Sudden death and paroxysmal autonomic dysfunction in stiff-man syndrome

Stiff person spectrum disorder: overview with emphasis on head and neck comorbidities

Stiff person spectrum disorder (SPSD) is a rare progressive autoimmune neuromuscular syndrome, primarily resulting in severely painful spasms and rigidity of the axial and appendicular musculature. Affected individuals are predisposed to develop an array of other neuropathies, including cerebellar ataxia and seizure activity, ophthalmologic abnormalities, and other autoimmune-based systemic diseases, notably type 1 diabetes mellitus, thyroiditis, pernicious anemia, and malignancy. Limited information exists in the oral medicine literature regarding SPSD. Thus, the objective of this paper is to review the clinicopathologic features of SPSD, with particular emphasis on head and neck involvement. Additionally, clinical guidelines for dental management of affected individuals and a summary of surgical procedures and outcomes performed in the head and neck are provided. (Oral Surg Oral Med Oral Pathol Oral Radiol YEAR;VOL:page range).

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.

Case Report: Dexmedetomidine for Intractable Clusters of Myoclonic Jerks and Paroxysmal Sympathetic Hyperactivity in Progressive Encephalomyelitis With Rigidity and Myoclonus

Introduction: Progressive encephalomyelitis with rigidity and myoclonus (PERM) is a severe form of stiff-person spectrum disorder characterized by painful spasms, myoclonic jerks, hyperekplexia, brainstem dysfunction, and dysautonomia, which is sometimes resistant to γ-amino-butyric acid (GABA)-ergic agents. The response to immunotherapy varies depending on identified autoantibodies. We report a dramatic response to dexmedetomidine in a patient with glycine receptor (GlyR) antibody-positive PERM who developed intractable clusters of myoclonic jerks and paroxysmal sympathetic hyperactivity (PSH) that was highly refractory to conventional symptomatic treatment with GABAergic drugs and immunotherapy.

Case Presentation: A 62-year-old Japanese man was transferred to our center for intermittent painful spasms that progressed in severity over the preceding 7 weeks. On admission, he had gaze-evoked nystagmus, and paroxysmal painful spasms/myoclonic jerks triggered by sound or touch. The myoclonic jerks rapidly worsened, along with the development of hyperekplexia, opisthotonus, and PSH, leading to prolonged apnea requiring mechanical ventilation. Brain and spinal cord magnetic resonance imaging was unremarkable. Cerebrospinal fluid (CSF) examination revealed mild pleocytosis and oligoclonal bands. Surface electromyography confirmed simultaneous agonist-antagonist continuous motor unit activity. Based on the clinico-electrophysiological features, PERM was suspected. He was initially treated with intravenous steroids, immunoglobulin, benzodiazepines, and propofol, but the symptoms persisted. On day 9, he received a continuous infusion of dexmedetomidine, which resulted in dramatic reduction in the frequency of clusters of myoclonic jerks and PSH. The effect of dexmedetomidine was confirmed by surface electromyography. The addition of plasma exchange resulted in further clinical improvement. GlyR antibodies were identified in the CSF but not the serum, leading to the diagnosis of GlyR antibody-positive PERM.

Conclusions: PERM is an immune-mediated disorder, but dexmedetomidine, a highly selective α2-adrenergic agonist, may alleviate paroxysmal symptoms by decreasing noradrenergic neuronal activity, resulting in attenuation of antibody-mediated disinhibited increased motor and sympathetic activity. Dexmedetomidine may be useful as an adjunctive symptomatic therapy in PERM and related disorders.

GAD antibody-spectrum disorders: progress in clinical phenotypes, immunopathogenesis and therapeutic interventions

Antibodies against glutamic acid decarboxylase (GAD), originally linked to stiff person syndrome (SPS), now denote the "GAD antibody-spectrum disorders" (GAD-SD) that also include autoimmune epilepsy, limbic encephalitis, cerebellar ataxia and nystagmus with overlapping symptomatology highlighting autoimmune neuronal excitability disorders. The reasons for the clinical heterogeneity among GAD-antibody associated syndromes remain still unsettled, implicating variable susceptibility of GABAergic neurons to anti-GAD or other still unidentified autoantibodies. Although anti-GAD antibody titers do not correlate with clinical severity, very high serum titers, often associated with intrathecal synthesis of anti-GAD-specific IgG, point to in-situ effects of GAD or related autoantibodies within the central nervous system. It remains, however, uncertain what drives these antibodies, why they persist and whether they are disease markers or have pathogenic potential. The review, focused on these concerns, describes the widened clinical manifestations and overlapping features of all GAD-SD; addresses the importance of GAD antibody titers and potential significance of GAD epitopes; summarizes the biologic basis of autoimmune hyperexcitability; highlights the electrophysiological basis of reciprocal inhibition in muscle stiffness; and provides practical guidelines on symptomatic therapies with gamma-aminobutyric acid-enhancing drugs or various immunotherapies.

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.

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.

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 and Type 1 Diabetes Mellitus: a Case of the Chicken or the Egg?

Anti-glutamic acid decarboxylase (anti-GAD) antibodies are linked with both autoimmune diabetes and the rare neurological disorder stiff person syndrome (SPS). SPS is an uncommon autoimmune-mediated condition characterized by painful episodic spasms and progressive muscle rigidity. We present the case of a 23-year-old non-diabetic, insulin-naïve woman with known SPS who was hospitalized for SPS-related symptomatology. The patient quickly developed type 1 diabetes mellitus (T1DM) with unexpectedly large insulin requirements. To our knowledge, there are no other reports describing rapid T1DM development during an acute hospitalization for SPS and fewer than 5 case reports describing the association of SPS with extreme insulin resistance. Our case highlights the key clinical features, pathology, and pathogenesis of both SPS and T1DM and explores the relationship between the two disease processes.

A brain within the heart: A review on the intracardiac nervous system

Cardiac function is under the control of the autonomic nervous system, composed by the parasympathetic and sympathetic divisions, which are finely tuned at different hierarchical levels. While a complex regulation occurs in the central nervous system involving the insular cortex, the amygdala and the hypothalamus, a local cardiac regulation also takes place within the heart, driven by an intracardiac nervous system. This complex system consists of a network of ganglionic plexuses and interconnecting ganglions and axons. Each ganglionic plexus contains numerous intracardiac ganglia that operate as local integration centres, modulating the intricate autonomic interactions between the extrinsic and intracardiac nervous systems. Herein, we summarize the current understanding on the intracardiac nervous system, and acknowledge its role in the pathophysiology of cardiovascular diseases.

Stiff person case misdiagnosed as conversion disorder: A case report

Background:

Stiff person syndrome (SPS) is a rare neurological disease resulting in stiffness and spasm of muscles. It initially affects the axial muscles and then spread to limb muscles. Emotional stress exacerbated the symptoms and signs of the disease. The pathophysiology of the disease is caused by the decreased level of the glutamic acid decarboxylase (GAD) activity due to an autoantibody against GAD that decreases the level of gamma-aminobutyric acid (GABA). In this paper, we present a case of atypical presentation of SPS with lower limb stiffness misdiagnosed as conversion disorder.

Case presentation:

We report a patient with atypical presentation of SPS with lower limb stiffness and gait disorder misdiagnosed as conversion disorder for a year. Her antithyroid peroxidase antibody (anti-TPO Ab) level was 75 IU (normal value: 0–34 IU). Intravenous immunoglobulin (IVIG) was administered (2gr/kg, 5 days) for the patient that showed significant improvement in the follow-up visit.

Conclusion:

It is essential that in any patient with bizarre gait disorder and suspicious to conversion disorder due to the reversibility of symptoms, SPS and other movement disorder should be considered.

Gastrointestinal and Urologic Sphincter Dysfunction in Stiff Person Syndrome

OBJECTIVES

Stiff person syndrome is a neurologic disorder characterized by axial rigidity leading to progressive disability, with broad clinical spectrum.

METHODS

We report 2 cases with unique clinical presentation.

RESULTS

Two young men suffered progressive urinary retention requiring bladder catheterization, anorectal spasms and constipation, complicated subsequently with lower extremity trigger-induced spasms, and gait instability. Associated symptoms revealed brainstem involvement (vertigo, diplopia, and cranial neuropathies) and dysautonomia (abnormal sweating and orthostatic hypotension). Anal manometry demonstrated incomplete relaxation of the anal sphincter. The first case was associated with diabetes mellitus type I, did not respond to classical therapies, but was responsive to rituximab. The second case responded to intravenous immunoglobulin infusions. Paraneoplastic profiles were negative, and anti-GAD65 antibody titers remained elevated despite successful therapeutic responses.

CONCLUSIONS

We want to raise awareness that stiff person syndrome can present with esophageal, anorectal, and urethral sphincter disturbance. Rituximab is a good therapeutic option in intractable cases.

Anesthetic management of a parturient with Stiff person syndrome for urgent cesarean delivery

Stiff person syndrome is a rare neurologic disorder with an estimated incidence of 1:1000000. The underlying pathophysiology is truncal and proximal limb muscle stiffness resulting from continuous co-contracture of agonist and antagonist muscle groups concomitant with superimposed episodic muscle spasms. Loss of gamma-aminobutyric acid-mediated inhibition creates chronic excitation manifested by tonic agonist-antagonist muscle contraction. To date, only three case reports referred indirectly to the anesthetic management of parturients with Stiff person syndrome. The authors describe their management of a parturient with Stiff person syndrome who underwent urgent cesarean delivery under epidural anesthesia.

Stiff-Man Syndrome: GABA, GAD, and Mechanisms of Disease

Stiff-man syndrome (SMS) is a rare disease of progressive muscle stiffness, most common in middle age, often associated with autoimmunity to glutamic acid decarboxylase (GAD) and responsive to treatment with GABA agonists. Diagnosis is established by clinical characteristics and confirmed by EMG or antibody testing. Anti-GAD antibodies are present in 60% of those with SMS and antiamphiphysin antibodies are found in fewer than 10%. The production of antibodies has an unclear relationship to the pathological processes of the disease. GABA receptors and GABA receptor mRNAs are found in high density in the spinal cord laminae and identify possible sites of dys-function in SMS. At some spinal cord synapses, GABA co-localizes with glycine, a neurotransmitter implicated in hyperekplexia. Failure of spinal cord reflexes explains the symptoms of SMS, but electrophysiological studies have not yet identified a single locus of inhibitory failure. Immunomodulation may alter the disease course, but consistently effective treatments for SMS await development.

Brain-heart interactions: physiology and clinical implications

The brain controls the heart directly through the sympathetic and parasympathetic branches of the autonomic nervous system, which consists of multi-synaptic pathways from myocardial cells back to peripheral ganglionic neurons and further to central preganglionic and premotor neurons. Cardiac function can be profoundly altered by the reflex activation of cardiac autonomic nerves in response to inputs from baro-, chemo-, nasopharyngeal and other receptors as well as by central autonomic commands, including those associated with stress, physical activity, arousal and sleep. In the clinical setting, slowly progressive autonomic failure frequently results from neurodegenerative disorders, whereas autonomic hyperactivity may result from vascular, inflammatory or traumatic lesions of the autonomic nervous system, adverse effects of drugs and chronic neurological disorders. Both acute and chronic manifestations of an imbalanced brain-heart interaction have a negative impact on health. Simple, widely available and reliable cardiovascular markers of the sympathetic tone and of the sympathetic-parasympathetic balance are lacking. A deeper understanding of the connections between autonomic cardiac control and brain dynamics through advanced signal and neuroimage processing may lead to invaluable tools for the early detection and treatment of pathological changes in the brain-heart interaction.

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

The stiff-person syndrome is a disorder of persistent, painful muscle contractions predominately affecting the axial musculature. We describe a patient with this disorder and review its pathophysiology. Molecular biologic and immunologic techniques have recently added to the understanding of the mechanism of this disorder. Association with diseases such as diabetes, vitiligo and hypothyroidism have strengthened the auto-immune nature of this syndrome. Auto-antibodies against glutamic acid decarboxylase (GAD), an intraneuronal enzyme, have been implicated in the etiology of this unique disease. Therapeutic intervention with agents such as benzodiazepines that modify central GABAergic activity have demonstrated significant benefit in patients with stiff-person syndrome.

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 Person Syndrome: A Rare Neurological Disorder, Heterogeneous in Clinical Presentation and Not Easy to Treat

Background. Stiff person syndrome (SPS) is a rare neurological disorder characterized by progressive rigidity of axial and limb muscles associated with painful spasms. SPS can be classified into classic SPS, paraneoplastic SPS, and SPS variants. Its underlying pathogenesis is probably autoimmune, as in most cases antibodies against glutamic acid decarboxylase (GAD) are observed. Similarly, paraneoplastic SPS is usually linked to anti-amphiphysin antibodies. Treatment is based on drugs enhancing gamma-aminobutyric acid (GABA) transmission and immunomodulatory agents. Case Series. Patient 1 is a 45-year-old male affected by the classic SPS, Patient 2 is a 73-year-old male affected by paraneoplastic SPS, and Patient 3 is a 68-year-old male affected by the stiff limb syndrome, a SPS variant where symptoms are confined to the limbs. Symptoms, diagnostic findings, and clinical course were extremely variable in the three patients, and treatment was often unsatisfactory and not well tolerated, thus reducing patient compliance. Clinical manifestations also included some unusual features such as recurrent vomiting and progressive dysarthria. Conclusions. SPS is a rare disorder that causes significant disability. Because of its extensive clinical variability, a multitask and personalized treatment is indicated. A clearer understanding of uncommon clinical features and better-tolerated therapeutic strategies are still needed.

[The stiff-person syndrome: a brief review and report of two cases]

The stiff-person syndrome is a rare and progressive neuromuscular disease which appears to have an immunpathological basis. It is characterised by painful muscle spasms and stiffness in the proximal muscles, especially those attached to the axial skeleton. The precise pathophysiology is still unknown, but several antibodies have been shown to be present in patients and these antibodies are directed against proteins which play a role in the inhibitor synapse linked to gamma-amino-butyrate. In the first part of the article the authors present two cases. In the second part they present a comprehensive review of our current knowledge about this rare disease. Orv.Hetil., 154(50), 1984-1990.

Stiff-person syndrome: a case report and review of the literature

We report a case of stiff-person syndrome associated with several autoimmune diseases. A 49-year-old male with type 1 diabetes presented with a 6-month history of muscle rigidity and spasms of his upper and lower extremities. Anti-glutamic acid decarboxylase 65 antibody was elevated at 609 nmol/L. Electromyography revealed continuous motor unit activity in agonist and antagonist muscles. He responded favorably to diazepam, baclofen, and intravenous immunoglobulin infusions. This case report describes stiff-person syndrome in association with pernicious anemia and diabetes mellitus. A review of the literature discusses the diagnosis and treatment of this rare entity.

Central nervous system destruction mediated by glutamic acid decarboxylase-specific CD4+ T cells

High titers of autoantibodies against glutamic acid decarboxylase (GAD) 65 are commonly observed in patients suffering from type 1 diabetes as well as stiff-person syndrome (SPS), a disorder that affects the CNS, and a variant of SPS, progressive encephalomyelitis with rigidity and myoclonus. Although there is a considerable amount of data focusing on the role of GAD65-specific CD4(+) T cells in type 1 diabetes, little is known about their role in SPS. In this study, we show that mice possessing a monoclonal GAD65-specific CD4(+) T cell population (4B5, PA19.9G11, or PA17.9G7) develop a lethal encephalomyelitis-like disease in the absence of any other T cells or B cells. GAD65-reactive CD4(+) T cells were found throughout the CNS in direct concordance with GAD65 expression and activated microglia: proximal to the circumventricular organs at the interface between the brain parenchyma and the blood-brain barrier. In the presence of B cells, high titer anti-GAD65 autoantibodies were generated, but these had no effect on the incidence or severity of disease. In addition, GAD65-specific CD4(+) T cells isolated from the brain were activated and produced IFN-gamma. These findings suggest that GAD65-reactive CD4(+) T cells alone mediate a lethal encephalomyelitis-like disease that may serve as a useful model to study GAD65-mediated diseases of the CNS.

Rigidity and spasms from autoimmune encephalomyelopathies: stiff-person syndrome

Stiff-person syndrome (SPS) is a disorder characterized by progressive muscle rigidity with superimposed painful muscle spasms and gait impairment due to continuous motor activity. Evidence has accumulated in favor of SPS representing an autoimmune, predominantly encephalomyelopathic disorder resulting from B-cell-mediated clonal production of autoantibodies against presynaptic inhibitory epitopes on the enzyme glutamic acid decarboxylase (GAD) and the synaptic membrane protein amphiphysin. Recognition of the clinical spectrum of SPS is important, particularly the upper-limb, cervical, and cranial nerve involvement that occurs in paraneoplastic variants. The correlation between antibody levels and severity of disease offers evidence for a pathogenic role for the anti-GAD and anti-amphiphysin autoantibodies. The scarcity of neuropathological correlates stand in sharp contrast with the severity of the disability in affected individuals and suggests that functional impairment of inhibitory circuits without structural damage is sufficient to develop the full clinical spectrum of SPS. The rarity of this condition limits the feasibility of controlled clinical trials in the treatment of SPS, but the available evidence suggest that drugs that increase cortical and spinal inhibition such as benzodiazepines and drugs that provide immune modulation such as intravenous immunoglobulin, plasmapheresis, and prednisone are effective treatments.

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

INTRODUCTION

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

MATERIAL AND METHODS

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

RESULTS

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

CONCLUSION

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

Movement disorder emergencies

Movement disorders may present acutely, and failure to recognize and exclude important differential diagnoses can result in significant morbidity or mortality. Unfortunately, much of the literature pertaining to this topic is scattered and not easily accessible. This review aims to address this deficit. Movement disorder emergencies are discussed according to their most likely mode of presentation. Diagnostic considerations and early management principles are reviewed, along with appropriate pathophysiology where relevant.

Stiff-Person Syndrome

BACKGROUND

Stiff-person syndrome (SPS) is a rare neurologic disorder with autoimmune features. It is characterized by progressive, severe muscle rigidity or stiffness most prominently affecting the spine and lower extremities.

REVIEW SUMMARY

Superimposed muscle spasms result in simultaneous contraction of agonist and antagonist muscles which are detectable by electromyography (EMG) and relieved by administration of benzodiazepines. The exacerbation of SPS by emotional stressors often results in the referral of these patients for psychiatric assessment although this was more common before the discovery of an association with antibodies to glutamic acid decarboxylase (GAD antibodies). Formerly known as stiff-man syndrome, the female to male ratio is 2:1 and the principle paraneoplastic variant is associated with breast cancer. Although rare, this is a disease of middle age that severely curtails the functional capacity of those it strikes. It is frequently associated with diabetes and other autoimmune diseases. IVIg is recently demonstrated to be effective in the treatment of SPS; diazepam remains useful in managing the symptoms.

CONCLUSIONS

This article summarizes the history of SPS, describes important clinical features, discusses management, touches upon areas of uncertainty, and postulates some avenues for research.

Stiff man syndrome and related conditions

The stiff man syndrome (SMS) and its variants, focal SMS, stiff limb (or leg) syndrome (SLS), jerking SMS, and progressive encephalomyelitis with rigidity and myoclonus (PERM), appear to occur more frequently than hitherto thought. A characteristic ensemble of symptoms and signs allows a tentative clinical diagnosis. Supportive ancillary findings include (1) the demonstration of continuous muscle activity in trunk and proximal limb muscles despite attempted relaxation, (2) enhanced exteroceptive reflexes, and (3) antibodies to glutamic acid decarboxylase (GAD) in both serum and spinal fluid. Antibodies to GAD are not diagnostic or specific for SMS and the role of these autoantibodies in the pathogenesis of SMS/SLS/PERM is the subject of debate and difficult to reconcile on the basis of our present knowledge. Nevertheless, evidence is emerging to suggest that SMS/SLS/PERM are manifestations of an immune-mediated chronic encephalomyelitis and immunomodulation is an effective therapeutic approach.

Pathological evidence of encephalomyelitis in the stiff man syndrome with anti-GAD antibodies

We report the case of a 57 year old woman with typical clinical features of the stiff man syndrome (SMS) and antibodies to glutamic acid decarboxylase (antiGADAb), who developed a supranuclear gaze palsy, ileus and died of bronchopneumonia eight years after the onset of illness. Post mortem examination revealed perivascular lymphocyte cuffing throughout the cerebral hemispheres, brainstem and spinal cord and neuronal loss in medial anterior horns of the cervical spinal cord. These findings support the notion that the SMS and progressive encephalomyelitis with rigidity (PER) form a clinical and pathologic continuum.

Stiff man syndrome

Stiff man syndrome (SMS), an uncommon neurological disease, is characterised by symmetrical muscle stiffness and spasms that often lead to skeletal deformity. Variants of the syndrome may involve one limb only (stiff leg syndrome), a variety of additional neurological symptoms and signs such as eye movement disturbances, ataxia, or Babinski signs (progressive encephalomyelitis with rigidity and myoclonus), or be associated with malignant disease (paraneoplastic SMS). Antineuronal autoimmunity and accompanying autoimmune diseases, most often insulin-dependent diabetes mellitus, are characteristic features of SMS and its variants. The condition is frequently misinterpreted as psychogenic movement disturbance, but electromyographic abnormalities and the presence of autoantibodies against glutamic acid decarboxylase (GAD) in both serum and cerebrospinal fluid help to establish the correct diagnosis. The aetiology of SMS is obscure. However, several features suggest that SMS is an autoimmune-mediated chronic encephalomyelitis. In line with this hypothesis, immunomodulation with a front-loaded methylprednisolone regimen reduces stiffness and spasms and improves other neurological symptoms in the majority of patients. Plasmapheresis or intravenous immunoglobulins are effective less frequently. For symptomatic treatment, the benzodiazepines are drugs of first choice. An alternative of last resort is baclofen administered intrathecally via an implanted pump device.

High-dose intravenous immune globulin for stiff-person syndrome

BACKGROUND

Stiff-person syndrome is a disabling central nervous system disorder with no satisfactory treatment that is characterized by muscle rigidity, episodic muscle spasms, high titers of antibodies against glutamic acid decarboxylase (GAD65), and a frequent association with autoimmune disorders. Because stiff-person syndrome is most likely immune-mediated, we evaluated the efficacy of intravenous immune globulin.

METHODS

We assigned 16 patients who had stiff-person syndrome and anti-GAD65 antibodies, in random order, to receive intravenous immune globulin or placebo for three months, followed by a one-month washout period and then by three months of therapy with the alternative agent. Efficacy was judged by improvements in scores on the distribution-of-stiffness index and heightened-sensitivity scale from base line (month 1) to the second and third month of each treatment phase. Direct and carryover effects of treatment were compared in the two groups.

RESULTS

Among patients who received immune globulin first, stiffness scores decreased significantly (P=0.02) and heightened-sensitivity scores decreased substantially during immune globulin therapy but rebounded during placebo administration. In contrast, the scores in the group that received placebo first remained constant during placebo administration but dropped significantly during immune globulin therapy (P=0.01). When the data were analyzed for a direct and a first-order carryover effect, there was a significant difference in stiffness scores (P=0.01 and P<0.001, respectively) between the immune globulin and placebo groups, and immune globulin therapy had a significant direct treatment effect on sensitivity scores (P=0.03). Eleven patients who received immune globulin became able to walk more easily or without assistance, their frequency of falls decreased, and they were able to perform work-related or household tasks. The duration of the beneficial effects of immune globulin varied from six weeks to one year. Anti-GAD65 antibody titers declined after immune globulin therapy but not after placebo administration.

CONCLUSIONS

Intravenous immune globulin is a well-tolerated and effective, albeit costly, therapy for patients with stiff-person syndrome and anti-GAD65 antibodies.

The stiff-man syndrome and related disorders

The stiff-man syndrome (SMS) is characterised by rigidity and spasm of predominantly axial and proximal limb muscles. The cause of the condition is unknown but the finding of antibodies to glutamic acid decarboxylase (GAD) in approximately 60% of patients has suggested an autoimmune basis. Pathological findings are limited to a small number of cases which are reviewed in this paper. In some, evidence of an inflammatory aetiology has been found, and there appears to be overlap with progressive encephalomyelitis with rigidity (PER) which may present with a similar clinical picture. The spontaneous muscle activity in SMS and PER is of central origin, related to release of polysynaptic spinal and brainstem reflexes. The SMS is readily distinguished from the continuous muscle activity, spasm and cramps of Isaac's syndrome and neuromyotonia which originate in the peripheral nervous system. Fasciculations, myokymia, myotonia and complex repetitive discharges are characteristic of these peripheral neuromuscular disorders.

Hyperekplexia in neonates

Hyperekplexia (startle disease) is a rare non-epileptic disorder characterised by an exaggerated persistent startle reaction to unexpected auditory, somatosensory and visual stimuli, generalised muscular rigidity, and nocturnal myoclonus. The genetic basis is a mutation usually of the arginine residue 271 leading to neuronal hyperexcitability by impairing glycinergic inhibition. Hyperekplexia is usually familial, most often autosomal dominant with complete penetrance and variable expression. It can present in fetal life as abnormal intrauterine movements, or later at any time from the neonatal period to adulthood. Early manifestations include abnormal responses to unexpected auditory, visual, and somatosensory stimuli such as sustained tonic spasm, exaggerated startle response, and fetal posture with clenched fists and anxious stare. The tonic spasms may mimic generalised tonic seizures, leading to apnoea and death. Consistent generalised flexor spasm in response to tapping of the nasal bridge (without habituation) is the clinical hallmark of hyperekplexia. Electroencephalography may show fast spikes initially during the tonic spasms, followed by slowing of background activity with eventual flattening corresponding to the phase of apnoea bradycardia and cyanosis. Electromyography shows a characteristic almost permanent muscular activity with periods of electrical quietness. Nerve conduction velocity is normal. No specific computed tomography findings have been reported yet. Clonazepam, a gamma aminobutyric acid (GABA) receptor agonist, is the treatment of choice for hypertonia and apnoeic episodes. It, however, may not influence the degree of stiffness significantly. A simple manoeuvre like forced flexion of the head and legs towards the trunk is known to be life saving when prolonged stiffness impedes respiration.

Stiff-person syndrome: autoimmunity and the central nervous system

Stiff-person syndrome (SPS) is a rare disease of severe progressive muscle stiffness in the spine and lower extremities with superimposed muscle spasms triggered by external stimuli. Patients with SPS are often referred for psychiatric evaluation and the psychiatrist may be the first to diagnosis SPS. Psychosocial stressors often precede the first manifestations of the disease; depression, anxiety, and alcohol abuse are comorbid illnesses. The identification of an association with antibodies to glutamic acid decarboxylase (GAD) was invaluable for definitively establishing a pathological basis for the disease; antibodies to amphiphysin and gephyrin are also found in cases of SPS but at much lower frequencies. Whether the antibodies inhibit GAD activity in vivo, target GAD-expressing neurons for immune-mediated destruction, are part of a wider immune process, or are merely a marker for destruction of GAD-expressing neurons by an independent neurodegenerative process is not yet clear. Both electromyography and the detection of GAD antibodies are useful in establishing a diagnosis of SPS. Treatment of SPS includes the use of immunomodulating therapies (plasmapheresis and intravenous immunoglobulins) and symptomatic treatment with benzodiazepines and baclofen. The use of tricyclic antidepressants and rapid withdrawal from therapy should be avoided.

Autoimmunity to gephyrin in Stiff-Man syndrome

Stiff-Man syndrome (SMS) is a rare disease of the central nervous system (CNS) characterized by chronic rigidity, spasms, and autoimmunity directed against synaptic antigens, most often the GABA-synthesizing enzyme glutamic acid decarboxylase (GAD). In a subset of cases, SMS has an autoimmune paraneoplastic origin. We report here the identification of high-titer autoantibodies directed against gephyrin in a patient with clinical features of SMS and mediastinal cancer. Gephyrin is a cytosolic protein selectively concentrated at the postsynaptic membrane of inhibitory synapses, where it is associated with GABA(A) and glycine receptors. Our findings provide new evidence for a close link between autoimmunity directed against components of inhibitory synapses and neurological conditions characterized by chronic rigidity and spasms.

The stiff-person syndrome: an autoimmune disorder affecting neurotransmission of gamma-aminobutyric acid

The stiff-person syndrome, a rare and disabling disorder, is characterized by muscle rigidity and episodic spasms that involve axial and limb musculature. Continuous contraction of agonist and antagonist muscles caused by involuntary motor-unit firing at rest are the hallmark clinical and electrophysiologic signs of the disease. Except for global muscle stiffness, results of neurologic examination are usually normal. Results of conventional computed tomography and magnetic resonance imaging of the brain are also normal. The cause of the stiff-person syndrome is unknown; however, an autoimmune pathogenesis is suspected because of 1) the presence of antibodies against glutamic acid decarboxylase (GAD), the rate-limiting enzyme for the synthesis of the inhibitory neurotransmitter gamma-aminobutyric acid (GABA); 2) the association of the disease with other autoimmune conditions; 3) the presence of various autoantibodies; and 4) a strong immunogenetic association. Anti-GAD antibodies, which are found in high titers in most patients, seem to be directed against conformational forms of GAD. New evidence suggests that these antibodies may be pathogenic because they interfere with the synthesis of GABA. In addition, a reduction in brain levels of GABA, which is prominent in the motor cortex, has been demonstrated with magnetic resonance spectroscopy in patients with the stiff-person syndrome. The stiff-person syndrome is clinically elusive but potentially treatable and should be considered in patients with unexplained stiffness and spasms. Drugs that enhance GABA neurotransmission, such as diazepam, vigabatrin, and baclofen, provide mild to modest relief of clinical symptoms. Immunomodulatory agents, such as steroids, plasmapheresis, and intravenous immunoglobulin, seem to offer substantial improvement. Results of an ongoing controlled trial will elucidate the role of these agents in the treatment of the disease.

Stiff-man syndrome: from the bedside to the bench

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

Effect of Lambert-Eaton myasthenic syndrome antibodies on autonomic neurons in the mouse

Somatic muscle weakness and autonomic symptoms characterize the autoimmune Lambert-Eaton myasthenic syndrome (LEMS). The former results from IgG autoantibody-mediated down-regulation of P/Q-type voltage-gated calcium channels at motor nerve terminals and consequent reduction in acetylcholine release; the basis for the autonomic symptoms is unknown. Using omega-conotoxins GVIA and MVIIC and omega-agatoxin IVA that block N-, Q-, and P-type channels, we investigated ex vivo the calcium channels subserving transmitter release from postganglionic parasympathetic neurons in the bladder and from postganglionic sympathetic neurons in the vas deferens of mice injected with IgG from LEMS patients or from controls. Calcium influx through N-, P-, and Q-type channels subserved transmitter release from parasympathetic and sympathetic neurons in control mice. In test mice, the component of transmitter release subserved by P-type channels was abolished by four of four LEMS IgG preparations, that subserved by Q-type channels was significantly reduced by three, and that subserved by N-type channels by one. Thus, LEMS IgG impairs transmitter release from parasympathetic and sympathetic neurons through down-regulation of one or more subtypes of voltage-gated calcium channels. The results suggest that antibody-mediated interference with specific ion channel function may also underlie autonomic dysfunction occurring in other autoimmune diseases.

Stiff-person syndrome with anti-glutamic acid decarboxylase autoantibodies: complete remission of symptoms after intrathecal baclofen administration

A female patient, aged 61 years, who developed a severe immobilizing stiff-person syndrome in conjunction with insulin-dependent diabetes mellitus, is described. In addition to the typical clinical symptoms, diagnosis was proven by the presence of autoantibodies against glutamic acid decarboxylase in serum and cerebrospinal fluid. Symptomatic treatment with continuous intrathecal application of baclofen administered by a subcutaneous pump resulted in rapid clinical improvement so that the patient became ambulatory. Intermittent withdrawal from intrathecal baclofen therapy led to complete remanifestation of stiff-person syndrome within 18 h; after re-introduction of intrathecal therapy stiffness disappeared completely within 48 h. The clinical course has been stable now for over 24 months and stiffness has completely disappeared. The effect of baclofen in this patient is discussed in the light of the suggested pathophysiological mechanisms in stiff-person syndromes.

Stiff man syndrome: clinical and laboratory findings in eight patients

The clinical, biochemical, neuroimaging and neurophysiological findings of eight patients with stiff man syndromes (SMS) [four of six being tested with autoantibodies against glutamic acid decarboxylase (GAD)] are presented. In two patients (one GAD-positive, one GAD-negative), transient oculomotor disturbances suggested progressive encephalomyelitis with rigidity and myoclonus (PERM) as differential diagnosis. The catalogue of characteristic clinical symptoms of SMS is extended by three new symptoms: (1) an aura-like feeling reported by five patients to precede spontaneous spasmodic attacks; (2) a stereotyped motor pattern seen in seven patients during spasmodic jerks, consisting of brief opisthotonos, stiffening of the slightly abducted legs and inversion of the plantar-flexed feet; (3) a paroxysmal fear when crossing a free space unaided, or even thinking of it. Clinical findings did not enable us to discriminate between patients tested GAD-positive or GAD-negative. Cerebrospinal fluid contained elevated immunoglobulin levels or cell counts, or both, in the majority of patients. Autopsy of one patient revealed scattered lymphocyte cuffs around leptomeningeal, intracerebral and particularly intraspinal vessels, suggesting a mild inflammatory process. Whether SMS and PERM are closely related is discussed; they are possibly both manifestations of a spectrum of encephalomyelopathies having autoimmunity against GABAergic neurons in common.