Severe Stiff-Person Syndrome After COVID: The First Video-Documented COVID Exacerbation and Viral Implications

OBJECTIVES

To describe a patient with mild GAD-positive stiff-leg syndrome (SLS) who developed severely disabling stiff-person syndrome (SPS) 1 week after mild COVID-19 and discuss the impact of viral implications.

METHODS

Video-documented serial clinical observations at baseline, after acute COVID-19, and after IVIG treatments.

RESULTS

A 39-year-old man with left-SLS was stable during a 2-year follow-up with low-dose antispasmodics, working fully and functioning normally, even able to run. One week after mild COVID-19, he started to experience generalized SPS symptomatology that steadily worsened the following 2-3 weeks, becoming unable to walk, requiring a walker, with significant thoracolumbar and bilateral leg stiffness and spasms. GAD ab were very high. After 3 monthly IVIg infusions he showed improvements, but his gait remains significantly stiff. All clinical changes, from baseline to post-Covid, and then post- IVIg have been video-documented.

DISCUSSION

This is the first, clearly documented, severe GAD-positive SPS after COVID-19. Although viral or postviral causation can be incidental, the temporal connection with acute COVID-19, the severe disease worsening after symptom-onset, and the subsequent steady improvement after IVIg, suggest viral-triggered autoimmunity. Because COVID-19 reportedly can trigger or worsen GAD-associated diabetes type 1 through proinflammatory mediators, and SPS has been reportedly triggered by West Nile Virus, possibly through molecular mimicry, this case of acutely converting GAD-SLS to GAD-SPS suggest the need to explore viral etiologies in patients with GAD-SPS experiencing acute, long-lasting episodic exacerbations of stiffness and spasms.

Axial dystonia as a manifestation of stiff-person syndrome in a paediatric patient

Stiff-person syndrome (SPS) is a rare neurological condition that frequently affects adults, with the neurologist diagnosing only one or two cases during his or her career. Reports of paediatric SPS are exceedingly rare, with less than 20 cases described in the literature.The patient presented was initially diagnosed with a functional movement disorder then a genetic dystonia, with a poor response to treatment trials and negative genetic testing. Consideration of Wilson's disease was refuted with non-supportive investigations and assessments.We aim to present the long road to diagnosing our first paediatric patient with SPS, who presented in middle childhood.

A case report of integrating Chinese and Western medicine: A new era in the treatment of stiff person syndrome

RATIONALE

At present, there are limitations to the treatment of stiff person syndrome (SPS). Current treatments are still ineffective or financially burdensome for some patients, so it is imperative to explore more appropriate treatments for patients. This is a case report of a SPS with a more significant effect of combined Chinese and Western medicine, which may provide new treatment ideas for other patients.

PATIENT CONCERNS

This patient presented with episodes of stiffness and pain in the lower back and lower extremities. His electromyography shows continued activation of normal motor units in the paraspinal and abdominal muscles. However, relevant laboratory tests including glutamic acid decarboxylase antibody and Amphiphysin antibody were negative. After a period of treatment including clonazepam, baclofen, prednisone and intravenous immunoglobulin, this patient experiences a shortened maintenance period of medication, accompanied by symptoms such as emotional anxiety and cognitive decline, which severely affects his life.

DIAGNOSES

This patient was diagnosed with SPS.

INTERVENTIONS

In May 2022 the patient decided to combine Chinese medicine for simultaneous treatment.

OUTCOMES

During the period of simultaneous treatment with Chinese and Western medicine, the patient experienced remission of clinical symptoms, reduction of concomitant symptoms and improved quality of life.

CONCLUSION

A combination of Western and Chinese medicine was effective in relieving this patient pain and stiffness and reducing the patient anxiety. Combined Chinese and Western medicine treatment may be able to bring better results to more patients with stiff person syndrome.

Prevalence, Clinical Profiles, and Prognosis of Stiff-Person Syndrome in a Japanese Nationwide Survey

BACKGROUND AND OBJECTIVES

To elucidate current epidemiologic, clinical, and immunologic profiles and treatments of stiff-person syndrome (SPS) in Japan.

METHODS

A nationwide mail survey was conducted using an established method. Data processing sheets were sent to randomly selected departments of internal medicine, neurology, pediatrics, psychiatry, and neurosurgery in hospitals and clinics throughout Japan to identify patients with SPS who were seen between January 2015 and December 2017.

RESULTS

Thirty cases were identified as glutamic acid decarboxylase 65 (GAD65)-positive SPS cases on the basis of detailed clinical data of 55 cases. Four patients had α1 subunit of glycine receptor (GlyR) antibodies, and 1 patient had both GAD65 and GlyR antibodies. The total estimated number of patients with GAD65-positive SPS was 140, and the estimated prevalence was 0.11 per 100,000 population. The median age at onset was 51 years (range, 26-83 years), and 23 (76%) were female. Of these, 70% had classic SPS, and 30% had stiff-limb syndrome. The median time from symptom onset to diagnosis was significantly longer in the high-titer GAD65 antibody group than in the low-titer group (13 months vs 2.5 months, p = 0.01). The median modified Rankin Scale (mRS) at baseline was 4, and the median mRS at the last follow-up was 2. Among the 29 GAD65-positive patients with ≥1 year follow-up, 7 received only symptomatic treatment, 9 underwent immunotherapy without long-term immunotherapy, and 13 received long-term immunotherapy such as oral prednisolone. The coexistence of type 1 diabetes mellitus and the lack of long-term immunotherapy were independent risk factors for poor outcome (mRS ≥3) in the GAD65-positive patients (odds ratio, 15.0; 95% CI 2.6-131.6; p = 0.001; odds ratio, 19.8; 95% CI 3.2-191.5; p = 0.001, respectively).

DISCUSSION

This study provides the current epidemiologic and clinical status of SPS in Japan. The symptom onset to the diagnosis of SPS was longer in patients with high-titer GAD65 antibodies than in those with low-titer GAD65 antibodies. The outcome of patients with SPS was generally favorable, but more aggressive immunotherapies are necessary for GAD65-positive patients with SPS.

H - 38 Neuropsychological Evaluation and Cognitive Profile of Stiff Person Syndrome (SPS) in a Predominantly Spanish-Speaking Older Adult: Is Cognition Really Affected?

OBJECTIVE

Stiff Person Syndrome (SPS) is a rare autoimmune disorder that affects approximately one in every million people. It is characterized by progressive muscle rigidity and intense, episodic muscle spasms triggered by environmental and psychosocial (i.e., emotional stress) factors. While original diagnostic criteria for classical SPS included the absence of frank cognitive impairment (aside from what would be expected from seizures), more recent literature suggests a number of neurocognitive difficulties potentially associated with reduced GABA levels.

METHOD

The following case study presents a 73-year-old, predominantly Spanish-speaking man with 14 years of education. His medical history is notable for over 20 years with diagnosed SPS, hypertension well managed with medications, and the absence of other medical conditions that may contribute to cerebrovascular burden. He completed a comprehensive neuropsychological evaluation in Spanish.

RESULTS

Overall, his profile was notable for mild inefficiencies in frontal-subcortical functions, with a relative weakness in rote learning and retention. He performed remarkably well relative to his level of motor compromise. There was no evidence of either a mild or major neurocognitive disorder, and his clinical interview and behavioral inventories were suspicious for a personality disorder.

CONCLUSIONS

Recent literature proposes SPS is related to impairment in verbal learning, retention, fluency, processing speed, and attention. The present case corroborated, at most, mild inefficiencies in these previously documented areas. Careful consideration should be used in the evaluation of studies on SPS and cognition, particularly in determining whether samples had high degrees of comorbid conditions (i.e., cerebrovascular burden) that could help explain positive findings related to cognition.

Centripetal Nystagmus, Slow Saccades, Cerebellar Ataxia, and Parkinsonism in a Patient With Anti-GAD65-Associated Stiff Person Syndrome Spectrum Disorder

ABSTRACT

A 68-year-old woman with positional dizziness and progressive imbalance presented for vestibular evaluation. Examination was notable for spontaneous downbeat nystagmus (DBN), horizontal and vertical gaze-evoked nystagmus (GEN) with centripetal and rebound nystagmus, and positional apogeotropic nystagmus. There was also mild-moderate slowing of saccades horizontally and vertically and poor fast phases with an optokinetic stimulus. Further consultation by a movement disorder specialist uncovered asymmetric decrementing bradykinesia and rigidity, masked facies, and a wide-based stance without camptocormia. Screening serum laboratory results for metabolic, rheumatologic, infectious, heavy metal, endocrine, or vitamin abnormalities was normal. Surveillance imaging for neoplasms was unremarkable, and cerebrospinal fluid (CSF) analysis was negative for 14-3-3 and real-time quaking-induced conversion (RT-QuIC). However, her anti-glutamic acid decarboxylase-65 (GAD65) immunoglobulin G (IgG) level was markedly elevated in serum to 426,202 IU/mL (reference range 0-5 IU/mL) and in CSF to 18.1 nmol/L (reference range <0.03 nmol/L). No other autoantibodies were identified on the expanded paraneoplastic panel. The patient was referred to neuroimmunology, where torso rigidity, spasticity, and significant paravertebral muscle spasms were noted. Overall, the clinical presentation, examination findings, and extensive workup were consistent with a diagnosis of anti-GAD65-associated stiff person syndrome-plus (musculoskeletal plus cerebellar and/or brainstem involvement). She was subsequently treated with intravenous immunoglobulin (IVIg) and has been stable since commencing this therapy. In patients with centripetal nystagmus, especially in association with other cerebellar findings, an autoimmune cerebellar workup should be considered.

Psychiatric Symptoms in Stiff-Person Syndrome: A Systematic Review and a Report of Two Cases

BACKGROUND

The clinical spectrum of stiff-person syndrome (SPS) encompasses a wide range of signs including psychiatric symptoms (PS).

OBJECTIVE

Our objective was to provide an overview of the spectrum of PS in SPS through a systematic literature search and 2 illustrative case reports.

METHODS

We reported 2 anti-glutamic acid decarboxylase-positive SPS cases that presented with phobic disorder, and we performed a systematic review by following the 2020 Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Articles published in PubMed, MEDLINE on Ovid, Embase, and via a manual search before October 20, 2020, were selected by 2 independent reviewers. Original studies, case reports, editorials, commentaries, and letters to the editor reporting cases of SPS with PS were all included. Conference abstracts, reviews and book chapters, unavailable articles, and those not reporting SPS cases or PS were excluded. Quantitative summary data were calculated.

RESULTS

In addition to our 2 cases, we identified 237 cases of SPS with PS from 74 additional included publications totaling 239 patients. Anxiety (56%) and depression (45%) were the most common PS in SPS. Mean diagnostic delay was 4.7 years. Among the 3 SPS phenotypes, the classic form was predominant (77%), followed by stiff-limb syndrome (13%) and progressive encephalomyelitis with rigidity and myoclonus (10%). The most frequent etiology of SPS with PS was autoimmune (90%), followed by cryptogenic (7%) and paraneoplastic forms (7%). These patients were mainly treated with immune-mediated therapies and GABAergic drugs.

CONCLUSIONS

Our review revealed that the most common PS of SPS are anxiety and depression occurring mostly in autoimmune and classic forms, allowing a clearer understanding of this entity, which may lead to earlier diagnosis and better outcome.

[Stiff person syndrome associated with thymoma]

Stiff-person syndrome is a rare neurological condition characterized by muscular rigidity of the trunk and extremities and muscle spasms triggered by sensory or emotional stimuli, which progresses towards prostration. It has a pathophysiogenic mechanism with an immunological basis, in which autoantibodies, such as antiGAD65, play a central role. Likewise, the detection of these antibodies corroborates the diagnosis in a patient with a suggestive clinical picture. Four to 6% of cases have underlying neoplasms. Treatment is based on symptomatic, immunomodulatory, and underlying disease management in paraneoplastic cases. We report a case of classic stiff person syndrome associated with thymoma and review the main characteristics of this entity.

[Isolated ACTH deficiency clinically presented as stiff-person syndrome, successfully treated by hormonal replacement: a case report]

A 65-year-old man was admitted to our hospital with a 6-year history of painful muscle stiffness in his trunk and lower limbs, preventing him from walking. Stiff-person syndrome (SPS) was diagnosed because the patient had symptoms of painful muscle spasms elicited by tactile stimulation without joint contracture. Although SPS- related autoantibodies in the serum, including anti-glycine R, anti-amphiphysin, anti-glutamic acid decarboxylase (GAD), anti-dipeptidyl peptidase-like protein (DPPX) and anti-γ-aminobutyric acid-A (GABA_A) R, were negative, the ACTH and cortisol levels were low. On the basis of additional loading tests for anterior pituitary function and ACTH, isolated ACTH deficiency (IAD) was diagnosed. Hormonal replacement therapy with hydrocortisone at 15 mg/day ameliorated the condition quickly, and the patient became asymptomatic after three months. Flexion contractures have been reported as musculoskeletal symptoms of IAD, but are not usually evident in patients with SPS. The present case illustrates that the painful muscle spasms elicited by tactile stimulation without joint contracture characteristic of SPS can also be symptoms of IAD.

Long-term Effectiveness of IVIg Maintenance Therapy in 36 Patients With GAD Antibody–Positive Stiff-Person Syndrome

Background and Objectives

IVIg has been the preferred immunotherapy in stiff-person syndrome (SPS) based on a 3-month controlled trial, but whether it is also effective in inducing long-term benefits or arresting disease progression is unknown. The information is needed because SPS is a progressively disabling disease and IVIg is liberally used as chronic therapy without efficacy data. The present study explores the long-term effects of IVIg in the largest cohort of well-characterized patients with SPS followed by the same clinicians over 10 years.

Methods

Data of 36 patients (32 glutamic acid decarboxylase [GAD] positive), diagnosed and treated with monthly maintenance IVIg by the same neurologists, were analyzed. Response was assessed by physician-observed changes, patients' reports of symptom improvement, modified Rankin Scale (mRS) scores, and dependency trials evaluating symptom recurrence after stopping IVIg, prolonging infusion frequency, decreasing monthly dose, or wearing-off effects in between doses. Clinically meaningful long-term response was defined by improved mRS scores, improvement in physician-assessed stiffness, balance and gait, and functional decline with dependency trials.

Results

Twenty-four of 36 (67%) patients had clinically meaningful response over a median 40-month period. Patients with improved mRS scores by 1–2 points manifested improved gait, posture, balance and decreased stiffness, spasms, and startle response; some patients using a wheelchair and those ambulating with devices walked unassisted. In 25% of responders, treatment benefit was sustained for a 40-month median period, but in 29.1%, it declined over a 39-month period; 12.5% exhibited a conditioning effect. Three of 5 patients with cerebellar GAD-SPS variant also improved over time. The 12 patients who did not respond the first 3 months remained unresponsive even if IVIg continued for several months.

Discussion

This is a large study in 36 patients with SPS demonstrating that monthly maintenance IVIg therapy offers long-term benefits in 67% of patients for a median 3.3-year period. Because 29.1% experienced diminishing benefit over time due to disease progression, the study highlights the need for more effective therapies.

Stiff person syndrome spectrum disorders; more than meets the eye

Stiff person syndrome spectrum disorders (SPSD) are a group of rare neuroimmunological disorders that often include painful spasms and rigidity. However, patients have highly heterogeneous signs and symptoms which may reflect different mechanistic disease processes. Understanding subsets of patients based on clinical phenotype may be important for prognosis and guiding treatment. The goal of this review is to provide updates on SPSD and its expanding clinical spectrum, prognostic markers, and treatment considerations. Further, we describe the current understanding in immunopathogenesis and highlight gaps in our knowledge appropriate for future research directions. Examples of revised diagnostic criteria for SPSD based on phenotype are also presented.

Stiff-person Syndrome and GAD Antibody-spectrum Disorders: GABAergic Neuronal Excitability, Immunopathogenesis and Update on Antibody Therapies

Although antibodies against Glutamic Acid Decarboxylase (GAD) were originally associated with Stiff Person Syndrome (SPS), they now denote the "GAD antibody-spectrum disorders (GAD-SD)" that include Cerebellar Ataxia, Autoimmune Epilepsy, Limbic Encephalitis, PERM and eye movement disorder. In spite of the unique clinical phenotype that each of these disorders has, there is significant overlapping symptomatology characterized by autoimmune neuronal excitability. In addition to GAD, three other autoantibodies, against glycine receptors, amphiphysin and gephyrin, are less frequently or rarely associated with SPS-SD. Very high serum anti-GAD antibody titers are a key diagnostic feature for all GAD-SD, commonly associated with the presence of GAD antibodies in the CSF, a reduced CSF GABA level and increased anti-GAD-specific IgG intrathecal synthesis denoting stimulation of B-cell clones in the CNS. Because anti-GAD antibodies from the various hyperexcitability syndromes recognize the same dominant GAD epitope, the clinical heterogeneity among GAD-SD patients remains unexplained. The paper highlights the biologic basis of autoimmune hyperexcitability connected with the phenomenon of reciprocal inhibition as the fundamental mechanism of the patients' muscle stiffness and spasms; addresses the importance of high-GAD antibody titers in diagnosis, pinpointing the diagnostic challenges in patients with low-GAD titers or their distinction from functional disorders; and discusses whether high GAD-antibodies are disease markers or pathogenic in the context of their association with reduced GABA level in the brain and CSF. Finally, it focuses on therapies providing details on symptomatic GABA-enhancing drugs and the currently available immunotherapies in a step-by-step approach. The prospects of future immunotherapeutic options with antibody therapies are also summarized.

Unusual presentation of stiff-person syndrome in a patient with type 1 diabetes mellitus

Stiff-person syndrome (SPS) is a rare, autoimmune, neurological disorder that often occurs concurrently with other autoimmune disorders, such as type 1 diabetes mellitus, pernicious anaemia, vitiligo and Hashimoto's thyroiditis. It also can manifest as a paraneoplastic syndrome. Although SPS classically presents with truncal and appendicular stiffness and lumbar hyperlordosis, it can present focally in a single limb (termed stiff-limb syndrome). Here, we describe a woman with stiff-limb syndrome who initially presented with concerns about right foot swelling and pain. She also was positive for anti-GAD65 (anti-GAD2) antibodies. With treatment, she regained the ability to drive and ambulate without a walker, and she had a noted reduction in stimulus-induced spasms.

[Stiff-Person Syndrome]

Stiff-person syndrome (SPS) is a neurological disorder characterized by fluctuating muscle rigidity and painful spasms that occur spontaneously or are triggered by diverse stimuli. Partial or segmental forms of the disorder, such as stiff-limb syndrome (SLS) and the more severe disease called progressive encephalomyelitis with rigidity and myoclonus (PERM), are usually considered within the spectrum of SPS. SPS responds to immunotherapies, and several autoantigens have been identified. Most patients with SPS have high titers of antibodies against glutamic acid decarboxylase (GAD), the enzyme that limits the rate of the synthesis of γ-aminobutyric acid (GABA), and up to 15% have antibodies against the glycine receptor α-subunit.

Use of subcutaneous immunoglobulin in stiff person syndrome: Case series

INTRODUCTION

Intravenous immunoglobulin (IVIG) has been shown to be effective for the treatment of stiff person syndrome (SPS). However, some patients might not tolerate it. We report the tolerability profile of subcutaneous immunoglobulin (SCIg) in patients with SPS who did not tolerate IVIG. To our knowledge, the use of SCIg in SPS has not been reported before in a case series.

PATIENT CONCERNS

The five patients included in this case series presented with various combinations of symptoms of spasms, axial and limb stiffness, and exaggerated responses to outside stimuli. These symptoms often lead to gait and functional impairment.

DIAGNOSIS

Patients were diagnosed with classic SPS as they met the clinical criteria, which require the presence of spasms, axial rigidity, and hyperexcitability.

INTERVENTIONS

Subcutaneous immunoglobulin infusion.

OUTCOMES

Five patients were identified that were treated with SCIg. Three tested positive for serum anti-glutamic acid decarboxylase 65 antibodies prior to any treatment. The mean age at SCIg initiation was 33 years (range: 22-47). The mean duration of SPS prior to SCIg initiation was 5.9 years (range: 2.5-7). All patients used IVIG for at least two months (up to 18 months) but switched to SCIg due to IVIG side effects. Duration of SCIg use ranged from 4 months to 6 years (mean, 19.2 months). Upon switching to SCIg, the SPS symptoms remained stable. SCIg was well-tolerated in most as only one patient discontinued SCIg due to side effects.

CONCLUSION

This case series highlights that SCIg could be a treatment option for patients with SPS, especially when IVIG is not feasible. Injection site reactions might be a limiting factor in some patients treated with SCIg. Prospective controlled studies are needed to confirm SCIg treatment durability and efficacy.

The effect of clinical pilates-based physiotherapy program for a Stiff Person Syndrome patient: a case report

The aim of the present report is to show the effects of a clinical pilates-based physiotherapy training program on physical functioning, including balance ability, flexibility, muscle strength, and pain severity in a case with Stiff Person Syndrome (SPS). A 43-year-old female with a 3-year history of SPS participated in the study. Clinical pilates training exercises were performed two times per week during 8 weeks. Static balance was evaluated with One Leg Stance Test and Tandem Stance Test, dynamic balance with Functional Reach Test and lower extremity strength and endurance measured by 30-s Chair Stand Test. Berg Balance Scale was used to assess balance and fall risk, and Timed Up and Go Test was used to assess functional mobility. Pain evaluation was done by Pain Quality Assessment Scale. Flexibility was measured with tape measure, range of motion with goniometer and muscle strength with manual muscle test. Among the balance and functional mobility tests, progress has been observed in all tests, except for 30-s Chair Stand test. Improvements have been observed in patient's range of motion, flexibility, strength, pain and balance parameters. Clinical pilates-based physiotherapy program had positive effects on many physical and functional parameters of the patient and can be used as a safe exercise method in physiotherapy rehabilitation of SPS.

Defining the Expanding Clinical Spectrum of Pediatric-Onset Stiff Person Syndrome

BACKGROUND

We aimed to characterize the spectrum of clinical features and examination findings in pediatric-onset stiff person syndrome.

METHODS

Medical records were reviewed for all patients treated for stiff person syndrome with symptom onset in childhood at a tertiary medical center between March 2001 and February 2019.

RESULTS

Of the 15 individuals who met inclusion criteria, 11 (73%) were female and 13 (87%) were Caucasian. Median age at symptom onset was 14.8 years (range 8.4 to 16.9), and median latency from symptom onset to diagnosis was 6.2 years (range 0.4 to 15.0). Nine individuals (60%) were not diagnosed until adulthood. The most common presenting features were painful spasms (n = 12, 80%), hyper-reflexia (n = 11, 73%), axial rigidity (n = =9, 60%), lower extremity rigidity or spasticity (n = 8, 53%), gait abnormalities (n = 6, 40%), and hyperlordosis (n = 6, 40%). Other noted features included anxiety (n = 5, 33%), dysautonomia (n = 3, 20%), and cranial neuropathies (n = 3, 20%). Personal (n = 9, 60%) and family history (n = 9, 60%) of autoimmune conditions was common. Serum antiglutamate decarboxylase 65 antibodies were found in 13 individuals (87%). Nearly all individuals received immunotherapy (n = 14, 93%), symptomatic medications (n = 15, 100%), and nonpharmacologic therapies (n = 14, 93%). However, most had persistent physical limitations, particularly impaired walking (n = 7, 47%) and inability to carry out previous activities (n = 14, 93%).

CONCLUSIONS

There is a wide spectrum of typical and less common features seen in individuals with pediatric-onset stiff person syndrome. Despite symptom onset in childhood, diagnosis is often delayed until adulthood, at which point disability accrual is frequently seen. Early recognition is vital to address symptoms and may potentially limit future disability.

Stiff-person syndrome coexisting with critical illness polyneuropathy: A case report

RATIONALE

Stiff-person syndrome (SPS) is an uncommon neurological disorder with autoimmune features. Here, we report a 60-year-old man with SPS associated with critical illness polyneuropathy (CIP). CIP was diagnosed during an episode of acute respiratory failure secondary to muscular rigidity and spasms, which has rarely been reported in this condition. The overlapping of CIP and SPS complicated the case.

PATIENT CONCERNS

A 60-year-old man presented with gradual onset of cramps, stiffness, and rigidity in his lower limbs 1 year before admission, which eventually led to inability to stand and walk. The persistent nature of his symptoms progressed to frequent acute episodes of dyspnea and he was admitted to intensive care unit (ICU).

DIAGNOSIS

SPS had been diagnosed after 2 tests of electromyography (EMG) and the detection of an elevated anti-GAD65 antibody titer. During the first EMG, low or absent compound muscle action potentials (CMAP), and sensory nerve action potentials (SNAP) were shown. Therefore, the diagnosis of SPS coexisting with CIP was made.

INTERVENTIONS

Symptomatic treatment was initiated with oral clonazepam (0.5 mg Bid) and baclofen (5 mg Bid). Intravenous immunoglobulin (IVIG) (0.4 g/kg/d) was administered for the patient for 5 days after admission. We observed a significant clinical improvement during the administration period, and the patient became ambulatory.

OUTCOMES

On follow-up, the patient reported complete relief of his pain and rigidity.

LESSONS

We report this special case to address the varied clinical features of SPS. Electrophysiological testing is an important diagnostic approach. Accurate recognition of the disease ensures that the patients can be given appropriate treatment without delay.

An Appraisal of Electrodiagnostic Studies in Stiff Person Syndrome

A literature review was performed on the use of electrodiagnostic (EDX) tests including nerve conduction study, electromyography, exteroceptive reflex, blink reflex, and late response in the evaluation of patients with stiff person syndrome (SPS). A web survey was conducted to report the extent of EDX testing usage in the evaluation of SPS among laboratories accredited by the American Academy of Neuromuscular and Electrodiagnostic Medicine. Coactivation of selected agonist and antagonist muscles was performed in 5 healthy subjects to determine its specificity for SPS. Observation of continuous motor unit activity on electromyography and elicitation of exteroceptive reflexes by electric stimulation are informative in assisting a diagnosis of SPS, but further studies focusing on their sensitivities in diagnosing SPS and specificities in differentiating SPS from other movement disorders are needed. The value of EDX testing in SPS lies in ruling out other neuromuscular disorders.

[The Frozen Man and the Chinese Alphabet]

The Confucian philosophy teaches us that the search for truth does not always follow a straight line. The clinical observation presented here illustrates this perfectly and is about a child afflicted by a rare neuromuscular disorder (in Chinese, the word 'myopathy' is translated to meaning 'frozen man') in whom was suspected a deficit in αB crystallin. The authors take the opportunity to put the spotlight on China, this great country which did not wait for Alain Peyrefitte to wake up or, more precisely, to rewake. In the light of past and recent missions in the former Middle Kingdom, an update is made on the medico-scientific but also societal issues of this country on the verge of becoming, perhaps, a giant in the field of neuromuscular diseases.

Hyperekplexia and other startle syndromes

Abnormal startle syndromes are classified into hyperekplexia, stimulus-induced, and neuropsychiatric startle syndromes. Hyperekplexia is attributed to a genetic, idiopathic, or symptomatic cause. Hereditary hyperekplexia is a treatable neurogenetic disorder. In patients with a hyperactive startle response, the first step is to characterize the extent and associations of 'response.' Secondary or symptomatic causes are particularly important in children, as they provide useful clinical clues to an underlying neurodevelopmental or neurodegenerative disorders. Particular attention should be given to any neonate or infant with generalized or episodic stiffness, drug-refractory seizures, recurrent apnea, stimulus-sensitive behavioral states, or sudden infant death syndrome. Eliciting a non-habituating head-retraction reflex to repeated nose tapping should be a part of routine examination of all new-borns. Vigevano maneuver should be taught to all families and health-care workers as an emergency rescue measure. The onset of excessive startle after infancy should direct investigations for an acquired cause such as brainstem injury, antibodies against glycine receptors, and neurodegeneration. Finally, one should not forget to evaluate unexplained cases of abnormal gait and frequent falls in adults for underlying undiagnosed startle syndromes. Oral clonazepam is an effective therapy besides behavioral and safety interventions for hereditary cases. The outcomes in genetic cases are good overall.

Neurological Syndromes Associated with Anti-GAD Antibodies

Glutamic acid decarboxylase (GAD) is an intracellular enzyme whose physiologic function is the decarboxylation of glutamate to gamma-aminobutyric acid (GABA), the main inhibitory neurotransmitter within the central nervous system. GAD antibodies (Ab) have been associated with multiple neurological syndromes, including stiff-person syndrome, cerebellar ataxia, and limbic encephalitis, which are all considered to result from reduced GABAergic transmission. The pathogenic role of GAD Ab is still debated, and some evidence suggests that GAD autoimmunity might primarily be cell-mediated. Diagnosis relies on the detection of high titers of GAD Ab in serum and/or in the detection of GAD Ab in the cerebrospinal fluid. Due to the relative rarity of these syndromes, treatment schemes and predictors of response are poorly defined, highlighting the unmet need for multicentric prospective trials in this population. Here, we reviewed the main clinical characteristics of neurological syndromes associated with GAD Ab, focusing on pathophysiologic mechanisms.

Stiff limb syndrome with lower limb myoclonus: A case report

RATIONALE

stiff limb syndrome (SLS) is a variant of stiff-man syndrome, primarily affecting a specific limb. Its diagnosis has always been challenging due to the lack of a specific confirmation test. We present a rare case of a patient with lower limb myoclonus and rigidity.

PATIENT CONCERNS

A 53-year-old male presented with a sudden onset of progressive left lower extremity myoclonus and muscle rigidity for 3 days. He rapidly showed signs of right lower limb involvement with severe joint stiffness and inability to walk.

DIAGNOSIS

The symptoms nature, physical examination, careful elimination of differential diagnosis suggested a diagnosis of stiff limb syndrome.

INTERVENTIONS

Intravenous infusion of gamma globulin 0.4 mg/kg coupled with baclofen and clonazepam were given after admission. He also received an injection of botulinum toxin A to relieve his muscle stiffness.

OUTCOMES

The patients' condition improved after the initial treatment with complete disappearance of muscle twitching. Further improvements were seen later on after the local administration of botulinum toxin A.

LESSONS

Stiff limb syndrome shares the same complex symptoms with many other conditions. Its diagnosis relies heavily on clinical presentations and on ruling out other conditions. However, unusual symptoms such as myoclonus can occur in few cases and together with the rarity of the condition, the prevalence of misdiagnosis is high. Therefore, being aware and recognizing the signs and symptoms is crucial for proper management. Additionally, EMG is a very important test if the present condition is suspected. However, a negative EMG result or a negative anti-glutamic acid decarboxylase antibody test should not exclude SLS diagnosis.

A Case of Treatment Resistance and Complications in a Patient with Stiff Person Syndrome and Cerebellar Ataxia

Background

Antibodies against glutamic acid decarboxylase (GAD) are associated with Stiff Person Syndrome (SPS).

Case report

A 50-year-old woman presented with symptoms progressed over 9 years, resulting in a cerebellar ataxia and right upper limb tremor. Investigations revealed elevated serum and CSF anti-GAD antibody titres (98.6 and 53.4 μ/ml, respectively). Treatment included intravenous immunoglobulin and immunomodulation (infliximab and rituximab), improving her stiffness, but with no impact on the ataxia-related symptoms. Subsequent high-dose steroids led to diabetic ketoacidosis and unmasking of an insulin-dependent diabetes mellitus.

Discussion

This case illustrates several key features: (1) the combined clinical picture of SPS and cerebellar ataxia is a rare phenotype associated with anti-GAD antibodies; (2) the cerebellar ataxia described was progressive and poorly responsive to immunomodulatory therapy; and (3) the potential for development of further autoimmune sequelae in response to immunosuppression, namely, the development of insulin-dependent diabetes in response to treatment with high-dose oral steroids.

[Stiff person syndrome: still a difficult and overlooked diagnosis]

We present a case of stiff person syndrome (SPS) with a description of the diagnostic challenges and a discussion of the implication of novel antibodies. SPS is a rare neurological disorder presenting with severe rigidity, muscle spasms and impaired gait function, and diagnosis is often delayed due to low awareness. SPS is classically associated with antibodies directed against glutamic acid decarboxylase or amphiphysin. However, recent advances have contributed to our understanding because of detection of several new antibodies, which cause SPS, mostly with additional neurological/systemic manifestations.

Novel clinical features of glycine receptor antibody syndrome: A series of 17 cases

Objective

To describe novel clinical features of GlyRα1-IgG-positive patients.

Methods

Patients with a positive serum GlyRα1-IgG were identified during a 2-year period from July 2016 to December 2018 at 2 academic centers and followed prospectively. All patients in this series were evaluated in the Neuroimmunology and Autoimmune Neurology clinics at the University of Utah or the University of Colorado.

Results

Thirteen of 17 patients had phenotypes more typically associated with glutamic acid decarboxylase (GAD65) antibody syndromes, consisting of stiff-person syndrome (SPS) with parkinsonism or cerebellar signs. One patient with parkinsonism had a presentation similar to rapidly progressive multiple system atrophy with severe dysautonomia. Ten of 17 patients had various visual symptoms including visual snow, spider web-like images forming shapes and 3-dimensional images, palinopsia, photophobia, visual hallucinations, synesthesia, and intermittent diplopia. Three of 17 patients presented with primarily autoimmune epilepsy accompanied by psychiatric symptoms.

Conclusions

Clinicians should consider testing for GlyR antibodies in GAD65 antibody-negative or low-positive GAD65 antibody patients with SPS-like presentations, especially in the setting of atypical features such as visual disturbances, parkinsonism, or epilepsy.

SPS: Understanding the complexity

INTRODUCTION

Stiff-person syndrome (SPS), first described in 1956 by Moersch and Woltman, is a progressive autoimmune disorder with core features of chronic fluctuating progressive truncal and limb rigidity and painful muscle spasms leading to gait difficulties, falls and an appearance that resembles tin soldiers. The syndrome is a rare, highly disabling disorder of the central nervous and frequently results in significant disability. Understanding of the etiology, clinical spectrum, diagnostic workup and therapeutic modalities for this painful and disabling disorder has vastly evolved over the past few years with more confidence in classifying and treating the patients. The purpose of this review is to increase the awareness, early detection, and treatment of this disabling disease.

METHOD

PubMed was searched, all date inclusive, using the following phrases: stiff person syndrome,anti-Glutamic acid decarboxylase (Anti-GAD) antibody syndrome, Progressive encephalomyelitis with rigidity and myoclonus (PERM), and Paraneoplastic Stiff Person syndrome. No filters or restrictions were used. A total of 888 articles were identified.

RESULTS

The results were narrowed to 190 citations after excluding non-English and duplicate reports. Clinical presentation, laboratory testing, treatment, and prognosis were categorized and summarized.

DISCUSSION

In this article we will discuss the epidemiology, presentation and classification. Explain the pathophysiology of SPS and the autoimmune mechanisms involved. Discuss the diagnostic approach and treatments available, as well as, the prognosis and outcome.

Stiff Person Syndrome With Evidence of Nonspecific Focal Myositis Secondary to Sustained Muscle Contraction: A Case Report

Stiff person syndrome (SPS) is a rare neuroimmunological disorder characterized by progressive muscular rigidity and spasms that affect axial and limb muscles. There have been a few reports that patients with SPS had evidences of polymyositis. There have been no clear explanations about the characteristics of polymyositis in SPS. We report the case of a 36-year-old woman with SPS in association with nonspecific focal myositis secondary to sustained muscle contraction. She presented with stiffness and pain in her extremities, and diazepam and baclofen were ineffective. With immunotherapy, her serum creatinine kinase levels reduced; however, her clinical symptoms progressively worsened. LEVEL OF EVIDENCE: V.

[Stiff-Person Syndrome and Related Autoantibodies]

Stiff-person syndrome (SPS) is a disorder characterized by fluctuating muscle rigidity and painful spasms that occur spontaneously or are triggered by diverse stimuli. Partial or segmental forms of the disorder, such as stiff-limb syndrome (SLS) and a more severe disease called progressive encephalomyelitis with rigidity and myoclonus (PERM), are usually considered within the spectrum of SPS. SPS responds to immunotherapies, and several autoantigens have been identified. Most patients with SPS have a high-titer of antibodies against glutamic acid decarboxylase (GAD), the rate-limiting enzyme for the synthesis of γ-aminobutyric acid (GABA), and up to 15% have antibodies to the glycine receptor α-subunit. This review explains milestones in defining SPS including autoantibodies.

[From stiff man syndrome to stiff person spectrum disorders]

The identification of new variants of the stiff man syndrome (SMS) and of new, probably pathogenic neuronal autoantibodies has led to the concept of stiff man (or person) spectrum disorders (SPSD). This is an expanding group of rare chronic autoimmune inflammatory diseases of the central nervous system (CNS) that have in common the main symptoms of fluctuating rigidity and spasms with pronounced stimulus sensitivity. These core symptoms are mandatory and can be accompanied by a wide variety of other neurological signs. The SPSDs are associated with autoantibodies directed against neuronal proteins that attenuate excitability. Neither clinical phenotypes nor the course of SPSD correlate closely with the antibody status. The treatment of these diseases aims at maintaining mobility and is pragmatically oriented to the degree of impediment and comprises antispastic, anticonvulsant and immunomodulating or immunosuppressive medication strategies.

[A case of stiff-person syndrome due to secondary adrenal insufficiency]

We report a case of flexion contractures in a patient's legs secondary to postpartum hypopituitarism. A 56-year-old woman presented with a 3-year history of worsening flexion contractures of the hips and knees. On admission, her hips and knees could not be extended, and she had muscle stiffness and tenderness to palpation of the lower extremities. We first suspected stiff-person syndrome or Isaacs' syndrome because of her muscle stiffness. However, multiple hormones did not respond to stimulation tests, and an MRI of the brain showed atrophy of the pituitary gland with an empty sella. A subsequent interview revealed that she had suffered a severe hemorrhage while delivering her third child. She was diagnosed with panhypopituitarism and started on cortisol replacement therapy. After 1 week of treatment with hydrocortisone (10 mg/day), her symptoms quickly improved. We then added 75 μg/day of thyroid hormone. During the course of her treatment, autoantibodies against VGKC complex were found to be weakly positive. However, we considered the antibodies to be unrelated to her disease, because her symptoms improved markedly with low-dose steroid treatment. There are a few reports describing flexion contractures of the legs in patients with primary and secondary adrenal insufficiency. As these symptoms are similar to those seen in stiff-person syndrome, adrenal and pituitary insufficiency should be taken into account to achieve the correct diagnosis and treatment in patients with flexion contractures and muscle stiffness.

A case of autoimmune polyendocrine syndrome type I with strong positive GAD antibody titer, followed up with glucose tolerance measured by oral glucose tolerance test

A 26-year-old Japanese woman presented with adrenal insufficiency, and treatment was started with cortisone and fludrocortisone in 1975. A few years later, she presented with hypoparathyroidism and was diagnosed with autoimmune polyendocrine syndrome type I (APS I), and treatment with calcium and alfacalcidol was started. She was found to have subacute thyroiditis and relative adrenal failure in 2006. Her condition remained stable under treatment with cortisone, fludrocortisone, levothyroxine, calcium lactate, precipitated calcium carbonate and alfacalcidol. While antibodies against pancreatic glutamic acid decarboxylase (GAD) were strongly positive (7,690 U/ml), fasting glucose level was 4.9 mmol/L and HbA1c was 6.3% on admission. As GAD antibody showed a high-titer of >10,000 U/ml and fasting plasma glucose level showed a rising trend, we performed 75-g oral glucose tolerance test (OGTT) 6 years after discharge. Whereas OGTT in 2012 showed impaired glucose tolerance, glucose tolerance had reverted to normal in 2014. A patient with a high-titer GAD antibody does not always have progressive glucose intolerance. GAD antibody positivity is common in not only type 1 diabetes, but also APS I and stiff-person syndrome (SPS). There are differences in recognized epitopes among the three disorders. Epitopes for GAD65 antibody associated with type 1 diabetes are located in the middle region and the COOH-terminal of the GAD65 protein, whereas epitopes associated with SPS reside in the NH2-terminal in addition to the middle region and COOH-terminal. The present case suggests that these differences in epitopes may be related to various pathogenic mechanisms including glucose intolerance.

Stiff Person Syndrome

Stiff-person syndrome or Moersch-Woltmann is a very rare and disabling neurologic disorder characterized by muscle rigidity and episodic spasms involving axial and limb musculature. It is an autoimmune disorder resulting in a malfunction of aminobutyric acid mediated inhibitory networks in the central nervous system. We describe a patient of stiff person syndrome.

[Stiff person syndrome is a rare autoimmune disorder]

Atypical symptoms raise classical diagnostic dilemmas of somatic versus functional disease. The challenge is greater when the condition is less frequent. Illustrating this issue is a case of stiff person syndrome (SPS) where a 46-year-old man was admitted with lower back and hip pain and stiffness of the musculature of the lower extremities resulting in stooped gait. Stiffness was absent while sleeping. Thorough clinical examination and tests were unable to explain the symptomology until suspicion of SPS was raised, supported by high levels of glutamic acid decarboxylase antibodies.

LADA type diabetes, celiac diasease, cerebellar ataxia and stiff person syndrome. A rare association of autoimmune disorders

Celiac disease--in its typical form--is a chronic immune-mediated enteropathy with typical clinical symptoms that develops against gliadin content of cereal grains, and is often associated with other autoimmune diseases. In cases of atypical manifestation classic symptoms may be absent or mild, and extra-intestinal symptoms or associated syndromes dominate clinical picture. The authors present a longitudinal follow-up of such a case. A 63-years old woman was diagnosed with epilepsy at the age of 19, and with progressive limb ataxia at the age of 36, which was initially thought to be caused by cerebellar atrophy, later probably by stiff person syndrome. At the age 59, her diabetes mellitus manifested with type 2 diabetic phenotype, but based on GAD positivity later was reclassified as type 1 diabetes. Only the last check-up discovered the celiac disease, retrospectively explaining the entire disease course and neurological symptoms. By presenting this case, the authors would like to draw attention to the fact that one should think of the possibility of celiac disease when cerebellar ataxia, progressive neurological symptoms and diabetes are present at the same time. An early diagnosis may help to delay the progression of disease and help better treatment.

[Stiff baby syndrome is a rare cause of neonatal hypertonicity]

Stiff baby syndrome (hyperekplexia) is a rare genetic disorder. The condition can easily be misdiagnosed as epilepsy or severe sepsis because of hypertonicity and seizure-like episodes and has an increased risk of severe apnoea and sudden infant death. Tapping of the nasal bridge inducing a startle response is the clinical hallmark. We report cases of two sisters born with stiff baby syndrome with hypertonicity, exaggerated startle reaction and cyanosis. The syndrome has a good prognosis if treated with clonazepam and both cases were developmental normal after one year.

[Stiff person syndrome--case report]

Stiff person syndrome (SPS) is the rare disease and cause great inefficient. It is characterized by progressive stiffness muscles of trunk and the limbs on which the cramps of muscles overlap. In the electrophysiological investigation of the patients the involuntary discharge of motor unit potentials find and also simultaneous contraction agonistic and antagonistic muscles. SPS is presented with insulin-dependent diabetes mellitus often or is the symptom of the paraneoplastic syndrome. It is commonly associated with high anti-glutamic acid decarboxylaze (GAD) antibody titters in the serum of the blood of patients. Establishing the diagnosis can cause difficulties. We observed the patient in the last period about the atypical course the disease. The diagnosis was confirmed occurrences of the high titters of antibodies anti-GAD, the discharge of motor unit potential in paraspinal muscles in the rest and good response the treatment with diazepamem.