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

BACKGROUND AND OBJECTIVES

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

METHODS

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

RESULTS

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

DISCUSSION

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

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.

The occurrence of stiff person syndrome in a patient with thymoma: case report and literature review

Stiff-person syndrome (SPS) is a rare disorder that affects the central nervous system, being characterized by intermittent episodes of muscle spasms, rigidity, and a significant increase in morbidity and mortality. We report a 29-year-old patient, with left-sided chylothorax and thymoma, who presented with truncal, lower extremities stiffness and painful cramps alleviated by diazepam and opiates. His clinical picture was suggestive of SPS secondary to invasive thymoma. This syndrome is best approached by its early recognition and prompt treatment since a missed diagnosis can have deleterious outcome. An intensive search for the underlying etiology is of utmost importance in the management of SPS. A review of the current literature is also included in this manuscript.

Determination of anti GAD65 autoantibodies with an ELISA before and after standardization with the new international reference serum

The serum of a stiff-man syndrome patient was declared international GAD reference standard at the "1st GAD Antibody Workshop" held at the "12th International Immunology and Diabetes Workshop" in Orlando, Florida, USA 1993. A comparative study was performed with 123 diabetic and non-diabetic patients to evaluate whether standardization of this reference serum had changed the properties of a commercially available ELISA assay. All samples classified positive with the old test were confirmed with the new assay. Four additional samples with high "normal" values became positive with the new test. One of them was a control person having a family history of diabetes and genetic loci DR4/DR11. These findings might implicate a higher risk for the development of IDDM. The new standardization and adaptation of the ELISA seems to have influenced the sensitivity of the test positively.

Amphiphysin autoimmunity: paraneoplastic accompaniments

Amphiphysin-IgG was identified in 71 patients among 120,000 evaluated serologically for paraneoplastic autoantibodies. Clinical information was available for 63 patients. Cancer was detected in 50 (mostly limited), proven histologically in 46, and was imaged intrathoracically in 4 patients (lung, small-cell [27] and non-small cell [1]), breast [16] and melanoma [2]). Neurological accompaniments included (decreasing frequency): neuropathy, encephalopathy, myelopathy, stiff-man phenomena, and cerebellar syndrome. In a case examined neuropathologically, parenchymal T-lymphocyte infiltration (predominantly CD8(+)) was prominent in lower brainstem, spinal cord, and dorsal root ganglion. Coexisting paraneoplastic autoantibodies, identified in 74% of patients, predicted a common neoplasm and indicated other neuronal autoantigen targets that plausibly explained several neurological manifestations; for example, P/Q-type Ca(2+)-channel antibody with Lambert-Eaton syndrome (n = 5), anti-neuronal nuclear antibody type 1 with sensory neuronopathy (n = 7), K(+)-channel antibody with limbic encephalitis (n = 1) or neuromyotonia (n = 1), and collapsin response-mediator protein-5-IgG with optic neuritis (n = 3). Patients with isolated amphiphysin-IgG (n = 19) were more likely to be women (with breast cancer, p < 0.05) and to have myelopathy or stiff-man phenomena (p < 0.01). Overall, a minority of women (39%) and men (12%) had stiff-man phenomena. Only 10% of women (some with lung carcinoma) and 4% of men fulfilled diagnostic criteria for stiff-man syndrome.

Psychiatric consultations in stiff-man syndrome

BACKGROUND

Stiff-man syndrome is a rare central nervous system disease first described nearly 40 years ago. Its cause has been attributed to both neurologic and psychiatric processes. In recent years, it has been accepted as a neurologic condition in which the gamma-aminobutyric acid (GABA) system malfunctions, probably because of an autoimmune process. Published reports that have described psychiatric manifestations of the disease have relied on descriptions of one or two cases and literature reviews.

METHOD

We reviewed the medical records of 24 patients with confirmed stiff-man syndrome, 12 of whom had received psychiatric consultation. This review was done to better determine the psychiatric manifestations of stiff-man syndrome.

RESULTS

Retrospective analysis of these 12 cases showed that the most common psychiatric symptoms were anxiety, depression, and alcohol abuse.

CONCLUSION

We speculate that the GABA system is involved in both the neurologic and psychiatric symptoms of these patients. Psychiatrists have a significant role in the management of patients with stiff-man syndrome and may be expected to manage anxiety, depression, and substance misuse.