross-validation.

RESULTS

Depression, hypothyroidism, GERD, and joint pain were the most characteristic features of SPS. Utilizing these features, the SVM model attained precision of 0.817 (95% CI 0.795-0.840), sensitivity of 0.766 (95% CI 0.743-0.790), F-score of 0.761 (95% CI 0.744-0.778), AUC of 0.808 (95% CI 0.791-0.825), and accuracy of 0.775 (95% CI 0.759-0.790).

CONCLUSIONS

This framework discerned features that, with further research, may help fully characterize the pathologic mechanism of SPS: depression, hypothyroidism, and GERD may respectively represent comorbidities through common inflammatory, genetic, and dysautonomic links. This methodology could address diagnostic challenges in neurology by uncovering latent associations and generating hypotheses for RNDs.

Thymoma-Related Stiff-Person Syndrome with Successfully Treated by Surgery

INTRODUCTION

Stiff-person syndrome (SPS) is a rare autoimmune neurological disorder. Paraneoplastic SPS associated with malignant tumors such as thymoma occurs in approximately 5% of all SPS cases. We present a rare case of thymoma accompanied by SPS successfully treated using surgery.

PRESENTATION OF CASE

A 26-year-old woman presented with lower limbs convulsions and gait disturbance and complained of leg pain. Cerebrospinal fluid and blood test results showed a high level of anti-glutamic acid decarboxylase (GAD) antibodies. Computed tomography showed anterior mediastinal tumor suggestive of a thymoma. She underwent extended thymectomy, and her symptoms gradually improved after surgery. No evidence of recurrent thymoma and SPS has been observed over 44 months.

CONCLUSION

Surgical treatment would be effective for patients with SPS and thymoma.

The case of a 30-year-old man with subacute gait instability, weakness, and muscle spasms

A 30‐year‐old healthy man presents after a fall with diffuse weakness and pain and recent onset left eye ptosis in the setting of three weeks of progressive bilateral leg weakness, gait instability, and difficulty washing his hair due to upper extremity weakness. He had also developed stiffness in his neck and shoulders and uncontrollable muscle spasms. Exam was notable for ptosis, fatiguing weakness in extremities, increased tone, hyperreflexia with clonus, and spastic gait. A mediastinal mass was found on chest CT (Fig. 1), and biopsy confirmed an invasive thymoma with positive nodes. Serum testing was positive for antibodies to acetylcholine receptors as well as glutamic acid decarboxylase.

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.

Guillain-Barré syndrome associated with myasthenia gravis: Three cases report and a literature review

RATIONALE

Myasthenia gravis (MG) and Guillain-Barré syndrome (GBS) are 2 common neurologic autoimmune diseases. Although both the diseases can present with acute or subacute onset of muscular weakness involving the limbs and bulb, the coexistence in the same patient is unusual and rarely described in the literature.

PATIENT CONCERNS

Three cases of combined MG and GBS at the department of Neurology were described. All the 3 patients developed GBS, who had had MG for 30 years, 6 years, and 6 months, respectively.

DIAGNOSES

The newly developed GBS was clinically confirmed by the clinical features, electromyographic (EMG) studies, typical albumino-cytologic dissociation in cerebrospinal fluid (CSF), and positive anti-ganglioside antibodies in serum.

INTERVENTIONS

The 3 patients had been treated with intravenous immunoglobulin (IVIG), or plasma-exchange (PE), or IVIG combined with PE in the acute stage of severe muscle weakness. In light of the MG symptoms, they have received glucocorticoids, oral pyridostigmine, and immunosuppressive agents.

OUTCOMES

The patient 1 was able to walk longer than 5 m with assistance (Hughes 3). The patient 2 had significantly improved, and completely recovered at the 1-year follow-up (Hughes 0). But unfortunately, the patient 3 was severely disabled and chair-bound at the last interview (Hughes 4).

LESSONS

The combination of MG and GBS is quite rare. Limbs and oculo-bulbar weakness are the cardinal manifestations of both the diseases. Although their characteristics are quite different, there are still some difficulties in diagnosing them when they occur in the same patient. Early diagnosis and proper treatment will yield satisfactory prognosis. Further researches are needed to elucidate the pathogenesis of the coexistence.

Stiff-Person Syndrome: A Case Report and Review of the Literature

AIM

To report a case of sudden onset vertical diplopia, blurred vision, and muscle spasms.

METHODS

This is a case report of a 57-year-old female who presented to the accident and emergency department with a one day history of vertical diplopia and a two week history of lower limb spasticity secondary to muscle spasms.

RESULTS

The patient had no significant medical or ocular history. Orthoptic investigation initially revealed a left inferior rectus (IR) underaction. Possible diagnoses at this point were thought to be isolated IR weakness, myasthenia gravis or skew deviation. An urgent MRI scan was arranged and blood tests were taken. MRI showed no abnormalities. Blood tests were normal, however, the acetylcholine receptor antibody serum test (ACH-R) was 0.43 nmol/L, which is at the high end of normal. At the follow-up visit, the IR weakness had deteriorated and the patient had also developed gaze-evoked nystagmus. An appointment with the neurologist and neuro-ophthalmologist was expedited. When the patient returned, she reported that her neurologist had diagnosed her with stiff-person syndrome (SPS). The patient had also developed a laterally alternating skew deviation and reported that she had undergone a course of intravenous immunoglobulin (IVIG). The patient was prescribed diazepam and gabapentin. Due to the lack of recovery, persistent diplopia and oscillopsia, monthly IVIG have been prescribed.

CONCLUSION

There is currently a paucity of literature relating to ophthalmic problems with SPS and how they are best treated. Previous reports have established that there is a link with myasthenia gravis, with many patients going on to develop myasthenia. Treatment of SPS is lacking large evidence-based studies. However, treatment with muscle relaxants and anticonvulsants has provided a good outcome for some. Further research is required to develop an evidence-based approach to treating the ophthalmological problems patients with SPS experience. This case report highlights the importance and value of orthoptists in investigating and monitoring patients with stiff-person syndrome.

The Stiff People: Two Rare Cases of Stiff-person Syndrome

Stiff-person syndrome (SPS) is a rare disorder that affects the central nervous system and is characterized by progressive muscle stiffness, rigidity, and spasm of axial and limb muscles. The syndrome is caused by a lack of gamma aminobutyric acid (GABA), which occurs because of antibodies against glutamic acid decarboxylase (GAD), an essential enzyme for GABA synthesis. Hence, the patients present with increased muscular activity. In this article, we will discuss two case studies of stiff-person syndrome.

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.

Stiff person syndrome: presentation of a case with repetitive complex discharges in electromiograms

INTRODUCTION

Stiff person syndrome is characterized by rigidity of axial and proximal limb muscles, associated with muscle spasms, triggered by unexpected acoustic or somesthetic stimuli. It usually has an autoimmune basis, in which the blood contains antiglutamate decarboxylase antibodies, and is associated with different types of autoimmune diseases. The electromyogram provides evidences of continuous muscular activity.

CASE REPORT

A 41-year-old woman with a history of diabetes mellitus type I, Hashimoto thyroiditis, vitiligo, and pernicious anemia developed symptoms compatible with stiff person syndrome. In the electromyogram, in addition to continuous muscular activity, there was evidence of complex repetitive activity in the form of doublets and triplets.

CONCLUSIONS

Given the absence of clinical or electrophysiological neuropathic affectation, the presence of doublets and triplets in our patient could be due to a subclinical functional alteration of alpha motoneurons. They could produce the complex repetitive discharges when released from the inhibition mediated by GABAergic neurons.

Stiff man syndrome with thymoma

Paraneoplastic stiff man syndrome with a thymoma is rare disease. We treated a 57-year-old woman with a type B1 thymoma, based on the World Health Organization classification, who had stiff man syndrome. Her symptoms were alleviated after a thymectomy. Herein we report a case of stiff man syndrome with a thymoma and also review three cases reported previously.

Le syndrome de l’homme raide : formes cliniques, traitement et profil évolutif

INTRODUCTION

Stiff-Man syndrome (SMS) is a rare neurological disease first described fifty years ago. There are several clinical forms, which are frequently misdiagnosed. The aim of this study is to review three of the main clinical forms.

MATERIAL AND METHODS

Case reports concerning three women suffering from different forms of SMS are presented, giving the main clinical features, their associations with other diseases, and the biological and electrophysiological findings.

RESULTS

The first patient presented a symmetric axial muscle rigidity, painful spasms and contractions of the trunk and limbs associated with anti-GAD antibodies. The common form of SMS was diagnosed and the patient was improved by intravenous immunoglobulin (IVIg). The second patient suffered from contractions and spasms localized to the lower limbs. In this patient, anti-GAD antibodies were absent. The Stiff-Leg syndrome was diagnosed and the patient was improved by intrathecal baclofen. The third patient presented rigidity of limb and trunk muscles associated with signs of encephalitis. In this patient, only anti-amphiphysin antibodies were present. The progressive encephalomyelitis with rigidity was diagnosed and the patient was improved by IVIg associated with corticosteroid.

CONCLUSION

Identifying patients with SMS makes it possible to propose appropriate medical management. There are several forms of the disease, and the severity of the evolution differs in each case. Treatment with GABA-ergic inhibitory drugs, IVIg and corticosteroid improve both the symptomatology and the quality of life of these patients.

Neuromuscular complications of cancer

Neuromuscular complications of cancer are common and can affect any component of the peripheral nervous system from peripheral nerve cell body to muscle. Perhaps the most common complication is a length-dependent symmetric axonal polyneuropathy that is often multifactorial in etiology, resulting from metabolic and treatment effects of the primary malignancy. However, neuromuscular disorders may also be the presenting complaint in many conditions, including disorders caused by malignant infiltration of nerve and disorders cause by paraneoplastic syndromes. Although many of the paraneoplastic conditions are poorly responsive to treatment, not all are, and one hopes that prompt diagnosis of the underlying malignancy will lead to improved patient outcome. Recognition of iatrogenic neuromuscular complications is also important to modify treatment protocols when possible and thus decrease the risk of long-term neurologic disability.

Effect of treatment with intravenous immunoglobulin on quality of life in patients with stiff-person syndrome

The therapeutic effects of intravenous immunoglobulin (IVIG) on the stiff-person syndrome (SPS) have been described exclusively in case reports or open-label studies in terms of clinical outcomes. We investigate whether IVIG improves quality of life (QoL) in the SPS. Six patients with the classic form of SPS completed a generic QoL instrument, the SF-36, and a Visual Analogue Scale (VAS) before treatment as well as 2 weeks after completion of a course of IVIG. There was significant improvement in the SF-36 subscores for pain, social functioning, general mental health, and energy-vitality with treatment. The VAS also improved significantly. We conclude that treatment with IVIG improves QoL in the SPS.

Atypical low back pain: stiff-person syndrome

Stiff-person syndrome was diagnosed in a patient with chronic low back pain. The diagnosis of this rare neurological condition rests mainly on the clinical findings of axial and proximal limb rigidity, increased lumbar lordosis often accompanied with pain, and normal neurological findings apart from brisk deep tendon reflexes. Electromyography of the lumbar paraspinal muscles shows motor unit firing at rest with normal appearance of the motor unit potentials. Titers of antibody to glutamic acid decarboxylase are elevated. Diazepam is the treatment of reference. Physical therapy can substantially improve quality of life.

Stiff-person syndrome associated with invasive thymoma: a case report

We report a case of a 40-year-old female with continuous muscle stiffness and painful muscle spasms. The symptoms worsened over a two-week period after onset. Electrophysiological examinations revealed continuous muscle discharge, which was markedly reduced by intravenous administration of diazepam. High levels of anti-glutamic acid decarboxylase (GAD) antibodies were detected in both serum and cerebrospinal fluid, suggesting that the patient suffered from stiff-person syndrome. Steroid pulse therapy and immunoadsorption therapy alleviated the clinical symptoms and decreased the anti-GAD antibody titer. A chest CT revealed the presence of an invasive thymoma. Neither anti-acetylcholine receptor (AChR) antibodies nor symptoms of myasthenia gravis (MG) were observed. The patient underwent a thymectomy and postoperative radiotherapy. These treatments further alleviated the clinical symptoms. The present case is the first that associates stiff-person syndrome with invasive thymoma, and not accompanied by MG. The autoimmune mechanism, in this case, may be triggered by the invasive thymoma.

Stiff-man syndrome: from the bedside to the bench

The study of SMS, a rare disease, has resulted in a better understanding of a more common disorder, IDDM, and has allowed investigators to gain insights into the molecular mechanisms of autoimmunity. Many unanswered questions remain, such as the specific site of disease activity in SMS, both at the bedside (cortex, brain stem, or spinal cord) and at the bench (neuronal cytoplasma or synapse). The association of SMS with neoplastic disease and the development of autonomicdysfunction are not understood. The next decade may provide answers to these puzzling issues.