Specific phobia is a frequent non-motor feature in stiff man syndrome

Glycine Receptor β-Targeting Autoantibodies Contribute to the Pathology of Autoimmune Diseases

BACKGROUND AND OBJECTIVES

Stiff-person syndrome (SPS) and progressive encephalomyelitis with rigidity and myoclonus (PERM) are rare neurologic disorders of the CNS. Until now, exclusive GlyRα subunit-binding autoantibodies with subsequent changes in function and surface numbers were reported. GlyR autoantibodies have also been described in patients with focal epilepsy. Autoimmune reactivity against the GlyRβ subunits has not yet been shown. Autoantibodies against GlyRα1 target the large extracellular N-terminal domain. This domain shares a high degree of sequence homology with GlyRβ making it not unlikely that GlyRβ-specific autoantibody (aAb) exist and contribute to the disease pathology.

METHODS

In this study, we investigated serum samples from 58 patients for aAb specifically detecting GlyRβ. Studies in microarray format, cell-based assays, and primary spinal cord neurons and spinal cord tissue immunohistochemistry were performed to determine specific GlyRβ binding and define aAb binding to distinct protein regions. Preadsorption approaches of aAbs using living cells and the purified extracellular receptor domain were further used. Finally, functional consequences for inhibitory neurotransmission upon GlyRβ aAb binding were resolved by whole-cell patch-clamp recordings.

RESULTS

Among 58 samples investigated, cell-based assays, tissue analysis, and preadsorption approaches revealed 2 patients with high specificity for GlyRβ aAb. Quantitative protein cluster analysis demonstrated aAb binding to synaptic GlyRβ colocalized with the scaffold protein gephyrin independent of the presence of GlyRα1. At the functional level, binding of GlyRβ aAb from both patients to its target impair glycine efficacy.

DISCUSSION

Our study establishes GlyRβ as novel target of aAb in patients with SPS/PERM. In contrast to exclusively GlyRα1-positive sera, which alter glycine potency, aAbs against GlyRβ impair receptor efficacy for the neurotransmitter glycine. Imaging and functional analyses showed that GlyRβ aAbs antagonize inhibitory neurotransmission by affecting receptor function rather than localization.

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.

Motor symptoms in nonparaneoplastic CNS disorders associated with neural antibodies

Motor symptoms are common, and sometimes predominant, in almost all nonparaneoplastic CNS disorders associated with neural antibodies. These CNS disorders can be classified into five groups: (1) Autoimmune encephalitis with antibodies against synaptic receptors, (2) cerebellar ataxias associated with neuronal antibodies that mostly target intracellular antigens. (3) Stiff-person syndrome and progressive encephalomyelitis with rigidity and myoclonus which have antibodies against glutamic acid decarboxylase and glycine receptor, respectively. Both diseases have in common the presence of predominant muscle stiffness and rigidity. (4) Three diseases associated with glial antibodies. Two present motor symptoms mainly due to the involvement of the spinal cord: neuromyelitis optica spectrum disorders with aquaporin-4 antibodies and myelin oligodendrocyte glycoprotein antibody-associated disease. The third disorder is the meningoencephalitis associated with glial fibrillar acidic protein antibodies which frequently also presents a myelopathy. (5) Two antibody-related diseases which are characterized by prominent sleep dysfunction: anti-IgLON5 disease, a disorder that frequently presents a variety of movement disorders, and Morvan syndrome associated with contactin-associated protein-like 2 antibodies and clinical manifestations of peripheral nerve hyperexcitability. In this chapter, we describe the main clinical features of these five groups with particular emphasis on the presence, frequency, and types of motor symptoms.

Affective and anxiety disorders in patients with different rare chronic diseases: a systematic review and meta-analysis

We aimed to identify the prevalence of affective and anxiety disorders across different rare disease and identify correlates of psychopathology. We performed a systematic review and meta-analysis. We systematically searched Medline, PSYNDEX, PsycINFO for observational studies examining clinically diagnosed affective and/or anxiety disorders in adults with rare chronic diseases. Two researchers reviewed titles and abstracts independently and, for eligible studies, independently extracted data. The prevalence rates were pooled using a random intercept logistic regression model. We published a review protocol (http://www.crd.york.ac.uk/PROSPERO/display_record.php?ID=CRD42018106614CRD42018106614). We identified and screened 34 402 records for eligibility and considered 39 studies in the qualitative and 37 studies in the quantitative analysis, including N = 5951 patients with 24 different rare diseases. Heterogeneity between studies was large. Prevalence rates ranged widely between studies, with pooled prevalence estimates of 13.1% (95% CI 9.6-17.7%; I2 = 87%, p < 0.001) for current and 39.3% (95% CI 31.7-47.4%; I2 = 84%, p < 0.001) for lifetime major depressive disorder, 21.2% (95% CI 15.4-28.6%; I2 = 90%, p < 0.001) for current and 46.1% (95% CI 35.8-56.8%; I2 = 90%, p < 0.001) for lifetime affective disorders, and 39.6% (95% CI 25.5-55.6%; I2 = 96%, p < 0.001) for current and 44.2% (95% CI 27.0-62.9%; I2 = 94%, p < 0.001) for lifetime anxiety disorders. Sensitivity analyses excluding studies of low quality revealed nearly the same results. We conducted the first systematic review examining affective and anxiety disorders in adults with different rare diseases and found high prevalence rates. Supporting patients in disease adjustment can be crucial for their overall health and well-being.

Treatable Hyperkinetic Movement Disorders Not to Be Missed

Hyperkinetic movement disorders are characterized by the presence of abnormal involuntary movements, comprising most notably dystonia, chorea, myoclonus, and tremor. Possible causes are numerous, including autoimmune disorders, infections of the central nervous system, metabolic disturbances, genetic diseases, drug-related causes and functional disorders, making the diagnostic process difficult for clinicians. Some diagnoses may be delayed without serious consequences, but diagnosis delays may prove detrimental in treatable disorders, ranging from functional disabilities, as in dopa-responsive dystonia, to death, as in Whipple's disease. In this review, we focus on treatable disorders that may present with prominent hyperkinetic movement disorders.

Autoantibody-associated psychiatric symptoms and syndromes in adults: A narrative review and proposed diagnostic approach

Background

Autoimmune-mediated encephalitis is a disease that often encompasses psychiatric symptoms as its first clinical manifestation’s predominant and isolated characteristic. Novel guidelines even distinguish autoimmune psychosis from autoimmune encephalitis. The aim of this review is thus to explore whether a wide range of psychiatric symptoms and syndromes are associated or correlate with autoantibodies.

Methods

We conducted a PubMed search to identify appropriate articles concerning serum and/or cerebrospinal fluid (CSF) autoantibodies associated with psychiatric symptoms and syndromes between 2000 and 2020. Relying on this data, we developed a diagnostic approach to optimize the detection of autoantibodies in psychiatric patients, potentially leading to the approval of an immunotherapy.

Results

We detected 10 major psychiatric symptoms and syndromes often reported to be associated with serum and/or CSF autoantibodies comprising altered consciousness, disorientation, memory impairment, obsessive-compulsive behavior, psychosis, catatonia, mood dysfunction, anxiety, behavioral abnormalities (autism, hyperkinetic), and sleeping dysfunction. The following psychiatric diagnoses were associated with serum and/or CSF autoantibodies: psychosis and schizophrenia spectrum disorders, mood disorders, minor and major neurocognitive impairment, obsessive-compulsive disorder, autism spectrum disorders (ASD), attention deficit hyperactivity disorder (ADHD), anxiety disorders, eating disorders and addiction. By relying on these symptom clusters and diagnoses in terms of onset and their duration, we classified a subacute or subchronic psychiatric syndrome in patients that should be screened for autoantibodies. We propose further diagnostics entailing CSF analysis, electroencephalography and magnetic resonance imaging of the brain. Exploiting these technologies enables standardized and accurate diagnosis of autoantibody-associated psychiatric symptoms and syndromes to deliver early immunotherapy.

Conclusions

We have developed a clinical diagnostic pathway for classifying subgroups of psychiatric patients whose psychiatric symptoms indicate a suspected autoimmune origin.

•

Autoantibodies are associated with a broad spectrum of psychiatric syndromes.

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More systematic studies are needed to elucidate the significance of autoantibodies.

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We developed a pathway to identify autoantibody-associated psychiatric syndromes.

Impaired Verbal Memory Recall in Patients With Axonal Degeneration and Serum Glycine-Receptor Autoantibodies-Case Series

BACKGROUND

Glycine receptor antibody-associated neuropsychiatric disease is currently known to be dominated by the phenotypes stiff-person syndrome and progressive encephalomyelitis entailing rigidity and myoclonus. In our case series we aim to depict the less-often reported feature of cognitive impairment associated with glycine receptor antibodies.

METHODS

We investigated five patients with cognitive impairment varying from mild cognitive impairment to dementia associated with serum glycine receptor antibodies. Mild and major neurocognitive disorders were diagnosed according to the DSM-5 (fifth edition of the Diagnostic and Statistical Manual of Mental Disorders). Neuropsychology via Consortium to Establish a Registry for Alzheimer's Disease (CERAD) testing results, psychopathology data via the Manual for the Assessment and Documentation of Psychopathology in Psychiatry (AMDP), cerebrospinal fluid analysis and magnetic resonance imaging data were retrospectively analyzed from patient files.

RESULTS

We identified five patients with cognitive impairment as the main neuropsychiatric feature associated with serum glycine receptor antibodies. One patient also presented akinetic rigidity syndrome. The psychopathology comprised disorders of attention and memory, orientation, formal thought, and affect. In addition to suffering deficits in verbal memory function, figural recall, phonematic fluency, and globally deteriorated cognitive function, these patients presented seriously impaired memory recall in particular. Tau protein and phosphorylated tau protein 181 were elevated in 75% of patients.

CONCLUSIONS

Our results suggest that axonal neurodegeneration and especially impaired verbal memory recall in addition to deficits in verbal and figural memory characterize patients with progressive cognitive impairment associated with glycine receptor antibodies. This unresolved issue should be clarified by researchers to discover whether axonal degeneration is merely an age-related phenomenon or one related to glycine-receptor autoantibodies in old age. Cognitive impairment as a neuropsychiatric syndrome of glycine-receptor antibody disease is a potential, conceivable, but so far unproven additional feature requiring deeper large-scale investigations and consideration during differential diagnosis in memory clinics.

Stiff-Person Syndrome and Psychiatric Comorbidities: A Systematic Review

BACKGROUND

Stiff-person syndrome (SPS) is a rare autoimmune neurologic disease characterized by painful rigidity and muscle spasms. Patients with SPS may present with psychiatric symptoms, and little is known about the presence of psychiatric comorbidities.

OBJECTIVE

The objective of this study was to provide an overview of the association between SPS and psychiatric illnesses.

METHODS

The protocol is registered in PROSPERO (Registration ID CRD42020159354). Peer-reviewed articles on adults with SPS and psychiatric comorbidities published before May 26, 2020, were selected by 2 independent reviewers. Qualitative summary data and relative risk of psychiatric disorders in patients with SPS compared with the general population and multiple sclerosis were calculated.

RESULTS

After screening 909 articles, 52 full texts were assessed for eligibility and 27 were ultimately included, 5 of which were selected for quantitative analysis. Although limited by small sample sizes leading to large confidence intervals, the relative risk of any psychiatric comorbidity in SPS was higher than that of the general population, ranging from estimates of 6.09 (95% confidence interval: 4.09, 9.08) to 11.25 (95% confidence interval: 3.27, 38.66). There was no statistically significant difference in the risk of any psychiatric comorbidity between SPS and multiple sclerosis. The review also highlighted delays in SPS diagnosis, often related to misattribution of symptoms as being solely secondary to a psychiatric cause.

CONCLUSIONS

The higher risk of psychiatric comorbidities emphasizes the important role of psychiatrists in recognizing the symptoms of SPS to reach timely diagnosis and treatment. The presence of psychiatric symptoms should support rather than delay the diagnosis of SPS.

Limited Utility for Benzodiazepines in Chronic Pain Management: A Narrative Review

INTRODUCTION

Controversy and uncertainty exist about the use of benzodiazepine receptor agonists (BZRAs) in pain management. This article curates available research to determine the appropriate role of BZRAs in the course of pain management, and how prescribers might address these challenges.

METHODS

A narrative review was performed to determine the appropriate role of BZRAs in pain management and to develop practice recommendations. Publications were identified by a search of PubMed, references of retrieved reports, guidelines, and the author's personal files.

RESULTS

BZRAs were found to have analgesic benefit for two pain conditions: burning mouth syndrome and stiff person syndrome. Absence of research, heterogeneity of trials, and small sample sizes precluded drawing conclusions about efficacy of BZRAs for the other 109 pain conditions explored. Data supports the use of BZRAs to treat co-occurring insomnia and anxiety disorders but only when alternatives are inadequate and only for short periods of time (2-4 weeks). The utility of BZRAs is limited by loss of efficacy that may be seen with continued use and adverse reactions including physiologic dependence which develops in 20-100% of those who take these agents for more than a month.

CONCLUSIONS

BZRAs are often used inappropriately in pain management. Their initiation and duration of use should be limited to a narrow range of conditions. When prescribed for 4 weeks or more, patients should be encouraged to discontinue them through a supported, slow tapering process that may take 12-18 months or longer.

Stiff-person syndrome in a patient with comorbid bipolar and panic disorders: A case report and literature review

Stiff-person syndrome (SPS) is a neurologic disorder characterized by muscle stiffness, rigidity, and muscle spasms, and it can increase a patient's risk for falls. It is recognized as a rare disease with limited clinical guidelines to manage the condition and its symptoms. Currently, there is even less clinical guidance for the management of common comorbid conditions in these patients. This patient case report aims to evaluate the efficacy of various medications for symptom management in a patient with SPS and comorbid psychiatric disorders, specifically bipolar I and panic disorder. Throughout the patient's course of treatment, various medications were trialed, including fluoxetine, hydroxyzine, valproic acid, propranolol, and clonazepam. Ultimately, fluoxetine, hydroxyzine, and propranolol were discontinued due to adverse drug reactions and incomplete symptom resolution. The patient's bipolar I disorder was adequately managed with valproic acid. Once the clonazepam was changed from as-needed to scheduled dosing, the patient's panic disorder and anxiety-triggered spasms were well controlled. The efficacy of benzodiazepines, specifically high doses of diazepam, in alleviating muscle spasms and anxiety in SPS has been demonstrated in the literature. Case reports including patients with SPS that are prescribed selective serotonin reuptake inhibitors provide controversial evidence as some studies report exacerbation of SPS symptoms with prolonged use. As this case report and literature review suggest, patients with SPS and comorbid panic disorder and anxiety-triggered spasms may benefit from the use of benzodiazepines. The use of other medication classes for the treatment of other comorbid psychiatric disorders in a patient with SPS is lacking evidence.

Pseudoagoraphobia, a Diagnostic Clue in Stiff-Limb Syndrome

BACKGROUND

Stiff-limb syndrome is part of stiff person spectrum, presenting with fluctuating gait disorders attributed to leg stiffness, spasms, and posturing. It could also manifest with anxiety and specific phobias such as pseudoagoraphobia. We aimed to describe the importance of specific gait phobia as a diagnostic clue to anti-glutamic acid decarboxylase stiff-limb syndrome.

CASES

We reported on 2 cases of stiff-limb syndrome sharing a similar diagnostic path and phenomenology. Both were featured by pseudoagoraphobia, which has documented to typically cover organic conditions, and a remarkable diagnostic delay attributed to misdiagnoses. Presence of pseudoagoraphobia should not point to the diagnosis of a functional disorder-although a negative instrumental workup is documented.

CONCLUSIONS

Both cases are emblematic of the high misdiagnosis rate affecting stiff person syndrome patients. A proper diagnostic process, including the identification of a pseudoagoraphobia, should help in reaching a diagnosis and providing an early and effective treatment.

A Case of Anti-glutamic Acid Decarboxylase-65 Antibody Positive Stiff Person Syndrome Presenting Initially as Acute Peripheral Vestibulopathy, Leading to Delayed Diagnosis After Multiple Hospitalizations

Stiff person syndrome (SPS), with a prevalence of one to two per million, is an extremely rare neurological condition that is characterized by axial muscle stiffness and rigidity along with intermittent painful muscle spasms. It is often associated with psychiatric co-morbidities such as anxiety and depression. The pathophysiology, although poorly understood, is widely believed to be autoimmune in nature due to the association of anti-glutamic acid decarboxylase-65 (anti-GAD 65) antibodies with this condition. There is also a paraneoplastic variant that is more commonly associated with anti-ampiphysin antibodies. It occurs most commonly in patients with breast cancer followed by colon cancer. Most of the practising neurologists encounter just one or two cases of SPS in their entire careers, hence this condition remains underdiagnosed, leading to significant disability and distress to the patient. In this case report we describe a postmenopausal female who presented initially with symptoms of vertigo and dizziness and was hospitalized multiple times before the diagnosis was reached. Through this article, we attempt to increase awareness about this condition among practising physicians so as to increase the likelihood of earlier diagnosis and treatment. 

Association of stiff-person syndrome with autoimmune endocrine diseases

BACKGROUND

Stiff-person syndrome (SPS) and its subtype, stiff limb syndrome (SLS), are rare neurological disorders characterized by progressive muscular rigidity and spasms. Glutamic acid decarboxylase (GAD) is the enzyme that catalyzes the production of γ-aminobutyric acid (GABA), a major inhibitory neurotransmitter of the central nervous system. SPS is an autoimmune disease triggered by anti-glutamic acid decarboxylase antibody (anti-GAD Ab). Clinically, anti-GAD Ab is associated with SPS, type 1 diabetes mellitus (T1DM), and other autoimmune diseases.

AIM

To investigate the link of autoimmune endocrine disorders with anti-GAD Ab in SPS subjects.

METHODS

This retrospective study was approved by the Institutional Review Board of Chang Gung Memorial Hospital, Taiwan. We collected the patients with SPS from January 2001 to June 2018. By reviewing 14 patients from medical records, we analyzed the clinical findings with coexisting autoimmune diseases, particularly diabetes mellitus and thyroid disease, which are associated with anti-GAD antibody titers or other immunological test results (anti-thyroid peroxidase and anti-nuclear antibodies). We also evaluated malignancies, major complications, and reported treatment to improve symptoms. Anti-GAD antibodies were measured using radioimmunoassay and enzyme-linked immunosorbent assay (ELISA). The cut-off values of these tests are < 1 U/mL and < 5 U/mL, respectively.

RESULTS

The median age of all patients was 39.3 (range, 28.0-54.0) years with a median follow-up period of 6.0 (2.7-13.3) years. Five (35.7%) patients were female; twelve (85.7%) were diagnosed with classic SPS and two (14.3%) with SLS. The median age of onset of symptoms was 35.0 (26.0-56.0) years with a median follow-up duration of 9.0 (2.1-14.9) years in the classic SPS group; the SLS group had a median age of onset of 46.7 years and a shorter follow-up duration of 4.3 years. Among nine classic SPS patients who underwent the anti-GAD Ab test, three were anti-GAD Ab seropositive and each of these three patients also had T1DM, latent autoimmune diabetes in adults, and autoimmune thyroid disease, respectively. In contrast, other rare autoimmune diseases co-existed in six anti-GAD Ab seronegative SPS patients. None of the SLS patients had additional autoimmune diseases.

CONCLUSION

While typical clinical symptoms are crucial for the diagnosis of SPS, the presence of anti-GAD autoantibody may consolidate the diagnosis and predict the association with other autoimmune diseases.

Femur Neck Fracture in a Patient with Stiff Person Syndrome: A Case Report

CASE

A 57-year-old man with a known case of stiff person syndrome (SPS) presented with an insidious-onset 3-month history of right groin pain and inability to bear weight on the right lower extremity. Radiographs demonstrated a displaced right neck of femur fracture. Pelvic magnetic resonance imaging was negative for any infective or neoplastic pathology. Right primary cementless total hip replacement was performed. Significant improvement in function was noted after surgery.

CONCLUSIONS

Femur neck fracture can result from severe muscle spasms and stiffness. Primary total hip replacement is a difficult but reasonable operative procedure for SPS with neck of femur fracture. The success of the procedure also depends on ideal medical control of muscle spasms and rigidity.

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.

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.

Stiff person syndrome in South Asia

BACKGROUND

Stiff person syndrome is a highly disabling, progressive autoimmune disorder of the central nervous system characterized by muscle rigidity and spasms. Stiff person syndrome is rare, but is believed to be under diagnosed with only 14 cases been reported among a 1.7 billion population in South Asia. We report the first authenticated case from Sri Lanka.

CASE PRESENTATION

A 55-year-old Sri Lankan female presented with difficulty in walking and recurrent falls due to progressive muscular rigidity in her lower limbs and trunk with superimposed muscle spasms that occurred in response to unexpected noise, startle or emotional upset. She had anxiety and specific phobias to open spaces, walking unaided and being among crowds of people. She had insulin-dependent diabetes mellitus and was on thyroxine replacement. On examination, she had hyperlordosis combined with board-like rigidity of her anterior abdomen and rigidity of her lower limbs bilaterally. Upper limbs were normal. Magnetic resonance imaging of her neuraxis was normal. Electromyography showed continuous motor unit activity at rest. Glutamic acid decarboxylase antibodies were detected in her serum at a titre of 15,500 IU/ml (normal <5). She showed a remarkable and sustained improvement to treatment with intravenous immunoglobulins, immunosuppressive and muscle relaxant medications, regaining independent ambulation.

CONCLUSIONS

Diagnosis of stiff person syndrome remains clinical, supported by electromyography and serology for glutamic acid decarboxylase antibodies, facilitated by a high index of clinical suspicion. An autoimmune basis lends stiff person syndrome amenable to treatment highlighting the importance of diagnosis. This case adds to map the worldwide distribution of stiff person syndrome.

Recent Advances and Review on Treatment of Stiff Person Syndrome in Adults and Pediatric Patients

Stiff Person Syndrome (SPS) is one of the rarest autoimmune neurological disorders, which is mostly reported in women. It is characterised by fluctuating muscle rigidity and spasms. There are many variants of SPS, these include the classical SPS, Stiff Leg Syndrome (SLS), paraneoplastic variant, gait ataxia, dysarthria, and abnormal eye movements. Studies have shown that the paraneoplastic variant of SPS is more common in patients with breast cancer who harbour amphiphysin antibodies, followed by colon cancer, lung cancer, Hodgkin's disease, and malignant thymoma. 

Currently, the treatment for SPS revolves around improving the quality of life by reducing the symptoms as far as possible with the use of GABAergic agonists, such as diazepam or other benzodiazepines, steroids, plasmapheresis, and intravenous immunoglobulin (IVIG). There have been random clinical trials with Rituximab, but nothing concrete has been suggested. A treatment approach with standard drugs and cognitive behavioral therapy (CBT) seems to be promising.

Stiff-person syndrome: insights into a complex autoimmune disorder

Stiff-person syndrome (SPS) is characterised by progressive rigidity and muscle spasms affecting the axial and limb muscles. Since its initial description in 1956, marked progress has been made in the clinical characterisation, understanding of pathogenesis and therapy of this disorder. SPS can be classified according to the clinical presentation into classic SPS and SPS variants: focal or segmental-SPS, jerking-SPS and progressive encephalomyelitis with rigidity and myoclonus. Most patients with SPS have antibodies directed against the glutamic acid decarboxylase, the rate-limiting enzyme for the production of the inhibitory neurotransmitter γ-aminobutyric acid (GABA). Antibodies directed against GABA(A) receptor-associated protein, and the glycine-α1 receptor can also be observed. Paraneoplastic SPS is commonly associated with antiamphiphysin antibodies and breast cancer. Treatment of SPS with drugs that increase the GABAergic tone combined with immunotherapy can improve the neurological manifestations of these patients. The prognosis, however, is unpredictable and spontaneous remissions are unlikely.

Stiff Limb Syndrome Mimicking Corticobasal Syndrome

Stiff limb syndrome (SLS) is a focal variant of the spectrum of stiff person syndrome. Its presentation with stiffness, limb posturing, and freezing-of-gait (FOG)-like episodes, together with the relative rareness of the disorder, make it conceivable that SLS might be misdiagnosed as atypical parkinsonism, in particular, corticobasal syndrome (CBS). To illustrate this, we present two cases of established SLS resembling CBS and discuss the distinguishing features that may alert the clinician to the correct diagnosis, with its obvious therapeutic and prognostic implications.

Stiff person-syndrome IgG affects presynaptic GABAergic release mechanisms

The majority of patients with stiff person-syndrome (SPS) are characterized by autoantibodies to glutamate decarboxylase 65 (GAD65). In previous passive-transfer studies, SPS immunoglobulin G (IgG) induced SPS core symptoms. We here provide evidence that SPS-IgG causes a higher frequency of spontaneous vesicle fusions. Sustained GABAergic transmission and presynaptic GABAergic vesicle pool size remained unchanged. Since these findings cannot be attributed to anti-GAD65 autoantibodies alone, we propose that additional autoantibodies with so far undefined antigen specificity might affect presynaptic release mechanisms.

High titers of autoantibodies to glutamate decarboxylase in type 1 diabetes patients: epitope analysis and inhibition of enzyme activity

OBJECTIVE

Autoantibodies to glutamate decarboxylase (GAD65Ab) are found in patients with autoimmune neurological disorders or type 1 diabetes. The correct diagnosis of GAD65Ab-associated neurological disorders is often delayed by the variability of symptoms and a lack of diagnostic markers. We hypothesized that the frequency of neurological disorders with high GAD65Ab titers is significantly higher than currently recognized.

METHODS

We analyzed GAD65Ab titer, GAD65 enzyme activity inhibition, and GAD65Ab epitope pattern in a cohort of type 1 diabetes patients (n = 100) and correlated our findings with neurological symptoms and diseases.

RESULTS

Overall, 43% (43/100) of patients had detectable GAD65Ab titers (median = 400 U/mL, range: 142-250,000 U/mL). The GAD65Ab titers in 10 type 1 diabetes patients exceeded the 90th percentile of the cohort (2,000-250,000 U/mL). Sera of these 10 patients were analyzed for their GAD65Ab epitope specificity and their ability to inhibit GAD65 enzyme activity in vitro. GAD65Ab of 5 patients inhibited the enzyme activity significantly (by 34-55%). Three patients complained of muscle stiffness and pain, which was documented in 2 of these patients.

CONCLUSIONS

Based on our findings, we suggest that neurological disorders with high GAD65Ab titers are more frequent in type 1 diabetes patients than currently recognized.

A case of childhood stiff-person syndrome with striatal lesions: a possible entity distinct from the classical adult form

Parainfectious or autoimmune striatal lesions have been repeatedly described in children. We report a 7-year-old girl with painful muscle spasms, leading to the diagnosis of childhood stiff-person syndrome (SPS). Striatal lesions were demonstrated by diffusion-weighted magnetic resonance imaging (MRI) and single-photon emission computed tomography but not by conventional MRI. Autoantibodies against glutamic acid decarboxylase (GAD) were absent. Steroid pulse therapy and high-dose intravenous immunoglobulin resolved all the symptoms with slight sequelae. Childhood SPS may be characterized by absent anti-GAD antibodies and a transient benign clinical course, and it may have a pathomechanism distinct from that in adult SPS.

Stiff person syndrome

Recognizing stiff person syndrome is clinically important. It is uncommon, characterized by body stiffness associated with painful muscle spasms, and varies in location and severity. It is subdivided into stiff trunk versus stiff limb presentation, and as a progressive encephalomyelitis. Stiff person-type syndrome also reflects a paraneoplastic picture. Most patients demonstrate exaggerated lumbar lordosis. Roughly 60% of patients have antiglutamic acid decarboxylase antibodies in the blood and the cerebrospinal fluid. The differential diagnosis includes many severe conditions. There are reports of response to muscle relaxants, immunosuppressants, intravenous gamma globulin, plasma exchange, a number of anticonvulsants, and botulinum toxin.

[Stiff man syndrome and variants]

Stiff man syndrome (SMS) and its variants are rare neurological disorders with unusual, often awkward motor and psychological symptoms. Misdiagnoses are frequent and differentiation from psychogenic movement disorder may be difficult. Clinical suspicion can be substantiated by neurophysiological and immunological testing. Autoimmunity against certain proteins of inhibitory synapses appears to be a key feature that links SMS to other autoimmune encephalopathies and endocrinopathies. According to retrospective analyses a front-loaded long-term methylprednisolone treatment appears to be most effective.

Autoimmune stiff person syndrome and related myelopathies: understanding of electrophysiological and immunological processes

Stiff person syndrome (SPS) is a disabling autoimmune central nervous system disorder characterized by progressive muscle rigidity and gait impairment with superimposed painful spasms that involve axial and limb musculature, triggered by heightened sensitivity to external stimuli. Impaired synaptic GABAergic inhibition resulting from intrathecal B-cell-mediated clonal synthesis of autoantibodies against various presynaptic and synaptic proteins in the inhibitory neurons of the brain and spinal cord is believed to be an underlying pathogenic mechanism. SPS is most often idiopathic, but it can occur as a paraneoplastic condition. Despite evidence that anti-GAD and related autoantibodies impair GABA synthesis, the exact pathogenic mechanism of SPS is not fully elucidated. The strong association with several MHC-II alleles and improvement of symptoms with immune-modulating therapies support an autoimmune etiology of SPS. In this review, we discuss the clinical spectrum, neurophysiological mechanisms, and therapeutic options, including a rationale for agents that modulate B-cell function in SPS.

Support for involvement of glutamate decarboxylase 1 and neuropeptide Y in anxiety susceptibility

Genetic mapping efforts have identified putative susceptibility genes for human anxiety disorders. The most intensively studied genes are involved in neurotransmitter metabolism and signaling or stress response. In addition, neuropeptides and targets of anxiolytics have been examined. It has become apparent that gene × environment interactions may explain individual variation in stress resilience and predisposition to mental disorders. We aimed to replicate previous genetic findings in 16 putative anxiety susceptibility genes and further test whether they modulate the risk for developing an anxiety disorder in adulthood after childhood stress exposure. We tested 93 single-nucleotide polymorphisms (SNPs) for genetic association to anxiety disorders in the Finnish population-based Health 2000 sample (282 cases and 575 matched controls). In addition, we examined by logistic regression modeling whether the SNP genotypes modified the effect of the number of self-reported childhood adversities on anxiety disorder risk. The most significant evidence for association was observed in glutamate decarboxylase 1 (GAD1) with phobias (P = 0.0005). A subsequent meta-analysis (N = 1985) incorporating previously published findings supported involvement of a single GAD1 risk haplotype in determining susceptibility to a broad range of internalizing disorders (P = 0.0009). We additionally found that SNPs and haplotypes in neuropeptide Y (NPY) modified the effect of childhood adversities on anxiety susceptibility (P = 0.003). In conclusion, we provide further support for involvement of mainly GAD1, but also NPY in determining predisposition to anxiety disorders.

Stiff-person syndrome presenting as eating disorder: a case report

OBJECTIVE

To report a case of a 35-year-old female initially treated for anorexia nervosa who was found to have Stiff-Person Syndrome (SPS).

METHOD

Case report.

RESULTS

The patient reported panic attacks at meal times that were found to consist of tetanic contractions of the axial musculature. Swallowing initiated reflexive painful muscle spasms that consequently resulted in cibophobia and significant weight loss. Her serum tested positive for anti-glutamic acid decarboxylase antibodies, and she subsequently improved with appropriate treatment for SPS.

DISCUSSION

SPS has not been previously reported in the context of eating disorders, although it has been linked to other psychiatric disorders. Often the psychiatrist may be the first physician to diagnose SPS. We present this case to alert practitioners to the potential co-morbidity and symptom overlap between SPS and eating disorders, to aid in early recognition and appropriate treatment of this rare illness.

Human stiff-person syndrome IgG induces anxious behavior in rats

Background

Anxiety is a heterogeneous behavioral domain playing a role in a variety of neuropsychiatric diseases. While anxiety is the cardinal symptom in disorders such as panic disorder, co-morbid anxious behavior can occur in a variety of diseases. Stiff person syndrome (SPS) is a CNS disorder characterized by increased muscle tone and prominent agoraphobia and anxiety. Most patients have high-titer antibodies against glutamate decarboxylase (GAD) 65. The pathogenic role of these autoantibodies is unclear.

Methodology/Principal Findings

We re-investigated a 53 year old woman with SPS and profound anxiety for GABA-A receptor binding in the amygdala with (11)C-flumazenil PET scan and studied the potential pathogenic role of purified IgG from her plasma filtrates containing high-titer antibodies against GAD 65. We passively transferred the IgG fraction intrathecally into rats and analyzed the effects using behavioral and in vivo electrophysiological methods. In cell culture, we measured the effect of patient IgG on GABA release from hippocampal neurons. Repetitive intrathecal application of purified patient IgG in rats resulted in an anxious phenotype resembling the core symptoms of the patient. Patient IgG selectively bound to rat amygdala, hippocampus, and frontal cortical areas. In cultured rat hippocampal neurons, patient IgG inhibited GABA release. In line with these experimental results, the GABA-A receptor binding potential was reduced in the patient's amygdala/hippocampus complex. No motor abnormalities were found in recipient rats.

Conclusion/Significance

The observations in rats after passive transfer lead us to propose that anxiety-like behavior can be induced in rats by passive transfer of IgG from a SPS patient positive for anti-GAD 65 antibodies. Anxiety, in this case, thus may be an antibody-mediated phenomenon with consecutive disturbance of GABAergic signaling in the amygdala region.

GAD antibodies associated neurological disorders: incidence and phenotype distribution among neurological inflammatory diseases

We investigated the prevalence and the clinical association of high titer of antibodies against glutamic acid decarboxylase (hGADAb) among unselected patients with inflammatory/autoimmune disorders of the nervous system. By indirect immunofluorescence examination of samples from 1435 patients, we identified 7 cases (0.48%) with hGADAb. Although stiff-person plus syndrome was the commonest clinical accompaniment, most of the patients presented with a combination of different symptoms, including psychiatric disturbances and intestinal motility disorders. Diagnosis delay and chronic evolution were common findings. In two cases persistently high values of hGADAb over the years were observed. The rarity and the phenotype heterogeneity of hGADAb clinical association should not discourage clinicians from antibody screening, at least in selected cases, as an early immunotherapy can change the otherwise chronic progression of this complex disorder spectrum.

Anxious depression and the stiff-person plus syndrome

OBJECTIVE

To present the case of a patient with anxiety and depressive symptoms who developed the clinical picture of stiff-person plus syndrome (SPS-plus).

BACKGROUND

Before the onset of typical SPS symptoms, psychiatric symptoms (like depression and anxiety) may be prominent and as such misleading, resulting in the diagnosis of a psychiatric condition.

METHOD

We describe the case of a woman who initially presented with anxious depression and remained resistant to treatment with different classes of antidepressants and additional therapy with lithium and atypical antipsychotics.

RESULTS

Evidence of neurologic dysfunction and significantly increased levels of serum autoantibodies for glutamic acid decarboxylase supported the diagnosis of SPS. The patient appeared to benefit from short-term immunosuppressive therapy with methylprednisolone.

CONCLUSIONS

The authors believe that anxious depression and SPS-plus seen in this patient are the result of the same underlying autoimmune process, together forming a unique syndrome. Anxious and depressive symptoms in SPS can be explained by alterations in GABAergic neurotransmission.

A Patient With Post-traumatic Stress Disorder Developing Stiff Person Syndrome

Stiff person syndrome (SPS) is an uncommon disorder characterized by progressive muscle stiffness, rigidity, and axial muscle spasms. It is presumed to be an autoimmune process, with glutamic acid decarboxylase antibodies present in most cases. Here, we present a case report of a patient diagnosed with post-traumatic stress disorder (PTSD) acquired by sexual trauma and by exposure to the severely wounded soldiers she attended as a nurse. Subsequently, she developed SPS confirmed by serology. The possibility of an association between PTSD and SPS is theorized, given their relationship to the GABAergic system. Further studies examining the relation between PTSD and SPS should be initiated.

Physical Therapy During In-Patient Rehabilitation for a Patient with Stiff-Person Syndrome

BACKGROUND AND PURPOSE

Patients with Stiff-Person Syndrome (SPS) typically show stiffness and spasms, primarily of the trunk and proximal lower extremities. The purpose of this case report is to provide an overview of SPS and a description of the specific physical therapy management strategies used during a brief inpatient rehabilitation stay for a patient with SPS, illustrating the use of the patient/client management model in the Guide to Physical Therapist Practice.

CASE DESCRIPTION

The patient was a 33-year-old with a 3- year history of SPS. He spent 10 days in an in-patient rehabilitation hospital where he received physical therapy daily. The initial examination revealed impairments of pain, range of motion, reflex integrity, and motor function, along with abnormalities of posture, balance, and function. The procedural interventions included therapeutic exercise and functional retraining. Stretching exercises were categorized according to their priority and level of difficulty to accommodate for the patient's varying symptoms, and relaxation exercises aimed to reduce the severity of the patient's spasms. The functional retraining program included transfer and progressive gait training.

OUTCOMES

The patient showed improvements in ankle range of motion, posture, and gait (distance, speed, and independence), despite continued problems with stiffness, spasms, and pain.

DISCUSSION

Physical therapists working with patients with SPS have challenges related to the paucity of information in the literature. The chronic, progressive, and variable nature of SPS indicates the need for life-long management, with the inclusion of an exercise program that can be adjusted accordingly, given the frequently changing symptoms experienced by the patient. As is shown with this case, it appears that physical therapy can improve function and some of the impairments associated with SPS.

Psychogenic movement disorders

PURPOSE OF REVIEW

This review focuses on recent studies assessing clinical features and laboratory findings that may help diagnose psychogenic movement disorders, and the ongoing controversy about the relationship of these disorders with preceding peripheral injury.

RECENT FINDINGS

'Organic' movement disorders may still be misdiagnosed as psychogenic. Probably more commonly, however, psychogenic movement disorders are underdiagnosed. Most features typically associated with recognized movement disorders, including geste antagoniste or treatment-induced dyskinesias, can be seen in psychogenic movement disorder, and abnormal movements that would not normally be considered psychogenic or produced by psychological factors, such as palatal tremor, may occur on a psychogenic basis. On the other hand, psychiatric features are sometimes seen in neurologically based movement disorders. The diagnostic criteria for psychogenic movement disorders provide a degree of diagnostic certainty based on a combination of clinical and psychiatric features. Laboratory investigations can help exclude specific diagnoses, such as Parkinson's disease with (123I)beta-CIT single photon emission computed tomography, and neurophysiological methods can demonstrate characteristic features of psychogenic movement disorders, such as entrainment or suppression of psychogenic tremor with contralateral hand movements. However, some tests reported to differentiate psychogenic from neurological movement disorders may have incomplete specificity; for example, psychogenic tremor may not always be associated with complete coherence of tremor frequency. An ongoing controversy surrounds movement disorders following peripheral injuries, but recent evidence suggests that such patients should always be screened for the presence of a psychogenic movement disorder.

SUMMARY

Psychogenic movement disorder continues to be a difficult diagnosis to make and is likely to be underrecognized. Clinical and laboratory features are emerging, however, that support this diagnosis. The controversy regarding posttraumatic movement disorders continues, but a diagnosis of a psychogenic movement disorder should be actively sought in such patients.

Hyperekplexia and stiff-man syndrome: abnormal brainstem reflexes suggest a physiological relationship

BACKGROUND AND OBJECTIVES

Hyperekplexia and the stiff-man syndrome (SMS) are both conditions with exaggerated startle suggesting abnormal brainstem function. Investigation of brainstem reflexes may provide insight into disturbed reflex excitation and inhibition underlying these movement disorders.

PATIENTS AND METHODS

Using four-channel EMG, we examined four trigeminal brainstem reflexes (monosynaptic masseter, masseter inhibitory, glabella, and orbicularis oculi blink reflexes) and their spread into pericranial muscles in five patients with familial hyperekplexia (FH), two with acquired hyperekplexia (AH), 10 with SMS, and 15 healthy control subjects.

RESULTS

Both FH/AH and SMS patients had abnormal propagation of brainstem reflexes into pericranial muscles. All patients with hyperekplexia showed an abnormal short-latency (15-20 ms) reflex in the trapezius muscle with a characteristic clinical appearance ("head retraction jerk") evoked by tactile or electrical stimulation of the trigeminal nerve, but normal monosynaptic masseter reflexes. Inhibitory brainstem reflexes were attenuated in some FH/AH patients. Four of 10 patients with SMS had similar short-latency reflexes in the neck muscles and frequently showed widespread enhancement of other excitatory reflexes, reflex spasms, and attenuation of inhibitory brainstem reflexes.

CONCLUSION

Reflex excitation is exaggerated and inhibition is attenuated in both stiff-man syndrome and familial or acquired hyperekplexia, indicating a physiological relationship. Reflex transmission in the brainstem appears biased towards excitation which may imply dysfunction of inhibitory glycinergic or GABAergic interneurons, or both.